> ## Documentation Index
> Fetch the complete documentation index at: https://cockroachlabs.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# SHOW {session variable}

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Use the `SHOW` <InternalLink path="sql-statements">statement</InternalLink> to display the value of one or all of the session variables. You configure session variables using <InternalLink path="set-vars">`SET`</InternalLink>.

## Required privileges

No <InternalLink path="security-reference/authorization#managing-privileges">privileges</InternalLink> are required to display the session variables.

## Synopsis

<img src="https://mintcdn.com/cockroachlabs/gtjMfbHiKZTUwAsm/images/sql-diagrams/v25.2/show_session.svg?fit=max&auto=format&n=gtjMfbHiKZTUwAsm&q=85&s=bc57801d0316b68dda2d3ddbc03da608" alt="show_session syntax diagram" style={{maxWidth: "100%", overflowX: "auto"}} width="381" height="69" data-path="images/sql-diagrams/v25.2/show_session.svg" />

<Note>
  The `SHOW` statement for session variables is unrelated to the other `SHOW` statements like <InternalLink path="show-cluster-setting">`SHOW CLUSTER SETTING`</InternalLink>, <InternalLink path="show-create">`SHOW CREATE`</InternalLink>, and <InternalLink path="show-databases">`SHOW DATABASES`</InternalLink>.
</Note>

## Parameters

| Parameter   | Description                                                                                                    |
| ----------- | -------------------------------------------------------------------------------------------------------------- |
| `var\_name` | The session variable name to show. The variable name is case-insensitive and can be enclosed in double quotes. |

### Supported variables

| Variable name                                                    | Description                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | Initial value                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | Modify with <InternalLink path="set-vars">`SET`</InternalLink>?                                                                                 | View with <InternalLink path="show-vars">`SHOW`</InternalLink>? |     |
| ---------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------- | --- |
| `always\_distribute\_full\_scans`                                | When set to `on`, full table scans are always <InternalLink path="architecture/sql-layer#distsql">distributed</InternalLink>.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | `off`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | Yes                                                                                                                                             | Yes                                                             |     |
| `application\_name`                                              | The current application name for statistics collection.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 | Empty string, or `cockroach` for sessions from the <InternalLink path="cockroach-sql">built-in SQL client</InternalLink>.                                                                                                                                                                                                                                                                                                                                                                                                                                                          | Yes                                                                                                                                             | Yes                                                             |     |
| `autocommit\_before\_ddl`                                        | When the <InternalLink path="set-vars">`autocommit\_before\_ddl` session setting</InternalLink> is set to `on`, any schema change statement that is sent during an <InternalLink path="transactions">explicit transaction</InternalLink> will cause the transaction to <InternalLink path="commit-transaction">commit</InternalLink> before executing the schema change. This is useful because <InternalLink path="online-schema-changes#schema-changes-within-transactions">CockroachDB does not fully support multiple schema changes in a single transaction</InternalLink>. : This setting is enabled by default. To disable it for <InternalLink path="alter-role#set-default-session-variable-values-for-all-users">all roles</InternalLink>, issue the following statement: `ALTER ROLE ALL SET autocommit\_before\_ddl = false`                                                                                                                                                                                                                                                                                                                                                                                                                                                | `on`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | Yes                                                                                                                                             | Yes                                                             |     |
| `bytea\_output`                                                  | The <InternalLink path="bytes#supported-conversions">mode for conversions from `STRING` to `BYTES`</InternalLink>.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | hex                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                | Yes                                                                                                                                             | Yes                                                             |     |
| `client\_min\_messages`                                          | The severity level of notices displayed in the <InternalLink path="cockroach-sql">SQL shell</InternalLink>. Accepted values include `debug5`, `debug4`, `debug3`, `debug2`, `debug1`, `log`, `notice`, `warning`, and `error`.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | `notice`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | Yes                                                                                                                                             | Yes                                                             |     |
| `copy\_from\_atomic\_enabled`                                    | If set to `on`, <InternalLink path="copy">`COPY FROM`</InternalLink> statements are committed atomically, matching PostgreSQL behavior. If set to `off`, `COPY FROM` statements are segmented into batches of 100 rows unless issued within an explicit transaction, matching the CockroachDB behavior in versions prior to v22.2.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | `on`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | Yes                                                                                                                                             | Yes                                                             |     |
| `copy\_transaction\_quality\_of\_service`                        | The default quality of service for <InternalLink path="copy">`COPY`</InternalLink> statements in the current session. The supported options are `regular`, `critical`, and `background`. See <InternalLink path="admission-control">Set quality of service level</InternalLink>.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        | `background`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | Yes                                                                                                                                             | Yes                                                             |     |
| `cost\_scans\_with\_default\_col\_size`                          | Whether to prevent the optimizer from considering column size when costing plans.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | `false`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | Yes                                                                                                                                             | Yes                                                             |     |
| `crdb\_version`                                                  | The version of CockroachDB.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | `CockroachDB OSS version`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | No                                                                                                                                              | Yes                                                             |     |
| `database`                                                       | The <InternalLink path="sql-name-resolution#current-database">current database</InternalLink>.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | Database in connection string, or empty if not specified.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | Yes                                                                                                                                             | Yes                                                             |     |
| <a id="datestyle" />                                             | `datestyle`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | The input string format for <InternalLink path="date">`DATE`</InternalLink> and <InternalLink path="timestamp">`TIMESTAMP`</InternalLink> values. Accepted values include `ISO,MDY`, `ISO,DMY`, and `ISO,YMD`.                                                                                                                                                                                                                                                                                                                                                                     | The value set by the `sql.defaults.datestyle`<InternalLink path="cluster-settings">cluster setting</InternalLink> (`ISO,MDY`, by default).      | Yes                                                             | Yes |
| `default\_int\_size`                                             | The size, in bytes, of an <InternalLink path="int">`INT`</InternalLink> type.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | `8`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                | Yes                                                                                                                                             | Yes                                                             |     |
| `default\_text\_search\_config`                                  | The dictionary used to normalize tokens and eliminate stop words when calling a <InternalLink path="functions-and-operators#full-text-search-functions">full-text search function</InternalLink> without a configuration parameter. See <InternalLink path="full-text-search">Full-Text Search</InternalLink>.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | `english`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | Yes                                                                                                                                             | Yes                                                             |     |
| `default\_transaction\_isolation`                                | The isolation level at which transactions in the session execute (<InternalLink path="demo-serializable">`SERIALIZABLE`</InternalLink> or <InternalLink path="read-committed">`READ COMMITTED`</InternalLink>). See <InternalLink path="transactions#isolation-levels">Isolation levels</InternalLink>.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 | `SERIALIZABLE`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     | Yes                                                                                                                                             | Yes                                                             |     |
| `default\_transaction\_priority`                                 | The default transaction priority for the current session. The supported options are `low`, `normal`, and `high`.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        | `normal`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | Yes                                                                                                                                             | Yes                                                             |     |
| `default\_transaction\_quality\_of\_service`                     | The default transaction quality of service for the current session. The supported options are `regular`, `critical`, and `background`. See <InternalLink path="admission-control#set-quality-of-service-level-for-a-session">Set quality of service level</InternalLink>.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | `regular`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | Yes                                                                                                                                             | Yes                                                             |     |
| `default\_transaction\_read\_only`                               | The default transaction access mode for the current session. If set to `on`, only read operations are allowed in transactions in the current session; if set to `off`, both read and write operations are allowed. See <InternalLink path="set-transaction">`SET TRANSACTION`</InternalLink> for more details.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | `off`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | Yes                                                                                                                                             | Yes                                                             |     |
| `default\_transaction\_use\_follower\_reads`                     | If set to on, all read-only transactions use <InternalLink path="as-of-system-time">`AS OF SYSTEM TIME follower\_read\_timestamp()`</InternalLink> to allow the transaction to use follower reads. If set to `off`, read-only transactions will only use follower reads if an `AS OF SYSTEM TIME` clause is specified in the statement, with an interval of at least 4.8 seconds.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | `off`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | Yes                                                                                                                                             | Yes                                                             |     |
| `disable\_changefeed\_replication`                               | When `true`, <InternalLink path="changefeed-messages#filtering-changefeed-messages">changefeeds</InternalLink> will not emit messages for any changes (e.g., `INSERT`, `UPDATE`) issued to watched tables during that session.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | `false`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | Yes                                                                                                                                             | Yes                                                             |     |
| `disallow\_full\_table\_scans`                                   | If set to `on`, queries on "large" tables with a row count greater than [`large\_full\_scan\_rows`](#large-full-scan-rows) will not use full table or index scans. If no other query plan is possible, queries will return an error message. This setting does not apply to internal queries, which may plan full table or index scans without checking the session variable.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | `off`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | Yes                                                                                                                                             | Yes                                                             |     |
| `distribute\_group\_by\_row\_count\_threshold`                   | Minimum number of rows that a `GROUP BY` operation must process in order to be <InternalLink path="architecture/sql-layer#distsql">distributed</InternalLink>.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | `1000`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | Yes                                                                                                                                             | Yes                                                             |     |
| `distribute\_scan\_row\_count\_threshold`                        | Minimum number of rows that a scan operation must process in order to be <InternalLink path="architecture/sql-layer#distsql">distributed</InternalLink>. This means that full table scans will not be distributed if they read fewer than this number of rows. To always distribute full table scans, set [`always\_distribute\_full\_scans`](#always-distribute-full-scans).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | `10000`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | Yes                                                                                                                                             | Yes                                                             |     |
| `distribute\_sort\_row\_count\_threshold`                        | Minimum number of rows that a sort operation must process in order to be <InternalLink path="architecture/sql-layer#distsql">distributed</InternalLink>.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                | `1000`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | Yes                                                                                                                                             | Yes                                                             |     |
| <a id="distsql" />                                               | `distsql`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | The query distribution mode for the session. By default, CockroachDB determines which queries are faster to execute if distributed across multiple nodes. Distribution preferences for `GROUP BY`, scan, and sort operations are set with [`distribute\_group\_by\_row\_count\_threshold`](#distribute-group-by-row-count-threshold), [`distribute\_scan\_row\_count\_threshold.`](#distribute-scan-row-count-threshold) and [`distribute\_sort\_row\_count\_threshold.`](#distribute-sort-row-count-threshold), respectively. All other queries are run through the gateway node. | `auto`                                                                                                                                          | Yes                                                             | Yes |
| `enable\_auto\_rehoming`                                         | When enabled, the <InternalLink path="alter-table">home regions</InternalLink> of rows in <InternalLink path="alter-table#set-the-table-locality-to-regional-by-row">`REGIONAL BY ROW`</InternalLink> tables are automatically set to the region of the <InternalLink path="ui-sessions-page">gateway node</InternalLink> from which any <InternalLink path="update">`UPDATE`</InternalLink> or <InternalLink path="upsert">`UPSERT`</InternalLink> statements that operate on those rows originate.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | `off`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | Yes                                                                                                                                             | Yes                                                             |     |
| `enable\_create\_stats\_using\_extremes`                         | If `on`, allows manual creation of <InternalLink path="cost-based-optimizer#partial-statistics">partial statistics</InternalLink> using the <InternalLink path="create-statistics#create-partial-statistics-using-extremes">`CREATE STATISTICS ... USING EXTREMES`</InternalLink> syntax.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | `on`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | Yes                                                                                                                                             | Yes                                                             |     |
| `enable\_durable\_locking\_for\_serializable`                    | Indicates whether CockroachDB replicates <InternalLink path="select-for-update#lock-strengths">`FOR UPDATE` and `FOR SHARE`</InternalLink> locks via <InternalLink path="architecture/replication-layer#raft">Raft</InternalLink>, allowing locks to be preserved when leases are transferred. Note that replicating `FOR UPDATE` and `FOR SHARE` locks will add latency to those statements. This setting only affects `SERIALIZABLE` transactions and matches the default `READ COMMITTED` behavior when enabled.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     | `off`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | Yes                                                                                                                                             | Yes                                                             |     |
| `enable\_implicit\_fk\_locking\_for\_serializable`               | Indicates whether CockroachDB uses <InternalLink path="select-for-update#lock-strengths">shared locks</InternalLink> to perform <InternalLink path="foreign-key">foreign key</InternalLink> checks. To take effect, the [`enable\_shared\_locking\_for\_serializable`](#enable-shared-locking-for-serializable) setting must also be enabled. This setting only affects `SERIALIZABLE` transactions and matches the default `READ COMMITTED` behavior when enabled.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     | `off`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | Yes                                                                                                                                             | Yes                                                             |     |
| `enable\_implicit\_select\_for\_update`                          | Indicates whether <InternalLink path="update">`UPDATE`</InternalLink>, <InternalLink path="upsert">`UPSERT`</InternalLink>, and <InternalLink path="delete">`DELETE`</InternalLink> statements acquire locks using the `FOR UPDATE` locking mode during their initial row scan, which improves performance for contended workloads.  For more information about how `FOR UPDATE` locking works, see the documentation for <InternalLink path="select-for-update">`SELECT FOR UPDATE`</InternalLink>.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | `on`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | Yes                                                                                                                                             | Yes                                                             |     |
| `enable\_implicit\_transaction\_for\_batch\_statements`          | Indicates whether multiple statements in a single query (a "batch statement") will all run in the same implicit transaction, which matches the PostgreSQL wire protocol.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                | `on`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | Yes                                                                                                                                             | Yes                                                             |     |
| `enable\_insert\_fast\_path`                                     | Indicates whether CockroachDB will use a specialized execution operator for inserting into a table. We recommend leaving this setting `on`.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | `on`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | Yes                                                                                                                                             | Yes                                                             |     |
| `enable\_shared\_locking\_for\_serializable`                     | Indicates whether <InternalLink path="select-for-update#lock-strengths">shared locks</InternalLink> are enabled for `SERIALIZABLE` transactions. When `off`, `SELECT` statements using `FOR SHARE` are still permitted under `SERIALIZABLE` isolation, but silently do not lock.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        | `off`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | Yes                                                                                                                                             | Yes                                                             |     |
| `enable\_super\_regions`                                         | When enabled, you can define a super region: a set of <InternalLink path="multiregion-overview#super-regions">database regions</InternalLink> on a multi-region cluster such that your <InternalLink path="schema-design-overview#database-schema-objects">schema objects</InternalLink> will have all of their <InternalLink path="architecture/overview">replicas</InternalLink> stored *only* in regions that are members of the super region.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | `off`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | Yes                                                                                                                                             | Yes                                                             |     |
| `enable\_zigzag\_join`                                           | Indicates whether the <InternalLink path="cost-based-optimizer">cost-based optimizer</InternalLink> will plan certain queries using a <InternalLink path="cost-based-optimizer#zigzag-joins">zigzag merge join algorithm</InternalLink>, which searches for the desired intersection by jumping back and forth between the indexes based on the fact that after constraining indexes, they share an ordering.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | `on`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | Yes                                                                                                                                             | Yes                                                             |     |
| `enforce\_home\_region`                                          | If set to `on`, queries return an error and in some cases a suggested resolution if they cannot run entirely in their home region. This can occur if a query has no home region (for example, if it reads from different home regions in a <InternalLink path="table-localities#regional-by-row-tables">regional by row table</InternalLink>) or a query's home region differs from the <InternalLink path="architecture/life-of-a-distributed-transaction#gateway">gateway</InternalLink> region. Note that only tables with `ZONE`<InternalLink path="multiregion-survival-goals#when-to-use-zone-vs-region-survival-goals">survivability</InternalLink> can be scanned without error when this is enabled. For more information about home regions, see <InternalLink path="multiregion-overview#table-localities">Table localities</InternalLink>.  This feature is in preview. It is subject to change.                                                                                                                                                                                                                                                                                                                                                                            | `off`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | Yes                                                                                                                                             | Yes                                                             |     |
| `enforce\_home\_region\_follower\_reads\_enabled`                | If `on` while the <InternalLink path="cost-based-optimizer#control-whether-queries-are-limited-to-a-single-region">`enforce\_home\_region`</InternalLink> setting is `on`, allows `enforce\_home\_region` to perform `AS OF SYSTEM TIME`<InternalLink path="follower-reads">follower reads</InternalLink> to detect and report a query's <InternalLink path="multiregion-overview#table-localities">home region</InternalLink>, if any.  This feature is in preview. It is subject to change.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | `off`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | Yes                                                                                                                                             | Yes                                                             |     |
| `expect\_and\_ignore\_not\_visible\_columns\_in\_copy`           | If `on`, <InternalLink path="copy">`COPY FROM`</InternalLink> with no column specifiers will assume that hidden columns are in the copy data, but will ignore them when applying `COPY FROM`.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | `off`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | Yes                                                                                                                                             | Yes                                                             |     |
| `extra\_float\_digits`                                           | The number of digits displayed for floating-point values. Only values between `-15` and `3` are supported.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | `0`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                | Yes                                                                                                                                             | Yes                                                             |     |
| `force\_savepoint\_restart`                                      | When set to `true`, allows the <InternalLink path="savepoint">`SAVEPOINT`</InternalLink> statement to accept any name for a savepoint.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | `off`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | Yes                                                                                                                                             | Yes                                                             |     |
| `foreign\_key\_cascades\_limit`                                  | Limits the number of <InternalLink path="foreign-key#use-a-foreign-key-constraint-with-cascade">cascading operations</InternalLink> that run as part of a single query.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 | `10000`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | Yes                                                                                                                                             | Yes                                                             |     |
| `idle\_in\_session\_timeout`                                     | Automatically terminates sessions that idle past the specified threshold.  When set to `0`, the session will not timeout.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | The value set by the `sql.defaults.idle\_in\_session\_timeout`<InternalLink path="cluster-settings">cluster setting</InternalLink> (`0s`, by default).                                                                                                                                                                                                                                                                                                                                                                                                                             | Yes                                                                                                                                             | Yes                                                             |     |
| `idle\_in\_transaction\_session\_timeout`                        | Automatically terminates sessions that are idle in a transaction past the specified threshold.  When set to `0`, the session will not timeout.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | The value set by the `sql.defaults.idle\_in\_transaction\_session\_timeout`<InternalLink path="cluster-settings">cluster setting</InternalLink> (0s, by default).                                                                                                                                                                                                                                                                                                                                                                                                                  | Yes                                                                                                                                             | Yes                                                             |     |
| `index\_recommendations\_enabled`                                | If `true`, display recommendations to create indexes required to eliminate full table scans. For more details, see <InternalLink path="explain#default-statement-plans">Default statement plans</InternalLink>.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         | `true`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | Yes                                                                                                                                             | Yes                                                             |     |
| `inject\_retry\_errors\_enabled`                                 | If `true`, any statement executed inside of an explicit transaction (with the exception of <InternalLink path="set-vars">`SET`</InternalLink> statements) will return a transaction retry error. If the client retries the transaction using the special <InternalLink path="savepoint#savepoints-for-client-side-transaction-retries">`cockroach\_restart SAVEPOINT` name</InternalLink>, after the 3rd retry error, the transaction will proceed as normal. Otherwise, the errors will continue until `inject\_retry\_errors\_enabled` is set to `false`. For more details, see <InternalLink path="transaction-retry-error-example#test-transaction-retry-logic">Test transaction retry logic</InternalLink>.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        | `false`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | Yes                                                                                                                                             | Yes                                                             |     |
| <a id="intervalstyle" />                                         | `intervalstyle`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         | The input string format for <InternalLink path="interval">`INTERVAL`</InternalLink> values. Accepted values include `postgres`, `iso\_8601`, and `sql\_standard`.                                                                                                                                                                                                                                                                                                                                                                                                                  | The value set by the `sql.defaults.intervalstyle`<InternalLink path="cluster-settings">cluster setting</InternalLink> (`postgres`, by default). | Yes                                                             | Yes |
| `is\_superuser`                                                  | If `on` or `true`, the current user is a member of the <InternalLink path="security-reference/authorization#admin-role">`admin` role</InternalLink>.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | User-dependent                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     | No                                                                                                                                              | Yes                                                             |     |
| `large\_full\_scan\_rows`                                        | Determines which tables are considered "large" such that `disallow\_full\_table\_scans` rejects full table or index scans of "large" tables. The default value is `0`, which disallows all full table or index scans.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | User-dependent                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     | No                                                                                                                                              | Yes                                                             |     |
| `legacy\_varchar\_typing`                                        | If `on`, type checking and overload resolution for <InternalLink path="string#related-types">`VARCHAR`</InternalLink> types ignore overloads that cause errors, allowing comparisons between `VARCHAR` and non-`STRING`-like placeholder values to execute successfully. If `off`, type checking of these comparisons is more strict and must be handled with explicit type casts.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | `off`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | Yes                                                                                                                                             | Yes                                                             |     |
| `locality`                                                       | The location of the node. For more information, see <InternalLink path="cockroach-start#locality">Locality</InternalLink>.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | Node-dependent                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     | No                                                                                                                                              | Yes                                                             |     |
| `lock\_timeout`                                                  | The amount of time a query can spend acquiring or waiting for a single <InternalLink path="architecture/transaction-layer#concurrency-control">row-level lock</InternalLink>. In CockroachDB, unlike in PostgreSQL, non-locking reads wait for conflicting locks to be released. As a result, the `lock\_timeout` configuration applies to writes, and to locking and non-locking reads in read-write and read-only transactions. If `lock\_timeout = 0`, queries do not timeout due to lock acquisitions.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | The value set by the `sql.defaults.lock\_timeout`<InternalLink path="cluster-settings">cluster setting</InternalLink> (`0`, by default)                                                                                                                                                                                                                                                                                                                                                                                                                                            | Yes                                                                                                                                             | Yes                                                             |     |
| `multiple\_active\_portals\_enabled`                             | Whether to enable the <InternalLink path="postgresql-compatibility#multiple-active-portals">multiple active portals</InternalLink> pgwire feature.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | `false`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | Yes                                                                                                                                             | Yes                                                             |     |
| `node\_id`                                                       | The ID of the node currently connected to.  This variable is particularly useful for verifying load balanced connections.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | Node-dependent                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     | No                                                                                                                                              | Yes                                                             |     |
| `null\_ordered\_last`                                            | Set the default ordering of `NULL`s. The default order is `NULL`s first for ascending order and `NULL`s last for descending order.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | `false`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | Yes                                                                                                                                             | Yes                                                             |     |
| `optimizer\_merge\_joins\_enabled`                               | If `on`, the optimizer will explore query plans with merge joins.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | `on`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | Yes                                                                                                                                             | Yes                                                             |     |
| `optimizer\_push\_offset\_into\_index\_join`                     | If `on`, the optimizer will attempt to push offset expressions into index join expressions to produce more efficient query plans.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | `on`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | Yes                                                                                                                                             | Yes                                                             |     |
| `optimizer\_use\_forecasts`                                      | If `on`, the optimizer uses forecasted statistics for query planning.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | `on`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | Yes                                                                                                                                             | Yes                                                             |     |
| `optimizer\_use\_histograms`                                     | If `on`, the optimizer uses collected histograms for cardinality estimation.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | `on`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | No                                                                                                                                              | Yes                                                             |     |
| `optimizer\_use\_improved\_multi\_column\_selectivity\_estimate` | If `on`, the optimizer uses an improved selectivity estimate for multi-column predicates.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | `on`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | Yes                                                                                                                                             | Yes                                                             |     |
| `optimizer\_use\_improved\_zigzag\_join\_costing`                | If `on`, the cost of <InternalLink path="cost-based-optimizer#zigzag-joins">zigzag joins</InternalLink> is updated so they will be never be chosen over scans unless they produce fewer rows. To take effect, the [`enable\_zigzag\_join`](#enable-zigzag-join) setting must also be enabled.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | `on`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | Yes                                                                                                                                             | Yes                                                             |     |
| `optimizer\_use\_lock\_op\_for\_serializable`                    | If `on`, the optimizer uses a `Lock` operator to construct query plans for `SELECT` statements using the <InternalLink path="select-for-update">`FOR UPDATE` and `FOR SHARE`</InternalLink> clauses. This setting only affects `SERIALIZABLE` transactions. `READ COMMITTED` transactions are evaluated with the `Lock` operator regardless of the setting.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | `off`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | Yes                                                                                                                                             | Yes                                                             |     |
| `optimizer\_use\_merged\_partial\_statistics`                    | If `on`, the optimizer uses <InternalLink path="cost-based-optimizer#partial-statistics">partial statistics</InternalLink> merged with existing full <InternalLink path="cost-based-optimizer#table-statistics">table statistics</InternalLink> to produce more accurate cardinality estimates.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         | `on`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | Yes                                                                                                                                             | Yes                                                             |     |
| `optimizer\_use\_multicol\_stats`                                | If `on`, the optimizer uses collected multi-column statistics for cardinality estimation.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | `on`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | No                                                                                                                                              | Yes                                                             |     |
| `optimizer\_use\_not\_visible\_indexes`                          | If `on`, the optimizer uses not visible indexes for planning.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | `off`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | No                                                                                                                                              | Yes                                                             |     |
| `optimizer\_use\_virtual\_computed\_column\_stats`               | If `on`, the optimizer uses table statistics on <InternalLink path="computed-columns">virtual computed columns</InternalLink>.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | `on`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | Yes                                                                                                                                             | Yes                                                             |     |
| `plan\_cache\_mode`                                              | The type of plan that is cached in the <InternalLink path="cost-based-optimizer#query-plan-cache">query plan cache</InternalLink>: `auto`, `force\_generic\_plan`, or `force\_custom\_plan`.  For more information, refer to <InternalLink path="cost-based-optimizer#query-plan-type">Query plan type</InternalLink>.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | `auto`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | Yes                                                                                                                                             | Yes                                                             |     |
| `plpgsql\_use\_strict\_into`                                     | If `on`, PL/pgSQL <InternalLink path="plpgsql#assign-a-result-to-a-variable">`SELECT ... INTO` and `RETURNING ... INTO` statements</InternalLink> behave as though the `STRICT` option is specified. This causes the SQL statement to error if it does not return exactly one row.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | `off`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | Yes                                                                                                                                             | Yes                                                             |     |
| `pg\_trgm.similarity\_threshold`                                 | The threshold above which a <InternalLink path="functions-and-operators#operators">`%`</InternalLink> string comparison returns `true`. The value must be between `0` and `1`. For more information, see <InternalLink path="trigram-indexes">Trigram Indexes</InternalLink>.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | `0.3`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | Yes                                                                                                                                             | Yes                                                             |     |
| `prefer\_lookup\_joins\_for\_fks`                                | If `on`, the optimizer prefers <InternalLink path="joins#lookup-joins">`lookup joins`</InternalLink> to <InternalLink path="joins#merge-joins">`merge joins`</InternalLink> when performing <InternalLink path="foreign-key">`foreign key`</InternalLink> checks.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | `off`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | Yes                                                                                                                                             | Yes                                                             |     |
| `reorder\_joins\_limit`                                          | Maximum number of joins that the optimizer will attempt to reorder when searching for an optimal query execution plan.  For more information, see <InternalLink path="cost-based-optimizer#join-reordering">Join reordering</InternalLink>.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | `8`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                | Yes                                                                                                                                             | Yes                                                             |     |
| `require\_explicit\_primary\_keys`                               | If `on`, CockroachDB throws an error for all tables created without an explicit primary key defined.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | `off`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | Yes                                                                                                                                             | Yes                                                             |     |
| `search\_path`                                                   | A list of schemas that will be searched to resolve unqualified table or function names. For more details, see <InternalLink path="sql-name-resolution">SQL name resolution</InternalLink>.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | `public`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | Yes                                                                                                                                             | Yes                                                             |     |
| `serial\_normalization`                                          | Specifies the default handling of <InternalLink path="serial">`SERIAL`</InternalLink> in table definitions. Valid options include `'rowid'`, `'virtual\_sequence'`, `sql\_sequence`, `sql\_sequence\_cached`, <InternalLink path="create-sequence">`sql\_sequence\_cached\_node`</InternalLink>, and `unordered\_rowid`. If set to `'virtual\_sequence'`, the `SERIAL` type auto-creates a sequence for [better compatibility with Hibernate sequences](https://forum.cockroachlabs.com/t/hibernate-sequence-generator-returns-negative-number-and-ignore-unique-rowid/1885). If set to `sql\_sequence\_cached` or `sql\_sequence\_cached\_node`, you can use the `sql.defaults.serial\_sequences\_cache\_size`<InternalLink path="cluster-settings">cluster setting</InternalLink> to control the number of values to cache in a user's session, with a default of 256. If set to `unordered\_rowid`, the `SERIAL` type generates a globally unique 64-bit integer (a combination of the insert timestamp and the ID of the node executing the statement) that does not have unique ordering.                                                                                                                                                                                          | `'rowid'`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | Yes                                                                                                                                             | Yes                                                             |     |
| `server\_version`                                                | The version of PostgreSQL that CockroachDB emulates.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | Version-dependent                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | No                                                                                                                                              | Yes                                                             |     |
| `server\_version\_num`                                           | The version of PostgreSQL that CockroachDB emulates.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | Version-dependent                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | Yes                                                                                                                                             | Yes                                                             |     |
| `session\_id`                                                    | The ID of the current session.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | Session-dependent                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | No                                                                                                                                              | Yes                                                             |     |
| `session\_user`                                                  | The user connected for the current session.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | User in connection string                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | No                                                                                                                                              | Yes                                                             |     |
| `sql\_safe\_updates`                                             | If `true`, the following potentially unsafe SQL statements are disallowed: <InternalLink path="drop-database">`DROP DATABASE`</InternalLink> of a non-empty database and all dependent objects; <InternalLink path="delete">`DELETE`</InternalLink> and <InternalLink path="update">`UPDATE`</InternalLink> without a `WHERE` clause, unless a <InternalLink path="limit-offset">`LIMIT`</InternalLink> clause is included; <InternalLink path="select-for-update">`SELECT ... FOR UPDATE`</InternalLink> and <InternalLink path="select-for-update">`SELECT ... FOR SHARE`</InternalLink> without a `WHERE` or <InternalLink path="limit-offset">`LIMIT`</InternalLink> clause; <InternalLink path="alter-table#drop-column">`ALTER TABLE ... DROP COLUMN`</InternalLink>; and converting an existing table to <InternalLink path="alter-table#set-the-table-locality-to-regional-by-row">`REGIONAL BY ROW`</InternalLink> using <InternalLink path="alter-table">`ALTER TABLE ... LOCALITY`</InternalLink>, unless a <InternalLink path="alter-table">region column</InternalLink> has already been added to the table. For more details, refer to <InternalLink path="cockroach-sql#allow-potentially-unsafe-sql-statements">Allow potentially unsafe SQL statements</InternalLink>. | `true` for interactive sessions from the <InternalLink path="cockroach-sql">built-in SQL client</InternalLink>, `false` for sessions from other clients                                                                                                                                                                                                                                                                                                                                                                                                                            | Yes                                                                                                                                             | Yes                                                             |     |
| `statement\_timeout`                                             | The amount of time a statement can run before being stopped. This value can be an `int` (e.g., `10`) and will be interpreted as milliseconds. It can also be an interval or string argument, where the string can be parsed as a valid interval (e.g., `'4s'`). A value of `0` turns it off.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | The value set by the `sql.defaults.statement\_timeout`<InternalLink path="cluster-settings">cluster setting</InternalLink> (`0s`, by default).                                                                                                                                                                                                                                                                                                                                                                                                                                     | Yes                                                                                                                                             | Yes                                                             |     |
| `stub\_catalog\_tables`                                          | If `off`, querying an unimplemented, empty <InternalLink path="pg-catalog">`pg\_catalog`</InternalLink> table will result in an error, as is the case in v20.2 and earlier. If `on`, querying an unimplemented, empty `pg\_catalog` table simply returns no rows.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | `on`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | Yes                                                                                                                                             | Yes                                                             |     |
| <a id="timezone" />                                              | `timezone`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | The default time zone for the current session.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     | `UTC`                                                                                                                                           | Yes                                                             | Yes |
| <a id="tracing" />                                               | `tracing`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | The trace recording state.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         | `off`                                                                                                                                           | Yes                                                             | Yes |
| `transaction\_isolation`                                         | The isolation level at which the transaction executes (<InternalLink path="demo-serializable">`SERIALIZABLE`</InternalLink> or <InternalLink path="read-committed">`READ COMMITTED`</InternalLink>). See <InternalLink path="transactions#isolation-levels">Isolation levels</InternalLink>.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | `SERIALIZABLE`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     | Yes                                                                                                                                             | Yes                                                             |     |
| `transaction\_priority`                                          | The priority of the current transaction. See Transactions: Transaction priorities for more details. This session variable was called transaction priority (with a space) in CockroachDB 1.x. It has been renamed for compatibility with PostgreSQL.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     | `NORMAL`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | Yes                                                                                                                                             | Yes                                                             |     |
| `transaction\_read\_only`                                        | The access mode of the current transaction. See <InternalLink path="set-transaction">`SET TRANSACTION`</InternalLink> for more details.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 | `off`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | Yes                                                                                                                                             | Yes                                                             |     |
| `transaction\_rows\_read\_err`                                   | The limit for the number of rows read by a SQL transaction. If this value is exceeded the transaction will fail (or the event will be logged to `SQL\_INTERNAL\_PERF` for internal transactions).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | `0`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                | Yes                                                                                                                                             | Yes                                                             |     |
| `transaction\_rows\_read\_log`                                   | The threshold for the number of rows read by a SQL transaction. If this value is exceeded, the event will be logged to `SQL\_PERF` (or `SQL\_INTERNAL\_PERF` for internal transactions).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                | `0`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                | Yes                                                                                                                                             | Yes                                                             |     |
| `transaction\_rows\_written\_err`                                | The limit for the number of rows written by a SQL transaction. If this value is exceeded the transaction will fail (or the event will be logged to `SQL\_INTERNAL\_PERF` for internal transactions).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | `0`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                | Yes                                                                                                                                             | Yes                                                             |     |
| `transaction\_rows\_written\_log`                                | The threshold for the number of rows written by a SQL transaction. If this value is exceeded, the event will be logged to `SQL\_PERF` (or `SQL\_INTERNAL\_PERF` for internal transactions).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | `0`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                | Yes                                                                                                                                             | Yes                                                             |     |
| `transaction\_status`                                            | The state of the current transaction. See <InternalLink path="transactions">Transactions</InternalLink> for more details.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | `NoTxn`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | No                                                                                                                                              | Yes                                                             |     |
| `transaction\_timeout`                                           | Aborts an explicit <InternalLink path="transactions">transaction</InternalLink> when it runs longer than the configured duration. Stored in milliseconds; can be expressed in milliseconds or as an <InternalLink path="interval">`INTERVAL`</InternalLink>.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | `0`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                | Yes                                                                                                                                             | Yes                                                             |     |
| `troubleshooting\_mode\_enabled`                                 | When enabled, avoid performing additional work on queries, such as collecting and emitting telemetry data. This session variable is particularly useful when the cluster is experiencing issues, unavailability, or failure.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | `off`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | Yes                                                                                                                                             | Yes                                                             |     |
| `use\_declarative\_schema\_changer`                              | Whether to use the declarative schema changer for supported statements.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 | `on`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | Yes                                                                                                                                             | Yes                                                             |     |
| `vector\_search\_beam\_size`                                     | The size of the vector search beam, which determines how many vector partitions are considered during query execution. For details, refer to <InternalLink path="vector-indexes#tune-vector-indexes">Tune vector indexes</InternalLink>.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                | `32`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | Yes                                                                                                                                             | Yes                                                             |     |
| <a id="vectorize" />                                             | `vectorize`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | The vectorized execution engine mode. Options include `on` and `off`. For more details, see <InternalLink path="vectorized-execution#configure-vectorized-execution">Configure vectorized execution for CockroachDB</InternalLink>.                                                                                                                                                                                                                                                                                                                                                | `on`                                                                                                                                            | Yes                                                             | Yes |
| `virtual\_cluster\_name`                                         | The name of the virtual cluster that the SQL client is connected to.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | Session-dependent                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | No                                                                                                                                              | Yes                                                             |     |

The following session variables are exposed only for backwards compatibility with earlier CockroachDB releases and have no impact on how CockroachDB runs:

| Variable name                                  | Initial value    | Modify with <InternalLink path="set-vars">`SET`</InternalLink>? | View with <InternalLink path="show-vars">`SHOW`</InternalLink>? |
| ---------------------------------------------- | ---------------- | --------------------------------------------------------------- | --------------------------------------------------------------- |
| `backslash\_quote`                             | `safe\_encoding` | No                                                              | Yes                                                             |
| `client\_encoding`                             | `UTF8`           | No                                                              | Yes                                                             |
| `default\_tablespace`                          |                  | No                                                              | Yes                                                             |
| `enable\_drop\_enum\_value`                    | `off`            | Yes                                                             | Yes                                                             |
| `enable\_seqscan`                              | `on`             | Yes                                                             | Yes                                                             |
| `escape\_string\_warning`                      | `on`             | No                                                              | Yes                                                             |
| `experimental\_enable\_hash\_sharded\_indexes` | `off`            | Yes                                                             | Yes                                                             |
| `integer\_datetimes`                           | `on`             | No                                                              | Yes                                                             |
| `max\_identifier\_length`                      | `128`            | No                                                              | Yes                                                             |
| `max\_index\_keys`                             | `32`             | No                                                              | Yes                                                             |
| `row\_security`                                | `off`            | No                                                              | Yes                                                             |
| `standard\_conforming\_strings`                | `on`             | No                                                              | Yes                                                             |
| `server\_encoding`                             | `UTF8`           | Yes                                                             | Yes                                                             |
| `synchronize\_seqscans`                        | `on`             | No                                                              | Yes                                                             |
| `synchronous\_commit`                          | `on`             | Yes                                                             | Yes                                                             |

For session variables on features in preview, see <InternalLink path="cockroachdb-feature-availability">Features in Preview</InternalLink>.

Special syntax cases supported for compatibility:

| Syntax                             | Equivalent to                        |
| ---------------------------------- | ------------------------------------ |
| `SHOW TRANSACTION PRIORITY`        | `SHOW "transaction priority"`        |
| `SHOW TRANSACTION ISOLATION LEVEL` | `SHOW "transaction isolation level"` |
| `SHOW TIME ZONE`                   | `SHOW "timezone"`                    |
| `SHOW TRANSACTION STATUS`          | `SHOW "transaction status"`          |

## Examples

### Showing the value of a single session variable

```sql theme={"theme":{"light":"catppuccin-mocha","dark":"catppuccin-mocha"}}
> SHOW DATABASE;
```

```text theme={"theme":{"light":"catppuccin-mocha","dark":"catppuccin-mocha"}}
  database
------------
  movr
(1 row)
```

### Showing the value of all session variables

```sql theme={"theme":{"light":"catppuccin-mocha","dark":"catppuccin-mocha"}}
> SHOW ALL;
```

```text theme={"theme":{"light":"catppuccin-mocha","dark":"catppuccin-mocha"}}
       variable       |      value
----------------------+-------------------
  application_name    | $ cockroach demo
  bytea_output        | hex
  client_encoding     | UTF8
  client_min_messages | notice
...
```

## See also

* <InternalLink path="set-vars">`SET session variable`</InternalLink>
* <InternalLink path="transactions">Transactions</InternalLink>, including <InternalLink path="transactions#transaction-priorities">Priority levels</InternalLink>
* <InternalLink path="show-cluster-setting">`SHOW CLUSTER SETTING`</InternalLink>
* <InternalLink path="show-columns">`SHOW COLUMNS`</InternalLink>
* <InternalLink path="show-constraints">`SHOW CONSTRAINTS`</InternalLink>
* <InternalLink path="show-create">`SHOW CREATE`</InternalLink>
* <InternalLink path="show-databases">`SHOW DATABASES`</InternalLink>
* <InternalLink path="show-grants">`SHOW GRANTS`</InternalLink>
* <InternalLink path="show-index">`SHOW INDEX`</InternalLink>
* <InternalLink path="show-users">`SHOW USERS`</InternalLink>
* <InternalLink path="show-default-session-variables-for-role">`SHOW DEFAULT SESSION VARIABLES FOR ROLE`</InternalLink>
