Session Variables

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The SET statement can modify one of the session configuration variables. These can also be queried via SHOW. By default, session variable values are set for the duration of the current session.

CockroachDB supports setting session variables for the duration of a single transaction, using the LOCAL keyword.

Supported variables

Variable name Description Initial value Modify with SET? View with SHOW?
application_name The current application name for statistics collection. Empty string, or cockroach for sessions from the built-in SQL client. Yes Yes
autocommit_before_ddl When the autocommit_before_ddl session setting is set to on, any schema change statement that is sent during an explicit transaction will cause the transaction to commit before executing the schema change. off Yes Yes
bytea_output The mode for conversions from STRING to BYTES. hex Yes Yes
client_min_messages The severity level of notices displayed in the SQL shell. Accepted values include debug5, debug4, debug3, debug2, debug1, log, notice, warning, and error. notice Yes Yes
copy_from_atomic_enabled If set to on, COPY FROM 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
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 current database. Database in connection string, or empty if not specified. Yes Yes
datestyle The input string format for DATE and TIMESTAMP values. Accepted values include ISO,MDY, ISO,DMY, and ISO,YMD. The value set by the sql.defaults.datestyle cluster setting (ISO,MDY, by default). Yes Yes
default_int_size The size, in bytes, of an INT type. 8 Yes Yes
default_text_search_config The dictionary used to normalize tokens and eliminate stop words when calling a full-text search function without a configuration parameter. See Full-Text Search. english Yes Yes
default_transaction_isolation The isolation level at which transactions in the session execute (SERIALIZABLE or READ COMMITTED). See Isolation levels. 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 Set quality of service level. 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 SET TRANSACTION for more details.
off Yes Yes
default_transaction_use_follower_reads If set to on, all read-only transactions use AS OF SYSTEM TIME follower_read_timestamp() 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, changefeeds 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 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
enable_auto_rehoming When enabled, the home regions of rows in REGIONAL BY ROW tables are automatically set to the region of the gateway node from which any UPDATE or UPSERT statements that operate on those rows originate. off Yes Yes
enable_durable_locking_for_serializable Indicates whether CockroachDB replicates FOR UPDATE and FOR SHARE locks via Raft, 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_experimental_alter_column_type_general If on, it is possible to alter column data types. off Yes Yes
enable_implicit_fk_locking_for_serializable Indicates whether CockroachDB uses shared locks to perform foreign key checks. To take effect, enable_shared_locking_for_serializable 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 UPDATE and UPSERT 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 SELECT FOR UPDATE.
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 shared locks 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 database regions on a multi-region cluster such that your schema objects will have all of their replicas stored only in regions that are members of the super region. off Yes Yes
enable_zigzag_join Indicates whether the cost-based optimizer will plan certain queries using a zig-zag merge join algorithm, 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 regional by row table) or a query's home region differs from the gateway region. Note that only tables with ZONE survivability can be scanned without error when this is enabled. For more information about home regions, see Table localities.

This feature is in preview. It is subject to change.
off Yes Yes
enforce_home_region_follower_reads_enabled If on while the enforce_home_region setting is on, allows enforce_home_region to perform AS OF SYSTEM TIME follower reads to detect and report a query's home region, 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, COPY FROM 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 SAVEPOINT statement to accept any name for a savepoint. off Yes Yes
foreign_key_cascades_limit Limits the number of cascading operations 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 cluster setting (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 cluster setting (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 Default statement plans.
true Yes Yes
inject_retry_errors_enabled If true, any statement executed inside of an explicit transaction (with the exception of SET statements) will return a transaction retry error. If the client retries the transaction using the special cockroach_restart SAVEPOINT name, 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 Test transaction retry logic. false Yes Yes
intervalstyle The input string format for INTERVAL values. Accepted values include postgres, iso_8601, and sql_standard. The value set by the sql.defaults.intervalstyle cluster setting (postgres, by default). Yes Yes
is_superuser If on or true, the current user is a member of the admin role. 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 1000. To reject all full table or index scans, set to 0. User-dependent No Yes
locality The location of the node.

For more information, see Locality.
Node-dependent No Yes
lock_timeout The amount of time a query can spend acquiring or waiting for a single row-level lock.
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 cluster setting (0, by default) Yes Yes
multiple_active_portals_enabled Whether to enable the multiple active portals 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 NULLs. The default order is NULLs first for ascending order and NULLs last for descending order. false 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_lock_op_for_serializable If on, the optimizer uses a Lock operator to construct query plans for SELECT statements using the FOR UPDATE and FOR SHARE 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_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 virtual computed columns. on Yes Yes
plpgsql_use_strict_into If on, PL/pgSQL SELECT ... INTO and RETURNING ... INTO statements 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 % string comparison returns true. The value must be between 0 and 1. For more information, see Trigram Indexes. 0.3 Yes Yes
prefer_lookup_joins_for_fks If on, the optimizer prefers lookup joins to merge joins when performing foreign key 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 Join reordering.
8 Yes Yes
results_buffer_size The default size of the buffer that accumulates results for a statement or a batch of statements before they are sent to the client.
This can also be set for all connections using the sql.defaults.results_buffer_size cluster setting. Note that auto-retries generally only happen while no results have been delivered to the client, so reducing this size can increase the number of retryable errors a client receives. On the other hand, increasing the buffer size can increase the delay until the client receives the first result row. Setting to 0 disables any buffering.
16384 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 SQL name resolution.
public Yes Yes
serial_normalization Specifies the default handling of SERIAL in table definitions. Valid options include 'rowid', 'virtual_sequence', sql_sequence, sql_sequence_cached, and unordered_rowid.
If set to 'virtual_sequence', the SERIAL type auto-creates a sequence for better compatibility with Hibernate sequences.
If set to sql_sequence_cached, you can use the sql.defaults.serial_sequences_cache_size cluster setting 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 false, potentially unsafe SQL statements are allowed, including DROP of a non-empty database and all dependent objects, DELETE without a WHERE clause, UPDATE without a WHERE clause, and ALTER TABLE .. DROP COLUMN.
See Allow Potentially Unsafe SQL Statements for more details.
true for interactive sessions from the built-in SQL client,
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 cluster setting (0s, by default). Yes Yes
stub_catalog_tables If off, querying an unimplemented, empty pg_catalog 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
timezone The default time zone for the current session. This session variable was named "time zone" (with a space) in CockroachDB 1.x. It has been renamed for compatibility with PostgreSQL. UTC Yes Yes
tracing The trace recording state. off Yes
transaction_isolation The isolation level at which the transaction executes (SERIALIZABLE or READ COMMITTED). See Isolation levels. 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 SET TRANSACTION 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 Transactions for more details. This session variable was called transaction status (with a space) in CockroachDB 1.x. It has been renamed for compatibility with PostgreSQL. NoTxn No Yes
transaction_timeout Aborts an explicit transaction when it runs longer than the configured duration. Stored in milliseconds; can be expressed in milliseconds or as an INTERVAL. 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. See Declarative schema changer for more details. on Yes Yes
vectorize The vectorized execution engine mode. Options include on and off. For more details, see Configure vectorized execution for CockroachDB. on Yes 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 SET? View with SHOW?
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

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