Session Variables

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
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
copy_transaction_quality_of_service	The default quality of service for COPY statements in the current session. The supported options are regular, critical, and background. See Set quality of service level.	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 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
distsql	The query distribution mode for the session. By default, CockroachDB determines which queries are faster to execute if distributed across multiple nodes, and all other queries are run through the gateway node.	auto	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, the 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 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 zigzag 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 prevents queries from performing full table or index scans on those tables. The default value is 1000. To prevent 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_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.	off	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.	off	Yes	Yes
optimizer_use_improved_zigzag_join_costing	If on, the cost of zigzag joins is updated so they will be never be chosen over scans unless they produce fewer rows. To take effect, the 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 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
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
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