Locks

The Locks window shows information about the locks.

Locks by mode

AccessShareLock Number of "AccessShareLock" locks.

The SELECT command acquires a lock of this mode on referenced tables. In general, any query that only reads a table and does not modify it will acquire this lock mode

RowShareLock Number of "RowShareLock" locks.

The SELECT FOR UPDATE and SELECT FOR SHARE commands acquire a lock of this mode on the target table(s) (in addition to ACCESS SHARE locks on any other tables that are referenced but not selected FOR UPDATE/FOR SHARE).

RowExclusiveLock Number of "RowExclusiveLock" locks.

The commands UPDATE, DELETE, and INSERT acquire this lock mode on the target table (in addition to ACCESS SHARE locks on any other referenced tables). In general, this lock mode will be acquired by any command that modifies the data in a table.

ShareUpdateExclusiveLock Number of "ShareUpdateExclusiveLock" locks.

Acquired by VACUUM (without FULL), ANALYZE, and CREATE INDEX CONCURRENTLY

ShareLock Number of "ShareLock" locks.

This mode protects a table against concurrent data changes.

ShareRowExclusiveLock Number of "ShareRowExclusiveLock" locks.

This lock mode is not automatically acquired by any PostgreSQL command.

ExclusiveLock Number of "ExclusiveLock" locks.

This lock mode is not automatically acquired on user tables by any PostgreSQL command. However it is acquired on certain system catalogs in some operations

AccessExclusiveLock Number of "AccessExclusiveLock" locks.

Acquired by the ALTER TABLE, DROP TABLE, TRUNCATE, REINDEX, CLUSTER, and VACUUM FULL commands. This is also the default lock mode for LOCK TABLE statements that do not specify a mode explicitly.

Locks

Waiting Number of locks waiting
Held Number of locks held

Pecent Lock waiting

Percentage of locks which are waiting. Any time a connection waits for another connection to complete its transaction, the overall response time for an application is affected.

Pecent waiting processes

Percentage of connections which are blocked by another connection. Any time a connection waits for another connectionto complete its transaction, the overall response time for an application is affected.

Processes holding locks

Numbner of processes which are holding locks

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