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Short Description

Waiting to read or update information about “heavyweight” locks.

Additional Information

PostgreSQL by default uses ‘fast path’ locks where possible as these are locks are light on resource utilisation. When use of ‘fast path’ locks is not possible, a ‘heavyweight’ lock will be used.

How to reduce this wait

Ensure PostgreSQL is using the current version.

Problems have been seen with TOAST storage and in heavily partitioned databases.

PostgreSQL docs - Wait Events of Type LWLock

PostgreSQL docs - pg_locks

PostgreSQL docs - TOAST

Postgrepro - LWLocks by LockManager slowing large DB

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