← recall

buffer mapping lock term

Postgres internal lock on buffer cache hash partition

Postgres has 128 buffer mapping lock partitions (NUM_BUFFER_PARTITIONS). Heavy concurrent buffer cache access can contend on these. Symptom: high CPU + low throughput, lock_manager waits in pg_stat_activity.

aliases: BufMappingLock

topics: databases, postgres

references:

• Postgres source — buf_internals.h
• Postgres — Wait Events