Wiki / Configuration Parameters

Specifies the maximum amount of memory to be used by maintenance operations, such as VACUUM, CREATE INDEX, and ALTER TABLE ADD FOREIGN KEY. If this value is specified without units, it is taken as kilobytes. It defaults to 64 megabytes (64MB). Since only one of these operations can be executed at a time by a database session, and an installation normally doesn't have many of them running concurrently, it's safe to set this value significantly larger than work_mem. Larger settings might improve performance for vacuuming and for restoring database dumps. Note that when autovacuum runs, up to autovacuum_max_workers times this memory may be allocated, so be careful not to set the default value too high. It may be useful to control for this by separately setting autovacuum_work_mem.

English manual coverage begins with PostgreSQL 7.4. Source history and runtime observations have their own recorded version boundaries.

boot val

65536

category

Resource Usage / Memory

context

user

documented

true

enumvals

Unknown

extra desc

This includes operations such as VACUUM and CREATE INDEX.

lang

en

max val

2147483647

metadata version

18

min val

64

name

maintenance_work_mem

short desc

Sets the maximum memory to be used for maintenance operations.

source

pg-settings-source-snapshot

unit

kB

vartype

integer