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.
Note that for the collection of dead tuple identifiers, VACUUM is only able to utilize up to a maximum of
1GB of memory.
- Re: Amcheck verification of GiST and GIN
- Re: Removing more vacuumlazy.c special cases, relfrozenxid optimizations
- Re: Allow parallel plan for referential integrity checks?
- Re: should vacuum's first heap pass be read-only?
- Re: Add the ability to limit the amount of memory that can be allocated to backends.