Wiki / Configuration Parameters

Sets the maximum number of parallel workers that can be started by a single utility command. Currently, the parallel utility commands that support the use of parallel workers are CREATE INDEX when building a B-tree, GIN, or BRIN index, and VACUUM without FULL option. Parallel workers are taken from the pool of processes established by max_worker_processes, limited by max_parallel_workers. Note that the requested number of workers may not actually be available at run time. If this occurs, the utility operation will run with fewer workers than expected. The default value is 2. Setting this value to 0 disables the use of parallel workers by utility commands. Note that parallel utility commands should not consume substantially more memory than equivalent non-parallel operations. This strategy differs from that of parallel query, where resource limits generally apply per worker process. Parallel utility commands treat the resource limit maintenance_work_mem as a limit to be applied to the entire utility command, regardless of the number of parallel worker processes. However, parallel utility commands may still consume substantially more CPU resources and I/O bandwidth.

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

boot val

2

category

Resource Usage / Worker Processes

context

user

documented

true

enumvals

Unknown

extra desc

Unknown

lang

en

max val

1024

metadata version

18

min val

0

name

max_parallel_maintenance_workers

short desc

Sets the maximum number of parallel processes per maintenance operation.

source

pg-settings-source-snapshot

unit

Unknown

vartype

integer