Wiki / Configuration Parameters

Allows the leader process to execute the query plan under Gather and Gather Merge nodes instead of waiting for worker processes. The default is on. Setting this value to off reduces the likelihood that workers will become blocked because the leader is not reading tuples fast enough, but requires the leader process to wait for worker processes to start up before the first tuples can be produced. The degree to which the leader can help or hinder performance depends on the plan type, number of workers and query duration.

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

boot val

on

category

Resource Usage / Worker Processes

context

user

documented

true

enumvals

Unknown

extra desc

Should gather nodes also run subplans or just gather tuples?

lang

en

max val

Unknown

metadata version

18

min val

Unknown

name

parallel_leader_participation

short desc

Controls whether Gather and Gather Merge also run subplans.

source

pg-settings-source-snapshot

unit

Unknown

vartype

bool