max_logical_replication_workers — PostgreSQL configuration parameter

Specifies maximum number of logical replication workers.

At a glance

What it does

Specifies maximum number of logical replication workers. This includes leader apply workers, parallel apply workers, and table/sequence synchronization workers.

Logical replication workers are taken from the pool defined by max_worker_processes.

(Description quoted from the official PostgreSQL documentation.)

How to apply a change

Can be set per session with SET, per role/database with ALTER ROLE/DATABASE ... SET, or globally in postgresql.conf.

Inspect the current value and source with SHOW max_logical_replication_workers; or SELECT name, setting, unit, context, source FROM pg_settings WHERE name = 'max_logical_replication_workers';.

Tuning guidance

Size it to the number of subscriptions plus desired parallel apply/sync workers; it is drawn from max_worker_processes, so raise that too. Too low serializes subscription apply.

Reference

PostgreSQL documentation — max_logical_replication_workers.