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help / color / mirror / Atom feedFrom: Gabriel Sánchez <[email protected]>
To: Postgres General <[email protected]>
Subject: How to query with more workers on a large table with many partitions
Date: Wed, 1 Apr 2026 10:56:20 -0400
Message-ID: <CANHuRqH7q6bi7UAmW3w+o=11Sy1pzoY5KYsLfkpjS3X3T_OQHw@mail.gmail.com> (raw)
Hi PostgreSQL community,
I have a large table (86 GB) that is declaratively partitioned by year,
sub-partitioned by month, and sub-sub-partitioned by day. It currently has
437 leaf partitions, and will continue to grow with a new partition each
day. When I query a simple count(*) by date, the query planner plans a
query with five workers, but I have the following in postgresql.conf:
max_worker_processes = 12
max_parallel_workers_per_gather = 12
max_parallel_workers = 12
shared_buffers = 32GB
temp_buffers = 1GB
work_mem = 512MB
The top-level partitioned table has been ANALYZEd.
I'm running PostgreSQL 16 on an AWS EC2 instance with 16 logical processors
and 128G of RAM. How can I get PG to run the query with more workers?
Thank you,
Gabriel
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