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Message-ID: <0b2865ee-b220-48c1-9314-86aa34048503@gmail.com>
Date: Wed, 1 Apr 2026 11:05:20 -0400
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Subject: Re: How to query with more workers on a large table with many
 partitions
To: pgsql-general@lists.postgresql.org
References: <CANHuRqH7q6bi7UAmW3w+o=11Sy1pzoY5KYsLfkpjS3X3T_OQHw@mail.gmail.com>
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From: Greg Hennessy <greg.hennessy@gmail.com>
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> 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?
>
Postgres allocates more workers based on the log3 of the ratio of the 
table size to min_parallel_table_scan_size.

You may want to try |ALTER TABLE ... SET (parallel_workers = 10) (or 
whatever your desired value is).

|
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    <br>
    <blockquote type="cite"
cite="mid:CANHuRqH7q6bi7UAmW3w+o=11Sy1pzoY5KYsLfkpjS3X3T_OQHw@mail.gmail.com">
      <div dir="ltr">
        <div>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? </div>
        <br>
      </div>
    </blockquote>
    Postgres allocates more workers based on the log3 of the ratio of
    the table size to min_parallel_table_scan_size.<br>
    <br>
    You may want to try <span class="T286Pc" data-sfc-cp=""
      data-sfc-root="c" data-sfc-cb="" data-processed="true"><code
        dir="ltr" class="KDcb0c" data-sfc-root="c" data-sfc-cb=""
        data-processed="true">ALTER TABLE ... SET (parallel_workers =
        10) (or whatever your desired value is).<br>
        <br>
      </code></span>
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