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Re: SELECT Query taking 200 ms on PostgreSQL compared to 4 ms on Oracle after migration. - Mailing list pgsql-performance

From Bharath Rupireddy
Subject Re: SELECT Query taking 200 ms on PostgreSQL compared to 4 ms on Oracle after migration.
Date
Msg-id CALj2ACXN9ZohCxP-y-5qwNrHKP4y3_aNqm=usZ=YPZEiEEpiyw@mail.gmail.com
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In response to SELECT Query taking 200 ms on PostgreSQL compared to 4 ms on Oracle after migration.  (aditya desai <admad123@gmail.com>)
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On Sat, Apr 3, 2021 at 7:08 PM aditya desai <admad123@gmail.com> wrote:
>
> Hi,
> We migrated our Oracle Databases to PostgreSQL. One of the simple select query that takes 4 ms on Oracle is taking
around200 ms on PostgreSQL. Could you please advise. Please find query and query plans below. Gather cost seems high.
Willincreasing max_parallel_worker_per_gather help? 

No it doesn't. For small tables, parallelism might not help since it
doesn't come for free. Try setting max_parallel_worker_per_gather to 0
i.e. without parallel query.

With Regards,
Bharath Rupireddy.
EnterpriseDB: http://www.enterprisedb.com

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