Slow planning time for simple query - Mailing list pgsql-general

From Jeremy Finzel
Subject Slow planning time for simple query
Date
Msg-id CAMa1XUhVCj1ZRB6XqC81MZrnb3biJfq4eR3tY5Bt1nP-YhrUBg@mail.gmail.com
Whole thread Raw
Responses Re: Slow planning time for simple query  (Tom Lane <tgl@sss.pgh.pa.us>)
Re: Slow planning time for simple query  (Pavel Stehule <pavel.stehule@gmail.com>)
Re: Slow planning time for simple query  (Adrian Klaver <adrian.klaver@aklaver.com>)
List pgsql-general
Hello - 

We have an odd scenario on one of our OLTP systems, which behaves the same way on a streamer, of a 700-1000ms planning time for a query like this:

SELECT *
FROM table1
WHERE  source_id IN (SELECT id FROM table2 WHERE customer_id = $1);

The actual execution time is sub-ms.

We initially thought maybe catalog bloat?  But we were able to reindex all of the highly churned catalog tables, and I even did VACUUM FULL on pg_attribute and pg_statistic, to no avail.

There are no custom settings for pg_attribute for the given tables either.

Interestingly, the problem goes away on a SAN snapshot of the target system.

Any ideas of what else we could try?  A PL function that caches the query plan works, but that is just a workaround.

Thanks!
Jeremy

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