| From: | Justin Pryzby <pryzby(at)telsasoft(dot)com> |
|---|---|
| To: | tiaswin(at)gmx(dot)de |
| Cc: | pgsql-performance(at)lists(dot)postgresql(dot)org |
| Subject: | Re: Query is sometimes fast and sometimes slow: what could be the reason? |
| Date: | 2022-09-14 15:59:53 |
| Message-ID: | 20220914155953.GY31833@telsasoft.com |
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| Thread: | |
| Lists: | pgsql-performance |
On Wed, Sep 14, 2022 at 05:02:07PM +0200, tiaswin(at)gmx(dot)de wrote:
> <html><head></head><body><div style="font-family: Verdana;font-size: 12.0px;"><div>What could be the reason of a query, which is sometimes fast and sometimes slow (factor >10x)?</div>
> <div>(running on a large table).</div>
> <div> </div>
> <div> </div></div></body></html>
Lots of possible issues. Is it using a different query plan ?
Collect a good plan and a bad one and compare, or send both.
Perhaps use autoexplain to do so.
Turn on logging and send as much information as you can as described
here.
https://wiki.postgresql.org/wiki/Slow_Query_Questions
Please try to configure your mail client to send text mail (instead of
or in addition to the html one).
--
Justin
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