From: Justin Pryzby <pryzby@telsasoft.com>
To: tiaswin@gmx.de
Cc: pgsql-performance@lists.postgresql.org
Subject: Re: Query is sometimes fast and sometimes slow: what could be the reason?
Date: Wed, 14 Sep 2022 10:59:53 -0500
Message-ID: <20220914155953.GY31833@telsasoft.com> (raw)
In-Reply-To: <trinity-e7635062-7f0a-42dc-985c-6af74dfa1787-1663167727005@3c-app-gmx-bs70>
References: <trinity-e7635062-7f0a-42dc-985c-6af74dfa1787-1663167727005@3c-app-gmx-bs70>
On Wed, Sep 14, 2022 at 05:02:07PM +0200, tiaswin@gmx.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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: pryzby@telsasoft.com, tiaswin@gmx.de, pgsql-performance@lists.postgresql.org
Subject: Re: Query is sometimes fast and sometimes slow: what could be the reason?
In-Reply-To: <20220914155953.GY31833@telsasoft.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox