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help / color / mirror / Atom feedFrom: Greg Sabino Mullane <[email protected]>
To: Scot Kreienkamp <[email protected]>
Cc: Tom Lane <[email protected]>
Cc: pgsql-generallists.postgresql.org <[email protected]>
Subject: Re: vacuum analyze query performance - help me understand
Date: Wed, 20 Aug 2025 12:26:19 -0400
Message-ID: <CAKAnmmJKOykz=xwGGTRJX9arvhOLa6rXShv-S_sZ52urDfaXnQ@mail.gmail.com> (raw)
In-Reply-To: <SJ0PR15MB5245E8979235B81FD116039B9A30A@SJ0PR15MB5245.namprd15.prod.outlook.com>
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<[email protected]>
<SJ0PR15MB5245E8979235B81FD116039B9A30A@SJ0PR15MB5245.namprd15.prod.outlook.com>
Moving forward advice:
* Run the query more than once before doing a manual vacuum to rule out
caching.
* Change your flags for the vacuumdb from --quiet to --verbose and we can
see exactly what vacuum has done. Ideally have cron append to a file on disk
* Similarly, set log_autovacuum_min_duration to 0 (which logs all
autovacuum activity).
* As mentioned upthread, use explain (analyze, buffers, settings) for
better output
* Using the pg_buffercache extension can show you exactly what is in shared
buffers (for future debugging)
Cheers,
Greg
--
Crunchy Data - https://www.crunchydata.com
Enterprise Postgres Software Products & Tech Support
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Subject: Re: vacuum analyze query performance - help me understand
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