Thanks Tom
Perfect.
Anthony Vitale
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-----Original Message-----
From: Tom Lane <t...@sss.pgh.pa.us>
Sent: Wednesday, April 9, 2025 11:02 AM
To: Vitale, Anthony, Sony Music <anthony.vit...@sonymusic.com>
Cc: pgsql-performance@lists.postgresql.org
Subject: Re: Question on what Duration in the log
EXTERNAL SENDER
"Vitale, Anthony, Sony Music" <anthony.vit...@sonymusic.com> writes:
> In my PG Version 14 log I have set to log the duration of sql (Example of one
> log row below).
> 2025-04-08 07:31:57 UTC:XXX(55994):XXX:[8949]:LOG: duration: 6555.756
> ms execute S_381: {Actual Parameterized Sql executed} This Shows the
> Execution of a JDBC Server Side Prepared statement (i.e S_381) which took 6.5
> seconds.
> When I run the Sql using explain analyze it runs shows an execution
> time of 73 ms Planning Time: 0.773 ms Execution Time: 73.578 ms
They're not measuring the same thing really, because EXPLAIN isn't counting the
time needed to transmit data to the client.
This is not just a matter of network overhead (though that can be
substantial) but also the time required to format the values into text. If you
are talking about large values, which I bet you are, there is also the time
needed to fetch them from out-of-line TOAST storage, which is another thing
that doesn't happen in EXPLAIN.
Since v17, EXPLAIN has grown a SERIALIZE option that causes it to do everything
except the network transmission, which might be of interest in analyzing this
further.
regards, tom lane
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