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From: Corey Huinker <corey.huinker@gmail.com>
Date: Sat, 12 Apr 2025 04:29:42 -0400
Message-ID: <CADkLM=fV95NKw4x9pBtaXHtQP4=21nmjDBuv2XJm3ZiNgc0AKw@mail.gmail.com>
Subject: Re: Can we use Statistics Import and Export feature to perforamance testing?
To: David Rowley <dgrowleyml@gmail.com>
Cc: "Ryohei Takahashi (Fujitsu)" <r.takahashi_2@fujitsu.com>, 
	"pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
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>
> at the *actual size* of the relation and takes that into account when
> scaling the statistics (see table_block_relation_estimate_size() in
> tableam.c). If the table sizes don't match between the two servers
> then there's no guarantees the planner will produce the same plan.
>

Sorry that I didn't see this thread until now. I would like to note that
table_block_relation_estimate_size() determines the actual size of the
relation by asking pg_class, and the relevant values there are set by
pg_restore_relation_stats().

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<div dir=3D"ltr"><div class=3D"gmail_quote gmail_quote_container"><blockquo=
te class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px =
solid rgb(204,204,204);padding-left:1ex">at the *actual size* of the relati=
on and takes that into account when<br>
scaling the statistics (see table_block_relation_estimate_size() in<br>
tableam.c). If the table sizes don&#39;t match between the two servers<br>
then there&#39;s no guarantees the planner will produce the same plan.<br><=
/blockquote><div><br></div><div>Sorry that I didn&#39;t see this thread unt=
il now. I would like to note that table_block_relation_estimate_size() dete=
rmines the actual size of the relation by asking pg_class, and the relevant=
 values there are set by pg_restore_relation_stats().</div><div><br></div><=
/div></div>

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