Re: Add important info about ANALYZE after create Functional Index

From: Fabrízio de Royes Mello <fabriziomello(at)gmail(dot)com>
To: Michael Paquier <michael(at)paquier(dot)xyz>
Cc: Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, "David G(dot) Johnston" <david(dot)g(dot)johnston(at)gmail(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>, Nikolay Samokhvalov <samokhvalov(at)gmail(dot)com>
Subject: Re: Add important info about ANALYZE after create Functional Index
Date: 2020-10-31 22:56:33
Message-ID: CAFcNs+pM5r+RrzksvLpG=rBRv4Lc==_6QrD4SQ0AfPq5t=EjTQ@mail.gmail.com
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On Fri, Oct 30, 2020 at 3:22 AM Michael Paquier <michael(at)paquier(dot)xyz> wrote:
>
> And in spirit, it is possible to address this issue with the patch
> attached which copies the set of stats from the old to the new index.

Did some tests and everything went ok... some comments below!

> For a non-concurrent REINDEX, this does not happen because we keep the
> same base relation, while we replace completely the relation with a
> concurrent operation.

Exactly!

> We have a RemoveStatistics() in heap.c, but I
> did not really see the point to invent a copy flavor for this
> particular case. Perhaps others have an opinion on that?
>

Even if we won't use it now, IMHO it is more legible to separate this
responsibility into its own CopyStatistics function as attached.

Regards,

--
Fabrízio de Royes Mello
PostgreSQL Developer at OnGres Inc. - https://ongres.com

Attachment Content-Type Size
reindex-stats-v2.patch text/x-patch 6.0 KB

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