Date: Tue, 6 Apr 2021 16:56:49 -0400
From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Tomas Vondra <tomas.vondra@enterprisedb.com>
Cc: yuzuko <yuzukohosoya@gmail.com>, David Steele <david@pgmasters.net>,
	Kyotaro Horiguchi <horikyota.ntt@gmail.com>,
	Justin Pryzby <pryzby@telsasoft.com>,
	Daniel Gustafsson <daniel@yesql.se>,
	Amit Langote <amitlangote09@gmail.com>,
	Masahiko Sawada <masahiko.sawada@2ndquadrant.com>,
	Laurenz Albe <laurenz.albe@cybertec.at>,
	PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>,
	Greg Stark <stark@mit.edu>
Subject: Re: Autovacuum on partitioned table (autoanalyze)
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On 2021-Apr-04, Tomas Vondra wrote:

> 1) I still don't understand why inheritance and declarative partitioning
> are treated differently. Seems unnecessary nad surprising, but maybe
> there's a good reason?

I think there is a good reason to treat them the same: pgstat does not
have a provision to keep stats both of the table with children, and the
table without children.  It can only have one of those.  For
partitioning that doesn't matter: since the table-without-children
doesn't have anything on its own (no scans, no tuples, no nothing) then
we can just use the entry to store the table-with-children data.  But
for the inheritance case, the parent can have its own tuples and counts
its own scans and so on; so if we change things, we'll overwrite the
stats.  Maybe in the long-term we should allow pgstat to differentiate
those cases, but that seems not in scope for this patch.

I'm working on the code to fix the other issues.

-- 
Álvaro Herrera                            39°49'30"S 73°17'W