From: Tom Lane <tgl@sss.pgh.pa.us>
To: Mark Dilger <hornschnorter@gmail.com>
cc: pgsql-hackers@lists.postgresql.org,
        Tomas Vondra <tomas.vondra@2ndquadrant.com>
Subject: Re: Missing dependency tracking for TableFunc nodes
In-reply-to: <997cbcae-7739-f871-84a0-1192380abb54@gmail.com>
References: <18427.1573508501@sss.pgh.pa.us>
 <997cbcae-7739-f871-84a0-1192380abb54@gmail.com>
Comments: In-reply-to Mark Dilger <hornschnorter@gmail.com>
	message dated "Wed, 13 Nov 2019 15:00:03 -0800"
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Date: Wed, 13 Nov 2019 20:37:59 -0500
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Mark Dilger <hornschnorter@gmail.com> writes:
> On 11/11/19 1:41 PM, Tom Lane wrote:
>> I happened to notice that find_expr_references_walker has not
>> been taught anything about TableFunc nodes, which means it will
>> miss the type and collation OIDs embedded in such a node.

> I can consistently generate errors like the following in master:
>    ERROR:  cache lookup failed for statistics object 31041

This is surely a completely different issue --- there are not,
one hopes, any extended-stats OIDs embedded in views or other
query trees.

I concur with Tomas' suspicion that this must be a race condition
during DROP STATISTICS.  If we're going to allow people to do that
separately from dropping the table(s), there has to be some kind of
locking around it, and it sounds like there's not :-(

			regards, tom lane