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Date: Sun, 1 Jan 2023 23:36:49 +0100
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Subject: Re: postgres_fdw: using TABLESAMPLE to collect remote sample
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: James Finnerty <jfinnert@amazon.com>, pgsql-hackers@lists.postgresql.org
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From: Tomas Vondra <tomas.vondra@enterprisedb.com>
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On 12/31/22 18:23, Tom Lane wrote:
> Tomas Vondra <tomas.vondra@enterprisedb.com> writes:
>> On 12/31/22 05:42, Tom Lane wrote:
>>> ERROR:  TABLESAMPLE clause can only be applied to tables and materialized views
>>> I think the patch avoids that, but only accidentally, because
>>> reltuples will be 0 or -1 for a view.  Maybe it'd be a good
>>> idea to pull back relkind along with reltuples, and check
>>> that too?
> 
>> Not sure. I guess we can rely on reltuples being 0 or -1 in such cases,
>> but maybe it'd be good to at least mention that in a comment? We're not
>> going to use other reltuples values for views etc.
> 
> Would anyone ever point a foreign table at a sequence?  I guess it
> would be a weird use-case, but it's possible, or was till now.
> 

Yeah, it's a weird use case. I can't quite imagine why would anyone do
that, but I guess the mere possibility is sufficient reason to add the
relkind check ...


regards

-- 
Tomas Vondra
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