Re: postgres_fdw: using TABLESAMPLE to collect remote sample - Mailing list pgsql-hackers

From Tomas Vondra
Subject Re: postgres_fdw: using TABLESAMPLE to collect remote sample
Date
Msg-id d13d28b9-30d0-27e8-d58e-d3e0c76b3bda@enterprisedb.com
Whole thread Raw
In response to Re: postgres_fdw: using TABLESAMPLE to collect remote sample  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: postgres_fdw: using TABLESAMPLE to collect remote sample
List pgsql-hackers
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
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company



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