[prev in list] [next in list] [prev in thread] [next in thread] 

List:       postgresql-general
Subject:    =?UTF-8?Q?Re:_Refresh_Publication_takes_hours_and_doesn=c2=b4t_fini?= =?UTF-8?Q?sh?=
From:       Peter Eisentraut <peter.eisentraut () 2ndquadrant ! com>
Date:       2019-05-23 13:08:37
Message-ID: 9285a255-3cf9-4bad-6e87-8668f179afa2 () 2ndquadrant ! com
[Download RAW message or body]

On 2019-05-20 23:30, Tom Lane wrote:
> Hmm ... given that pg_get_publication_tables() shouldn't return any
> duplicate OIDs, it does seem unnecessarily inefficient to put it in
> an IN-subselect condition.  Peter, is there a reason why this isn't
> a straight lateral join?  I get a much saner-looking plan from
> 
>     FROM pg_publication P, pg_class C
> -        JOIN pg_namespace N ON (N.oid = C.relnamespace)
> -   WHERE C.oid IN (SELECT relid FROM pg_get_publication_tables(P.pubname));
> +        JOIN pg_namespace N ON (N.oid = C.relnamespace),
> +        LATERAL pg_get_publication_tables(P.pubname)
> +   WHERE C.oid = pg_get_publication_tables.relid;

No reason I think, just didn't quite manage to recognize the possibility
of using LATERAL at the time.

-- 
Peter Eisentraut              http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services


[prev in list] [next in list] [prev in thread] [next in thread]