From: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
To: Andres Freund <andres@anarazel.de>
Cc: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Michael Paquier <michael@paquier.xyz>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Subject: Re: ALTER TABLE on system catalogs
Date: Fri, 28 Sep 2018 22:58:36 +0200
Message-ID: <61666008-d1cd-7a66-33c8-215449f5d1b0@2ndquadrant.com> (raw)
In-Reply-To: <20180821152444.4reji5otfekmvtoc@alap3.anarazel.de>
References: <20180627203733.bfpibxdleimvwdg2@alap3.anarazel.de>
<20180627230838.GI2667@paquier.xyz>
<9fb22a98-fd64-1426-a4f4-b927ce1a9a5e@2ndquadrant.com>
<920b7cde-6926-4ad3-936b-7637f0a8188f@2ndquadrant.com>
<20180820023749.GD7403@paquier.xyz>
<20180820104825.a7yryvlycwimgttf@alap3.anarazel.de>
<b49018c4-6592-eece-f5db-5978fda1f5df@2ndquadrant.com>
<20180820125022.kh37mj7sxtaxeize@alap3.anarazel.de>
<19365.1534772090@sss.pgh.pa.us>
<a33f9d7f-4afe-a351-3528-cc32b0603845@2ndquadrant.com>
<20180821152444.4reji5otfekmvtoc@alap3.anarazel.de>
On 21/08/2018 17:24, Andres Freund wrote:
>> Attached is a patch that instead moves those special cases into
>> needs_toast_table(), which was one of the options suggested by Andres.
>> There were already similar checks there, so I guess this makes a bit of
>> sense.
> The big difference is that that then only takes effect when called with
> check=true. The callers without it, importantly NewHeapCreateToastTable
> & NewRelationCreateToastTable, then won't run into this check. But still
> into the error (see below).
I don't follow. The call to needs_toast_table() is not conditional on
the check argument. The check argument only checks that the correct
lock level is passed in.
>> @@ -145,21 +146,6 @@ create_toast_table(Relation rel, Oid toastOid, Oid toastIndexOid,
>> ObjectAddress baseobject,
>> toastobject;
>>
>> - /*
>> - * Toast table is shared if and only if its parent is.
>> - *
>> - * We cannot allow toasting a shared relation after initdb (because
>> - * there's no way to mark it toasted in other databases' pg_class).
>> - */
>> - shared_relation = rel->rd_rel->relisshared;
>> - if (shared_relation && !IsBootstrapProcessingMode())
>> - ereport(ERROR,
>> - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
>> - errmsg("shared tables cannot be toasted after initdb")));
> This error check imo shouldn't be removed, but moved down.
We could keep it, but it would probably be dead code since
needs_toast_table() would return false for all shared tables anyway.
--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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To: pgsql-hackers@postgresql.org
Cc: peter.eisentraut@2ndquadrant.com, andres@anarazel.de, tgl@sss.pgh.pa.us, michael@paquier.xyz
Subject: Re: ALTER TABLE on system catalogs
In-Reply-To: <61666008-d1cd-7a66-33c8-215449f5d1b0@2ndquadrant.com>
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