Re: Add check constraint bug - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: Add check constraint bug
Date
Msg-id 200209060044.g860i5h28529@candle.pha.pa.us
Whole thread Raw
In response to Re: Add check constraint bug  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: Add check constraint bug
List pgsql-hackers
Is there a TODO here?

---------------------------------------------------------------------------

Tom Lane wrote:
> Peter Eisentraut <peter_e@gmx.net> writes:
> > The following happens in latest CVS and a fresh database:
> > create table test (a int);
> > insert into test values (1);
> > alter table test add column b text check (b <> '');
> 
> This bug's been there awhile I fear.  The failure occurs when
> AlterTableAddColumn needs to add a check constraint AND the
> new column causes AlterTableCreateToastTable to do its thing.
> 
> The reason there is a bug is that AlterTableCreateToastTable
> gratuitously does a heap_mark4update, thereby selecting the un-updated
> version of the pg_class tuple as its basis for modification (and
> ignoring the HeapTupleSelfUpdated return code that warned that there
> was a problem).
> 
> I've said before that I do not like heap_mark4update in catalog
> manipulations, and here's a perfect example of why it's a bad idea.
> 
>             regards, tom lane
> 
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--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
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