Re: pg_group_name_index corrupt? - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: pg_group_name_index corrupt?
Date
Msg-id 200005050455.AAA11416@candle.pha.pa.us
Whole thread Raw
In response to Re: pg_group_name_index corrupt?  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: pg_group_name_index corrupt?  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
> > "Hiroshi Inoue" <Inoue@tpf.co.jp> writes:
> >> Why does pg_group exist under $PGDATA though the indexes exist
> >> under each $PGDATA/base/db_name ?
> >> Could it be consistent on all databases ?
> 
> > Oh my, I think you've got it!  The indexes must be SharedSystemRelations!!
> 
> Yup, Hiroshi has spotted the problem.  Turning the indexes on pg_group
> into shared relations fixes the cross-database misbehavior shown in my
> prior message, and I'll bet this bug explains Marc's report too.
> 
> We never had any indexes on pg_group (or any shared relation) before,
> which is why we hadn't seen this kind of failure before.  (Another
> limitation of the regression tests exposed --- they don't test
> cross-database behaviors.)

Oh, so it was my indexes on system relations, and because pg_group is a
shared one, there was a problem.

> So, now what?  This is a simple fix, but it will require initdb (or at
> least pg_upgrade), which I'd really rather not do at this point in the
> release cycle.  But I'm not sure we have any choice.  As it stands,
> pg_group is broken.
> 
> If we are going to have to force a new initdb here, we probably ought
> to reconsider a couple of recent past decisions that were put off on
> grounds of "we don't want another initdb before 7.0".  I'm thinking of
> the remaining ODBC support functions and the new LIKE estimator in
> particular.  Do we want to revisit those decisions, or leave well enough
> alone?

Well, pg_group is not used very much.  Can we disable the cache from
using the index?  I think that would get us out of the problem.

--  Bruce Momjian                        |  http://www.op.net/~candle pgman@candle.pha.pa.us               |  (610)
853-3000+  If your life is a hard drive,     |  830 Blythe Avenue +  Christ can be your backup.        |  Drexel Hill,
Pennsylvania19026
 


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