Re: erroneous restore into pg_catalog schema

On 2013-05-13 13:40:57 -0400, Tom Lane wrote:
> Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> > On Mon, May 13, 2013 at 1:03 PM, Andres Freund <andres(at)2ndquadrant(dot)com> wrote:
> >> Why don't we just prohibit deletion/modification for anything below
> >> FirstNormalObjectId instead of using the schema as a restriction? Then
> >> we can allow creation for tables as well.
>
> > We currently do, but that led to problems with $SUBJECT.

> AFAIR there are no code restrictions based on OID value. We've got
> restrictions based on things being in pg_catalog or not, and we've got
> restrictions based on things being marked pinned in pg_depend.

> Looking at the OID range might be a reasonable proxy for pinned-ness,
> though, and it would certainly be a lot cheaper than a lookup in
> pg_depend.

It might need a slight change in GetNewObjectId() though:
if (IsPostmasterEnvironment)
{
/* wraparound in normal environment */
ShmemVariableCache->nextOid = FirstNormalObjectId;
ShmemVariableCache->oidCount = 0;
}
else
{
/* we may be bootstrapping, so don't enforce the full range */
if (ShmemVariableCache->nextOid < ((Oid) FirstBootstrapObjectId))
{
/* wraparound in standalone environment? */
ShmemVariableCache->nextOid = FirstBootstrapObjectId;
ShmemVariableCache->oidCount = 0;
}
}

I think we shouldn't check IsPostmasterEnvironment here but instead
IsBootstrapProcessingMode() since we otherwise can generate oids below
FirstNormalObjectId in --single mode. Imo that should be fixed
independently though, given the comment it looks like either an
oversight or the check predating the existance of
IsBootstrapProcessingMode().

Greetings,

Andres Freund

--
Andres Freund http://www.2ndQuadrant.com/
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