Re: erroneous restore into pg_catalog schema

On 2013-05-13 13:40:57 -0400, Tom Lane wrote:
> Robert Haas <robertmhaas@gmail.com> writes:
> > On Mon, May 13, 2013 at 1:03 PM, Andres Freund <andres@2ndquadrant.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/
 PostgreSQL Development, 24x7 Support, Training & Services