Re: [GENERAL] large object does not exist after pg_migrator

Bruce Momjian wrote:
> Alvaro Herrera wrote:
> > Bruce Momjian wrote:
> > > Jamie Fox wrote:
> > 
> > > > I can also see that the pg_largeobject table is different, in the pg_restore
> > > > version the Rows (estimated) is 316286 and Rows (counted) is the same, in
> > > > the pg_migrator version the Rows (counted) is only 180507.
> > 
> > > Wow, I didn't test large objects specifically, and I am confused why
> > > there would be a count discrepancy. I will need to do some research
> > > unless someone else can guess about the cause.
> > 
> > Maybe pg_largeobject is not getting frozen?
> 
> That would explain the change in count, but I thought we froze
> _everything_, and had to.

After a quick chat with Bruce it was determined that we don't freeze
anything (it would be horrid for downtime if we did so in pg_migrator;
and it would be useless if ran anywhere else).  What we do is migrate
pg_clog from the old cluster to the new.  So never mind that hypothesis.

Bruce noticed that the pg_dump/pg_migrator combo is failing to restore
pg_largeobject's relfrozenxid.  We're not sure how this is causing the
errors Jamie is seeing, because what I think should happen is that scans
of the table should fail with failures to open pg_clog files
such-and-such, but not missing tuples ...

-- 
Alvaro Herrera                                http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.