Re: pg_migrator progress - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: pg_migrator progress
Date
Msg-id 200903280155.n2S1tnq04102@momjian.us
Whole thread Raw
In response to Re: pg_migrator progress  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: pg_migrator progress  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Tom Lane wrote:
> Gregory Stark <stark@enterprisedb.com> writes:
> > Tom Lane <tgl@sss.pgh.pa.us> writes:
> >> No, but this would just be the same situation that prevails after
> >> OID-counter wraparound, so I don't see a compelling need for us to
> >> change the OID counter in the new DB.  If the user has done the Proper
> >> Things (ie, made unique indexes on his OIDs) then it won't matter.
> >> If he didn't, his old DB was a time bomb anyway.
> 
> > Also I wonder about the performance of skipping over thousands or even
> > millions of OIDs for something like a toast table.
> 
> I think that argument is a red herring.  In the first place, it's
> unlikely that there'd be a huge run of consecutive OIDs *in the same
> table*.  In the second place, if he does have such runs, the claim that
> he can't possibly have dealt with OID wraparound before seems pretty
> untenable --- he's obviously been eating lots of OIDs.
> 
> But having said that, there isn't any real harm in fixing the OID
> counter to match what it was.  You need to run pg_resetxlog to set the
> WAL position and XID counter anyway, and it can set the OID counter too.

FYI, I decided against restoring the oid counter because it might
collide with an oid assigned during pg_migrator schema creation.

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
 + If your life is a hard drive, Christ can be your backup. +


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