Re: pg_migrator progress - Mailing list pgsql-hackers

From Tom Lane
Subject Re: pg_migrator progress
Date
Msg-id 7261.1234972045@sss.pgh.pa.us
Whole thread Raw
In response to Re: pg_migrator progress  (Gregory Stark <stark@enterprisedb.com>)
Responses Re: pg_migrator progress  (Gregory Stark <stark@enterprisedb.com>)
Re: pg_migrator progress  (Robert Treat <xzilla@users.sourceforge.net>)
Re: pg_migrator progress  (Bruce Momjian <bruce@momjian.us>)
List pgsql-hackers
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.
        regards, tom lane


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