Re: Is it safe to reset relfrozenxid without using vacuum? - Mailing list pgsql-admin

From Tom Lane
Subject Re: Is it safe to reset relfrozenxid without using vacuum?
Date
Msg-id 22056.1227031636@sss.pgh.pa.us
Whole thread Raw
In response to Re: Is it safe to reset relfrozenxid without using vacuum?  (Alvaro Herrera <alvherre@commandprompt.com>)
Responses Re: Is it safe to reset relfrozenxid without using vacuum?
List pgsql-admin
Alvaro Herrera <alvherre@commandprompt.com> writes:
> AFAICS this should be safe.  In fact, in 8.3 TRUNCATE advances
> relfrozenxid.  (Perhaps you should consider upgrading if possible.)
> ...
> Tou could just obtain the xid of the transaction that's going to do the
> import (for example by creating a temp table and getting it's xmin from
> pg_class)

That seems a bit risky.  8.3 resets relfrozenxid to RecentXmin, not the
current transaction's XID.  The OP's thought of taking the max existing
relfrozenxid should be safe though.

Or I guess you could make a temp table and take the relfrozenxid, rather
than the xmin, from its pg_class entry.

            regards, tom lane

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