Re: pg_dump after transaction id wraparound failure

On Mon, May 15, 2006 at 11:44:01AM -0700, Michael L. Boscia wrote:
> Hello-
>
> I currently have a 1.4 TB database (pg version 7.4.8) that is experiencing
> transaction id wraparound.  I plan to pg_dump the database and initdb and
> reload.  I may reload into an 8.1 database at this time.
>
> I am curious how to make sure that I indeed get all the data out of the
> tables from a pg_dump.  I want to ensure that there would not be anything
> "hidden" by the transaction id wraparound failure.

pg_dump obviously won't see anything that's hidden by wraparound
failure.

Vacuum will make anything that disappeared by wraparound in the last
billion transactions reappear, so a databasewide vacuum should solve
all your problems, no need to dump...

> My current plan is selectively dump a portion of the data (most current,
> organized in tables by date ex xxx_2006_may) and reload.  I plan to vaccuum
> each table before dumping.  Please warn me if this is not enough.  Any
> assistance is greatly appreciated.

I'd say do the vacuum first, dumping the data isn't really helping much
in this case I think (although for backups it's obviously important).

Have a nice day,
--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> From each according to his ability. To each according to his ability to litigate.