Re: How to lose transaction history (xmin values, WAL, etc.)?

Excerpts from Richard Walker's message of jue may 20 02:19:17 -0400 2010:

> (a) (ii) It seems a breach is possible via the xmin values.
> In that case, what about doing updates inside a transaction
> that does a trivial update of all rows, e.g.:
>    begin transaction;
>    update mytable ....; -- change one row
>    update mytable set id=id; -- change all rows
>    commit;
> So now all rows have the same xmin values.
> Does this work?  Performance is not so good, is it?
> Is there a better way?

The easiest way to do this is probably VACUUM FREEZE.

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