Alvaro Herrera <[EMAIL PROTECTED]> writes:
> Tom Lane wrote:
>> A possible objection to this is that it would foreclose running VACUUM
>> and ANALYZE as a single transaction, exactly because of the point that
>> we couldn't insert pg_statistic rows using a lazy vacuum's XID.

> Hmm, what about having a single scan for both, and then starting a
> normal transaction just for the sake of inserting the pg_statistics
> tuple?

We could, but I think memory consumption would be the issue.  VACUUM
wants a lotta memory for the dead-TIDs array, ANALYZE wants a lot for
its statistics gathering ... even more if it's trying to take a larger
sample than before.  (This is probably why we kept them separate in
the last rewrite.)

> I think the interactions of Xids and vacuum and other stuff are starting
> to get complex; IMHO it warrants having a README.vacuum, or something.

Go for it ...

                        regards, tom lane

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