Tom Lane wrote:
"Matthew T. O'Connor" <matthew@zeut.net> writes:
The current implementation of XID wraparound requires that the vacuum
command be run against the entire database, you can not run it on a per
table basis and have it work. At least that is my understanding,
No, you're wrong. VACUUMing of individual tables is perfectly good
enough as far as XID wrap protection goes, it's just that we chose to
track whether it had been done at the database level. If we tracked it
in, say, a new pg_class column then in principle you could protect
against XID wrap with only table-at-a-time VACUUMs. (I think you'd
still want the pg_database column, but you'd update it to be the minimum
of the per-table values at the completion of any VACUUM.)
At the time this didn't seem particularly worth the complication since
no one would be likely to try to do that manually --- but with
autovacuum handling the work, it starts to sound more realistic.
Good, I'm glad I'm wrong on this. This will be another nice advantage
of autovacuum then and should be fairly easy to do. Any thoughts on
this being a change we can get in for 8.1?
Matt
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