Re: Avoid Wraparound Failures

On Fri, 2022-03-25 at 23:45 -0500, Ron wrote:
> > If you want to prevent that autovacuum run from happening while your system is
> > busy (which normally also is no problem), you can trigger a manual VACUUM at
> > a time of lower database activity.  But make it a plain VACUUM, not a
> > VACUUM (FREEZE)
> 
> Why not VACUUM FREEZE?

Because then you freeze *all* visible rows, not only those that are older than
"vacuum_freeze_min_age".  That will cause more pages to get dirtied, so there will
be more writing I/O.  And unless all these rows won't get modified in the forseeable
future, that is a waste.  "vacuum_freeze_min_age" is there for a reason: the
expectation is that rows that have not been modified for 50 million transactions
have better odds at not getting modified soon.

Yours,
Laurenz Albe
-- 
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