Re: Concurrent VACUUM and ANALYZE - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Concurrent VACUUM and ANALYZE
Date
Msg-id 19487.1216684741@sss.pgh.pa.us
Whole thread Raw
In response to Concurrent VACUUM and ANALYZE  ("Jonah H. Harris" <jonah.harris@gmail.com>)
Responses Re: Concurrent VACUUM and ANALYZE
List pgsql-hackers
"Jonah H. Harris" <jonah.harris@gmail.com> writes:
> Because we wouldn't want multiple ANALYZEs running on the same table,
> changing the lock back to an AccessShareLock doesn't sound like a
> solution.

It flat will not work.  We used to do it that way, and it didn't
(search for "tuple concurrently updated" in the archives).

> However, what are the thoughts around creating another,
> more-specific lock?  Perhaps something like ShareUpdateAnalysisLock?

The general overhead involved in a whole new lock type is high enough
that I would resist taking this path.  (It's certainly a lot more than
adding an entry to one enum someplace --- offhand I can name docs and
grammar as important issues.  And no you don't get to have a hidden lock
type that no one can see.)


Also, as Alvaro points out, it's far from clear that concurrent VACUUM
and ANALYZE is as safe as you think --- they both want to write the same
fields in pg_class.
        regards, tom lane


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