Re: Autovacuum loose ends

From: Tom Lane
Subject: Re: Autovacuum loose ends
Date: ,
Msg-id: 25124.1121575395@sss.pgh.pa.us
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In response to: Re: Autovacuum loose ends  (Ron Mayer)
List: pgsql-hackers

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Autovacuum loose ends  (Tom Lane, )
 Re: Autovacuum loose ends  ("Matthew T. O'Connor", )
  Re: Autovacuum loose ends  (Tom Lane, )
   Re: Autovacuum loose ends  ("Matthew T. O'Connor", )
   Re: Autovacuum loose ends  (Greg Stark, )
   Re: Autovacuum loose ends  (Hannu Krosing, )
   Re: Autovacuum loose ends  (Ron Mayer, )
    Re: Autovacuum loose ends  (Tom Lane, )
 Re: Autovacuum loose ends  (Alvaro Herrera <-ip.org>, )
  Re: Autovacuum loose ends  (Tom Lane, )
  Re: Autovacuum loose ends  (Tom Lane, )
 Re: Autovacuum loose ends  (Alvaro Herrera <-ip.org>, )
  Re: Autovacuum loose ends  (Tom Lane, )
   Re: Autovacuum loose ends  (Alvaro Herrera <-ip.org>, )

Ron Mayer <> writes:
> Tom Lane wrote:
>> ISTM the point of the delay parameters
>> for autovac is to put a lid on its impact on interactive response.  Seen
>> in that light, you do not care exactly which table it's hitting at the
>> moment.

> Unless the table in question takes a big lock when it's VACUUMed
> like tables with GiST indexes do today.

Well, the issue there is not at the table level, but only while the
individual index is being cleaned.

I suggested a few days ago that we ought not do vacuum delays at all
while processing an index that needs an exclusive lock (this no longer
includes gist, but rtree and to a lesser extent hash still have issues).

If you don't like that, I think you'd pretty much have to invent autovac
delays that are tunable on a *per index* basis, not per table.  That
seems a bit over the top to me; it'd be a nontrivial amount of work to
implement, and there's no evidence that it's better than just removing
the vacuum_delay_point calls in rtree and hash.
        regards, tom lane



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