Re: [PERFORM] pg_dump and thousands of schemas - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: [PERFORM] pg_dump and thousands of schemas
Date
Msg-id 20120531150054.GF26894@momjian.us
Whole thread Raw
In response to Re: [PERFORM] pg_dump and thousands of schemas  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
On Thu, May 31, 2012 at 10:50:51AM -0400, Tom Lane wrote:
> Robert Haas <robertmhaas@gmail.com> writes:
> > On Thu, May 31, 2012 at 10:31 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> >> I'm not; Jeff Janes is. �But you shouldn't be holding your breath
> >> anyway, since it's 9.3 material at this point.
>
> > I agree we can't back-patch that change, but then I think we ought to
> > consider back-patching some variant of Tatsuo's patch.  Maybe it's not
> > reasonable to thunk an arbitrary number of relation names in there on
> > one line, but how about 1000 relations per LOCK statement or so?  I
> > guess we'd need to see how much that erodes the benefit, but we've
> > certainly done back-branch rearrangements in pg_dump in the past to
> > fix various kinds of issues, and this is pretty non-invasive.
>
> I am not convinced either that this patch will still be useful after
> Jeff's fix goes in, or that it provides any meaningful savings when
> you consider a complete pg_dump run.  Yeah, it will make the lock
> acquisition phase faster, but that's not a big part of the runtime
> except in very limited scenarios (--schema-only, perhaps).

FYI, that is the pg_upgrade use-case, and pg_dump/restore time is
reportedly taking the majority of time in many cases.

--
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + It's impossible for everything to be true. +

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