Horton

Re: 9.2beta1, parallel queries, ReleasePredicateLocks, CheckForSerializableConflictIn in the oprofile

Stephen Frost <sfrost@snowman.net>

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From: Stephen Frost <sfrost@snowman.net>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Sergey Koposov <koposov@ast.cam.ac.uk>, Jeff Janes <jeff.janes@gmail.com>, Florian Pflug <fgp@phlo.org>, Merlin Moncure <mmoncure@gmail.com>, pgsql-hackers@postgresql.org
Date: 2012-05-31T02:00:23Z
Lists: pgsql-hackers

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Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Improve bulk-insert performance by keeping the current target buffer pinned

Robert,

* Robert Haas (robertmhaas@gmail.com) wrote:
> On Wed, May 30, 2012 at 9:10 PM, Sergey Koposov <koposov@ast.cam.ac.uk> wrote:
> > I understand the need of significant locking when there concurrent writes,
> > but not when there only reads. But I'm not a RDBMS expert, so that's maybe
> > that's misunderstanding on my side.
> 
> If we knew in advance that no writes would come along during the
> execution of a particular test case, then we could skip a lot of
> locking on the reads.  But we don't, so we have to be prepared for the
> possibility of writes at any time, which means doing things taking
> share-locks on data while it's actively being read.

Uh, we have a read-only transaction mode, don't we?  Or does that not
help, because someone else, in another transaction, could take a
read-write lock?

	Thanks,

		Stephen