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

On Thu, May 24, 2012 at 4:46 PM, Merlin Moncure <mmoncure@gmail.com> wrote:
> Wait -- OP's gripe this isn't regarding standard pgbench, but multiple
> large concurrent 'insert into foo select...'.  I looked in the code
> and it appears that the only bulk insert strategy using operations are
> copy, create table as select, and table rewrite operations. Concurrent
> INSERT SELECT apparently doesn't get the benefit of a strategy and
> should be fighting over the freelist once the pool exhausts.

I think you are right.

> We don't get to skip wal of course, but we should be able to use a
> bulk insert strategy, especially if there was some way of predicting
> that a large number of tuples were going to be inserted.  I'm
> wondering though of contention on the free list is in fact the OP's
> problem.

Not sure.  It might be some other LWLock, but it's hard to tell which
one from the information provided.

--
Robert Haas
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