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

Merlin Moncure <mmoncure@gmail.com>

From: Merlin Moncure <mmoncure@gmail.com>

To: Jeff Janes <jeff.janes@gmail.com>

Cc: Sergey Koposov <koposov@ast.cam.ac.uk>, Robert Haas <robertmhaas@gmail.com>, pgsql-hackers@postgresql.org, Stephen Frost <sfrost@snowman.net>

Date: 2012-05-30T20:19:20Z

Lists: pgsql-hackers

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Improve bulk-insert performance by keeping the current target buffer pinned
- 85e2cedf985b 8.4.0 cited

On Wed, May 30, 2012 at 3:15 PM, Jeff Janes <jeff.janes@gmail.com> wrote:
> On Wed, May 30, 2012 at 11:45 AM, Sergey Koposov <koposov@ast.cam.ac.uk> wrote:
>> On Wed, 30 May 2012, Merlin Moncure wrote:
>>>
>>>
>>> Hm, why aren't we getting a IOS?  Just for kicks (assuming this is
>>> test data), can we drop the index on just transitid, leaving the index
>>> on transitid, healpixid?    Is enable_indexonlyscan on?  Has idt_match
>>> been vacuumed?  What kind of plan do you get when do:
>>
>>
>> Okay dropping the index on transitid solved the issue with indexonlyscan but
>> didn't solve the original problem. Actually the indexonlyscan made the
>> sequential queries faster but not the parallel ones.
>
> How big is idt_match?  What if you drop all indexes on idt_match,
> encouraging all the backends to do hash joins against it, which occur
> in local memory and so don't have contention?

You just missed his post -- it's only 3G.   can you run your 'small'
working set against 48gb shared buffers?

merlin