| From: | Jeff Janes <jeff(dot)janes(at)gmail(dot)com> |
|---|---|
| To: | Sergey Koposov <koposov(at)ast(dot)cam(dot)ac(dot)uk> |
| Cc: | Merlin Moncure <mmoncure(at)gmail(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com>, pgsql-hackers(at)postgresql(dot)org, Stephen Frost <sfrost(at)snowman(dot)net> |
| Subject: | Re: 9.2beta1, parallel queries, ReleasePredicateLocks, CheckForSerializableConflictIn in the oprofile |
| Date: | 2012-05-30 20:15:14 |
| Message-ID: | CAMkU=1yBF=9TfJUc9kZfJogTvi8PEhQe3GfVzeQags4vdBLsRQ@mail.gmail.com |
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On Wed, May 30, 2012 at 11:45 AM, Sergey Koposov <koposov(at)ast(dot)cam(dot)ac(dot)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?
Cheers,
Jeff
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