Re: Performance issue with NestedLoop query - Mailing list pgsql-performance

From Qingqing Zhou
Subject Re: Performance issue with NestedLoop query
Date
Msg-id CAJjS0u3J44pJWptmd+Em2Ru8fe-qNMk0ysxwBXCeVka2Z3Rf3g@mail.gmail.com
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In response to Re: Performance issue with NestedLoop query  (Ram N <yramiyer@gmail.com>)
Responses Re: Performance issue with NestedLoop query
List pgsql-performance
On Fri, Jul 31, 2015 at 10:55 AM, Ram N <yramiyer@gmail.com> wrote:
>
> Thanks Qingqing for responding. That didn't help. It in fact increased the
> scan time. Looks like a lot of time is being spent on the NestedLoop Join
> than index lookups though I am not sure how to optimize the join.
>

Good news is that optimizer is right this time :-). The NLJ here does
almost nothing but schedule each outer row to probing the inner index.
So the index seek is the major cost.

Have you tried build a two column index on (b.start_date, b.end_date)?

Regards,
Qingqing


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