Thanks much for responding guys. I have tried both, building multi column indexes and GIST, with no improvement. I have reduced the window from 180 days to 30 days and below are the numbers
Composite index - takes 30 secs
With Btree indexing - takes 9 secs
With GIST - takes >30 secs with kind of materialize plan in explain
Any other ideas I can do for window based joins.
--yr
On Fri, Jul 31, 2015 at 11:37 AM, Qingqing Zhou <zhouqq.postgres@xxxxxxxxx> wrote:
On Fri, Jul 31, 2015 at 10:55 AM, Ram N <yramiyer@xxxxxxxxx> 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
