Re: totally different plan when using partitions

Scara Maccai wrote:

> explain analyze
> select nome1,
> thv3tralacc,
> dltbfpgpdch
> FROM cell_bsc_60_0610 as cell_bsc
> left outer join teststscell73_0610_1 as data on data.ne_id=cell_bsc.nome1
> left outer join teststscell13_0610_1 as data1 on data1.ne_id=cell_bsc.nome1 and data1.time=data.time
> where
>
> data.time >=cell_bsc.starttime and data.time <=cell_bsc.endtime and
> data.time between '2006-10-01 00:00:00' and '2006-10-06 00:00:00'
> and data1.time >=cell_bsc.starttime and data1.time <=cell_bsc.endtime
> and data1.time between '2006-10-01 00:00:00' and '2006-10-06 00:00:00'
> and cell_bsc.nome2=2
>
> explain analyze:
>
> http://explain-analyze.info/query_plans/3805-query-plan-2509
>
>
> same query, but using postgresql's partition pruning ("2"):
>
> explain analyze
> select nome1,
> thv3tralacc,
> dltbfpgpdch
> FROM cell_bsc_60_0610 as cell_bsc
> left outer join teststscell73 as data on data.ne_id=cell_bsc.nome1
> left outer join teststscell13 as data1 on data1.ne_id=cell_bsc.nome1 and data1.time=data.time
> where
>
> data.time >=cell_bsc.starttime and data.time <=cell_bsc.endtime and
> data.time between '2006-10-01 00:00:00' and '2006-10-06 00:00:00'
> and data1.time >=cell_bsc.starttime and data1.time <=cell_bsc.endtime
> and data1.time between '2006-10-01 00:00:00' and '2006-10-06 00:00:00'
> and cell_bsc.nome2=2

Huh, clearly not the same query (you're using the partition directly in
the first query) ... Doing two changes at once is not helping your
case.

--
Alvaro Herrera http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support