Re: Partition-wise aggregation/grouping - Mailing list pgsql-hackers

From Jeevan Chalke
Subject Re: Partition-wise aggregation/grouping
Date
Msg-id CAM2+6=XLbADYS8msY9gxwQPe6ZYh5K-sWdWBtGUvqW2kQ8oW+A@mail.gmail.com
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In response to Re: Partition-wise aggregation/grouping  (legrand legrand <legrand_legrand@hotmail.com>)
Responses Re: Partition-wise aggregation/grouping
List pgsql-hackers


On Fri, Dec 8, 2017 at 3:08 AM, legrand legrand <legrand_legrand@hotmail.com> wrote:
Hello,

I'm testing Partition wise and found a strange result in V8 patch
see  init_star_schema_agg.sql
<http://www.postgresql-archive.org/file/t348768/init_star_schema_agg.sql>

Explain gives
  ->  Seq Scan on facts_p2  (...) (actual time=0.012..0.012 rows=1 loops=1)
for partitions that are joined with empty partitions

I was expecting a message saying that partition facts_p2 was not accessed

Am I wrong ?

Is this related to partition-wise aggregation as you saying you found this behaviour on v8 patch?

I have tried your testcase on master and see similar plan.

I had a look over the plan and I did not see any empty relation at the planning time.
 
Regards
PAscal



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