Re: Partition-wise join for join between (declaratively) partitioned tables

Rafia Sabih wrote:

> On completing the benchmark for all queries for the above mentioned
> setup, following performance improvement can be seen,
> Query | Patch | Head
> 3 | 1455 | 1631
> 4 | 499 | 4344
> 5 | 1464 | 1606
> 10 | 1475 | 1599
> 12 | 1465 | 1790
>
> Note that all values of execution time are in seconds.
> To summarise, apart from Q4, all other queries are showing somewhat
> 10-20% improvement.

Saving 90% of time on the slowest query looks like a worthy improvement
on its own right. However, you're reporting execution time only, right?
What happens to planning time? In a quick look,

$ grep 'Planning time' pg_part_*/4*
pg_part_head/4_1.out: Planning time: 3390.699 ms
pg_part_head/4_2.out: Planning time: 194.211 ms
pg_part_head/4_3.out: Planning time: 210.964 ms
pg_part_head/4_4.out: Planning time: 4150.647 ms
pg_part_patch/4_1.out: Planning time: 7577.247 ms
pg_part_patch/4_2.out: Planning time: 312.421 ms
pg_part_patch/4_3.out: Planning time: 304.697 ms
pg_part_patch/4_4.out: Planning time: 269.778 ms

I think the noise in these few results is too large to draw any
conclusions. Maybe a few dozen runs of EXPLAIN (w/o ANALYZE) would tell
something significant?

--
Álvaro Herrera https://www.2ndQuadrant.com/
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