Re: Performance Issue on Query 18 of TPC-H Benchmark
| От | Ba Jinsheng |
|---|---|
| Тема | Re: Performance Issue on Query 18 of TPC-H Benchmark |
| Дата | |
| Msg-id | SEZPR06MB6494FDE43CEBAAEEEB732C918A462@SEZPR06MB6494.apcprd06.prod.outlook.com обсуждение исходный текст |
| Ответ на | Re: Performance Issue on Query 18 of TPC-H Benchmark (Alena Rybakina <a.rybakina@postgrespro.ru>) |
| Ответы |
Re: Performance Issue on Query 18 of TPC-H Benchmark
Re: Performance Issue on Query 18 of TPC-H Benchmark |
| Список | pgsql-bugs |
>I believe you are not allowing the optimizer to generate a different aggregation path (Group Aggregate) because it requires a sort operation. So I think this is not correct.
Yes, this is what I did. I though it is what you were asking? I have not found another way to enforce HashAggregate, so I directly modified the code. Can you eliberate why it is incorrect?
>You may notice that disabling parallelism results in improved cardinality estimation and therefore a better query plan, since the optimizer selects paths based on their cost. If parallelism is disabled, query plan have become more correct.
Can I understand disabling parallelism is a good setup for finding performance issues?
Best regards,
Jinsheng Ba
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