| From: | "James Pang (chaolpan)" <chaolpan(at)cisco(dot)com> |
|---|---|
| To: | "pgsql-performance(at)lists(dot)postgresql(dot)org" <pgsql-performance(at)lists(dot)postgresql(dot)org> |
| Subject: | extended statistics n-distinct on multiple columns not used when join two tables |
| Date: | 2023-06-13 09:21:25 |
| Message-ID: | PH0PR11MB519189611860A0F7FDE53509D655A@PH0PR11MB5191.namprd11.prod.outlook.com |
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| Lists: | pgsql-hackers pgsql-performance |
Hi,
When join two table on multiple columns equaljoin, rows estimation always use selectivity = multiplied by distinct multiple individual columns, possible to use extended n-distinct statistics on multiple columns?
PG v14.8-1, attached please check test case with details.
Thanks,
James
| Attachment | Content-Type | Size |
|---|---|---|
| test_join_selectivity_rows_estimation_join.txt | text/plain | 6.3 KB |
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