| From: | Andy Fan <zhihui(dot)fan1213(at)gmail(dot)com> |
|---|---|
| To: | PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org> |
| Subject: | [PATCH] Erase the distinctClause if the result is unique by definition |
| Date: | 2020-01-31 12:39:37 |
| Message-ID: | CAKU4AWqZvSyxroHkbpiHSCEAY2C41dG7VWs=c188KKznSK_2Zg@mail.gmail.com |
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| Thread: | |
| Lists: | pgsql-hackers |
Hi:
I wrote a patch to erase the distinctClause if the result is unique by
definition, I find this because a user switch this code from oracle
to PG and find the performance is bad due to this, so I adapt pg for
this as well.
This patch doesn't work for a well-written SQL, but some drawback
of a SQL may be not very obvious, since the cost of checking is pretty
low as well, so I think it would be ok to add..
Please see the patch for details.
Thank you.
| Attachment | Content-Type | Size |
|---|---|---|
| 0001-Erase-the-distinctClause-if-the-result-is-unique-by-.patch | application/octet-stream | 23.3 KB |
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