Re: BUG #16303: A condtion whether an index-only scan is possibleincludes a wrong
От | David G. Johnston |
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Тема | Re: BUG #16303: A condtion whether an index-only scan is possibleincludes a wrong |
Дата | |
Msg-id | CAKFQuwaJYP75bMkRZfFqJZaYLQULC_kkLB_nYc2Y3p3oUPOGQg@mail.gmail.com обсуждение исходный текст |
Ответ на | Re: BUG #16303: A condtion whether an index-only scan is possibleincludes a wrong (Horimoto Yasuhiro <horimoto@clear-code.com>) |
Ответы |
Re: BUG #16303: A condtion whether an index-only scan is possibleincludes a wrong
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Список | pgsql-bugs |
On Sunday, March 15, 2020, Horimoto Yasuhiro <horimoto@clear-code.com> wrote:
I send a patch for this problem.!
From: PG Bug reporting form <noreply@postgresql.org>
Subject: BUG #16303: A condtion whether an index-only scan is possible includes a wrong
Date: Mon, 16 Mar 2020 06:02:25 +0000
> I think that the condition of whether an index-only scan is possible
> includes a wrong.
>
> For example, in the following case, the index has no data to return. Because
> the query doesn't use specify columns.
> However, the query planner choice index-only scan.
> In my opinion, we expected that the query planner doesn't choose an
> index-only scan in the above case.
>
I don't see a behavioral bug here. I would expect that any index would be an acceptable match for a query whose set of return columns is the empty set. The empty set is a subset of all sets.
David J.
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