Re: Reverse btree indexes
От | David G. Johnston |
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Тема | Re: Reverse btree indexes |
Дата | |
Msg-id | CAKFQuwYsDe8gVLL66oSDKbDZ6Ln72ygDp=R2CPfd7Ri7acRPkg@mail.gmail.com обсуждение исходный текст |
Ответ на | Reverse btree indexes (Zach Aysan <zachaysan@gmail.com>) |
Ответы |
Re: Reverse btree indexes
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Список | pgsql-docs |
On Tue, Jun 22, 2021 at 2:28 PM Zach Aysan <zachaysan@gmail.com> wrote:
Desired improvement:for example, col LIKE 'foo%' or col ~ '^foo', but not col LIKE '%bar', which would require a reversed index on the field. Postgres will automatically use the reverse index for LIKE '%bar'Or if it doesn't:
It doesn't, otherwise the documentation wouldn't need to point out: but not col LIKE '%bar' ...
for example, col LIKE 'foo%' or col ~ '^foo', but not col LIKE '%bar', which would require a reversed index on the field. To use the reversed index, query with reverse(col) like reverse('%bar').
This type of commentary isn't usually something we include in the documentation...and I'm not too keen on "reversed index" as a phrase regardless.
David J.
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