Re: Reverse btree indexes

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От David G. Johnston
Тема Re: Reverse btree indexes
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Msg-id CAKFQuwYsDe8gVLL66oSDKbDZ6Ln72ygDp=R2CPfd7Ri7acRPkg@mail.gmail.com
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Ответ на Reverse btree indexes  (Zach Aysan <zachaysan@gmail.com>)
Ответы Re: Reverse btree indexes  (Alvaro Herrera <alvherre@alvh.no-ip.org>)
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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