Details
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Task
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Status: Closed (View Workflow)
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Major
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Resolution: Won't Fix
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Description
First time poster... please bare with me...
I'm looking for a reverse key index. I'm storing URLs. I could create two columns, on store the fields in reverse, but I feel a more elegant solution would be to offer a Reverse Key Index strategy.
Attachments
Issue Links
- is part of
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MDEV-6017 Add support for Indexes on Expressions
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- Stalled
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Activity
I suppose this ticket should be titled to more accurately: better support for postfix indexes.
The issue is well covered here:
CREATE [UNIQUE|FULLTEXT|SPATIAL|REVERSE] INDEX index_name ON tbl_name (index_col_name,...) |
A workaround could be using a persistent virtual column with the reversed data and then index it... If your database is not very big (or hammered) the penalty of this solution would not be very dramatic... but each case is different 
A solution to this problem would be to allow functional indexes, it's like
CREATE INDEX ... (REVERSE(a)) |
that is, to allow index expressions instead of columns. This is being discussed. But there're no immediate plans to have it implemented in the near future.
As a workaround you can, indeed, create a virtual column using this expression and create an index over it.
We won't implement "REVERSE" indexes. We might implement functional indexes though.
What do you mean by "reverse key index", could you elaborate on that please?