Re: Reverse Key Index

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On 02/26/2015 12:31 AM, Josh Berkus wrote:
On 02/14/2015 10:35 AM, Sven R. Kunze wrote:
Thanks for the immediate reply.

I understand the use case is quite limited.

On the other hand, I see potential when it comes to applications which
use PostgreSQL. There, programmers would have to change a lot of code to
tweak existing (and more importantly working) queries to hash/reverse an
id column first. Using ORMs would make this change even more painful and
maybe even impossible.

When reading
https://richardfoote.wordpress.com/2008/01/14/introduction-to-reverse-key-indexes-part-i/
carefully, it also seems to work with index scan partially in case of
equality comparisons.

Seems like a good use for SP-GiST.  Go for it!

A b-tree opclass that just compares from right-to-left would work just
as well, and perform better.

- Heikki



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