Re: Save Hash Indexes - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Save Hash Indexes
Date
Msg-id 9877.1383313797@sss.pgh.pa.us
Whole thread Raw
In response to Save Hash Indexes  (Dimitri Fontaine <dimitri@2ndQuadrant.fr>)
Responses Re: Save Hash Indexes  (Dimitri Fontaine <dimitri@2ndQuadrant.fr>)
Re: Save Hash Indexes  (Andrew Dunstan <andrew@dunslane.net>)
Re: Save Hash Indexes  (Andres Freund <andres@2ndquadrant.com>)
Re: Save Hash Indexes  (Robert Haas <robertmhaas@gmail.com>)
List pgsql-hackers
Dimitri Fontaine <dimitri@2ndQuadrant.fr> writes:
> Here's an idea: when a user ask for an Hash Index transparently build a
> BTree index over an hash function instead.

-1.  If someone asks for a hash index, they should get a hash index.
If you feel the documentation isn't sufficiently clear about the problems
involved, we can work on that.

The bigger picture here is that such an approach amounts to deciding that
no one will ever be allowed to fix hash indexes.  I'm not for that, even
if I'm not volunteering to be the fixer myself.

I also don't believe your claim that this would always be faster than a
real hash index.  What happened to O(1) vs O(log N)?

Lastly: what real-world problem are we solving by kicking that code
to the curb?
        regards, tom lane



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