Re: What is wrong with hashed index usage? - Mailing list pgsql-hackers

From Tom Lane
Subject Re: What is wrong with hashed index usage?
Date
Msg-id 19635.1024670840@sss.pgh.pa.us
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In response to Re: What is wrong with hashed index usage?  (Bruce Momjian <pgman@candle.pha.pa.us>)
Responses Re: What is wrong with hashed index usage?  (Bruce Momjian <pgman@candle.pha.pa.us>)
List pgsql-hackers
Bruce Momjian <pgman@candle.pha.pa.us> writes:
> OK, which part of is "demonstrably false"?  I think the old "should
> generally be preferred" is too vague.  No one has come up with a case
> where hash has shown to be faster, and a lot of cases where it is slower.

The only thing I recall being lots worse is initial index build.

I have not tested it much, but I would expect that hash holds up better
in the presence of many equal keys than btree does...
        regards, tom lane


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