Re: What is wrong with hashed index usage?

Bruce Momjian <pgman@candle.pha.pa.us> writes:
>       <para>
> !      Because of the limited utility of hash indexes, a B-tree index
> !      should generally be preferred over a hash index.  We do not have
> !      sufficient evidence that hash indexes are actually faster than
> !      B-trees even for <literal>=</literal> comparisons.  Moreover,
> !      hash indexes require coarser locks; see <xref
> !      linkend="locking-indexes">.
>       </para>
>      </note>  
>     </para>
> --- 181,189 ----
>   </synopsis>
>      <note>
>       <para>
> !      Testing has shown that hash indexes are slower than btree indexes,
> !      and the size and build time for hash indexes is much worse. For
> !      these reasons, hash index use is discouraged.

This change strikes me as a step backwards.  The existing wording tells
the truth; the proposed revision removes the facts in favor of a blanket
assertion that is demonstrably false.
        regards, tom lane