Re: on hash indexes - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: on hash indexes
Date
Msg-id 200902072006.n17K60D18556@momjian.us
Whole thread Raw
In response to Re: on hash indexes  (Kenneth Marshall <ktm@rice.edu>)
List pgsql-hackers
Kenneth Marshall wrote:
> I had submitted the documentation change as part of my
> hash function patch but it was removed as not relevant.
> (It wasn't really.) I would basically remove the first
> sentence:
>
>         Note: Hash index operations are not presently WAL-logged,
>   so hash indexes might need to be rebuilt with REINDEX  after a
>   database crash. For this reason, hash index use is presently
>   discouraged.

Change made and attached;  thanks.

--
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +
Index: doc/src/sgml/indices.sgml
===================================================================
RCS file: /cvsroot/pgsql/doc/src/sgml/indices.sgml,v
retrieving revision 1.75
diff -c -c -r1.75 indices.sgml
*** doc/src/sgml/indices.sgml    23 Sep 2008 09:20:34 -0000    1.75
--- doc/src/sgml/indices.sgml    7 Feb 2009 20:03:51 -0000
***************
*** 190,202 ****

    <note>
     <para>
!     Testing has shown <productname>PostgreSQL</productname>'s hash
!     indexes to perform no better than B-tree indexes, and the
!     index size and build time for hash indexes is much worse.
!     Furthermore, hash index operations are not presently WAL-logged,
      so hash indexes might need to be rebuilt with <command>REINDEX</>
      after a database crash.
!     For these reasons, hash index use is presently discouraged.
     </para>
    </note>

--- 190,199 ----

    <note>
     <para>
!     Hash index operations are not presently WAL-logged,
      so hash indexes might need to be rebuilt with <command>REINDEX</>
      after a database crash.
!     For this reason, hash index use is presently discouraged.
     </para>
    </note>


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