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R-tree is dead ... long live GiST.

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This commit is contained in:
Tom Lane
2005-11-07 17:36:47 +00:00
parent 645adf5de8
commit 2a8d3d83ef
46 changed files with 213 additions and 2954 deletions
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27
doc/src/sgml/ref/create_index.sgml
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@@ -1,5 +1,5 @@
<!--
$PostgreSQL: pgsql/doc/src/sgml/ref/create_index.sgml,v 1.51 2005/01/04 00:39:53 tgl Exp $
$PostgreSQL: pgsql/doc/src/sgml/ref/create_index.sgml,v 1.52 2005/11/07 17:36:44 tgl Exp $
PostgreSQL documentation
-->
@@ -34,7 +34,7 @@ CREATE [ UNIQUE ] INDEX <replaceable class="parameter">name</replaceable> ON <re
<command>CREATE INDEX</command> constructs an index <replaceable
class="parameter">index_name</replaceable> on the specified table.
Indexes are primarily used to enhance database performance (though
inappropriate use will result in slower performance).
inappropriate use can result in slower performance).
</para>
<para>
@@ -55,11 +55,7 @@ CREATE [ UNIQUE ] INDEX <replaceable class="parameter">name</replaceable> ON <re
<para>
<productname>PostgreSQL</productname> provides the index methods
B-tree, R-tree, hash, and GiST. The B-tree index method is an
implementation of Lehman-Yao high-concurrency B-trees. The R-tree
index method implements standard R-trees using Guttman's quadratic
split algorithm. The hash index method is an implementation of
Litwin's linear hashing. Users can also define their own index
B-tree, hash, and GiST. Users can also define their own index
methods, but that is fairly complicated.
</para>
@@ -137,9 +133,9 @@ CREATE [ UNIQUE ] INDEX <replaceable class="parameter">name</replaceable> ON <re
<term><replaceable class="parameter">method</replaceable></term>
<listitem>
<para>
The name of the method to be used for the index. Choices are
The name of the index method to be used. Choices are
<literal>btree</literal>, <literal>hash</literal>,
<literal>rtree</literal>, and <literal>gist</literal>. The
and <literal>gist</literal>. The
default method is <literal>btree</literal>.
</para>
</listitem>
@@ -243,6 +239,15 @@ CREATE [ UNIQUE ] INDEX <replaceable class="parameter">name</replaceable> ON <re
The best way to use indexes in such cases is to create a partial index
using an <literal>IS NULL</> predicate.
</para>
<para>
Prior releases of <productname>PostgreSQL</productname> also had an
R-tree index method. This method has been removed because
it had no significant advantages over the GiST method.
If <literal>USING rtree</> is specified, <command>CREATE INDEX</>
will interpret it as <literal>USING gist</>, to simplify conversion
of old databases to GiST.
</para>
</refsect1>
<refsect1>
@@ -270,13 +275,13 @@ CREATE INDEX code_idx ON films(code) TABLESPACE indexspace;
Is this example correct?
</comment>
<para>
To create a R-tree index on a point attribute so that we
To create a GiST index on a point attribute so that we
can efficiently use box operators on the result of the
conversion function:
</para>
<programlisting>
CREATE INDEX pointloc
ON points USING RTREE (point2box(location) box_ops);
ON points USING GIST (point2box(location) box_ops);
SELECT * FROM points
WHERE point2box(points.pointloc) = boxes.box;
</programlisting>