Add mention of performance impact on LIKE of non-C locales.

diff --git a/doc/src/sgml/charset.sgml b/doc/src/sgml/charset.sgml
index 0ab0680aef56301b2a03bcb0d7f9def1d7741f83..c6e9694918c968fffe4acad16ff2dd9b84e5b0cd 100644 (file)
--- a/doc/src/sgml/charset.sgml
+++ b/doc/src/sgml/charset.sgml
@@ -189,10 +189,10 @@ initdb --locale=sv_SE
   </sect2>
 
   <sect2>
-   <title>Benefits</>
+   <title>Behavior</>
 
    <para>
-    Locale support influences in particular the following features:
+    Locale support influences the following features:
 
     <itemizedlist>
      <listitem>
@@ -202,6 +202,13 @@ initdb --locale=sv_SE
       </para>
      </listitem>
 
+     <listitem>
+      <para>
+       The ability to use indexes with <literal>LIKE</> clauses
+       <indexterm><primary>LIKE</><secondary>and locales</></indexterm>
+      </para>
+     </listitem>
+
      <listitem>
       <para>
        The <function>to_char</> family of functions
@@ -211,9 +218,11 @@ initdb --locale=sv_SE
    </para>
 
    <para>
-    The only severe drawback of using the locale support in
-    <productname>PostgreSQL</> is its speed.  So use locales only if
-    you actually need them.
+    The drawback of using locales other than <literal>C</> or
+    <literal>POSIX</> in <productname>PostgreSQL</> is its performance
+    impact. It slows character handling and prevents ordinary indexes
+    from being used by <literal>LIKE</>. For this reason use locales
+    only if you actually need them.
    </para>
   </sect2>
 

diff --git a/doc/src/sgml/ref/initdb.sgml b/doc/src/sgml/ref/initdb.sgml
index e0c9fa26adaeb464477b69b1285e16085b042c1d..47f29b7cfc3726e07c48a65b80170b0cacbfd433 100644 (file)
--- a/doc/src/sgml/ref/initdb.sgml
+++ b/doc/src/sgml/ref/initdb.sgml
@@ -54,21 +54,22 @@ PostgreSQL documentation
   </para>
 
   <para>
-   <command>initdb</command> initializes the database cluster's
-   default locale and character set encoding.  Some locale categories
-   are fixed for the lifetime of the cluster, so it is important to
-   make the right choice when running <command>initdb</command>.
-   Other locale categories can be changed later when the server is
-   started.  <command>initdb</command> will write those locale
-   settings into the <filename>postgresql.conf</filename>
-   configuration file so they are the default, but they can be changed
-   by editing that file.  To set the locale that
-   <command>initdb</command> uses, see the description of the
-   <option>--locale</option> option.  The character set encoding can
+   <command>initdb</command> initializes the database cluster's default
+   locale and character set encoding. Some locale categories are fixed
+   for the lifetime of the cluster. There is also a performance impact
+   in using locales other than <literal>C</> or <literal>POSIX</>.
+   Therefore it is important to make the right choice when running
+   <command>initdb</command>. Other locale categories can be changed
+   later when the server is started. <command>initdb</command> will
+   write those locale settings into the
+   <filename>postgresql.conf</filename> configuration file so they are
+   the default, but they can be changed by editing that file. To set the
+   locale that <command>initdb</command> uses, see the description of
+   the <option>--locale</option> option. The character set encoding can
    be set separately for each database as it is created.
    <command>initdb</command> determines the encoding for the
    <literal>template1</literal> database, which will serve as the
-   default for all other databases.  To alter the default encoding use
+   default for all other databases. To alter the default encoding use
    the <option>--encoding</option> option.
   </para>
 

diff --git a/doc/src/sgml/runtime.sgml b/doc/src/sgml/runtime.sgml
index 262b53183e16a3803ad64381f66c1716878d4204..fe55d4133b8892360a77b5e3f23b464cf6ae5f31 100644 (file)
--- a/doc/src/sgml/runtime.sgml
+++ b/doc/src/sgml/runtime.sgml
@@ -144,9 +144,10 @@ postgres$ <userinput>initdb -D /usr/local/pgsql/data</userinput>
    that can be found in <xref linkend="locale">.  The sort order used
    within a particular database cluster is set by
    <command>initdb</command> and cannot be changed later, short of
-   dumping all data, rerunning <command>initdb</command>, and
-   reloading the data. So it's important to make this choice correctly
-   the first time.
+   dumping all data, rerunning <command>initdb</command>, and reloading
+   the data. There is also a performance impact for using locales
+   other than <literal>C</> or <literal>POSIX</>. Therefore, it is
+   important to make this choice correctly the first time.
   </para>
  </sect1>