Update xoper.sgml-200704

——row5，调英为：
  <title>User-Defined Operators</title>

——row141至150，增英和翻为：
<!--==========================orignal english content==========================
  <indexterm zone="xoper-optimization">
   <primary>optimization information</primary>
   <secondary>for operators</secondary>
  </indexterm>
____________________________________________________________________________-->
  <indexterm zone="xoper-optimization">
   <primary>optimization information</primary>
   <secondary>for operators</secondary>
  </indexterm>

——row181至191，增英和翻为：
<!--==========================orignal english content==========================
   <para>
    It is also possible to attach a planner support function to the function
    that underlies an operator, providing another way of telling the system
    about the behavior of the operator.
    See <xref linkend="xfunc-optimization"/> for more information.
   </para>
____________________________________________________________________________-->
   <para>
    还可以将计划器支持的函数附加到作为操作符基础的函数中，从而提供另一种向系统讲述操作符行为的方法。更多信息参见<xref linkend="xfunc-optimization"/>。
   </para>

Author: chegong18

postgresql/doc/src/sgml/xoper.sgml

@@ -2,7 +2,7 @@
 
  <sect1 id="xoper">
 <!--==========================orignal english content==========================
-  <title>User-defined Operators</title>
+  <title>User-Defined Operators</title>
 ____________________________________________________________________________-->
   <title>用户定义的操作符</title>
 
@@ -138,6 +138,17 @@ ____________________________________________________________________________-->
 ____________________________________________________________________________-->
    <title>操作符优化信息</title>
 
+<!--==========================orignal english content==========================
+  <indexterm zone="xoper-optimization">
+   <primary>optimization information</primary>
+   <secondary>for operators</secondary>
+  </indexterm>
+____________________________________________________________________________-->
+  <indexterm zone="xoper-optimization">
+   <primary>optimization information</primary>
+   <secondary>for operators</secondary>
+  </indexterm>
+
 <!--==========================orignal english content==========================
    <para>
     A <productname>PostgreSQL</productname> operator definition can include
@@ -167,6 +178,18 @@ ____________________________________________________________________________-->
     在<productname>PostgreSQL</productname>的未来版本中可能会增加更多的优化子句。这里描述的优化子句都是版本 &version; 能理解的。
    </para>
 
+<!--==========================orignal english content==========================
+   <para>
+    It is also possible to attach a planner support function to the function
+    that underlies an operator, providing another way of telling the system
+    about the behavior of the operator.
+    See <xref linkend="xfunc-optimization"/> for more information.
+   </para>
+____________________________________________________________________________-->
+   <para>
+    还可以将计划器支持的函数附加到作为操作符基础的函数中，从而提供另一种向系统讲述操作符行为的方法。更多信息参见<xref linkend="xfunc-optimization"/>。
+   </para>
+
    <sect2>
 <!--==========================orignal english content==========================
     <title><literal>COMMUTATOR</literal></title>