Update bgworker.sgml

Author: chegong18

postgresql/doc/src/sgml/bgworker.sgml

@@ -220,14 +220,14 @@ ____________________________________________________________________________-->
 <!--==========================orignal english content==========================
   <para>
    <structfield>bgw_restart_time</structfield> is the interval, in seconds, that
-   <command>postgres</command> should wait before restarting the process, in
-   case it crashes.  It can be any positive value,
+   <command>postgres</command> should wait before restarting the process in
+   the event that it crashes.  It can be any positive value,
    or <literal>BGW_NEVER_RESTART</literal>, indicating not to restart the
    process in case of a crash.
   </para>
 ____________________________________________________________________________-->
   <para>
-   <structfield>bgw_restart_time</structfield>是在崩溃情况下<command>postgres</command>启动进程之前等待的时间间隔，以秒计。它可以是任何正值，或者<literal>BGW_NEVER_RESTART</literal>，表示在出现崩溃后不重启进程。
+   <structfield>bgw_restart_time</structfield>是时间间隔，以秒计；是在进程崩溃情况下，<command>postgres</command>重新启动进程之前等待的时间间隔。它可以是任何正值，或者<literal>BGW_NEVER_RESTART</literal>，表示在出现崩溃后不重启进程。
   </para>
 
 <!--==========================orignal english content==========================
@@ -466,19 +466,19 @@ ____________________________________________________________________________-->
 
 <!--==========================orignal english content==========================
   <para>
-   If a background worker sends asynchronous notifications with the
-   <command>NOTIFY</command> command via the Server Programming Interface
-   (<acronym>SPI</acronym>), it should call
-   <function>ProcessCompletedNotifies</function> explicitly after committing
-   the enclosing transaction so that any notifications can be delivered.  If a
-   background worker registers to receive asynchronous notifications with
-   the <command>LISTEN</command> through <acronym>SPI</acronym>, the worker
-   will log those notifications, but there is no programmatic way for the
-   worker to intercept and respond to those notifications.
+   Background workers can send asynchronous notification messages, either by
+   using the <command>NOTIFY</command> command via <acronym>SPI</acronym>,
+   or directly via <function>Async_Notify()</function>.  Such notifications
+   will be sent at transaction commit.
+   Background workers should not register to receive asynchronous
+   notifications with the <command>LISTEN</command> command, as there is no
+   infrastructure for a worker to consume such notifications.
   </para>
 ____________________________________________________________________________-->
   <para>
-   如果一个后台工作者通过服务器编程接口（<acronym>SPI</acronym>）用<command>NOTIFY</command>命令发送异步通知，在提交外层事务之后它应该显式地调用<function>ProcessCompletedNotifies</function>，这样通知才能被发送出去。如果一个后台工作者通过<acronym>SPI</acronym>使用<command>LISTEN</command>注册为接收异步通知，它将记录那些通知，但是对于工作者来说没有程序化的方式可以拦截以及响应那些通知。
+   后台工作者可以发送异步通知消息，可以通过<acronym>SPI</acronym>的<command>NOTIFY</command> 命令，或者直接通过 <function>Async_Notify()</function>。
+   这样的通知将在事务提交的时候发送。
+   后台工作者不应该使用<command>LISTEN</command>命令接收异步通知，因为工作者没有可以使用这些通知的基础架构。
   </para>
 
 <!--==========================orignal english content==========================