Assorted corrections to the patch to add WAL receiver replies.

robertmhaas · robertmhaas · commit 883a9659faf6 · 2011-02-15T12:05:00.000-05:00
Per reports from Fujii Masao.
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
@@ -1984,29 +1984,6 @@ SET ENABLE_SEQSCAN TO OFF;
        </listitem>
       </varlistentry>
 
-      <varlistentry id="guc-wal-receiver-status-interval" xreflabel="wal_receiver_status_interval">
-       <term><varname>wal_receiver_status_interval</varname> (<type>integer</type>)</term>
-       <indexterm>
-        <primary><varname>wal_receiver_status_interval</> configuration parameter</primary>
-       </indexterm>
-       <listitem>
-       <para>
-        Specifies the minimum frequency, in seconds, for the WAL receiver
-        process on the standby to send information about replication progress
-        to the primary, where they can be seen using the
-        <literal>pg_stat_replication</literal> view.  The standby will report
-        the last transaction log position it has written, the last position it
-        has flushed to disk, and the last position it has applied.  Updates are
-        sent each time the write or flush positions changed, or at least as
-        often as specified by this parameter.  Thus, the apply position may
-        lag slightly behind the true position.  Setting this parameter to zero
-        disables status updates completely.  This parameter can only be set in
-        the <filename>postgresql.conf</> file or on the server command line.
-        The default value is 10 seconds.
-       </para>
-       </listitem>
-      </varlistentry>
-
      <varlistentry id="guc-vacuum-defer-cleanup-age" xreflabel="vacuum_defer_cleanup_age">
       <term><varname>vacuum_defer_cleanup_age</varname> (<type>integer</type>)</term>
       <indexterm>
@@ -2121,6 +2098,29 @@ SET ENABLE_SEQSCAN TO OFF;
       </listitem>
      </varlistentry>
 
+     <varlistentry id="guc-wal-receiver-status-interval" xreflabel="wal_receiver_status_interval">
+      <term><varname>wal_receiver_status_interval</varname> (<type>integer</type>)</term>
+      <indexterm>
+       <primary><varname>wal_receiver_status_interval</> configuration parameter</primary>
+      </indexterm>
+      <listitem>
+      <para>
+       Specifies the minimum frequency, in seconds, for the WAL receiver
+       process on the standby to send information about replication progress
+       to the primary, where they can be seen using the
+       <literal>pg_stat_replication</literal> view.  The standby will report
+       the last transaction log position it has written, the last position it
+       has flushed to disk, and the last position it has applied.  Updates are
+       sent each time the write or flush positions changed, or at least as
+       often as specified by this parameter.  Thus, the apply position may
+       lag slightly behind the true position.  Setting this parameter to zero
+       disables status updates completely.  This parameter can only be set in
+       the <filename>postgresql.conf</> file or on the server command line.
+       The default value is 10 seconds.
+      </para>
+      </listitem>
+     </varlistentry>
+
      </variablelist>
     </sect2>
    </sect1>
diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
@@ -89,6 +89,11 @@ static uint32 sendOff = 0;
  */
 static XLogRecPtr sentPtr = {0, 0};
 
+/*
+ * Buffer for processing reply messages.
+ */
+static StringInfoData reply_message;
+
 /* Flags set by signal handlers for later service in main loop */
 static volatile sig_atomic_t got_SIGHUP = false;
 volatile sig_atomic_t walsender_shutdown_requested = false;
@@ -469,7 +474,7 @@ ProcessRepliesIfAny(void)
 	switch (firstchar)
 	{
 			/*
-			 * 'd' means a standby reply wrapped in a COPY BOTH packet.
+			 * 'd' means a standby reply wrapped in a CopyData packet.
 			 */
 		case 'd':
 			ProcessStandbyReplyMessage();
@@ -495,16 +500,15 @@ ProcessRepliesIfAny(void)
 static void
 ProcessStandbyReplyMessage(void)
 {
-	static StringInfoData input_message;
 	StandbyReplyMessage	reply;
 	char msgtype;
 
-	initStringInfo(&input_message);
+	resetStringInfo(&reply_message);
 
 	/*
 	 * Read the message contents.
 	 */
-	if (pq_getmessage(&input_message, 0))
+	if (pq_getmessage(&reply_message, 0))
 	{
 		ereport(COMMERROR,
 				(errcode(ERRCODE_PROTOCOL_VIOLATION),
@@ -516,13 +520,16 @@ ProcessStandbyReplyMessage(void)
 	 * Check message type from the first byte. At the moment, there is only
 	 * one type.
 	 */
-	msgtype = pq_getmsgbyte(&input_message);
+	msgtype = pq_getmsgbyte(&reply_message);
 	if (msgtype != 'r')
+	{
 		ereport(COMMERROR,
 				(errcode(ERRCODE_PROTOCOL_VIOLATION),
 				 errmsg("unexpected message type %c", msgtype)));
+		proc_exit(0);
+	}
 
-	pq_copymsgbytes(&input_message, (char *) &reply, sizeof(StandbyReplyMessage));
+	pq_copymsgbytes(&reply_message, (char *) &reply, sizeof(StandbyReplyMessage));
 
 	elog(DEBUG2, "write %X/%X flush %X/%X apply %X/%X ",
 		 reply.write.xlogid, reply.write.xrecoff,
@@ -559,6 +566,12 @@ WalSndLoop(void)
 	 */
 	output_message = palloc(1 + sizeof(WalDataMessageHeader) + MAX_SEND_SIZE);
 
+	/*
+	 * Allocate buffer that will be used for processing reply messages.  As
+	 * above, do this just once to reduce palloc overhead.
+	 */
+	initStringInfo(&reply_message);
+
 	/* Loop forever, unless we get an error */
 	for (;;)
 	{
