Reduce CPU utilisation of WALSender process. Process was using 10% CPU

doing nothing, caused by naptime specified in milliseconds yet units of
pg_usleep() parameter is microseconds. Correctly specifying units
reduces call frequency by 1000. Reduction in CPU consumption verified.

diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index 0a648e7..fa0b363 100644 (file)
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -30,7 +30,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/replication/walsender.c,v 1.10 2010/03/16 09:09:55 heikki Exp $
+ *       $PostgreSQL: pgsql/src/backend/replication/walsender.c,v 1.11 2010/03/24 20:11:12 sriggs Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -67,7 +67,7 @@ bool          am_walsender = false;           /* Am I a walsender process ? */
 int                    MaxWalSenders = 0;      /* the maximum number of concurrent walsenders */
 int                    WalSndDelay = 200;      /* max sleep time between some actions */
 
-#define NAPTIME_PER_CYCLE 100  /* max sleep time between cycles (100ms) */
+#define NAPTIME_PER_CYCLE 100000L      /* max sleep time between cycles (100ms) */
 
 /*
  * These variables are used similarly to openLogFile/Id/Seg/Off,
@@ -396,7 +396,7 @@ WalSndLoop(void)
                 * sleep into NAPTIME_PER_CYCLE (ms) increments, and check for
                 * interrupts after each nap.
                 */
-               remain = WalSndDelay;
+               remain = WalSndDelay * 1000L;
                while (remain > 0)
                {
                        if (got_SIGHUP || shutdown_requested || ready_to_stop)