Remove redundant gettimeofday() calls to the extent practical without

changing semantics too much.  statement_timestamp is now set immediately
upon receipt of a client command message, and the various places that used
to do their own gettimeofday() calls to mark command startup are referenced
to that instead.  I have also made stats_command_string use that same
value for pg_stat_activity.query_start for both the command itself and
its eventual replacement by <IDLE> or <idle in transaction>.  There was
some debate about that, but no argument that seemed convincing enough to
justify an extra gettimeofday() call.

3 files changed, 61 insertions, 8 deletions

diff --git a/src/backend/utils/adt/timestamp.c b/src/backend/utils/adt/timestamp.c
index fd40c1ebfdd..f4f23c9dd31 100644
--- a/src/backend/utils/adt/timestamp.c
+++ b/src/backend/utils/adt/timestamp.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.163 2006/04/25 00:25:18 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.164 2006/06/20 22:52:00 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -963,6 +963,39 @@ GetCurrentTimestamp(void)
 	return result;
 }
 
+/*
+ * TimestampDifference -- convert the difference between two timestamps
+ *		into integer seconds and microseconds
+ *
+ * Both inputs must be ordinary finite timestamps (in current usage,
+ * they'll be results from GetCurrentTimestamp()).
+ *
+ * We expect start_time <= stop_time.  If not, we return zeroes; for current
+ * callers there is no need to be tense about which way division rounds on
+ * negative inputs.
+ */
+void
+TimestampDifference(TimestampTz start_time, TimestampTz stop_time,
+					long *secs, int *microsecs)
+{
+	TimestampTz diff = stop_time - start_time;
+
+	if (diff <= 0)
+	{
+		*secs = 0;
+		*microsecs = 0;
+	}
+	else
+	{
+#ifdef HAVE_INT64_TIMESTAMP
+		*secs = (long) (diff / USECS_PER_SEC);
+		*microsecs = (int) (diff % USECS_PER_SEC);
+#else
+		*secs = (long) diff;
+		*microsecs = (int) ((diff - *secs) * 1000000.0);
+#endif
+	}
+}
 
 /*
  * Convert a time_t to TimestampTz.
@@ -985,6 +1018,27 @@ time_t_to_timestamptz(time_t tm)
 	return result;
 }
 
+/*
+ * Convert a TimestampTz to time_t.
+ *
+ * This too is just marginally useful, but some places need it.
+ */
+time_t
+timestamptz_to_time_t(TimestampTz t)
+{
+	time_t		result;
+
+#ifdef HAVE_INT64_TIMESTAMP
+	result = (time_t) (t / USECS_PER_SEC +
+		((POSTGRES_EPOCH_JDATE - UNIX_EPOCH_JDATE) * SECS_PER_DAY));
+#else
+	result = (time_t) (t +
+		((POSTGRES_EPOCH_JDATE - UNIX_EPOCH_JDATE) * SECS_PER_DAY));
+#endif
+
+	return result;
+}
+
 
 void
 dt2time(Timestamp jd, int *hour, int *min, int *sec, fsec_t *fsec)
diff --git a/src/backend/utils/error/elog.c b/src/backend/utils/error/elog.c
index e0f3c9d8868..54db791f613 100644
--- a/src/backend/utils/error/elog.c
+++ b/src/backend/utils/error/elog.c
@@ -42,7 +42,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/error/elog.c,v 1.169 2006/03/05 15:58:46 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/error/elog.c,v 1.170 2006/06/20 22:52:00 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1408,7 +1408,7 @@ log_line_prefix(StringInfo buf)
 				if (MyProcPort)
 				{
 					appendStringInfo(buf, "%lx.%x",
-								   (long) (MyProcPort->session_start.tv_sec),
+									 (long) (MyProcPort->session_start),
 									 MyProcPid);
 				}
 				break;
@@ -1440,7 +1440,7 @@ log_line_prefix(StringInfo buf)
 
 					strftime(strfbuf, sizeof(strfbuf),
 					/* leave room for milliseconds... */
-					/* Win32 timezone names are too long so don't print them. */
+					/* Win32 timezone names are too long so don't print them */
 #ifndef WIN32
 							 "%Y-%m-%d %H:%M:%S     %Z",
 #else
@@ -1474,12 +1474,11 @@ log_line_prefix(StringInfo buf)
 			case 's':
 				if (MyProcPort)
 				{
-					time_t		stamp_time = MyProcPort->session_start.tv_sec;
 					char		strfbuf[128];
 
 					strftime(strfbuf, sizeof(strfbuf),
 							 "%Y-%m-%d %H:%M:%S %Z",
-							 localtime(&stamp_time));
+							 localtime(&MyProcPort->session_start));
 					appendStringInfoString(buf, strfbuf);
 				}
 				break;
diff --git a/src/backend/utils/mmgr/portalmem.c b/src/backend/utils/mmgr/portalmem.c
index 9af7a5f0d86..a32cad08d30 100644
--- a/src/backend/utils/mmgr/portalmem.c
+++ b/src/backend/utils/mmgr/portalmem.c
@@ -12,7 +12,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/mmgr/portalmem.c,v 1.87 2006/04/25 14:11:58 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/mmgr/portalmem.c,v 1.88 2006/06/20 22:52:00 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -202,7 +202,7 @@ CreatePortal(const char *name, bool allowDup, bool dupSilent)
 	portal->atStart = true;
 	portal->atEnd = true;		/* disallow fetches until query is set */
 	portal->visible = true;
-	portal->creation_time = GetCurrentTimestamp();
+	portal->creation_time = GetCurrentStatementStartTimestamp();
 
 	/* put portal in table (sets portal->name) */
 	PortalHashTableInsert(portal, name);