Clean up the rather historically encumbered interface to now() and

current time: provide a GetCurrentTimestamp() function that returns
current time in the form of a TimestampTz, instead of separate time_t
and microseconds fields.  This is what all the callers really want
anyway, and it eliminates low-level dependencies on AbsoluteTime,
which is a deprecated datatype that will have to disappear eventually.

src/backend/utils/adt/datetime.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/datetime.c,v 1.150 2005/05/27 21:31:23 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/datetime.c,v 1.151 2005/06/29 22:51:56 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -20,6 +20,7 @@
 #include <limits.h>
 #include <math.h>
 
+#include "access/xact.h"
 #include "miscadmin.h"
 #include "utils/datetime.h"
 #include "utils/guc.h"
@@ -674,6 +675,41 @@ j2day(int date)
 }	/* j2day() */
 
 
+/*
+ * GetCurrentDateTime()
+ *
+ * Get the transaction start time ("now()") broken down as a struct pg_tm.
+ */
+void
+GetCurrentDateTime(struct pg_tm * tm)
+{
+	int			tz;
+	fsec_t		fsec;
+
+	timestamp2tm(GetCurrentTransactionStartTimestamp(), &tz, tm, &fsec,
+				 NULL, NULL);
+	/* Note: don't pass NULL tzp to timestamp2tm; affects behavior */
+}
+
+/*
+ * GetCurrentTimeUsec()
+ *
+ * Get the transaction start time ("now()") broken down as a struct pg_tm,
+ * including fractional seconds and timezone offset.
+ */
+void
+GetCurrentTimeUsec(struct pg_tm * tm, fsec_t *fsec, int *tzp)
+{
+	int			tz;
+
+	timestamp2tm(GetCurrentTransactionStartTimestamp(), &tz, tm, fsec,
+				 NULL, NULL);
+	/* Note: don't pass NULL tzp to timestamp2tm; affects behavior */
+	if (tzp != NULL)
+		*tzp = tz;
+}
+
+
 /* TrimTrailingZeros()
  * ... resulting from printing numbers with full precision.
  */

src/backend/utils/adt/nabstime.c

@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/nabstime.c,v 1.133 2005/06/15 00:34:08 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/nabstime.c,v 1.134 2005/06/29 22:51:56 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -27,7 +27,7 @@
 #include "miscadmin.h"
 #include "pgtime.h"
 #include "utils/builtins.h"
-#include "utils/timestamp.h"
+#include "utils/nabstime.h"
 
 #define MIN_DAYNUM -24856		/* December 13, 1901 */
 #define MAX_DAYNUM 24854		/* January 18, 2038 */
@@ -99,84 +99,6 @@ GetCurrentAbsoluteTime(void)
 }
 
 
-/*
- * GetCurrentAbsoluteTimeUsec()
- *
- * Get the current system time (relative to Unix epoch), including fractional
- * seconds expressed as microseconds.
- */
-AbsoluteTime
-GetCurrentAbsoluteTimeUsec(int *usec)
-{
-	time_t		now;
-	struct timeval tp;
-
-	gettimeofday(&tp, NULL);
-	now = tp.tv_sec;
-	*usec = tp.tv_usec;
-	return (AbsoluteTime) now;
-}
-
-
-/*
- * AbsoluteTimeUsecToTimestampTz()
- *
- * Convert system time including microseconds to TimestampTz representation.
- */
-TimestampTz
-AbsoluteTimeUsecToTimestampTz(AbsoluteTime sec, int usec)
-{
-	TimestampTz result;
-
-#ifdef HAVE_INT64_TIMESTAMP
-	result = ((sec - ((POSTGRES_EPOCH_JDATE - UNIX_EPOCH_JDATE) * SECS_PER_DAY))
-			  * USECS_PER_SEC) + usec;
-#else
-	result = sec - ((POSTGRES_EPOCH_JDATE - UNIX_EPOCH_JDATE) * SECS_PER_DAY)
-		+ (usec / 1000000.0);
-#endif
-
-	return result;
-}
-
-
-/*
- * GetCurrentDateTime()
- *
- * Get the transaction start time ("now()") broken down as a struct pg_tm.
- */
-void
-GetCurrentDateTime(struct pg_tm * tm)
-{
-	int			tz;
-
-	abstime2tm(GetCurrentTransactionStartTime(), &tz, tm, NULL);
-}
-
-/*
- * GetCurrentTimeUsec()
- *
- * Get the transaction start time ("now()") broken down as a struct pg_tm,
- * including fractional seconds and timezone offset.
- */
-void
-GetCurrentTimeUsec(struct pg_tm * tm, fsec_t *fsec, int *tzp)
-{
-	int			tz;
-	int			usec;
-
-	abstime2tm(GetCurrentTransactionStartTimeUsec(&usec), &tz, tm, NULL);
-	/* Note: don't pass NULL tzp to abstime2tm; affects behavior */
-	if (tzp != NULL)
-		*tzp = tz;
-#ifdef HAVE_INT64_TIMESTAMP
-	*fsec = usec;
-#else
-	*fsec = usec / 1000000.0;
-#endif
-}
-
-
 void
 abstime2tm(AbsoluteTime _time, int *tzp, struct pg_tm * tm, char **tzn)
 {
@@ -458,15 +380,6 @@ abstime_cmp_internal(AbsoluteTime a, AbsoluteTime b)
 	if (b == INVALID_ABSTIME)
 		return -1;				/* non-INVALID < INVALID */
 
-#if 0
-	/* CURRENT is no longer stored internally... */
-	/* XXX this is broken, should go away: */
-	if (a == CURRENT_ABSTIME)
-		a = GetCurrentTransactionStartTime();
-	if (b == CURRENT_ABSTIME)
-		b = GetCurrentTransactionStartTime();
-#endif
-
 	if (a > b)
 		return 1;
 	else if (a == b)

src/backend/utils/adt/pgstatfuncs.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/pgstatfuncs.c,v 1.23 2005/06/28 05:09:00 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/pgstatfuncs.c,v 1.24 2005/06/29 22:51:56 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -341,13 +341,9 @@ pg_stat_get_backend_activity(PG_FUNCTION_ARGS)
 Datum
 pg_stat_get_backend_activity_start(PG_FUNCTION_ARGS)
 {
-	PgStat_StatBeEntry *beentry;
-	int32		beid;
-	AbsoluteTime sec;
-	int			usec;
+	int32		beid = PG_GETARG_INT32(0);
 	TimestampTz result;
-
-	beid = PG_GETARG_INT32(0);
+	PgStat_StatBeEntry *beentry;
 
 	if ((beentry = pgstat_fetch_stat_beentry(beid)) == NULL)
 		PG_RETURN_NULL();
@@ -355,31 +351,24 @@ pg_stat_get_backend_activity_start(PG_FUNCTION_ARGS)
 	if (!superuser() && beentry->userid != GetUserId())
 		PG_RETURN_NULL();
 
-	sec = beentry->activity_start_sec;
-	usec = beentry->activity_start_usec;
+	result = beentry->activity_start_timestamp;
 
 	/*
 	 * No time recorded for start of current query -- this is the case if
 	 * the user hasn't enabled query-level stats collection.
 	 */
-	if (sec == 0 && usec == 0)
+	if (result == 0)
 		PG_RETURN_NULL();
 
-	result = AbsoluteTimeUsecToTimestampTz(sec, usec);
-
 	PG_RETURN_TIMESTAMPTZ(result);
 }
 
 Datum
 pg_stat_get_backend_start(PG_FUNCTION_ARGS)
 {
-	PgStat_StatBeEntry *beentry;
-	int32       beid;
-	AbsoluteTime sec;
-	int         usec;
+	int32       beid = PG_GETARG_INT32(0);
 	TimestampTz result;
-
-	beid = PG_GETARG_INT32(0);
+	PgStat_StatBeEntry *beentry;
 
 	if ((beentry = pgstat_fetch_stat_beentry(beid)) == NULL)
 		PG_RETURN_NULL();
@@ -387,14 +376,11 @@ pg_stat_get_backend_start(PG_FUNCTION_ARGS)
 	if (!superuser() && beentry->userid != GetUserId())
 		PG_RETURN_NULL();
 
-	sec = beentry->start_sec;
-	usec = beentry->start_usec;
+	result = beentry->start_timestamp;
 
-	if (sec == 0 && usec == 0)
+	if (result == 0)			/* probably can't happen? */
 		PG_RETURN_NULL();
 
-	result = AbsoluteTimeUsecToTimestampTz(sec, usec);
-
 	PG_RETURN_TIMESTAMPTZ(result);
 }
 

src/backend/utils/adt/selfuncs.c

@@ -15,7 +15,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/selfuncs.c,v 1.182 2005/06/13 23:14:48 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/selfuncs.c,v 1.183 2005/06/29 22:51:56 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -105,6 +105,7 @@
 #include "utils/datum.h"
 #include "utils/int8.h"
 #include "utils/lsyscache.h"
+#include "utils/nabstime.h"
 #include "utils/pg_locale.h"
 #include "utils/selfuncs.h"
 #include "utils/syscache.h"

src/backend/utils/adt/timestamp.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.126 2005/06/15 00:34:09 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.127 2005/06/29 22:51:56 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -28,6 +28,8 @@
 #include "parser/scansup.h"
 #include "utils/array.h"
 #include "utils/builtins.h"
+#include "utils/datetime.h"
+
 
 /*
  * gcc's -ffast-math switch breaks routines that expect exact results from
@@ -38,6 +40,10 @@
 #endif
 
 
+/* Set at postmaster start */
+TimestampTz PgStartTime;
+
+
 #ifdef HAVE_INT64_TIMESTAMP
 static int64 time2t(const int hour, const int min, const int sec, const fsec_t fsec);
 
@@ -927,21 +933,39 @@ EncodeSpecialTimestamp(Timestamp dt, char *str)
 Datum
 now(PG_FUNCTION_ARGS)
 {
-	TimestampTz result;
-	AbsoluteTime sec;
-	int			usec;
-
-	sec = GetCurrentTransactionStartTimeUsec(&usec);
-
-	result = AbsoluteTimeUsecToTimestampTz(sec, usec);
-
-	PG_RETURN_TIMESTAMPTZ(result);
+	PG_RETURN_TIMESTAMPTZ(GetCurrentTransactionStartTimestamp());
 }
 
 Datum
 pgsql_postmaster_start_time(PG_FUNCTION_ARGS)
 {
-	PG_RETURN_TIMESTAMPTZ(StartTime);
+	PG_RETURN_TIMESTAMPTZ(PgStartTime);
+}
+
+/*
+ * GetCurrentTimestamp -- get the current operating system time
+ *
+ * Result is in the form of a TimestampTz value, and is expressed to the
+ * full precision of the gettimeofday() syscall
+ */
+TimestampTz
+GetCurrentTimestamp(void)
+{
+	TimestampTz result;
+	struct timeval tp;
+
+	gettimeofday(&tp, NULL);
+
+	result = tp.tv_sec -
+		((POSTGRES_EPOCH_JDATE - UNIX_EPOCH_JDATE) * SECS_PER_DAY);
+
+#ifdef HAVE_INT64_TIMESTAMP
+	result = (result * USECS_PER_SEC) + tp.tv_usec;
+#else
+	result = result + (tp.tv_usec / 1000000.0);
+#endif
+
+	return result;
 }
 
 void