From b5f7cff84f57a189ed5c9dd59efe8d2568649d0d Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Wed, 29 Jun 2005 22:51:57 +0000
Subject: 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/timestamp.c | 46 +++++++++++++++++++++++++++++----------
 1 file changed, 35 insertions(+), 11 deletions(-)

(limited to 'src/backend/utils/adt/timestamp.c')

diff --git a/src/backend/utils/adt/timestamp.c b/src/backend/utils/adt/timestamp.c
index 035a422bfcc..f9f4ec24b1a 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 1.126 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
-- 
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