3 files changed, 36 insertions, 2 deletions
diff --git a/src/backend/utils/adt/date.c b/src/backend/utils/adt/date.c
index 3e280f76322..9014c255e87 100644
--- a/src/backend/utils/adt/date.c
+++ b/src/backend/utils/adt/date.c
@@ -316,6 +316,39 @@ date2timestamptz(DateADT dateVal)
 	return result;
 }
 
+/*
+ * date2timestamp_no_overflow
+ *
+ * This is chartered to produce a double value that is numerically
+ * equivalent to the corresponding Timestamp value, if the date is in the
+ * valid range of Timestamps, but in any case not throw an overflow error.
+ * We can do this since the numerical range of double is greater than
+ * that of non-erroneous timestamps.  The results are currently only
+ * used for statistical estimation purposes.
+ */
+double
+date2timestamp_no_overflow(DateADT dateVal)
+{
+	double	result;
+
+	if (DATE_IS_NOBEGIN(dateVal))
+		result = -DBL_MAX;
+	else if (DATE_IS_NOEND(dateVal))
+		result = DBL_MAX;
+	else
+	{
+#ifdef HAVE_INT64_TIMESTAMP
+		/* date is days since 2000, timestamp is microseconds since same... */
+		result = dateVal * (double) USECS_PER_DAY;
+#else
+		/* date is days since 2000, timestamp is seconds since same... */
+		result = dateVal * (double) SECS_PER_DAY;
+#endif
+	}
+
+	return result;
+}
+
 
 /*
  * Crosstype comparison functions for dates
diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c
index 3325a495d76..ece3654d697 100644
--- a/src/backend/utils/adt/selfuncs.c
+++ b/src/backend/utils/adt/selfuncs.c
@@ -3301,8 +3301,7 @@ convert_timevalue_to_scalar(Datum value, Oid typid)
 			return DatumGetTimestamp(DirectFunctionCall1(abstime_timestamp,
 														 value));
 		case DATEOID:
-			return DatumGetTimestamp(DirectFunctionCall1(date_timestamp,
-														 value));
+			return date2timestamp_no_overflow(DatumGetDateADT(value));
 		case INTERVALOID:
 			{
 				Interval   *interval = DatumGetIntervalP(value);
diff --git a/src/include/utils/date.h b/src/include/utils/date.h
index 44eb8e81143..15307047504 100644
--- a/src/include/utils/date.h
+++ b/src/include/utils/date.h
@@ -81,6 +81,8 @@ typedef struct
 
 
 /* date.c */
+extern double date2timestamp_no_overflow(DateADT dateVal);
+
 extern Datum date_in(PG_FUNCTION_ARGS);
 extern Datum date_out(PG_FUNCTION_ARGS);
 extern Datum date_recv(PG_FUNCTION_ARGS);