Consistently declare timestamp variables as TimestampTz.

Twiddle the replication-related code so that its timestamp variables
are declared TimestampTz, rather than the uninformative "int64" that
was previously used for meant-to-be-always-integer timestamps.
This resolves the int64-vs-TimestampTz declaration inconsistencies
introduced by commit 7c030783a, though in the opposite direction to
what was originally suggested.

This required including datatype/timestamp.h in a couple more places
than before.  I decided it would be a good idea to slim down that
header by not having it pull in <float.h> etc, as those headers are
no longer at all relevant to its purpose.  Unsurprisingly, a small number
of .c files turn out to have been depending on those inclusions, so add
them back in the .c files as needed.

Discussion: https://postgr.es/m/26788.1487455319@sss.pgh.pa.us
Discussion: https://postgr.es/m/27694.1487456324@sss.pgh.pa.us

3 files changed, 6 insertions, 11 deletions

diff --git a/src/include/utils/snapmgr.h b/src/include/utils/snapmgr.h
index 2618cc4546e..ab953669bf2 100644
--- a/src/include/utils/snapmgr.h
+++ b/src/include/utils/snapmgr.h
@@ -51,8 +51,8 @@ extern PGDLLIMPORT int old_snapshot_threshold;
 
 extern Size SnapMgrShmemSize(void);
 extern void SnapMgrInit(void);
-extern int64 GetSnapshotCurrentTimestamp(void);
-extern int64 GetOldSnapshotThresholdTimestamp(void);
+extern TimestampTz GetSnapshotCurrentTimestamp(void);
+extern TimestampTz GetOldSnapshotThresholdTimestamp(void);
 
 extern bool FirstSnapshotSet;
 
@@ -93,7 +93,8 @@ extern void DeleteAllExportedSnapshotFiles(void);
 extern bool ThereAreNoPriorRegisteredSnapshots(void);
 extern TransactionId TransactionIdLimitedForOldSnapshots(TransactionId recentXmin,
 									Relation relation);
-extern void MaintainOldSnapshotTimeMapping(int64 whenTaken, TransactionId xmin);
+extern void MaintainOldSnapshotTimeMapping(TimestampTz whenTaken,
+							   TransactionId xmin);
 
 extern char *ExportSnapshot(Snapshot snapshot);
 
diff --git a/src/include/utils/snapshot.h b/src/include/utils/snapshot.h
index ebd5d5a85cb..2bcaa42277e 100644
--- a/src/include/utils/snapshot.h
+++ b/src/include/utils/snapshot.h
@@ -15,6 +15,7 @@
 
 #include "access/htup.h"
 #include "access/xlogdefs.h"
+#include "datatype/timestamp.h"
 #include "lib/pairingheap.h"
 #include "storage/buf.h"
 
@@ -107,7 +108,7 @@ typedef struct SnapshotData
 	uint32		regd_count;		/* refcount on RegisteredSnapshots */
 	pairingheap_node ph_node;	/* link in the RegisteredSnapshots heap */
 
-	int64		whenTaken;		/* timestamp when snapshot was taken */
+	TimestampTz whenTaken;		/* timestamp when snapshot was taken */
 	XLogRecPtr	lsn;			/* position in the WAL stream when taken */
 } SnapshotData;
 
diff --git a/src/include/utils/timestamp.h b/src/include/utils/timestamp.h
index d9098354a85..7fd1c7692ff 100644
--- a/src/include/utils/timestamp.h
+++ b/src/include/utils/timestamp.h
@@ -76,13 +76,6 @@ extern bool TimestampDifferenceExceeds(TimestampTz start_time,
 						   TimestampTz stop_time,
 						   int msec);
 
-/*
- * Prototypes for functions to deal with integer timestamps, when the native
- * format is float timestamps.
- */
-#define GetCurrentIntegerTimestamp()	GetCurrentTimestamp()
-#define IntegerTimestampToTimestampTz(timestamp) (timestamp)
-
 extern TimestampTz time_t_to_timestamptz(pg_time_t tm);
 extern pg_time_t timestamptz_to_time_t(TimestampTz t);