3 files changed, 15 insertions, 59 deletions

diff --git a/src/include/storage/buf_internals.h b/src/include/storage/buf_internals.h
index d4dc9eb3429..406db6be783 100644
--- a/src/include/storage/buf_internals.h
+++ b/src/include/storage/buf_internals.h
@@ -92,66 +92,29 @@ typedef struct buftag
 {
 	Oid			spcOid;			/* tablespace oid */
 	Oid			dbOid;			/* database oid */
-
-	/*
-	 * relForkDetails[] stores the fork number in the high 8 bits of the first
-	 * integer; the remaining 56 bits are used to store the relfilenmber.
-	 * Expanding the relfilenumber to a full 64 bits would require widening
-	 * the BufferTag, which is undesirable for performance reasons. We use
-	 * two 32-bit values here rather than a single 64-bit value to avoid
-	 * padding the struct out to a multiple of 8 bytes.
-	 */
-	uint32		relForkDetails[2];
+	RelFileNumber relNumber;	/* relation file number */
+	ForkNumber	forkNum;		/* fork number */
 	BlockNumber blockNum;		/* blknum relative to begin of reln */
 } BufferTag;
 
-/* High relNumber bits in relForkDetails[0] */
-#define	BUFTAG_RELNUM_HIGH_BITS	24
-
-/* Low relNumber bits in relForkDetails[1] */
-#define	BUFTAG_RELNUM_LOW_BITS	32
-
-/* Mask to fetch high bits of relNumber from relForkDetails[0] */
-#define	BUFTAG_RELNUM_HIGH_MASK	((1U << BUFTAG_RELNUM_HIGH_BITS) - 1)
-
-/* Mask to fetch low bits of relNumber from relForkDetails[1] */
-#define	BUFTAG_RELNUM_LOW_MASK	0XFFFFFFFF
-
 static inline RelFileNumber
 BufTagGetRelNumber(const BufferTag *tag)
 {
-	uint64		relnum;
-
-	relnum = ((uint64) tag->relForkDetails[0]) & BUFTAG_RELNUM_HIGH_MASK;
-	relnum = (relnum << BUFTAG_RELNUM_LOW_BITS) | tag->relForkDetails[1];
-
-	Assert(relnum <= MAX_RELFILENUMBER);
-	return (RelFileNumber) relnum;
+	return tag->relNumber;
 }
 
 static inline ForkNumber
 BufTagGetForkNum(const BufferTag *tag)
 {
-	ForkNumber		ret;
-
-	StaticAssertStmt(MAX_FORKNUM <= INT8_MAX,
-					 "MAX_FORKNUM can't be greater than INT8_MAX");
-
-	ret = (ForkNumber) (tag->relForkDetails[0] >> BUFTAG_RELNUM_HIGH_BITS);
-	return ret;
+	return tag->forkNum;
 }
 
 static inline void
 BufTagSetRelForkDetails(BufferTag *tag, RelFileNumber relnumber,
 						ForkNumber forknum)
 {
-	Assert(relnumber <= MAX_RELFILENUMBER);
-	Assert(forknum <= MAX_FORKNUM);
-
-	tag->relForkDetails[0] = (relnumber >> BUFTAG_RELNUM_LOW_BITS) &
-		BUFTAG_RELNUM_HIGH_MASK;
-	tag->relForkDetails[0] |= (forknum << BUFTAG_RELNUM_HIGH_BITS);
-	tag->relForkDetails[1] = relnumber & BUFTAG_RELNUM_LOW_MASK;
+	tag->relNumber = relnumber;
+	tag->forkNum = forknum;
 }
 
 static inline RelFileLocator
@@ -190,9 +153,9 @@ BufferTagsEqual(const BufferTag *tag1, const BufferTag *tag2)
 {
 	return (tag1->spcOid == tag2->spcOid) &&
 		(tag1->dbOid == tag2->dbOid) &&
-		(tag1->relForkDetails[0] == tag2->relForkDetails[0]) &&
-		(tag1->relForkDetails[1] == tag2->relForkDetails[1]) &&
-		(tag1->blockNum == tag2->blockNum);
+		(tag1->relNumber == tag2->relNumber) &&
+		(tag1->blockNum == tag2->blockNum) &&
+		(tag1->forkNum == tag2->forkNum);
 }
 
 static inline bool
diff --git a/src/include/storage/relfilelocator.h b/src/include/storage/relfilelocator.h
index ef904644fa4..10f41f3abb3 100644
--- a/src/include/storage/relfilelocator.h
+++ b/src/include/storage/relfilelocator.h
@@ -32,11 +32,10 @@
  * Nonzero dbOid values correspond to pg_database.oid.
  *
  * relNumber identifies the specific relation.  relNumber corresponds to
- * pg_class.relfilenode.  Notice that relNumber values are assigned by
- * GetNewRelFileNumber(), which will only ever assign the same value once
- * during the lifetime of a cluster.  However, since CREATE DATABASE duplicates
- * the relfilenumbers of the template database, the values are in practice only
- * unique within a database, not globally.
+ * pg_class.relfilenode (NOT pg_class.oid, because we need to be able
+ * to assign new physical files to relations in some situations).
+ * Notice that relNumber is only unique within a database in a particular
+ * tablespace.
  *
  * Note: spcOid must be GLOBALTABLESPACE_OID if and only if dbOid is
  * zero.  We support shared relations only in the "global" tablespace.
@@ -76,9 +75,6 @@ typedef struct RelFileLocatorBackend
 	BackendId	backend;
 } RelFileLocatorBackend;
 
-#define SizeOfRelFileLocatorBackend \
-	(offsetof(RelFileLocatorBackend, backend) + sizeof(BackendId))
-
 #define RelFileLocatorBackendIsTemp(rlocator) \
 	((rlocator).backend != InvalidBackendId)
 
diff --git a/src/include/storage/sinval.h b/src/include/storage/sinval.h
index 4a267be935c..aca0347a3d3 100644
--- a/src/include/storage/sinval.h
+++ b/src/include/storage/sinval.h
@@ -86,14 +86,11 @@ typedef struct
 
 typedef struct
 {
-	/* note: field layout chosen to pack into 20 bytes */
+	/* note: field layout chosen to pack into 16 bytes */
 	int8		id;				/* type field --- must be first */
 	int8		backend_hi;		/* high bits of backend ID, if temprel */
 	uint16		backend_lo;		/* low bits of backend ID, if temprel */
-	Oid			dbOid;
-	Oid			spcOid;
-	uint32		relNumber_hi;	/* avoid 8 byte alignment requirement */
-	uint32		relNumber_lo;
+	RelFileLocator rlocator;	/* spcOid, dbOid, relNumber */
 } SharedInvalSmgrMsg;
 
 #define SHAREDINVALRELMAP_ID	(-4)