Repair possible failure to update hint bits back to disk, per

http://archives.postgresql.org/pgsql-hackers/2004-10/msg00464.php.
This fix is intended to be permanent: it moves the responsibility for
calling SetBufferCommitInfoNeedsSave() into the tqual.c routines,
eliminating the requirement for callers to test whether t_infomask changed.
Also, tighten validity checking on buffer IDs in bufmgr.c --- several
routines were paranoid about out-of-range shared buffer numbers but not
about out-of-range local ones, which seems a tad pointless.

2 files changed, 16 insertions, 34 deletions

diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index 232ec9a89e6..3d0c6e0e996 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -13,7 +13,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/vacuum.c,v 1.294 2004/10/07 14:19:58 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/vacuum.c,v 1.295 2004/10/15 22:39:56 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1190,6 +1190,12 @@ scan_heap(VRelStats *vacrelstats, Relation onerel,
 		buf = ReadBuffer(onerel, blkno);
 		page = BufferGetPage(buf);
 
+		/*
+		 * We don't bother to do LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE)
+		 * because we assume that holding exclusive lock on the relation
+		 * will keep other backends from looking at the page.
+		 */
+
 		vacpage->blkno = blkno;
 		vacpage->offsets_used = 0;
 		vacpage->offsets_free = 0;
@@ -1235,7 +1241,6 @@ scan_heap(VRelStats *vacrelstats, Relation onerel,
 			 offnum <= maxoff;
 			 offnum = OffsetNumberNext(offnum))
 		{
-			uint16		sv_infomask;
 			ItemId		itemid = PageGetItemId(page, offnum);
 			bool		tupgone = false;
 
@@ -1255,9 +1260,7 @@ scan_heap(VRelStats *vacrelstats, Relation onerel,
 			tuple.t_len = ItemIdGetLength(itemid);
 			ItemPointerSet(&(tuple.t_self), blkno, offnum);
 
-			sv_infomask = tuple.t_data->t_infomask;
-
-			switch (HeapTupleSatisfiesVacuum(tuple.t_data, OldestXmin))
+			switch (HeapTupleSatisfiesVacuum(tuple.t_data, OldestXmin, buf))
 			{
 				case HEAPTUPLE_DEAD:
 					tupgone = true;		/* we can delete the tuple */
@@ -1348,10 +1351,6 @@ scan_heap(VRelStats *vacrelstats, Relation onerel,
 					break;
 			}
 
-			/* check for hint-bit update by HeapTupleSatisfiesVacuum */
-			if (sv_infomask != tuple.t_data->t_infomask)
-				pgchanged = true;
-
 			if (tupgone)
 			{
 				ItemId		lpp;
diff --git a/src/backend/commands/vacuumlazy.c b/src/backend/commands/vacuumlazy.c
index ebdb27f336f..62ba05f9698 100644
--- a/src/backend/commands/vacuumlazy.c
+++ b/src/backend/commands/vacuumlazy.c
@@ -31,7 +31,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/vacuumlazy.c,v 1.46 2004/09/30 23:21:19 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/vacuumlazy.c,v 1.47 2004/10/15 22:39:56 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -291,7 +291,6 @@ lazy_scan_heap(Relation onerel, LVRelStats *vacrelstats,
 			 offnum = OffsetNumberNext(offnum))
 		{
 			ItemId		itemid;
-			uint16		sv_infomask;
 
 			itemid = PageGetItemId(page, offnum);
 
@@ -307,9 +306,8 @@ lazy_scan_heap(Relation onerel, LVRelStats *vacrelstats,
 			ItemPointerSet(&(tuple.t_self), blkno, offnum);
 
 			tupgone = false;
-			sv_infomask = tuple.t_data->t_infomask;
 
-			switch (HeapTupleSatisfiesVacuum(tuple.t_data, OldestXmin))
+			switch (HeapTupleSatisfiesVacuum(tuple.t_data, OldestXmin, buf))
 			{
 				case HEAPTUPLE_DEAD:
 					tupgone = true;		/* we can delete the tuple */
@@ -364,10 +362,6 @@ lazy_scan_heap(Relation onerel, LVRelStats *vacrelstats,
 					break;
 			}
 
-			/* check for hint-bit update by HeapTupleSatisfiesVacuum */
-			if (sv_infomask != tuple.t_data->t_infomask)
-				pgchanged = true;
-
 			if (tupgone)
 			{
 				lazy_record_dead_tuple(vacrelstats, &(tuple.t_self));
@@ -399,9 +393,9 @@ lazy_scan_heap(Relation onerel, LVRelStats *vacrelstats,
 		LockBuffer(buf, BUFFER_LOCK_UNLOCK);
 
 		if (pgchanged)
-			SetBufferCommitInfoNeedsSave(buf);
-
-		ReleaseBuffer(buf);
+			WriteBuffer(buf);
+		else
+			ReleaseBuffer(buf);
 	}
 
 	/* save stats for use later */
@@ -790,8 +784,7 @@ count_nondeletable_pages(Relation onerel, LVRelStats *vacrelstats)
 		Page		page;
 		OffsetNumber offnum,
 					maxoff;
-		bool		pgchanged,
-					tupgone,
+		bool		tupgone,
 					hastup;
 
 		vacuum_delay_point();
@@ -813,7 +806,6 @@ count_nondeletable_pages(Relation onerel, LVRelStats *vacrelstats)
 			continue;
 		}
 
-		pgchanged = false;
 		hastup = false;
 		maxoff = PageGetMaxOffsetNumber(page);
 		for (offnum = FirstOffsetNumber;
@@ -821,7 +813,6 @@ count_nondeletable_pages(Relation onerel, LVRelStats *vacrelstats)
 			 offnum = OffsetNumberNext(offnum))
 		{
 			ItemId		itemid;
-			uint16		sv_infomask;
 
 			itemid = PageGetItemId(page, offnum);
 
@@ -834,9 +825,8 @@ count_nondeletable_pages(Relation onerel, LVRelStats *vacrelstats)
 			ItemPointerSet(&(tuple.t_self), blkno, offnum);
 
 			tupgone = false;
-			sv_infomask = tuple.t_data->t_infomask;
 
-			switch (HeapTupleSatisfiesVacuum(tuple.t_data, OldestXmin))
+			switch (HeapTupleSatisfiesVacuum(tuple.t_data, OldestXmin, buf))
 			{
 				case HEAPTUPLE_DEAD:
 					tupgone = true;		/* we can delete the tuple */
@@ -862,10 +852,6 @@ count_nondeletable_pages(Relation onerel, LVRelStats *vacrelstats)
 					break;
 			}
 
-			/* check for hint-bit update by HeapTupleSatisfiesVacuum */
-			if (sv_infomask != tuple.t_data->t_infomask)
-				pgchanged = true;
-
 			if (!tupgone)
 			{
 				hastup = true;
@@ -875,10 +861,7 @@ count_nondeletable_pages(Relation onerel, LVRelStats *vacrelstats)
 
 		LockBuffer(buf, BUFFER_LOCK_UNLOCK);
 
-		if (pgchanged)
-			WriteBuffer(buf);
-		else
-			ReleaseBuffer(buf);
+		ReleaseBuffer(buf);
 
 		/* Done scanning if we found a tuple here */
 		if (hastup)