Fix free space map to correctly track the total amount of FSM space needed

even when a single relation requires more than max_fsm_pages pages.  Also,
make VACUUM emit a warning in this case, since it likely means that VACUUM
FULL or other drastic corrective measure is needed.  Per reports from Jeff
Frost and others of unexpected changes in the claimed max_fsm_pages need.

3 files changed, 29 insertions, 21 deletions

diff --git a/src/backend/access/gin/ginvacuum.c b/src/backend/access/gin/ginvacuum.c
index 2bc80a26433..31e5f647f07 100644
--- a/src/backend/access/gin/ginvacuum.c
+++ b/src/backend/access/gin/ginvacuum.c
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *          $PostgreSQL: pgsql/src/backend/access/gin/ginvacuum.c,v 1.5 2006/07/31 20:08:59 tgl Exp $
+ *          $PostgreSQL: pgsql/src/backend/access/gin/ginvacuum.c,v 1.6 2006/09/21 20:31:21 tgl Exp $
  *-------------------------------------------------------------------------
  */
 
@@ -575,7 +575,8 @@ ginvacuumcleanup(PG_FUNCTION_ARGS) {
 	bool	 needLock;
     BlockNumber npages,
 				blkno;
-	BlockNumber nFreePages,
+	BlockNumber totFreePages,
+				nFreePages,
 			   *freePages,
 			   maxFreePages;
 	BlockNumber lastBlock = GIN_ROOT_BLKNO,
@@ -610,7 +611,7 @@ ginvacuumcleanup(PG_FUNCTION_ARGS) {
 	if (maxFreePages > MaxFSMPages)
 		maxFreePages = MaxFSMPages;
 
-	nFreePages = 0;
+	totFreePages = nFreePages = 0;
 	freePages = (BlockNumber *) palloc(sizeof(BlockNumber) * maxFreePages);
 
 	for (blkno = GIN_ROOT_BLKNO + 1; blkno < npages; blkno++) {
@@ -626,6 +627,7 @@ ginvacuumcleanup(PG_FUNCTION_ARGS) {
 		if ( GinPageIsDeleted(page) ) {
 			if (nFreePages < maxFreePages)
 				freePages[nFreePages++] = blkno;
+			totFreePages++;
 		} else
 			lastFilledBlock = blkno;
 
@@ -638,7 +640,7 @@ ginvacuumcleanup(PG_FUNCTION_ARGS) {
 		int         i;
 		for (i = 0; i < nFreePages; i++) 
 			if (freePages[i] >= lastFilledBlock) {
-				nFreePages = i;
+				totFreePages = nFreePages = i;
 				break;
 			}
 
@@ -648,8 +650,8 @@ ginvacuumcleanup(PG_FUNCTION_ARGS) {
 		stats->pages_removed = lastBlock - lastFilledBlock;
 	}
 
-	RecordIndexFreeSpace(&index->rd_node, nFreePages, freePages);
-	stats->pages_free = nFreePages;
+	RecordIndexFreeSpace(&index->rd_node, totFreePages, nFreePages, freePages);
+	stats->pages_free = totFreePages;
 
 	if (needLock)
 		LockRelationForExtension(index, ExclusiveLock);
diff --git a/src/backend/access/gist/gistvacuum.c b/src/backend/access/gist/gistvacuum.c
index 37b5631b281..e5c73c8c224 100644
--- a/src/backend/access/gist/gistvacuum.c
+++ b/src/backend/access/gist/gistvacuum.c
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/gist/gistvacuum.c,v 1.26 2006/07/31 20:08:59 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/gist/gistvacuum.c,v 1.27 2006/09/21 20:31:21 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -491,7 +491,8 @@ gistvacuumcleanup(PG_FUNCTION_ARGS)
 	Relation	rel = info->index;
 	BlockNumber npages,
 				blkno;
-	BlockNumber nFreePages,
+	BlockNumber totFreePages,
+				nFreePages,
 			   *freePages,
 				maxFreePages;
 	BlockNumber lastBlock = GIST_ROOT_BLKNO,
@@ -563,8 +564,9 @@ gistvacuumcleanup(PG_FUNCTION_ARGS)
 	if (maxFreePages > MaxFSMPages)
 		maxFreePages = MaxFSMPages;
 
-	nFreePages = 0;
+	totFreePages = nFreePages = 0;
 	freePages = (BlockNumber *) palloc(sizeof(BlockNumber) * maxFreePages);
+
 	for (blkno = GIST_ROOT_BLKNO + 1; blkno < npages; blkno++)
 	{
 		Buffer		buffer;
@@ -579,10 +581,8 @@ gistvacuumcleanup(PG_FUNCTION_ARGS)
 		if (PageIsNew(page) || GistPageIsDeleted(page))
 		{
 			if (nFreePages < maxFreePages)
-			{
-				freePages[nFreePages] = blkno;
-				nFreePages++;
-			}
+				freePages[nFreePages++] = blkno;
+			totFreePages++;
 		}
 		else
 			lastFilledBlock = blkno;
@@ -597,7 +597,7 @@ gistvacuumcleanup(PG_FUNCTION_ARGS)
 		for (i = 0; i < nFreePages; i++)
 			if (freePages[i] >= lastFilledBlock)
 			{
-				nFreePages = i;
+				totFreePages = nFreePages = i;
 				break;
 			}
 
@@ -606,11 +606,11 @@ gistvacuumcleanup(PG_FUNCTION_ARGS)
 		stats->std.pages_removed = lastBlock - lastFilledBlock;
 	}
 
-	RecordIndexFreeSpace(&rel->rd_node, nFreePages, freePages);
+	RecordIndexFreeSpace(&rel->rd_node, totFreePages, nFreePages, freePages);
 	pfree(freePages);
 
 	/* return statistics */
-	stats->std.pages_free = nFreePages;
+	stats->std.pages_free = totFreePages;
 	if (needLock)
 		LockRelationForExtension(rel, ExclusiveLock);
 	stats->std.num_pages = RelationGetNumberOfBlocks(rel);
diff --git a/src/backend/access/nbtree/nbtree.c b/src/backend/access/nbtree/nbtree.c
index c58974cca13..fa5b162c908 100644
--- a/src/backend/access/nbtree/nbtree.c
+++ b/src/backend/access/nbtree/nbtree.c
@@ -12,7 +12,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/nbtree/nbtree.c,v 1.150 2006/08/24 01:18:34 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/nbtree/nbtree.c,v 1.151 2006/09/21 20:31:22 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -53,8 +53,9 @@ typedef struct
 	void	   *callback_state;
 	BTCycleId	cycleid;
 	BlockNumber *freePages;
-	int			nFreePages;
-	int			maxFreePages;
+	int			nFreePages;		/* number of entries in freePages[] */
+	int			maxFreePages;	/* allocated size of freePages[] */
+	BlockNumber	totFreePages;	/* true total # of free pages */
 	MemoryContext pagedelcontext;
 } BTVacState;
 
@@ -636,6 +637,7 @@ btvacuumscan(IndexVacuumInfo *info, IndexBulkDeleteResult *stats,
 	vstate.freePages = NULL;	/* temporarily */
 	vstate.nFreePages = 0;
 	vstate.maxFreePages = 0;
+	vstate.totFreePages = 0;
 
 	/* Create a temporary memory context to run _bt_pagedel in */
 	vstate.pagedelcontext = AllocSetContextCreate(CurrentMemoryContext,
@@ -716,6 +718,7 @@ btvacuumscan(IndexVacuumInfo *info, IndexBulkDeleteResult *stats,
 			new_pages--;
 			stats->pages_deleted--;
 			vstate.nFreePages--;
+			vstate.totFreePages = vstate.nFreePages;	/* can't be more */
 		}
 		if (new_pages != num_pages)
 		{
@@ -736,7 +739,8 @@ btvacuumscan(IndexVacuumInfo *info, IndexBulkDeleteResult *stats,
 	 * pages in the index, discarding any old info the map may have. We do not
 	 * need to sort the page numbers; they're in order already.
 	 */
-	RecordIndexFreeSpace(&rel->rd_node, vstate.nFreePages, vstate.freePages);
+	RecordIndexFreeSpace(&rel->rd_node, vstate.totFreePages,
+						 vstate.nFreePages, vstate.freePages);
 
 	pfree(vstate.freePages);
 
@@ -744,7 +748,7 @@ btvacuumscan(IndexVacuumInfo *info, IndexBulkDeleteResult *stats,
 
 	/* update statistics */
 	stats->num_pages = num_pages;
-	stats->pages_free = vstate.nFreePages;
+	stats->pages_free = vstate.totFreePages;
 }
 
 /*
@@ -816,6 +820,7 @@ restart:
 		/* Okay to recycle this page */
 		if (vstate->nFreePages < vstate->maxFreePages)
 			vstate->freePages[vstate->nFreePages++] = blkno;
+		vstate->totFreePages++;
 		stats->pages_deleted++;
 	}
 	else if (P_ISDELETED(opaque))
@@ -954,6 +959,7 @@ restart:
 		{
 			if (vstate->nFreePages < vstate->maxFreePages)
 				vstate->freePages[vstate->nFreePages++] = blkno;
+			vstate->totFreePages++;
 		}
 
 		MemoryContextSwitchTo(oldcontext);