Fixed bug where FlushRelationBuffers() did call StrategyInvalidateBuffer()

for already empty buffers because their buffer tag was not cleard out
when the buffers have been invalidated before.

Also removed the misnamed BM_FREE bufhdr flag and replaced the checks,
which effectively ask if the buffer is unpinned, with checks against the
refcount field.

Jan

1 files changed, 26 insertions, 111 deletions

diff --git a/src/backend/storage/buffer/freelist.c b/src/backend/storage/buffer/freelist.c
index 74ec4518ab9..595e4905a80 100644
--- a/src/backend/storage/buffer/freelist.c
+++ b/src/backend/storage/buffer/freelist.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/storage/buffer/freelist.c,v 1.40 2004/02/06 19:36:18 wieck Exp $
+ *	  $PostgreSQL: pgsql/src/backend/storage/buffer/freelist.c,v 1.41 2004/02/12 15:06:56 wieck Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -662,9 +662,6 @@ void
 StrategyInvalidateBuffer(BufferDesc *buf)
 {
 	int					cdb_id;
-#ifdef USE_ASSERT_CHECKING
-	int					buf_id;
-#endif
 	BufferStrategyCDB  *cdb;
 
 	/* The buffer cannot be dirty or pinned */
@@ -672,41 +669,37 @@ StrategyInvalidateBuffer(BufferDesc *buf)
 	Assert(buf->refcount == 0);
 
 	/*
-	 * If we have the buffer somewhere in the directory, remove it,
-	 * add the CDB to the list of unused CDB's. and the buffer to
-	 * the list of free buffers
+	 * Lookup the cache directory block for this buffer
 	 */
 	cdb_id = BufTableLookup(&(buf->tag));
-	if (cdb_id >= 0)
-	{
-		cdb = &StrategyCDB[cdb_id];
-		BufTableDelete(&(cdb->buf_tag));
-		STRAT_LIST_REMOVE(cdb);
-		cdb->buf_id = -1;
-		cdb->next = StrategyControl->listUnusedCDB;
-		StrategyControl->listUnusedCDB = cdb_id;
-
-		buf->bufNext = StrategyControl->listFreeBuffers;
-		StrategyControl->listFreeBuffers = buf->buf_id;
-		return;
-	}
+	if (cdb_id < 0)
+		elog(ERROR, "StrategyInvalidateBuffer() buffer %d not in directory",
+				buf->buf_id);
+	cdb = &StrategyCDB[cdb_id];
 
-#ifdef USE_ASSERT_CHECKING
 	/*
-	 * Check that we have this buffer in the freelist already.
+	 * Remove the CDB from the hashtable and the ARC queue it is
+	 * currently on.
 	 */
-	buf_id = StrategyControl->listFreeBuffers;
-	while (buf_id >= 0)
-	{
-		if (buf == &BufferDescriptors[buf_id])
-			return;
+	BufTableDelete(&(cdb->buf_tag));
+	STRAT_LIST_REMOVE(cdb);
 
-		buf_id = BufferDescriptors[buf_id].bufNext;
-	}
+	/*
+	 * Clear out the CDB's buffer tag and association with the buffer
+	 * and add it to the list of unused CDB's
+	 */
+	CLEAR_BUFFERTAG(&(cdb->buf_tag));
+	cdb->buf_id = -1;
+	cdb->next = StrategyControl->listUnusedCDB;
+	StrategyControl->listUnusedCDB = cdb_id;
 
-	elog(ERROR, "StrategyInvalidateBuffer() buffer %d not in directory or freelist",
-				buf->buf_id);
-#endif
+	/*
+	 * Clear out the buffers tag and add it to the list of
+	 * currently unused buffers.
+	 */
+	CLEAR_BUFFERTAG(&(buf->tag));
+	buf->bufNext = StrategyControl->listFreeBuffers;
+	StrategyControl->listFreeBuffers = buf->buf_id;
 }
 
 
@@ -869,12 +862,6 @@ PinBuffer(BufferDesc *buf)
 {
 	int			b = BufferDescriptorGetBuffer(buf) - 1;
 
-	if (buf->refcount == 0)
-	{
-		/* mark buffer as no longer free */
-		buf->flags &= ~BM_FREE;
-	}
-
 	if (PrivateRefCount[b] == 0)
 		buf->refcount++;
 	PrivateRefCount[b]++;
@@ -917,12 +904,7 @@ UnpinBuffer(BufferDesc *buf)
 	if (PrivateRefCount[b] == 0)
 		buf->refcount--;
 
-	if (buf->refcount == 0)
-	{
-		/* buffer is now unpinned */
-		buf->flags |= BM_FREE;
-	}
-	else if ((buf->flags & BM_PIN_COUNT_WAITER) != 0 &&
+	if ((buf->flags & BM_PIN_COUNT_WAITER) != 0 &&
 			 buf->refcount == 1)
 	{
 		/* we just released the last pin other than the waiter's */
@@ -953,70 +935,3 @@ refcount = %ld, file: %s, line: %d\n",
 #endif
 
 
-/*
- * print out the free list and check for breaks.
- */
-#ifdef NOT_USED
-void
-DBG_FreeListCheck(int nfree)
-{
-	int			i;
-	BufferDesc *buf;
-
-	buf = &(BufferDescriptors[SharedFreeList->freeNext]);
-	for (i = 0; i < nfree; i++, buf = &(BufferDescriptors[buf->freeNext]))
-	{
-		if (!(buf->flags & (BM_FREE)))
-		{
-			if (buf != SharedFreeList)
-				printf("\tfree list corrupted: %d flags %x\n",
-					   buf->buf_id, buf->flags);
-			else
-				printf("\tfree list corrupted: too short -- %d not %d\n",
-					   i, nfree);
-		}
-		if ((BufferDescriptors[buf->freeNext].freePrev != buf->buf_id) ||
-			(BufferDescriptors[buf->freePrev].freeNext != buf->buf_id))
-			printf("\tfree list links corrupted: %d %ld %ld\n",
-				   buf->buf_id, buf->freePrev, buf->freeNext);
-	}
-	if (buf != SharedFreeList)
-		printf("\tfree list corrupted: %d-th buffer is %d\n",
-			   nfree, buf->buf_id);
-}
-#endif
-
-#ifdef NOT_USED
-/*
- * PrintBufferFreeList -
- *	  prints the buffer free list, for debugging
- */
-static void
-PrintBufferFreeList()
-{
-	BufferDesc *buf;
-
-	if (SharedFreeList->freeNext == Free_List_Descriptor)
-	{
-		printf("free list is empty.\n");
-		return;
-	}
-
-	buf = &(BufferDescriptors[SharedFreeList->freeNext]);
-	for (;;)
-	{
-		int			i = (buf - BufferDescriptors);
-
-		printf("[%-2d] (%s, %d) flags=0x%x, refcnt=%d %ld, nxt=%ld prv=%ld)\n",
-			   i, buf->blind.relname, buf->tag.blockNum,
-			   buf->flags, buf->refcount, PrivateRefCount[i],
-			   buf->freeNext, buf->freePrev);
-
-		if (buf->freeNext == Free_List_Descriptor)
-			break;
-
-		buf = &(BufferDescriptors[buf->freeNext]);
-	}
-}
-
-#endif