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Diffstat (limited to 'src/backend/storage/buffer/bufmgr.c')
-rw-r--r--src/backend/storage/buffer/bufmgr.c76
1 files changed, 26 insertions, 50 deletions
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index d5ff24df022..06abd2e8675 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/storage/buffer/bufmgr.c,v 1.111 2001/05/12 19:58:27 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/storage/buffer/bufmgr.c,v 1.112 2001/06/09 18:16:57 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -96,43 +96,6 @@ static int ReleaseBufferWithBufferLock(Buffer buffer);
static int BufferReplace(BufferDesc *bufHdr);
void PrintBufferDescs(void);
-/* ---------------------------------------------------
- * RelationGetBufferWithBuffer
- * see if the given buffer is what we want
- * if yes, we don't need to bother the buffer manager
- * ---------------------------------------------------
- */
-Buffer
-RelationGetBufferWithBuffer(Relation relation,
- BlockNumber blockNumber,
- Buffer buffer)
-{
- BufferDesc *bufHdr;
-
- if (BufferIsValid(buffer))
- {
- if (!BufferIsLocal(buffer))
- {
- bufHdr = &BufferDescriptors[buffer - 1];
- SpinAcquire(BufMgrLock);
- if (bufHdr->tag.blockNum == blockNumber &&
- RelFileNodeEquals(bufHdr->tag.rnode, relation->rd_node))
- {
- SpinRelease(BufMgrLock);
- return buffer;
- }
- return ReadBufferInternal(relation, blockNumber, false, true);
- }
- else
- {
- bufHdr = &LocalBufferDescriptors[-buffer - 1];
- if (bufHdr->tag.blockNum == blockNumber &&
- RelFileNodeEquals(bufHdr->tag.rnode, relation->rd_node))
- return buffer;
- }
- }
- return ReadBufferInternal(relation, blockNumber, false, false);
-}
/*
* ReadBuffer -- returns a buffer containing the requested
@@ -141,7 +104,8 @@ RelationGetBufferWithBuffer(Relation relation,
* allocate a new block.
*
* Returns: the buffer number for the buffer containing
- * the block read or NULL on an error.
+ * the block read, or NULL on an error. If successful,
+ * the returned buffer has been pinned.
*
* Assume when this function is called, that reln has been
* opened already.
@@ -300,8 +264,8 @@ ReadBufferInternal(Relation reln, BlockNumber blockNum,
}
/*
- * BufferAlloc -- Get a buffer from the buffer pool but dont
- * read it.
+ * BufferAlloc -- Get a buffer from the buffer pool but don't
+ * read it. If successful, the returned buffer is pinned.
*
* Returns: descriptor for buffer
*
@@ -684,6 +648,11 @@ WriteNoReleaseBuffer(Buffer buffer)
* Note: it is OK to pass buffer = InvalidBuffer, indicating that no old
* buffer actually needs to be released. This case is the same as ReadBuffer
* except for the isExtend option.
+ *
+ * Also, if the passed buffer is valid and already contains the desired block
+ * number, we simply return it without ever acquiring the spinlock at all.
+ * Since the passed buffer must be pinned, it's OK to examine its block
+ * number without getting the lock first.
*/
Buffer
ReleaseAndReadBuffer(Buffer buffer,
@@ -698,12 +667,19 @@ ReleaseAndReadBuffer(Buffer buffer,
if (BufferIsLocal(buffer))
{
Assert(LocalRefCount[-buffer - 1] > 0);
+ bufHdr = &LocalBufferDescriptors[-buffer - 1];
+ if (bufHdr->tag.blockNum == blockNum &&
+ RelFileNodeEquals(bufHdr->tag.rnode, relation->rd_node))
+ return buffer;
LocalRefCount[-buffer - 1]--;
}
else
{
- bufHdr = &BufferDescriptors[buffer - 1];
Assert(PrivateRefCount[buffer - 1] > 0);
+ bufHdr = &BufferDescriptors[buffer - 1];
+ if (bufHdr->tag.blockNum == blockNum &&
+ RelFileNodeEquals(bufHdr->tag.rnode, relation->rd_node))
+ return buffer;
if (PrivateRefCount[buffer - 1] > 1)
PrivateRefCount[buffer - 1]--;
else
@@ -1002,7 +978,7 @@ BufferPoolCheckLeak()
BufferDesc *buf = &(BufferDescriptors[i - 1]);
elog(NOTICE,
- "Buffer Leak: [%03d] (freeNext=%ld, freePrev=%ld, \
+ "Buffer Leak: [%03d] (freeNext=%d, freePrev=%d, \
relname=%s, blockNum=%d, flags=0x%x, refcount=%d %ld)",
i - 1, buf->freeNext, buf->freePrev,
buf->blind.relname, buf->tag.blockNum, buf->flags,
@@ -1396,7 +1372,7 @@ PrintBufferDescs()
SpinAcquire(BufMgrLock);
for (i = 0; i < NBuffers; ++i, ++buf)
{
- elog(DEBUG, "[%02d] (freeNext=%ld, freePrev=%ld, relname=%s, \
+ elog(DEBUG, "[%02d] (freeNext=%d, freePrev=%d, relname=%s, \
blockNum=%d, flags=0x%x, refcount=%d %ld)",
i, buf->freeNext, buf->freePrev,
buf->blind.relname, buf->tag.blockNum, buf->flags,
@@ -1426,7 +1402,7 @@ PrintPinnedBufs()
for (i = 0; i < NBuffers; ++i, ++buf)
{
if (PrivateRefCount[i] > 0)
- elog(NOTICE, "[%02d] (freeNext=%ld, freePrev=%ld, relname=%s, \
+ elog(NOTICE, "[%02d] (freeNext=%d, freePrev=%d, relname=%s, \
blockNum=%d, flags=0x%x, refcount=%d %ld)\n",
i, buf->freeNext, buf->freePrev, buf->blind.relname,
buf->tag.blockNum, buf->flags,
@@ -1719,7 +1695,7 @@ IncrBufferRefCount_Debug(char *file, int line, Buffer buffer)
{
BufferDesc *buf = &BufferDescriptors[buffer - 1];
- fprintf(stderr, "PIN(Incr) %ld relname = %s, blockNum = %d, \
+ fprintf(stderr, "PIN(Incr) %d relname = %s, blockNum = %d, \
refcount = %ld, file: %s, line: %d\n",
buffer, buf->blind.relname, buf->tag.blockNum,
PrivateRefCount[buffer - 1], file, line);
@@ -1737,7 +1713,7 @@ ReleaseBuffer_Debug(char *file, int line, Buffer buffer)
{
BufferDesc *buf = &BufferDescriptors[buffer - 1];
- fprintf(stderr, "UNPIN(Rel) %ld relname = %s, blockNum = %d, \
+ fprintf(stderr, "UNPIN(Rel) %d relname = %s, blockNum = %d, \
refcount = %ld, file: %s, line: %d\n",
buffer, buf->blind.relname, buf->tag.blockNum,
PrivateRefCount[buffer - 1], file, line);
@@ -1765,7 +1741,7 @@ ReleaseAndReadBuffer_Debug(char *file,
{
BufferDesc *buf = &BufferDescriptors[buffer - 1];
- fprintf(stderr, "UNPIN(Rel&Rd) %ld relname = %s, blockNum = %d, \
+ fprintf(stderr, "UNPIN(Rel&Rd) %d relname = %s, blockNum = %d, \
refcount = %ld, file: %s, line: %d\n",
buffer, buf->blind.relname, buf->tag.blockNum,
PrivateRefCount[buffer - 1], file, line);
@@ -1774,7 +1750,7 @@ refcount = %ld, file: %s, line: %d\n",
{
BufferDesc *buf = &BufferDescriptors[b - 1];
- fprintf(stderr, "PIN(Rel&Rd) %ld relname = %s, blockNum = %d, \
+ fprintf(stderr, "PIN(Rel&Rd) %d relname = %s, blockNum = %d, \
refcount = %ld, file: %s, line: %d\n",
b, buf->blind.relname, buf->tag.blockNum,
PrivateRefCount[b - 1], file, line);
@@ -2057,7 +2033,7 @@ LockBuffer(Buffer buffer, int mode)
{
S_UNLOCK(&(buf->cntx_lock));
RESUME_INTERRUPTS();
- elog(ERROR, "UNLockBuffer: buffer %lu is not locked", buffer);
+ elog(ERROR, "UNLockBuffer: buffer %d is not locked", buffer);
}
}
else if (mode == BUFFER_LOCK_SHARE)
generated by cgit v1.2.3 (git 2.25.1) at 2025-05-22 23:36:53 +0000