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Blowaway relation buffers from buffer pool before truncation:

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+ BlowawayRelationBuffers(relation, blocknumber)
This commit is contained in:
Vadim B. Mikheev 1997-09-22 07:13:56 +00:00
parent 708f67c7a9
commit 5fb82eb4c7
1 changed files with 65 additions and 1 deletions
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66
src/backend/storage/buffer/bufmgr.c
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@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/storage/buffer/bufmgr.c,v 1.25 1997/09/18 20:21:21 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/storage/buffer/bufmgr.c,v 1.26 1997/09/22 07:13:56 vadim Exp $
*
*-------------------------------------------------------------------------
*/
@ -99,6 +99,9 @@ static int FlushBuffer(Buffer buffer, bool release);
static void BufferSync(void);
static int BufferReplace(BufferDesc *bufHdr, bool bufferLockHeld);
/* not static but used by vacuum only ... */
int BlowawayRelationBuffers(Relation rdesc, BlockNumber block);
/* ---------------------------------------------------
* RelationGetBufferWithBuffer
* see if the given buffer is what we want
@ -1603,6 +1606,67 @@ BufferPoolBlowaway()
#endif
/* ---------------------------------------------------------------------
* BlowawayRelationBuffers
*
* This function blowaway all the pages with blocknumber >= passed
* of a relation in the buffer pool. Used by vacuum before truncation...
*
* Returns: 0 - Ok, -1 - DIRTY, -2 - PINNED
*
* XXX currently it sequentially searches the buffer pool, should be
* changed to more clever ways of searching.
* --------------------------------------------------------------------
*/
int
BlowawayRelationBuffers(Relation rdesc, BlockNumber block)
{
register int i;
BufferDesc *buf;
if (rdesc->rd_islocal)
{
for (i = 0; i < NLocBuffer; i++)
{
buf = &LocalBufferDescriptors[i];
if (buf->tag.relId.relId == rdesc->rd_id &&
buf->tag.blockNum >= block)
{
if (buf->flags & BM_DIRTY)
return (-1);
if (LocalRefCount[i] > 0)
return (-2);
buf->tag.relId.relId = InvalidOid;
}
}
return (0);
}
SpinAcquire(BufMgrLock);
for (i = 0; i < NBuffers; i++)
{
buf = &BufferDescriptors[i];
if (buf->tag.relId.dbId == MyDatabaseId &&
buf->tag.relId.relId == rdesc->rd_id &&
buf->tag.blockNum >= block)
{
if (buf->flags & BM_DIRTY)
{
SpinRelease(BufMgrLock);
return (-1);
}
if (!(buf->flags & BM_FREE))
{
SpinRelease(BufMgrLock);
return (-2);
}
BufTableDelete(buf);
}
}
SpinRelease(BufMgrLock);
return (0);
}
#undef IncrBufferRefCount
#undef ReleaseBuffer