mirrors/postgres
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Various utils for WAL

Browse Source
This commit is contained in:
Vadim B. Mikheev 2000-10-13 12:06:40 +00:00
parent deee783052
commit b33428d20c
1 changed files with 120 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

120
src/backend/access/transam/xlogutils.c Normal file
View File

@ -0,0 +1,120 @@
/*-------------------------------------------------------------------------
*
* xlog.c
*
*
* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
* Portions Copyright (c) 1994, Regents of the University of California
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/xlog.h"
#include "access/xact.h"
#ifdef XLOG
/*
* Check if specified heap tuple was inserted by given
* xaction/command and return
*
* - -1 if not
* - 0 if there is no tuple at all
* - 1 if yes
*/
int
XLogIsOwnerOfTuple(RelFileNode hnode, ItemPointer iptr,
TransactionId xid, CommandId cid)
{
Relation reln;
Buffer buffer;
Page page;
ItemId lp;
HeapTupleHeader htup;
reln = XLogOpenRelation(false, RM_HEAP_ID, hnode);
if (!RelationIsValid(reln))
return(0);
buffer = ReadBuffer(reln, ItemPointerGetBlockNumber(iptr));
if (!BufferIsValid(buffer))
return(0);
LockBuffer(buffer, BUFFER_LOCK_SHARE);
page = (Page) BufferGetPage(buffer);
if (PageIsNew((PageHeader) page) ||
ItemPointerGetOffsetNumber(iptr) > PageGetMaxOffsetNumber(page))
{
UnlockAndReleaseBuffer(buffer);
return(0);
}
lp = PageGetItemId(page, ItemPointerGetOffsetNumber(iptr));
if (!ItemIdIsUsed(lp) || ItemIdDeleted(lp))
{
UnlockAndReleaseBuffer(buffer);
return(0);
}
htup = (HeapTupleHeader) PageGetItem(page, lp);
if (PageGetSUI(page) != ThisStartUpID || htup->t_xmin != xid || htup->t_cmin != cid)
{
UnlockAndReleaseBuffer(buffer);
return(-1);
}
UnlockAndReleaseBuffer(buffer);
return(1);
}
/*
* Check if exists valid (inserted by not aborted xaction) heap tuple
* for given item pointer
*/
bool
XLogIsValidTuple(RelFileNode hnode, ItemPointer iptr)
{
Relation reln;
Buffer buffer;
Page page;
ItemId lp;
HeapTupleHeader htup;
reln = XLogOpenRelation(false, RM_HEAP_ID, hnode);
if (!RelationIsValid(reln))
return(false);
buffer = ReadBuffer(reln, ItemPointerGetBlockNumber(iptr));
if (!BufferIsValid(buffer))
return(false);
LockBuffer(buffer, BUFFER_LOCK_SHARE);
page = (Page) BufferGetPage(buffer);
if (PageIsNew((PageHeader) page) ||
ItemPointerGetOffsetNumber(iptr) > PageGetMaxOffsetNumber(page))
{
UnlockAndReleaseBuffer(buffer);
return(false);
}
lp = PageGetItemId(page, ItemPointerGetOffsetNumber(iptr));
if (!ItemIdIsUsed(lp) || ItemIdDeleted(lp))
{
UnlockAndReleaseBuffer(buffer);
return(false);
}
htup = (HeapTupleHeader) PageGetItem(page, lp);
if (XLogIsAborted(PageGetSUI(page), htup->t_xmin))
{
UnlockAndReleaseBuffer(buffer);
return(false);
}
UnlockAndReleaseBuffer(buffer);
return(true);
}
#endif