1. xact.c: update comments about changing MyProc->xid and MyProc->xmin.

2. varsup.c:ReadNewTransactionId(): don't read nextXid from disk -
   this func doesn't allocate next xid, so ShmemVariableCache->nextXid
   may be used (but GetNewTransactionId() must be called first).
3. vacuum.c: change elog(ERROR, "Child item....") to elog(NOTICE) -
   this is not ERROR, proper handling is just not implemented, yet.
4. s_lock.c: increase S_MAX_BUSY by 2 times.
5. shmem.c:GetSnapshotData(): have to call ReadNewTransactionId()
   _after_ SpinAcquire(ShmemIndexLock).
This commit is contained in:
Vadim B. Mikheev 1999-06-06 20:19:35 +00:00
parent 48c1887964
commit 1b812d9358
5 changed files with 44 additions and 26 deletions

View File

@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/access/transam/varsup.c,v 1.21 1999/06/03 04:41:40 vadim Exp $
* $Header: /cvsroot/pgsql/src/backend/access/transam/varsup.c,v 1.22 1999/06/06 20:19:33 vadim Exp $
*
*-------------------------------------------------------------------------
*/
@ -335,16 +335,13 @@ ReadNewTransactionId(TransactionId *xid)
SpinAcquire(OidGenLockId); /* not good for concurrency... */
if (ShmemVariableCache->xid_count == 0)
{
TransactionId nextid;
VariableRelationGetNextXid(&nextid);
TransactionIdStore(nextid, &(ShmemVariableCache->nextXid));
ShmemVariableCache->xid_count = VAR_XID_PREFETCH;
TransactionIdAdd(&nextid, VAR_XID_PREFETCH);
VariableRelationPutNextXid(nextid);
}
/*
* Note that we don't check is ShmemVariableCache->xid_count equal
* to 0 or not. This will work as long as we don't call
* ReadNewTransactionId() before GetNewTransactionId().
*/
if (ShmemVariableCache->nextXid == 0)
elog(ERROR, "ReadNewTransactionId: ShmemVariableCache->nextXid is not initialized");
TransactionIdStore(ShmemVariableCache->nextXid, xid);

View File

@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/access/transam/xact.c,v 1.39 1999/06/03 13:33:12 vadim Exp $
* $Header: /cvsroot/pgsql/src/backend/access/transam/xact.c,v 1.40 1999/06/06 20:19:34 vadim Exp $
*
* NOTES
* Transaction aborts can now occur two ways:
@ -942,15 +942,11 @@ CommitTransaction()
/*
* Let others know about no transaction in progress by me.
* Note that this must be done _before_ releasing locks we hold
* and SpinAcquire(ShmemIndexLock) is required - or bad (too high)
* XmaxRecent value might be used by vacuum: UPDATE with xid 0 is
* and SpinAcquire(ShmemIndexLock) is required: UPDATE with xid 0 is
* blocked by xid 1' UPDATE, xid 1 is doing commit while xid 2
* gets snapshot - if xid 2' GetSnapshotData sees xid 1 as running
* then it must see xid 0 as running as well or XmaxRecent = 1
* might be used by concurrent vacuum causing
* ERROR: Child itemid marked as unused
* This bug was reported by Hiroshi Inoue and I was able to reproduce
* it with 3 sessions and gdb. - vadim 06/03/99
* then it must see xid 0 as running as well or it will see two
* tuple versions - one deleted by xid 1 and one inserted by xid 0.
*/
if (MyProc != (PROC *) NULL)
{

View File

@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/commands/vacuum.c,v 1.106 1999/06/03 13:25:54 vadim Exp $
* $Header: /cvsroot/pgsql/src/backend/commands/vacuum.c,v 1.107 1999/06/06 20:19:34 vadim Exp $
*
*-------------------------------------------------------------------------
*/
@ -1238,11 +1238,28 @@ vc_rpfheap(VRelStats *vacrelstats, Relation onerel,
Citemid = PageGetItemId(Cpage,
ItemPointerGetOffsetNumber(&Ctid));
if (!ItemIdIsUsed(Citemid))
elog(ERROR, "Child itemid marked as unused");
{
/*
* This means that in the middle of chain there was
* tuple updated by older (than XmaxRecent) xaction
* and this tuple is already deleted by me. Actually,
* upper part of chain should be removed and seems
* that this should be handled in vc_scanheap(), but
* it's not implemented at the moment and so we
* just stop shrinking here.
*/
ReleaseBuffer(Cbuf);
pfree(vtmove);
vtmove = NULL;
elog(NOTICE, "Child itemid in update-chain marked as unused - can't continue vc_rpfheap");
break;
}
tp.t_data = (HeapTupleHeader) PageGetItem(Cpage, Citemid);
tp.t_self = Ctid;
tlen = tp.t_len = ItemIdGetLength(Citemid);
}
if (vtmove == NULL)
break;
/* first, can chain be moved ? */
for (;;)
{
@ -1336,6 +1353,7 @@ vc_rpfheap(VRelStats *vacrelstats, Relation onerel,
Ptp.t_data = (HeapTupleHeader) PageGetItem(Ppage, Pitemid);
Assert(Ptp.t_data->t_xmax == tp.t_data->t_xmin);
#ifdef NOT_USED /* I'm not sure that this will wotk properly... */
/*
* If this tuple is updated version of row and it
* was created by the same transaction then no one
@ -1353,6 +1371,7 @@ vc_rpfheap(VRelStats *vacrelstats, Relation onerel,
WriteBuffer(Pbuf);
continue;
}
#endif
tp.t_data = Ptp.t_data;
tlen = tp.t_len = ItemIdGetLength(Pitemid);
if (freeCbuf)
@ -1763,7 +1782,7 @@ Elapsed %u/%u sec.",
page = BufferGetPage(buf);
num_tuples = 0;
for (offnum = FirstOffsetNumber;
offnum < maxoff;
offnum <= maxoff;
offnum = OffsetNumberNext(offnum))
{
itemid = PageGetItemId(page, offnum);

View File

@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/storage/buffer/Attic/s_lock.c,v 1.20 1999/05/25 22:04:32 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/storage/buffer/Attic/s_lock.c,v 1.21 1999/06/06 20:19:35 vadim Exp $
*
*-------------------------------------------------------------------------
*/
@ -28,7 +28,7 @@
* note: total time to cycle through all 16 entries might be about .07 sec.
*/
#define S_NSPINCYCLE 20
#define S_MAX_BUSY 500 * S_NSPINCYCLE
#define S_MAX_BUSY 1000 * S_NSPINCYCLE
int s_spincycle[S_NSPINCYCLE] =
{0, 0, 0, 0, 10000, 0, 0, 0, 10000, 0,

View File

@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/storage/ipc/shmem.c,v 1.41 1999/06/03 13:33:13 vadim Exp $
* $Header: /cvsroot/pgsql/src/backend/storage/ipc/shmem.c,v 1.42 1999/06/06 20:19:35 vadim Exp $
*
*-------------------------------------------------------------------------
*/
@ -652,9 +652,15 @@ GetSnapshotData(bool serializable)
snapshot->xip = (TransactionId *) malloc(have * sizeof(TransactionId));
snapshot->xmin = cid;
ReadNewTransactionId(&(snapshot->xmax));
SpinAcquire(ShmemIndexLock);
/*
* Unfortunately, we have to call ReadNewTransactionId()
* after acquiring ShmemIndexLock above. It's not good because of
* ReadNewTransactionId() does SpinAcquire(OidGenLockId) but
* _necessary_.
*/
ReadNewTransactionId(&(snapshot->xmax));
hash_seq((HTAB *) NULL);
while ((result = (ShmemIndexEnt *) hash_seq(ShmemIndex)) != NULL)