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Code Activity

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

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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
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19
src/backend/access/transam/varsup.c
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);

12
src/backend/access/transam/xact.c
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)
{