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Use Snapshot in heap access methods.

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This commit is contained in:
Vadim B. Mikheev
1998-07-27 19:38:40 +00:00
parent f7f989c990
commit be8300b18f
54 changed files with 352 additions and 339 deletions
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75
src/backend/storage/ipc/shmem.c
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@@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/storage/ipc/shmem.c,v 1.28 1998/07/21 06:17:35 vadim Exp $
* $Header: /cvsroot/pgsql/src/backend/storage/ipc/shmem.c,v 1.29 1998/07/27 19:38:10 vadim Exp $
*
*-------------------------------------------------------------------------
*/
@@ -585,7 +585,6 @@ ShmemInitStruct(char *name, unsigned long size, bool *foundPtr)
return (structPtr);
}
/*
* TransactionIdIsInProgress -- is given transaction running by some backend
*
@@ -625,3 +624,75 @@ TransactionIdIsInProgress(TransactionId xid)
elog(ERROR, "TransactionIdIsInProgress: ShmemIndex corrupted");
return (false);
}
#ifdef LowLevelLocking
/*
* GetSnapshotData -- returns information about running transactions.
*
* InvalidTransactionId is used as terminator in snapshot->xip array.
* If serialized is true then XID >= current xact ID will not be
* placed in array. Current xact ID are never placed there (just
* to reduce its length, xmin/xmax may be equal to cid).
* MyProc->xmin will be setted if equal to InvalidTransactionId.
*
* Yet another strange func for this place... - vadim 07/21/98
*/
Snapshot
GetSnapshotData(bool serialized)
{
Snapshot snapshot = (Snapshot) malloc(sizeof(SnapshotData));
TransactionId snapshot->xip = (TransactionId*)
malloc(32 * sizeof(TransactionId));
ShmemIndexEnt *result;
PROC *proc;
TransactionId cid = GetCurrentTransactionId();
uint count = 0;
unit free = 31;
Assert(ShmemIndex);
snapshot->xmax = cid;
snapshot->xmin = cid;
SpinAcquire(ShmemIndexLock);
hash_seq((HTAB *) NULL);
while ((result = (ShmemIndexEnt *) hash_seq(ShmemIndex)) != NULL)
{
if (result == (ShmemIndexEnt *) TRUE)
{
if (MyProc->xmin == InvalidTransactionId)
MyProc->xmin = snapshot->xmin;
SpinRelease(ShmemIndexLock);
snapshot->xip[count] = InvalidTransactionId;
return (snapshot);
}
if (result->location == INVALID_OFFSET ||
strncmp(result->key, "PID ", 4) != 0)
continue;
proc = (PROC *) MAKE_PTR(result->location);
if (proc == MyProc || proc->xid < FirstTransactionId ||
serialized && proc->xid >= cid)
continue;
if (proc->xid < snapshot->xmin)
snapshot->xmin = proc->xid;
else if (proc->xid > snapshot->xmax)
snapshot->xmax = proc->xid;
if (free == 0)
{
snapshot->xip = (TransactionId*) realloc(snapshot->xip,
(count + 33) * sizeof(TransactionId));
free = 32;
}
snapshot->xip[count] = proc->xid;
free--;
count++;
}
SpinRelease(ShmemIndexLock);
free(snapshot->xip);
free(snapshot);
elog(ERROR, "GetSnapshotData: ShmemIndex corrupted");
return (NULL);
}
#endif