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-rw-r--r--src/backend/storage/ipc/sinval.c24
-rw-r--r--src/backend/storage/ipc/sinvaladt.c65
2 files changed, 50 insertions, 39 deletions
diff --git a/src/backend/storage/ipc/sinval.c b/src/backend/storage/ipc/sinval.c
index c610147fc5f..fb2e4804dd3 100644
--- a/src/backend/storage/ipc/sinval.c
+++ b/src/backend/storage/ipc/sinval.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/storage/ipc/sinval.c,v 1.22 2000/11/05 22:50:20 vadim Exp $
+ * $Header: /cvsroot/pgsql/src/backend/storage/ipc/sinval.c,v 1.23 2000/11/12 20:51:51 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -185,6 +185,9 @@ void
/*
* DatabaseHasActiveBackends -- are there any backends running in the given DB
*
+ * If 'ignoreMyself' is TRUE, ignore this particular backend while checking
+ * for backends in the target database.
+ *
* This function is used to interlock DROP DATABASE against there being
* any active backends in the target DB --- dropping the DB while active
* backends remain would be a Bad Thing. Note that we cannot detect here
@@ -194,7 +197,7 @@ void
*/
bool
-DatabaseHasActiveBackends(Oid databaseId)
+DatabaseHasActiveBackends(Oid databaseId, bool ignoreMyself)
{
bool result = false;
SISeg *segP = shmInvalBuffer;
@@ -203,7 +206,7 @@ DatabaseHasActiveBackends(Oid databaseId)
SpinAcquire(SInvalLock);
- for (index = 0; index < segP->maxBackends; index++)
+ for (index = 0; index < segP->lastBackend; index++)
{
SHMEM_OFFSET pOffset = stateP[index].procStruct;
@@ -213,6 +216,9 @@ DatabaseHasActiveBackends(Oid databaseId)
if (proc->databaseId == databaseId)
{
+ if (ignoreMyself && proc == MyProc)
+ continue;
+
result = true;
break;
}
@@ -237,7 +243,7 @@ TransactionIdIsInProgress(TransactionId xid)
SpinAcquire(SInvalLock);
- for (index = 0; index < segP->maxBackends; index++)
+ for (index = 0; index < segP->lastBackend; index++)
{
SHMEM_OFFSET pOffset = stateP[index].procStruct;
@@ -275,7 +281,7 @@ GetXmaxRecent(TransactionId *XmaxRecent)
SpinAcquire(SInvalLock);
- for (index = 0; index < segP->maxBackends; index++)
+ for (index = 0; index < segP->lastBackend; index++)
{
SHMEM_OFFSET pOffset = stateP[index].procStruct;
@@ -309,11 +315,11 @@ GetSnapshotData(bool serializable)
int count = 0;
/*
- * There can be no more than maxBackends active transactions, so this
+ * There can be no more than lastBackend active transactions, so this
* is enough space:
*/
snapshot->xip = (TransactionId *)
- malloc(segP->maxBackends * sizeof(TransactionId));
+ malloc(segP->lastBackend * sizeof(TransactionId));
snapshot->xmin = GetCurrentTransactionId();
SpinAcquire(SInvalLock);
@@ -326,7 +332,7 @@ GetSnapshotData(bool serializable)
*/
ReadNewTransactionId(&(snapshot->xmax));
- for (index = 0; index < segP->maxBackends; index++)
+ for (index = 0; index < segP->lastBackend; index++)
{
SHMEM_OFFSET pOffset = stateP[index].procStruct;
@@ -386,7 +392,7 @@ GetUndoRecPtr(void)
SpinAcquire(SInvalLock);
- for (index = 0; index < segP->maxBackends; index++)
+ for (index = 0; index < segP->lastBackend; index++)
{
SHMEM_OFFSET pOffset = stateP[index].procStruct;
diff --git a/src/backend/storage/ipc/sinvaladt.c b/src/backend/storage/ipc/sinvaladt.c
index fcea99dd043..f4b29983433 100644
--- a/src/backend/storage/ipc/sinvaladt.c
+++ b/src/backend/storage/ipc/sinvaladt.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/storage/ipc/sinvaladt.c,v 1.34 2000/10/02 21:45:32 petere Exp $
+ * $Header: /cvsroot/pgsql/src/backend/storage/ipc/sinvaladt.c,v 1.35 2000/11/12 20:51:51 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -117,6 +117,7 @@ SISegInit(SISeg *segP, int maxBackends)
/* Clear message counters, save size of procState array */
segP->minMsgNum = 0;
segP->maxMsgNum = 0;
+ segP->lastBackend = 0;
segP->maxBackends = maxBackends;
/* The buffer[] array is initially all unused, so we need not fill it */
@@ -126,7 +127,6 @@ SISegInit(SISeg *segP, int maxBackends)
{
segP->procState[i].nextMsgNum = -1; /* inactive */
segP->procState[i].resetState = false;
- segP->procState[i].tag = InvalidBackendTag;
segP->procState[i].procStruct = INVALID_OFFSET;
}
}
@@ -145,47 +145,45 @@ SIBackendInit(SISeg *segP)
int index;
ProcState *stateP = NULL;
- Assert(MyBackendTag > 0);
-
- /* Check for duplicate backend tags (should never happen) */
- for (index = 0; index < segP->maxBackends; index++)
- {
- if (segP->procState[index].tag == MyBackendTag)
- elog(FATAL, "SIBackendInit: tag %d already in use", MyBackendTag);
- }
-
/* Look for a free entry in the procState array */
- for (index = 0; index < segP->maxBackends; index++)
+ for (index = 0; index < segP->lastBackend; index++)
{
- if (segP->procState[index].tag == InvalidBackendTag)
+ if (segP->procState[index].nextMsgNum < 0) /* inactive slot? */
{
stateP = &segP->procState[index];
break;
}
}
- /*
- * elog() with spinlock held is probably not too cool, but this
- * condition should never happen anyway.
- */
if (stateP == NULL)
{
- elog(NOTICE, "SIBackendInit: no free procState slot available");
- MyBackendId = InvalidBackendTag;
- return 0;
+ if (segP->lastBackend < segP->maxBackends)
+ {
+ stateP = &segP->procState[segP->lastBackend];
+ Assert(stateP->nextMsgNum < 0);
+ segP->lastBackend++;
+ }
+ else
+ {
+ /*
+ * elog() with spinlock held is probably not too cool, but this
+ * condition should never happen anyway.
+ */
+ elog(NOTICE, "SIBackendInit: no free procState slot available");
+ MyBackendId = InvalidBackendId;
+ return 0;
+ }
}
MyBackendId = (stateP - &segP->procState[0]) + 1;
#ifdef INVALIDDEBUG
- elog(DEBUG, "SIBackendInit: backend tag %d; backend id %d.",
- MyBackendTag, MyBackendId);
+ elog(DEBUG, "SIBackendInit: backend id %d", MyBackendId);
#endif /* INVALIDDEBUG */
/* mark myself active, with all extant messages already read */
stateP->nextMsgNum = segP->maxMsgNum;
stateP->resetState = false;
- stateP->tag = MyBackendTag;
stateP->procStruct = MAKE_OFFSET(MyProc);
/* register exit routine to mark my entry inactive at exit */
@@ -206,17 +204,26 @@ SIBackendInit(SISeg *segP)
static void
CleanupInvalidationState(int status, Datum arg)
{
- SISeg *segP = (void*) DatumGetPointer(arg);
+ SISeg *segP = (SISeg *) DatumGetPointer(arg);
+ int i;
Assert(PointerIsValid(segP));
SpinAcquire(SInvalLock);
+ /* Mark myself inactive */
segP->procState[MyBackendId - 1].nextMsgNum = -1;
segP->procState[MyBackendId - 1].resetState = false;
- segP->procState[MyBackendId - 1].tag = InvalidBackendTag;
segP->procState[MyBackendId - 1].procStruct = INVALID_OFFSET;
+ /* Recompute index of last active backend */
+ for (i = segP->lastBackend; i > 0; i--)
+ {
+ if (segP->procState[i - 1].nextMsgNum >= 0)
+ break;
+ }
+ segP->lastBackend = i;
+
SpinRelease(SInvalLock);
}
@@ -299,7 +306,7 @@ SISetProcStateInvalid(SISeg *segP)
segP->minMsgNum = 0;
segP->maxMsgNum = 0;
- for (i = 0; i < segP->maxBackends; i++)
+ for (i = 0; i < segP->lastBackend; i++)
{
if (segP->procState[i].nextMsgNum >= 0) /* active backend? */
{
@@ -325,8 +332,6 @@ SIGetDataEntry(SISeg *segP, int backendId,
{
ProcState *stateP = &segP->procState[backendId - 1];
- Assert(stateP->tag == MyBackendTag);
-
if (stateP->resetState)
{
@@ -373,7 +378,7 @@ SIDelExpiredDataEntries(SISeg *segP)
/* Recompute minMsgNum = minimum of all backends' nextMsgNum */
- for (i = 0; i < segP->maxBackends; i++)
+ for (i = 0; i < segP->lastBackend; i++)
{
h = segP->procState[i].nextMsgNum;
if (h >= 0)
@@ -392,7 +397,7 @@ SIDelExpiredDataEntries(SISeg *segP)
{
segP->minMsgNum -= MSGNUMWRAPAROUND;
segP->maxMsgNum -= MSGNUMWRAPAROUND;
- for (i = 0; i < segP->maxBackends; i++)
+ for (i = 0; i < segP->lastBackend; i++)
{
if (segP->procState[i].nextMsgNum >= 0)
segP->procState[i].nextMsgNum -= MSGNUMWRAPAROUND;
generated by cgit v1.2.3 (git 2.25.1) at 2025-05-30 13:51:09 +0000