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Move "hot" members of PGPROC into a separate PGXACT array.

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This speeds up snapshot-taking and reduces ProcArrayLock contention.
Also, the PGPROC (and PGXACT) structures used by two-phase commit are
now allocated as part of the main array, rather than in a separate
array, and we keep ProcArray sorted in pointer order.  These changes
are intended to minimize the number of cache lines that must be pulled
in to take a snapshot, and testing shows a substantial increase in
performance on both read and write workloads at high concurrencies.

Pavan Deolasee, Heikki Linnakangas, Robert Haas
This commit is contained in:
Robert Haas
2011-11-25 08:02:10 -05:00
parent 9ed439a9c0
commit ed0b409d22
14 changed files with 356 additions and 208 deletions
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2
src/backend/storage/ipc/ipci.c
View File

@ -192,7 +192,6 @@ CreateSharedMemoryAndSemaphores(bool makePrivate, int port)
XLOGShmemInit();
CLOGShmemInit();
SUBTRANSShmemInit();
TwoPhaseShmemInit();
MultiXactShmemInit();
InitBufferPool();
@ -213,6 +212,7 @@ CreateSharedMemoryAndSemaphores(bool makePrivate, int port)
InitProcGlobal();
CreateSharedProcArray();
CreateSharedBackendStatus();
TwoPhaseShmemInit();
/*
* Set up shared-inval messaging

276
src/backend/storage/ipc/procarray.c
View File

@ -82,14 +82,17 @@ typedef struct ProcArrayStruct
TransactionId lastOverflowedXid;
/*
* We declare procs[] as 1 entry because C wants a fixed-size array, but
* We declare pgprocnos[] as 1 entry because C wants a fixed-size array, but
* actually it is maxProcs entries long.
*/
PGPROC *procs[1]; /* VARIABLE LENGTH ARRAY */
int pgprocnos[1]; /* VARIABLE LENGTH ARRAY */
} ProcArrayStruct;
static ProcArrayStruct *procArray;
static PGPROC *allProcs;
static PGXACT *allPgXact;
/*
* Bookkeeping for tracking emulated transactions in recovery
*/
@ -169,8 +172,8 @@ ProcArrayShmemSize(void)
/* Size of the ProcArray structure itself */
#define PROCARRAY_MAXPROCS (MaxBackends + max_prepared_xacts)
size = offsetof(ProcArrayStruct, procs);
size = add_size(size, mul_size(sizeof(PGPROC *), PROCARRAY_MAXPROCS));
size = offsetof(ProcArrayStruct, pgprocnos);
size = add_size(size, mul_size(sizeof(int), PROCARRAY_MAXPROCS));
/*
* During Hot Standby processing we have a data structure called
@ -211,8 +214,8 @@ CreateSharedProcArray(void)
/* Create or attach to the ProcArray shared structure */
procArray = (ProcArrayStruct *)
ShmemInitStruct("Proc Array",
add_size(offsetof(ProcArrayStruct, procs),
mul_size(sizeof(PGPROC *),
add_size(offsetof(ProcArrayStruct, pgprocnos),
mul_size(sizeof(int),
PROCARRAY_MAXPROCS)),
&found);
@ -231,6 +234,9 @@ CreateSharedProcArray(void)
procArray->lastOverflowedXid = InvalidTransactionId;
}
allProcs = ProcGlobal->allProcs;
allPgXact = ProcGlobal->allPgXact;
/* Create or attach to the KnownAssignedXids arrays too, if needed */
if (EnableHotStandby)
{
@ -253,6 +259,7 @@ void
ProcArrayAdd(PGPROC *proc)
{
ProcArrayStruct *arrayP = procArray;
int index;
LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);
@ -269,7 +276,28 @@ ProcArrayAdd(PGPROC *proc)
errmsg("sorry, too many clients already")));
}
arrayP->procs[arrayP->numProcs] = proc;
/*
* Keep the procs array sorted by (PGPROC *) so that we can utilize
* locality of references much better. This is useful while traversing the
* ProcArray because there is a increased likelyhood of finding the next
* PGPROC structure in the cache.
*
* Since the occurance of adding/removing a proc is much lower than the
* access to the ProcArray itself, the overhead should be marginal
*/
for (index = 0; index < arrayP->numProcs; index++)
{
/*
* If we are the first PGPROC or if we have found our right position in
* the array, break
*/
if ((arrayP->pgprocnos[index] == -1) || (arrayP->pgprocnos[index] > proc->pgprocno))
break;
}
memmove(&arrayP->pgprocnos[index + 1], &arrayP->pgprocnos[index],
(arrayP->numProcs - index) * sizeof (int));
arrayP->pgprocnos[index] = proc->pgprocno;
arrayP->numProcs++;
LWLockRelease(ProcArrayLock);
@ -301,7 +329,7 @@ ProcArrayRemove(PGPROC *proc, TransactionId latestXid)
if (TransactionIdIsValid(latestXid))
{
Assert(TransactionIdIsValid(proc->xid));
Assert(TransactionIdIsValid(allPgXact[proc->pgprocno].xid));
/* Advance global latestCompletedXid while holding the lock */
if (TransactionIdPrecedes(ShmemVariableCache->latestCompletedXid,
@ -311,15 +339,17 @@ ProcArrayRemove(PGPROC *proc, TransactionId latestXid)
else
{
/* Shouldn't be trying to remove a live transaction here */
Assert(!TransactionIdIsValid(proc->xid));
Assert(!TransactionIdIsValid(allPgXact[proc->pgprocno].xid));
}
for (index = 0; index < arrayP->numProcs; index++)
{
if (arrayP->procs[index] == proc)
if (arrayP->pgprocnos[index] == proc->pgprocno)
{
arrayP->procs[index] = arrayP->procs[arrayP->numProcs - 1];
arrayP->procs[arrayP->numProcs - 1] = NULL; /* for debugging */
/* Keep the PGPROC array sorted. See notes above */
memmove(&arrayP->pgprocnos[index], &arrayP->pgprocnos[index + 1],
(arrayP->numProcs - index - 1) * sizeof (int));
arrayP->pgprocnos[arrayP->numProcs - 1] = -1; /* for debugging */
arrayP->numProcs--;
LWLockRelease(ProcArrayLock);
return;
@ -349,29 +379,31 @@ ProcArrayRemove(PGPROC *proc, TransactionId latestXid)
void
ProcArrayEndTransaction(PGPROC *proc, TransactionId latestXid)
{
PGXACT *pgxact = &allPgXact[proc->pgprocno];
if (TransactionIdIsValid(latestXid))
{
/*
* We must lock ProcArrayLock while clearing proc->xid, so that we do
* not exit the set of "running" transactions while someone else is
* taking a snapshot. See discussion in
* We must lock ProcArrayLock while clearing our advertised XID, so
* that we do not exit the set of "running" transactions while someone
* else is taking a snapshot. See discussion in
* src/backend/access/transam/README.
*/
Assert(TransactionIdIsValid(proc->xid));
Assert(TransactionIdIsValid(allPgXact[proc->pgprocno].xid));
LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);
proc->xid = InvalidTransactionId;
pgxact->xid = InvalidTransactionId;
proc->lxid = InvalidLocalTransactionId;
proc->xmin = InvalidTransactionId;
pgxact->xmin = InvalidTransactionId;
/* must be cleared with xid/xmin: */
proc->vacuumFlags &= ~PROC_VACUUM_STATE_MASK;
proc->inCommit = false; /* be sure this is cleared in abort */
pgxact->vacuumFlags &= ~PROC_VACUUM_STATE_MASK;
pgxact->inCommit = false; /* be sure this is cleared in abort */
proc->recoveryConflictPending = false;
/* Clear the subtransaction-XID cache too while holding the lock */
proc->subxids.nxids = 0;
proc->subxids.overflowed = false;
pgxact->nxids = 0;
pgxact->overflowed = false;
/* Also advance global latestCompletedXid while holding the lock */
if (TransactionIdPrecedes(ShmemVariableCache->latestCompletedXid,
@ -387,17 +419,17 @@ ProcArrayEndTransaction(PGPROC *proc, TransactionId latestXid)
* anyone else's calculation of a snapshot. We might change their
* estimate of global xmin, but that's OK.
*/
Assert(!TransactionIdIsValid(proc->xid));
Assert(!TransactionIdIsValid(allPgXact[proc->pgprocno].xid));
proc->lxid = InvalidLocalTransactionId;
proc->xmin = InvalidTransactionId;
pgxact->xmin = InvalidTransactionId;
/* must be cleared with xid/xmin: */
proc->vacuumFlags &= ~PROC_VACUUM_STATE_MASK;
proc->inCommit = false; /* be sure this is cleared in abort */
pgxact->vacuumFlags &= ~PROC_VACUUM_STATE_MASK;
pgxact->inCommit = false; /* be sure this is cleared in abort */
proc->recoveryConflictPending = false;
Assert(proc->subxids.nxids == 0);
Assert(proc->subxids.overflowed == false);
Assert(pgxact->nxids == 0);
Assert(pgxact->overflowed == false);
}
}
@ -413,24 +445,26 @@ ProcArrayEndTransaction(PGPROC *proc, TransactionId latestXid)
void
ProcArrayClearTransaction(PGPROC *proc)
{
PGXACT *pgxact = &allPgXact[proc->pgprocno];
/*
* We can skip locking ProcArrayLock here, because this action does not
* actually change anyone's view of the set of running XIDs: our entry is
* duplicate with the gxact that has already been inserted into the
* ProcArray.
*/
proc->xid = InvalidTransactionId;
pgxact->xid = InvalidTransactionId;
proc->lxid = InvalidLocalTransactionId;
proc->xmin = InvalidTransactionId;
pgxact->xmin = InvalidTransactionId;
proc->recoveryConflictPending = false;
/* redundant, but just in case */
proc->vacuumFlags &= ~PROC_VACUUM_STATE_MASK;
proc->inCommit = false;
pgxact->vacuumFlags &= ~PROC_VACUUM_STATE_MASK;
pgxact->inCommit = false;
/* Clear the subtransaction-XID cache too */
proc->subxids.nxids = 0;
proc->subxids.overflowed = false;
pgxact->nxids = 0;
pgxact->overflowed = false;
}
/*
@ -811,15 +845,17 @@ TransactionIdIsInProgress(TransactionId xid)
/* No shortcuts, gotta grovel through the array */
for (i = 0; i < arrayP->numProcs; i++)
{
volatile PGPROC *proc = arrayP->procs[i];
TransactionId pxid;
int pgprocno = arrayP->pgprocnos[i];
volatile PGPROC *proc = &allProcs[pgprocno];
volatile PGXACT *pgxact = &allPgXact[pgprocno];
TransactionId pxid;
/* Ignore my own proc --- dealt with it above */
if (proc == MyProc)
continue;
/* Fetch xid just once - see GetNewTransactionId */
pxid = proc->xid;
pxid = pgxact->xid;
if (!TransactionIdIsValid(pxid))
continue;
@ -844,7 +880,7 @@ TransactionIdIsInProgress(TransactionId xid)
/*
* Step 2: check the cached child-Xids arrays
*/
for (j = proc->subxids.nxids - 1; j >= 0; j--)
for (j = pgxact->nxids - 1; j >= 0; j--)
{
/* Fetch xid just once - see GetNewTransactionId */
TransactionId cxid = proc->subxids.xids[j];
@ -864,7 +900,7 @@ TransactionIdIsInProgress(TransactionId xid)
* we hold ProcArrayLock. So we can't miss an Xid that we need to
* worry about.)
*/
if (proc->subxids.overflowed)
if (pgxact->overflowed)
xids[nxids++] = pxid;
}
@ -965,10 +1001,13 @@ TransactionIdIsActive(TransactionId xid)
for (i = 0; i < arrayP->numProcs; i++)
{
volatile PGPROC *proc = arrayP->procs[i];
int pgprocno = arrayP->pgprocnos[i];
volatile PGPROC *proc = &allProcs[pgprocno];
volatile PGXACT *pgxact = &allPgXact[pgprocno];
TransactionId pxid;
/* Fetch xid just once - see GetNewTransactionId */
TransactionId pxid = proc->xid;
pxid = pgxact->xid;
if (!TransactionIdIsValid(pxid))
continue;
@ -1060,9 +1099,11 @@ GetOldestXmin(bool allDbs, bool ignoreVacuum)
for (index = 0; index < arrayP->numProcs; index++)
{
volatile PGPROC *proc = arrayP->procs[index];
int pgprocno = arrayP->pgprocnos[index];
volatile PGPROC *proc = &allProcs[pgprocno];
volatile PGXACT *pgxact = &allPgXact[pgprocno];
if (ignoreVacuum && (proc->vacuumFlags & PROC_IN_VACUUM))
if (ignoreVacuum && (pgxact->vacuumFlags & PROC_IN_VACUUM))
continue;
if (allDbs ||
@ -1070,7 +1111,7 @@ GetOldestXmin(bool allDbs, bool ignoreVacuum)
proc->databaseId == 0) /* always include WalSender */
{
/* Fetch xid just once - see GetNewTransactionId */
TransactionId xid = proc->xid;
TransactionId xid = pgxact->xid;
/* First consider the transaction's own Xid, if any */
if (TransactionIdIsNormal(xid) &&
@ -1084,7 +1125,7 @@ GetOldestXmin(bool allDbs, bool ignoreVacuum)
* have an Xmin but not (yet) an Xid; conversely, if it has an
* Xid, that could determine some not-yet-set Xmin.
*/
xid = proc->xmin; /* Fetch just once */
xid = pgxact->xmin; /* Fetch just once */
if (TransactionIdIsNormal(xid) &&
TransactionIdPrecedes(xid, result))
result = xid;
@ -1261,31 +1302,33 @@ GetSnapshotData(Snapshot snapshot)
if (!snapshot->takenDuringRecovery)
{
int *pgprocnos = arrayP->pgprocnos;
int numProcs;
/*
* Spin over procArray checking xid, xmin, and subxids. The goal is
* to gather all active xids, find the lowest xmin, and try to record
* subxids. During recovery no xids will be assigned, so all normal
* backends can be ignored, nor are there any VACUUMs running. All
* prepared transaction xids are held in KnownAssignedXids, so these
* will be seen without needing to loop through procs here.
* subxids.
*/
for (index = 0; index < arrayP->numProcs; index++)
numProcs = arrayP->numProcs;
for (index = 0; index < numProcs; index++)
{
volatile PGPROC *proc = arrayP->procs[index];
TransactionId xid;
int pgprocno = pgprocnos[index];
volatile PGXACT *pgxact = &allPgXact[pgprocno];
TransactionId xid;
/* Ignore procs running LAZY VACUUM */
if (proc->vacuumFlags & PROC_IN_VACUUM)
if (pgxact->vacuumFlags & PROC_IN_VACUUM)
continue;
/* Update globalxmin to be the smallest valid xmin */
xid = proc->xmin; /* fetch just once */
xid = pgxact->xmin; /* fetch just once */
if (TransactionIdIsNormal(xid) &&
TransactionIdPrecedes(xid, globalxmin))
globalxmin = xid;
globalxmin = xid;
/* Fetch xid just once - see GetNewTransactionId */
xid = proc->xid;
xid = pgxact->xid;
/*
* If the transaction has been assigned an xid < xmax we add it to
@ -1300,7 +1343,7 @@ GetSnapshotData(Snapshot snapshot)
{
if (TransactionIdFollowsOrEquals(xid, xmax))
continue;
if (proc != MyProc)
if (pgxact != MyPgXact)
snapshot->xip[count++] = xid;
if (TransactionIdPrecedes(xid, xmin))
xmin = xid;
@ -1321,16 +1364,17 @@ GetSnapshotData(Snapshot snapshot)
*
* Again, our own XIDs are not included in the snapshot.
*/
if (!suboverflowed && proc != MyProc)
if (!suboverflowed && pgxact != MyPgXact)
{
if (proc->subxids.overflowed)
if (pgxact->overflowed)
suboverflowed = true;
else
{
int nxids = proc->subxids.nxids;
int nxids = pgxact->nxids;
if (nxids > 0)
{
volatile PGPROC *proc = &allProcs[pgprocno];
memcpy(snapshot->subxip + subcount,
(void *) proc->subxids.xids,
nxids * sizeof(TransactionId));
@ -1372,9 +1416,8 @@ GetSnapshotData(Snapshot snapshot)
suboverflowed = true;
}
if (!TransactionIdIsValid(MyProc->xmin))
MyProc->xmin = TransactionXmin = xmin;
if (!TransactionIdIsValid(MyPgXact->xmin))
MyPgXact->xmin = TransactionXmin = xmin;
LWLockRelease(ProcArrayLock);
/*
@ -1436,14 +1479,16 @@ ProcArrayInstallImportedXmin(TransactionId xmin, TransactionId sourcexid)
for (index = 0; index < arrayP->numProcs; index++)
{
volatile PGPROC *proc = arrayP->procs[index];
TransactionId xid;
int pgprocno = arrayP->pgprocnos[index];
volatile PGPROC *proc = &allProcs[pgprocno];
volatile PGXACT *pgxact = &allPgXact[pgprocno];
TransactionId xid;
/* Ignore procs running LAZY VACUUM */
if (proc->vacuumFlags & PROC_IN_VACUUM)
if (pgxact->vacuumFlags & PROC_IN_VACUUM)
continue;
xid = proc->xid; /* fetch just once */
xid = pgxact->xid; /* fetch just once */
if (xid != sourcexid)
continue;
@ -1459,7 +1504,7 @@ ProcArrayInstallImportedXmin(TransactionId xmin, TransactionId sourcexid)
/*
* Likewise, let's just make real sure its xmin does cover us.
*/
xid = proc->xmin; /* fetch just once */
xid = pgxact->xmin; /* fetch just once */
if (!TransactionIdIsNormal(xid) ||
!TransactionIdPrecedesOrEquals(xid, xmin))
continue;
@ -1470,7 +1515,7 @@ ProcArrayInstallImportedXmin(TransactionId xmin, TransactionId sourcexid)
* GetSnapshotData first, we'll be overwriting a valid xmin here,
* so we don't check that.)
*/
MyProc->xmin = TransactionXmin = xmin;
MyPgXact->xmin = TransactionXmin = xmin;
result = true;
break;
@ -1562,12 +1607,14 @@ GetRunningTransactionData(void)
*/
for (index = 0; index < arrayP->numProcs; index++)
{
volatile PGPROC *proc = arrayP->procs[index];
int pgprocno = arrayP->pgprocnos[index];
volatile PGPROC *proc = &allProcs[pgprocno];
volatile PGXACT *pgxact = &allPgXact[pgprocno];
TransactionId xid;
int nxids;
/* Fetch xid just once - see GetNewTransactionId */
xid = proc->xid;
xid = pgxact->xid;
/*
* We don't need to store transactions that don't have a TransactionId
@ -1585,7 +1632,7 @@ GetRunningTransactionData(void)
* Save subtransaction XIDs. Other backends can't add or remove
* entries while we're holding XidGenLock.
*/
nxids = proc->subxids.nxids;
nxids = pgxact->nxids;
if (nxids > 0)
{
memcpy(&xids[count], (void *) proc->subxids.xids,
@ -1593,7 +1640,7 @@ GetRunningTransactionData(void)
count += nxids;
subcount += nxids;
if (proc->subxids.overflowed)
if (pgxact->overflowed)
suboverflowed = true;
/*
@ -1653,11 +1700,12 @@ GetOldestActiveTransactionId(void)
*/
for (index = 0; index < arrayP->numProcs; index++)
{
volatile PGPROC *proc = arrayP->procs[index];
int pgprocno = arrayP->pgprocnos[index];
volatile PGXACT *pgxact = &allPgXact[pgprocno];
TransactionId xid;
/* Fetch xid just once - see GetNewTransactionId */
xid = proc->xid;
xid = pgxact->xid;
if (!TransactionIdIsNormal(xid))
continue;
@ -1709,12 +1757,14 @@ GetTransactionsInCommit(TransactionId **xids_p)
for (index = 0; index < arrayP->numProcs; index++)
{
volatile PGPROC *proc = arrayP->procs[index];
int pgprocno = arrayP->pgprocnos[index];
volatile PGXACT *pgxact = &allPgXact[pgprocno];
TransactionId pxid;
/* Fetch xid just once - see GetNewTransactionId */
TransactionId pxid = proc->xid;
pxid = pgxact->xid;
if (proc->inCommit && TransactionIdIsValid(pxid))
if (pgxact->inCommit && TransactionIdIsValid(pxid))
xids[nxids++] = pxid;
}
@ -1744,12 +1794,14 @@ HaveTransactionsInCommit(TransactionId *xids, int nxids)
for (index = 0; index < arrayP->numProcs; index++)
{
volatile PGPROC *proc = arrayP->procs[index];
int pgprocno = arrayP->pgprocnos[index];
volatile PGXACT *pgxact = &allPgXact[pgprocno];
TransactionId pxid;
/* Fetch xid just once - see GetNewTransactionId */
TransactionId pxid = proc->xid;
pxid = pgxact->xid;
if (proc->inCommit && TransactionIdIsValid(pxid))
if (pgxact->inCommit && TransactionIdIsValid(pxid))
{
int i;
@ -1792,7 +1844,7 @@ BackendPidGetProc(int pid)
for (index = 0; index < arrayP->numProcs; index++)
{
PGPROC *proc = arrayP->procs[index];
PGPROC *proc = &allProcs[arrayP->pgprocnos[index]];
if (proc->pid == pid)
{
@ -1833,9 +1885,11 @@ BackendXidGetPid(TransactionId xid)
for (index = 0; index < arrayP->numProcs; index++)
{
volatile PGPROC *proc = arrayP->procs[index];
int pgprocno = arrayP->pgprocnos[index];
volatile PGPROC *proc = &allProcs[pgprocno];
volatile PGXACT *pgxact = &allPgXact[pgprocno];
if (proc->xid == xid)
if (pgxact->xid == xid)
{
result = proc->pid;
break;
@ -1901,18 +1955,20 @@ GetCurrentVirtualXIDs(TransactionId limitXmin, bool excludeXmin0,
for (index = 0; index < arrayP->numProcs; index++)
{
volatile PGPROC *proc = arrayP->procs[index];
int pgprocno = arrayP->pgprocnos[index];
volatile PGPROC *proc = &allProcs[pgprocno];
volatile PGXACT *pgxact = &allPgXact[pgprocno];
if (proc == MyProc)
continue;
if (excludeVacuum & proc->vacuumFlags)
if (excludeVacuum & pgxact->vacuumFlags)
continue;
if (allDbs || proc->databaseId == MyDatabaseId)
{
/* Fetch xmin just once - might change on us */
TransactionId pxmin = proc->xmin;
TransactionId pxmin = pgxact->xmin;
if (excludeXmin0 && !TransactionIdIsValid(pxmin))
continue;
@ -1996,7 +2052,9 @@ GetConflictingVirtualXIDs(TransactionId limitXmin, Oid dbOid)
for (index = 0; index < arrayP->numProcs; index++)
{
volatile PGPROC *proc = arrayP->procs[index];
int pgprocno = arrayP->pgprocnos[index];
volatile PGPROC *proc = &allProcs[pgprocno];
volatile PGXACT *pgxact = &allPgXact[pgprocno];
/* Exclude prepared transactions */
if (proc->pid == 0)
@ -2006,7 +2064,7 @@ GetConflictingVirtualXIDs(TransactionId limitXmin, Oid dbOid)
proc->databaseId == dbOid)
{
/* Fetch xmin just once - can't change on us, but good coding */
TransactionId pxmin = proc->xmin;
TransactionId pxmin = pgxact->xmin;
/*
* We ignore an invalid pxmin because this means that backend has
@ -2050,8 +2108,9 @@ CancelVirtualTransaction(VirtualTransactionId vxid, ProcSignalReason sigmode)
for (index = 0; index < arrayP->numProcs; index++)
{
VirtualTransactionId procvxid;
PGPROC *proc = arrayP->procs[index];
int pgprocno = arrayP->pgprocnos[index];
volatile PGPROC *proc = &allProcs[pgprocno];
VirtualTransactionId procvxid;
GET_VXID_FROM_PGPROC(procvxid, *proc);
@ -2104,7 +2163,9 @@ MinimumActiveBackends(int min)
*/
for (index = 0; index < arrayP->numProcs; index++)
{
volatile PGPROC *proc = arrayP->procs[index];
int pgprocno = arrayP->pgprocnos[index];
volatile PGPROC *proc = &allProcs[pgprocno];
volatile PGXACT *pgxact = &allPgXact[pgprocno];
/*
* Since we're not holding a lock, need to check that the pointer is
@ -2122,10 +2183,10 @@ MinimumActiveBackends(int min)
if (proc == MyProc)
continue; /* do not count myself */
if (pgxact->xid == InvalidTransactionId)
continue; /* do not count if no XID assigned */
if (proc->pid == 0)
continue; /* do not count prepared xacts */
if (proc->xid == InvalidTransactionId)
continue; /* do not count if no XID assigned */
if (proc->waitLock != NULL)
continue; /* do not count if blocked on a lock */
count++;
@ -2150,7 +2211,8 @@ CountDBBackends(Oid databaseid)
for (index = 0; index < arrayP->numProcs; index++)
{
volatile PGPROC *proc = arrayP->procs[index];
int pgprocno = arrayP->pgprocnos[index];
volatile PGPROC *proc = &allProcs[pgprocno];
if (proc->pid == 0)
continue; /* do not count prepared xacts */
@ -2179,7 +2241,8 @@ CancelDBBackends(Oid databaseid, ProcSignalReason sigmode, bool conflictPending)
for (index = 0; index < arrayP->numProcs; index++)
{
volatile PGPROC *proc = arrayP->procs[index];
int pgprocno = arrayP->pgprocnos[index];
volatile PGPROC *proc = &allProcs[pgprocno];
if (databaseid == InvalidOid || proc->databaseId == databaseid)
{
@ -2217,7 +2280,8 @@ CountUserBackends(Oid roleid)
for (index = 0; index < arrayP->numProcs; index++)
{
volatile PGPROC *proc = arrayP->procs[index];
int pgprocno = arrayP->pgprocnos[index];
volatile PGPROC *proc = &allProcs[pgprocno];
if (proc->pid == 0)
continue; /* do not count prepared xacts */
@ -2277,7 +2341,9 @@ CountOtherDBBackends(Oid databaseId, int *nbackends, int *nprepared)
for (index = 0; index < arrayP->numProcs; index++)
{
volatile PGPROC *proc = arrayP->procs[index];
int pgprocno = arrayP->pgprocnos[index];
volatile PGPROC *proc = &allProcs[pgprocno];
volatile PGXACT *pgxact = &allPgXact[pgprocno];
if (proc->databaseId != databaseId)
continue;
@ -2291,7 +2357,7 @@ CountOtherDBBackends(Oid databaseId, int *nbackends, int *nprepared)
else
{
(*nbackends)++;
if ((proc->vacuumFlags & PROC_IS_AUTOVACUUM) &&
if ((pgxact->vacuumFlags & PROC_IS_AUTOVACUUM) &&
nautovacs < MAXAUTOVACPIDS)
autovac_pids[nautovacs++] = proc->pid;
}
@ -2321,8 +2387,8 @@ CountOtherDBBackends(Oid databaseId, int *nbackends, int *nprepared)
#define XidCacheRemove(i) \
do { \
MyProc->subxids.xids[i] = MyProc->subxids.xids[MyProc->subxids.nxids - 1]; \
MyProc->subxids.nxids--; \
MyProc->subxids.xids[i] = MyProc->subxids.xids[MyPgXact->nxids - 1]; \
MyPgXact->nxids--; \
} while (0)
/*
@ -2361,7 +2427,7 @@ XidCacheRemoveRunningXids(TransactionId xid,
{
TransactionId anxid = xids[i];
for (j = MyProc->subxids.nxids - 1; j >= 0; j--)
for (j = MyPgXact->nxids - 1; j >= 0; j--)
{
if (TransactionIdEquals(MyProc->subxids.xids[j], anxid))
{
@ -2377,11 +2443,11 @@ XidCacheRemoveRunningXids(TransactionId xid,
* error during AbortSubTransaction. So instead of Assert, emit a
* debug warning.
*/
if (j < 0 && !MyProc->subxids.overflowed)
if (j < 0 && !MyPgXact->overflowed)
elog(WARNING, "did not find subXID %u in MyProc", anxid);
}
for (j = MyProc->subxids.nxids - 1; j >= 0; j--)
for (j = MyPgXact->nxids - 1; j >= 0; j--)
{
if (TransactionIdEquals(MyProc->subxids.xids[j], xid))
{
@ -2390,7 +2456,7 @@ XidCacheRemoveRunningXids(TransactionId xid,
}
}
/* Ordinarily we should have found it, unless the cache has overflowed */
if (j < 0 && !MyProc->subxids.overflowed)
if (j < 0 && !MyPgXact->overflowed)
elog(WARNING, "did not find subXID %u in MyProc", xid);
/* Also advance global latestCompletedXid while holding the lock */