diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index a4599e9661..65aa8841f7 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -295,7 +295,7 @@ TransactionIdSetPageStatus(TransactionId xid, int nsubxids, */ if (all_xact_same_page && xid == MyProc->xid && nsubxids <= THRESHOLD_SUBTRANS_CLOG_OPT && - nsubxids == MyPgXact->nxids && + nsubxids == MyProc->subxidStatus.count && memcmp(subxids, MyProc->subxids.xids, nsubxids * sizeof(TransactionId)) == 0) { @@ -510,16 +510,15 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, while (nextidx != INVALID_PGPROCNO) { PGPROC *proc = &ProcGlobal->allProcs[nextidx]; - PGXACT *pgxact = &ProcGlobal->allPgXact[nextidx]; /* * Transactions with more than THRESHOLD_SUBTRANS_CLOG_OPT sub-XIDs * should not use group XID status update mechanism. */ - Assert(pgxact->nxids <= THRESHOLD_SUBTRANS_CLOG_OPT); + Assert(proc->subxidStatus.count <= THRESHOLD_SUBTRANS_CLOG_OPT); TransactionIdSetPageStatusInternal(proc->clogGroupMemberXid, - pgxact->nxids, + proc->subxidStatus.count, proc->subxids.xids, proc->clogGroupMemberXidStatus, proc->clogGroupMemberLsn, diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 744b8a7f39..ef4f9981e3 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -21,9 +21,9 @@ * GIDs and aborts the transaction if there already is a global * transaction in prepared state with the same GID. * - * A global transaction (gxact) also has dummy PGXACT and PGPROC; this is - * what keeps the XID considered running by TransactionIdIsInProgress. - * It is also convenient as a PGPROC to hook the gxact's locks to. + * A global transaction (gxact) also has dummy PGPROC; this is what keeps + * the XID considered running by TransactionIdIsInProgress. It is also + * convenient as a PGPROC to hook the gxact's locks to. * * Information to recover prepared transactions in case of crash is * now stored in WAL for the common case. In some cases there will be @@ -447,14 +447,12 @@ MarkAsPreparingGuts(GlobalTransaction gxact, TransactionId xid, const char *gid, TimestampTz prepared_at, Oid owner, Oid databaseid) { PGPROC *proc; - PGXACT *pgxact; int i; Assert(LWLockHeldByMeInMode(TwoPhaseStateLock, LW_EXCLUSIVE)); Assert(gxact != NULL); proc = &ProcGlobal->allProcs[gxact->pgprocno]; - pgxact = &ProcGlobal->allPgXact[gxact->pgprocno]; /* Initialize the PGPROC entry */ MemSet(proc, 0, sizeof(PGPROC)); @@ -480,8 +478,8 @@ MarkAsPreparingGuts(GlobalTransaction gxact, TransactionId xid, const char *gid, for (i = 0; i < NUM_LOCK_PARTITIONS; i++) SHMQueueInit(&(proc->myProcLocks[i])); /* subxid data must be filled later by GXactLoadSubxactData */ - pgxact->overflowed = false; - pgxact->nxids = 0; + proc->subxidStatus.overflowed = false; + proc->subxidStatus.count = 0; gxact->prepared_at = prepared_at; gxact->xid = xid; @@ -510,19 +508,18 @@ GXactLoadSubxactData(GlobalTransaction gxact, int nsubxacts, TransactionId *children) { PGPROC *proc = &ProcGlobal->allProcs[gxact->pgprocno]; - PGXACT *pgxact = &ProcGlobal->allPgXact[gxact->pgprocno]; /* We need no extra lock since the GXACT isn't valid yet */ if (nsubxacts > PGPROC_MAX_CACHED_SUBXIDS) { - pgxact->overflowed = true; + proc->subxidStatus.overflowed = true; nsubxacts = PGPROC_MAX_CACHED_SUBXIDS; } if (nsubxacts > 0) { memcpy(proc->subxids.xids, children, nsubxacts * sizeof(TransactionId)); - pgxact->nxids = nsubxacts; + proc->subxidStatus.count = nsubxacts; } } diff --git a/src/backend/access/transam/varsup.c b/src/backend/access/transam/varsup.c index 4c91b343ec..2d2b05be36 100644 --- a/src/backend/access/transam/varsup.c +++ b/src/backend/access/transam/varsup.c @@ -222,22 +222,31 @@ GetNewTransactionId(bool isSubXact) */ if (!isSubXact) { + Assert(ProcGlobal->subxidStates[MyProc->pgxactoff].count == 0); + Assert(!ProcGlobal->subxidStates[MyProc->pgxactoff].overflowed); + Assert(MyProc->subxidStatus.count == 0); + Assert(!MyProc->subxidStatus.overflowed); + /* LWLockRelease acts as barrier */ MyProc->xid = xid; ProcGlobal->xids[MyProc->pgxactoff] = xid; } else { - int nxids = MyPgXact->nxids; + XidCacheStatus *substat = &ProcGlobal->subxidStates[MyProc->pgxactoff]; + int nxids = MyProc->subxidStatus.count; + + Assert(substat->count == MyProc->subxidStatus.count); + Assert(substat->overflowed == MyProc->subxidStatus.overflowed); if (nxids < PGPROC_MAX_CACHED_SUBXIDS) { MyProc->subxids.xids[nxids] = xid; pg_write_barrier(); - MyPgXact->nxids = nxids + 1; + MyProc->subxidStatus.count = substat->count = nxids + 1; } else - MyPgXact->overflowed = true; + MyProc->subxidStatus.overflowed = substat->overflowed = true; } LWLockRelease(XidGenLock); diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c index 224da4f951..8262abd42e 100644 --- a/src/backend/storage/ipc/procarray.c +++ b/src/backend/storage/ipc/procarray.c @@ -4,9 +4,10 @@ * POSTGRES process array code. * * - * This module maintains arrays of the PGPROC and PGXACT structures for all - * active backends. Although there are several uses for this, the principal - * one is as a means of determining the set of currently running transactions. + * This module maintains arrays of PGPROC substructures, as well as associated + * arrays in ProcGlobal, for all active backends. Although there are several + * uses for this, the principal one is as a means of determining the set of + * currently running transactions. * * Because of various subtle race conditions it is critical that a backend * hold the correct locks while setting or clearing its xid (in @@ -85,7 +86,7 @@ typedef struct ProcArrayStruct /* * Highest subxid that has been removed from KnownAssignedXids array to * prevent overflow; or InvalidTransactionId if none. We track this for - * similar reasons to tracking overflowing cached subxids in PGXACT + * similar reasons to tracking overflowing cached subxids in PGPROC * entries. Must hold exclusive ProcArrayLock to change this, and shared * lock to read it. */ @@ -96,7 +97,7 @@ typedef struct ProcArrayStruct /* oldest catalog xmin of any replication slot */ TransactionId replication_slot_catalog_xmin; - /* indexes into allPgXact[], has PROCARRAY_MAXPROCS entries */ + /* indexes into allProcs[], has PROCARRAY_MAXPROCS entries */ int pgprocnos[FLEXIBLE_ARRAY_MEMBER]; } ProcArrayStruct; @@ -239,7 +240,6 @@ typedef struct ComputeXidHorizonsResult static ProcArrayStruct *procArray; static PGPROC *allProcs; -static PGXACT *allPgXact; /* * Bookkeeping for tracking emulated transactions in recovery @@ -325,8 +325,7 @@ static int KnownAssignedXidsGetAndSetXmin(TransactionId *xarray, static TransactionId KnownAssignedXidsGetOldestXmin(void); static void KnownAssignedXidsDisplay(int trace_level); static void KnownAssignedXidsReset(void); -static inline void ProcArrayEndTransactionInternal(PGPROC *proc, - PGXACT *pgxact, TransactionId latestXid); +static inline void ProcArrayEndTransactionInternal(PGPROC *proc, TransactionId latestXid); static void ProcArrayGroupClearXid(PGPROC *proc, TransactionId latestXid); static void MaintainLatestCompletedXid(TransactionId latestXid); static void MaintainLatestCompletedXidRecovery(TransactionId latestXid); @@ -411,7 +410,6 @@ CreateSharedProcArray(void) } allProcs = ProcGlobal->allProcs; - allPgXact = ProcGlobal->allPgXact; /* Create or attach to the KnownAssignedXids arrays too, if needed */ if (EnableHotStandby) @@ -476,11 +474,14 @@ ProcArrayAdd(PGPROC *proc) (arrayP->numProcs - index) * sizeof(*arrayP->pgprocnos)); memmove(&ProcGlobal->xids[index + 1], &ProcGlobal->xids[index], (arrayP->numProcs - index) * sizeof(*ProcGlobal->xids)); + memmove(&ProcGlobal->subxidStates[index + 1], &ProcGlobal->subxidStates[index], + (arrayP->numProcs - index) * sizeof(*ProcGlobal->subxidStates)); memmove(&ProcGlobal->vacuumFlags[index + 1], &ProcGlobal->vacuumFlags[index], (arrayP->numProcs - index) * sizeof(*ProcGlobal->vacuumFlags)); arrayP->pgprocnos[index] = proc->pgprocno; ProcGlobal->xids[index] = proc->xid; + ProcGlobal->subxidStates[index] = proc->subxidStatus; ProcGlobal->vacuumFlags[index] = proc->vacuumFlags; arrayP->numProcs++; @@ -534,6 +535,8 @@ ProcArrayRemove(PGPROC *proc, TransactionId latestXid) MaintainLatestCompletedXid(latestXid); ProcGlobal->xids[proc->pgxactoff] = 0; + ProcGlobal->subxidStates[proc->pgxactoff].overflowed = false; + ProcGlobal->subxidStates[proc->pgxactoff].count = 0; } else { @@ -542,6 +545,8 @@ ProcArrayRemove(PGPROC *proc, TransactionId latestXid) } Assert(TransactionIdIsValid(ProcGlobal->xids[proc->pgxactoff] == 0)); + Assert(TransactionIdIsValid(ProcGlobal->subxidStates[proc->pgxactoff].count == 0)); + Assert(TransactionIdIsValid(ProcGlobal->subxidStates[proc->pgxactoff].overflowed == false)); ProcGlobal->vacuumFlags[proc->pgxactoff] = 0; for (index = 0; index < arrayP->numProcs; index++) @@ -553,6 +558,8 @@ ProcArrayRemove(PGPROC *proc, TransactionId latestXid) (arrayP->numProcs - index - 1) * sizeof(*arrayP->pgprocnos)); memmove(&ProcGlobal->xids[index], &ProcGlobal->xids[index + 1], (arrayP->numProcs - index - 1) * sizeof(*ProcGlobal->xids)); + memmove(&ProcGlobal->subxidStates[index], &ProcGlobal->subxidStates[index + 1], + (arrayP->numProcs - index - 1) * sizeof(*ProcGlobal->subxidStates)); memmove(&ProcGlobal->vacuumFlags[index], &ProcGlobal->vacuumFlags[index + 1], (arrayP->numProcs - index - 1) * sizeof(*ProcGlobal->vacuumFlags)); @@ -597,8 +604,6 @@ ProcArrayRemove(PGPROC *proc, TransactionId latestXid) void ProcArrayEndTransaction(PGPROC *proc, TransactionId latestXid) { - PGXACT *pgxact = &allPgXact[proc->pgprocno]; - if (TransactionIdIsValid(latestXid)) { /* @@ -616,7 +621,7 @@ ProcArrayEndTransaction(PGPROC *proc, TransactionId latestXid) */ if (LWLockConditionalAcquire(ProcArrayLock, LW_EXCLUSIVE)) { - ProcArrayEndTransactionInternal(proc, pgxact, latestXid); + ProcArrayEndTransactionInternal(proc, latestXid); LWLockRelease(ProcArrayLock); } else @@ -630,15 +635,14 @@ ProcArrayEndTransaction(PGPROC *proc, TransactionId latestXid) * estimate of global xmin, but that's OK. */ Assert(!TransactionIdIsValid(proc->xid)); + Assert(proc->subxidStatus.count == 0); + Assert(!proc->subxidStatus.overflowed); proc->lxid = InvalidLocalTransactionId; proc->xmin = InvalidTransactionId; proc->delayChkpt = false; /* be sure this is cleared in abort */ proc->recoveryConflictPending = false; - Assert(pgxact->nxids == 0); - Assert(pgxact->overflowed == false); - /* must be cleared with xid/xmin: */ /* avoid unnecessarily dirtying shared cachelines */ if (proc->vacuumFlags & PROC_VACUUM_STATE_MASK) @@ -659,8 +663,7 @@ ProcArrayEndTransaction(PGPROC *proc, TransactionId latestXid) * We don't do any locking here; caller must handle that. */ static inline void -ProcArrayEndTransactionInternal(PGPROC *proc, PGXACT *pgxact, - TransactionId latestXid) +ProcArrayEndTransactionInternal(PGPROC *proc, TransactionId latestXid) { size_t pgxactoff = proc->pgxactoff; @@ -683,8 +686,15 @@ ProcArrayEndTransactionInternal(PGPROC *proc, PGXACT *pgxact, } /* Clear the subtransaction-XID cache too while holding the lock */ - pgxact->nxids = 0; - pgxact->overflowed = false; + Assert(ProcGlobal->subxidStates[pgxactoff].count == proc->subxidStatus.count && + ProcGlobal->subxidStates[pgxactoff].overflowed == proc->subxidStatus.overflowed); + if (proc->subxidStatus.count > 0 || proc->subxidStatus.overflowed) + { + ProcGlobal->subxidStates[pgxactoff].count = 0; + ProcGlobal->subxidStates[pgxactoff].overflowed = false; + proc->subxidStatus.count = 0; + proc->subxidStatus.overflowed = false; + } /* Also advance global latestCompletedXid while holding the lock */ MaintainLatestCompletedXid(latestXid); @@ -774,9 +784,8 @@ ProcArrayGroupClearXid(PGPROC *proc, TransactionId latestXid) while (nextidx != INVALID_PGPROCNO) { PGPROC *proc = &allProcs[nextidx]; - PGXACT *pgxact = &allPgXact[nextidx]; - ProcArrayEndTransactionInternal(proc, pgxact, proc->procArrayGroupMemberXid); + ProcArrayEndTransactionInternal(proc, proc->procArrayGroupMemberXid); /* Move to next proc in list. */ nextidx = pg_atomic_read_u32(&proc->procArrayGroupNext); @@ -820,7 +829,6 @@ ProcArrayGroupClearXid(PGPROC *proc, TransactionId latestXid) void ProcArrayClearTransaction(PGPROC *proc) { - PGXACT *pgxact = &allPgXact[proc->pgprocno]; size_t pgxactoff; /* @@ -845,8 +853,15 @@ ProcArrayClearTransaction(PGPROC *proc) Assert(!proc->delayChkpt); /* Clear the subtransaction-XID cache too */ - pgxact->nxids = 0; - pgxact->overflowed = false; + Assert(ProcGlobal->subxidStates[pgxactoff].count == proc->subxidStatus.count && + ProcGlobal->subxidStates[pgxactoff].overflowed == proc->subxidStatus.overflowed); + if (proc->subxidStatus.count > 0 || proc->subxidStatus.overflowed) + { + ProcGlobal->subxidStates[pgxactoff].count = 0; + ProcGlobal->subxidStates[pgxactoff].overflowed = false; + proc->subxidStatus.count = 0; + proc->subxidStatus.overflowed = false; + } LWLockRelease(ProcArrayLock); } @@ -1267,6 +1282,7 @@ TransactionIdIsInProgress(TransactionId xid) { static TransactionId *xids = NULL; static TransactionId *other_xids; + XidCacheStatus *other_subxidstates; int nxids = 0; ProcArrayStruct *arrayP = procArray; TransactionId topxid; @@ -1329,6 +1345,7 @@ TransactionIdIsInProgress(TransactionId xid) } other_xids = ProcGlobal->xids; + other_subxidstates = ProcGlobal->subxidStates; LWLockAcquire(ProcArrayLock, LW_SHARED); @@ -1351,7 +1368,6 @@ TransactionIdIsInProgress(TransactionId xid) for (size_t pgxactoff = 0; pgxactoff < numProcs; pgxactoff++) { int pgprocno; - PGXACT *pgxact; PGPROC *proc; TransactionId pxid; int pxids; @@ -1386,9 +1402,7 @@ TransactionIdIsInProgress(TransactionId xid) /* * Step 2: check the cached child-Xids arrays */ - pgprocno = arrayP->pgprocnos[pgxactoff]; - pgxact = &allPgXact[pgprocno]; - pxids = pgxact->nxids; + pxids = other_subxidstates[pgxactoff].count; pg_read_barrier(); /* pairs with barrier in GetNewTransactionId() */ pgprocno = arrayP->pgprocnos[pgxactoff]; proc = &allProcs[pgprocno]; @@ -1412,7 +1426,7 @@ TransactionIdIsInProgress(TransactionId xid) * we hold ProcArrayLock. So we can't miss an Xid that we need to * worry about.) */ - if (pgxact->overflowed) + if (other_subxidstates[pgxactoff].overflowed) xids[nxids++] = pxid; } @@ -2019,6 +2033,7 @@ GetSnapshotData(Snapshot snapshot) size_t numProcs = arrayP->numProcs; TransactionId *xip = snapshot->xip; int *pgprocnos = arrayP->pgprocnos; + XidCacheStatus *subxidStates = ProcGlobal->subxidStates; uint8 *allVacuumFlags = ProcGlobal->vacuumFlags; /* @@ -2095,17 +2110,16 @@ GetSnapshotData(Snapshot snapshot) */ if (!suboverflowed) { - int pgprocno = pgprocnos[pgxactoff]; - PGXACT *pgxact = &allPgXact[pgprocno]; - if (pgxact->overflowed) + if (subxidStates[pgxactoff].overflowed) suboverflowed = true; else { - int nsubxids = pgxact->nxids; + int nsubxids = subxidStates[pgxactoff].count; if (nsubxids > 0) { + int pgprocno = pgprocnos[pgxactoff]; PGPROC *proc = &allProcs[pgprocno]; pg_read_barrier(); /* pairs with GetNewTransactionId */ @@ -2498,8 +2512,6 @@ GetRunningTransactionData(void) */ for (index = 0; index < arrayP->numProcs; index++) { - int pgprocno = arrayP->pgprocnos[index]; - PGXACT *pgxact = &allPgXact[pgprocno]; TransactionId xid; /* Fetch xid just once - see GetNewTransactionId */ @@ -2520,7 +2532,7 @@ GetRunningTransactionData(void) if (TransactionIdPrecedes(xid, oldestRunningXid)) oldestRunningXid = xid; - if (pgxact->overflowed) + if (ProcGlobal->subxidStates[index].overflowed) suboverflowed = true; /* @@ -2540,27 +2552,28 @@ GetRunningTransactionData(void) */ if (!suboverflowed) { + XidCacheStatus *other_subxidstates = ProcGlobal->subxidStates; + for (index = 0; index < arrayP->numProcs; index++) { int pgprocno = arrayP->pgprocnos[index]; PGPROC *proc = &allProcs[pgprocno]; - PGXACT *pgxact = &allPgXact[pgprocno]; - int nxids; + int nsubxids; /* * Save subtransaction XIDs. Other backends can't add or remove * entries while we're holding XidGenLock. */ - nxids = pgxact->nxids; - if (nxids > 0) + nsubxids = other_subxidstates[index].count; + if (nsubxids > 0) { /* barrier not really required, as XidGenLock is held, but ... */ pg_read_barrier(); /* pairs with GetNewTransactionId */ memcpy(&xids[count], (void *) proc->subxids.xids, - nxids * sizeof(TransactionId)); - count += nxids; - subcount += nxids; + nsubxids * sizeof(TransactionId)); + count += nsubxids; + subcount += nsubxids; /* * Top-level XID of a transaction is always less than any of @@ -3627,14 +3640,6 @@ ProcArrayGetReplicationSlotXmin(TransactionId *xmin, LWLockRelease(ProcArrayLock); } - -#define XidCacheRemove(i) \ - do { \ - MyProc->subxids.xids[i] = MyProc->subxids.xids[MyPgXact->nxids - 1]; \ - pg_write_barrier(); \ - MyPgXact->nxids--; \ - } while (0) - /* * XidCacheRemoveRunningXids * @@ -3650,6 +3655,7 @@ XidCacheRemoveRunningXids(TransactionId xid, { int i, j; + XidCacheStatus *mysubxidstat; Assert(TransactionIdIsValid(xid)); @@ -3667,6 +3673,8 @@ XidCacheRemoveRunningXids(TransactionId xid, */ LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE); + mysubxidstat = &ProcGlobal->subxidStates[MyProc->pgxactoff]; + /* * Under normal circumstances xid and xids[] will be in increasing order, * as will be the entries in subxids. Scan backwards to avoid O(N^2) @@ -3676,11 +3684,14 @@ XidCacheRemoveRunningXids(TransactionId xid, { TransactionId anxid = xids[i]; - for (j = MyPgXact->nxids - 1; j >= 0; j--) + for (j = MyProc->subxidStatus.count - 1; j >= 0; j--) { if (TransactionIdEquals(MyProc->subxids.xids[j], anxid)) { - XidCacheRemove(j); + MyProc->subxids.xids[j] = MyProc->subxids.xids[MyProc->subxidStatus.count - 1]; + pg_write_barrier(); + mysubxidstat->count--; + MyProc->subxidStatus.count--; break; } } @@ -3692,20 +3703,23 @@ XidCacheRemoveRunningXids(TransactionId xid, * error during AbortSubTransaction. So instead of Assert, emit a * debug warning. */ - if (j < 0 && !MyPgXact->overflowed) + if (j < 0 && !MyProc->subxidStatus.overflowed) elog(WARNING, "did not find subXID %u in MyProc", anxid); } - for (j = MyPgXact->nxids - 1; j >= 0; j--) + for (j = MyProc->subxidStatus.count - 1; j >= 0; j--) { if (TransactionIdEquals(MyProc->subxids.xids[j], xid)) { - XidCacheRemove(j); + MyProc->subxids.xids[j] = MyProc->subxids.xids[MyProc->subxidStatus.count - 1]; + pg_write_barrier(); + mysubxidstat->count--; + MyProc->subxidStatus.count--; break; } } /* Ordinarily we should have found it, unless the cache has overflowed */ - if (j < 0 && !MyPgXact->overflowed) + if (j < 0 && !MyProc->subxidStatus.overflowed) elog(WARNING, "did not find subXID %u in MyProc", xid); /* Also advance global latestCompletedXid while holding the lock */ diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index f6113b2d24..aa9fbd8054 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -63,9 +63,8 @@ int LockTimeout = 0; int IdleInTransactionSessionTimeout = 0; bool log_lock_waits = false; -/* Pointer to this process's PGPROC and PGXACT structs, if any */ +/* Pointer to this process's PGPROC struct, if any */ PGPROC *MyProc = NULL; -PGXACT *MyPgXact = NULL; /* * This spinlock protects the freelist of recycled PGPROC structures. @@ -110,10 +109,8 @@ ProcGlobalShmemSize(void) size = add_size(size, mul_size(TotalProcs, sizeof(PGPROC))); size = add_size(size, sizeof(slock_t)); - size = add_size(size, mul_size(MaxBackends, sizeof(PGXACT))); - size = add_size(size, mul_size(NUM_AUXILIARY_PROCS, sizeof(PGXACT))); - size = add_size(size, mul_size(max_prepared_xacts, sizeof(PGXACT))); size = add_size(size, mul_size(TotalProcs, sizeof(*ProcGlobal->xids))); + size = add_size(size, mul_size(TotalProcs, sizeof(*ProcGlobal->subxidStates))); size = add_size(size, mul_size(TotalProcs, sizeof(*ProcGlobal->vacuumFlags))); return size; @@ -161,7 +158,6 @@ void InitProcGlobal(void) { PGPROC *procs; - PGXACT *pgxacts; int i, j; bool found; @@ -202,18 +198,6 @@ InitProcGlobal(void) /* XXX allProcCount isn't really all of them; it excludes prepared xacts */ ProcGlobal->allProcCount = MaxBackends + NUM_AUXILIARY_PROCS; - /* - * Also allocate a separate array of PGXACT structures. This is separate - * from the main PGPROC array so that the most heavily accessed data is - * stored contiguously in memory in as few cache lines as possible. This - * provides significant performance benefits, especially on a - * multiprocessor system. There is one PGXACT structure for every PGPROC - * structure. - */ - pgxacts = (PGXACT *) ShmemAlloc(TotalProcs * sizeof(PGXACT)); - MemSet(pgxacts, 0, TotalProcs * sizeof(PGXACT)); - ProcGlobal->allPgXact = pgxacts; - /* * Allocate arrays mirroring PGPROC fields in a dense manner. See * PROC_HDR. @@ -224,6 +208,8 @@ InitProcGlobal(void) ProcGlobal->xids = (TransactionId *) ShmemAlloc(TotalProcs * sizeof(*ProcGlobal->xids)); MemSet(ProcGlobal->xids, 0, TotalProcs * sizeof(*ProcGlobal->xids)); + ProcGlobal->subxidStates = (XidCacheStatus *) ShmemAlloc(TotalProcs * sizeof(*ProcGlobal->subxidStates)); + MemSet(ProcGlobal->subxidStates, 0, TotalProcs * sizeof(*ProcGlobal->subxidStates)); ProcGlobal->vacuumFlags = (uint8 *) ShmemAlloc(TotalProcs * sizeof(*ProcGlobal->vacuumFlags)); MemSet(ProcGlobal->vacuumFlags, 0, TotalProcs * sizeof(*ProcGlobal->vacuumFlags)); @@ -372,7 +358,6 @@ InitProcess(void) (errcode(ERRCODE_TOO_MANY_CONNECTIONS), errmsg("sorry, too many clients already"))); } - MyPgXact = &ProcGlobal->allPgXact[MyProc->pgprocno]; /* * Cross-check that the PGPROC is of the type we expect; if this were not @@ -569,7 +554,6 @@ InitAuxiliaryProcess(void) ((volatile PGPROC *) auxproc)->pid = MyProcPid; MyProc = auxproc; - MyPgXact = &ProcGlobal->allPgXact[auxproc->pgprocno]; SpinLockRelease(ProcStructLock); diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h index 9f3a8b518e..9c9a50ae45 100644 --- a/src/include/storage/proc.h +++ b/src/include/storage/proc.h @@ -35,6 +35,14 @@ */ #define PGPROC_MAX_CACHED_SUBXIDS 64 /* XXX guessed-at value */ +typedef struct XidCacheStatus +{ + /* number of cached subxids, never more than PGPROC_MAX_CACHED_SUBXIDS */ + uint8 count; + /* has PGPROC->subxids overflowed */ + bool overflowed; +} XidCacheStatus; + struct XidCache { TransactionId xids[PGPROC_MAX_CACHED_SUBXIDS]; @@ -187,6 +195,8 @@ struct PGPROC */ SHM_QUEUE myProcLocks[NUM_LOCK_PARTITIONS]; + XidCacheStatus subxidStatus; /* mirrored with + * ProcGlobal->subxidStates[i] */ struct XidCache subxids; /* cache for subtransaction XIDs */ /* Support for group XID clearing. */ @@ -235,22 +245,6 @@ struct PGPROC extern PGDLLIMPORT PGPROC *MyProc; -extern PGDLLIMPORT struct PGXACT *MyPgXact; - -/* - * Prior to PostgreSQL 9.2, the fields below were stored as part of the - * PGPROC. However, benchmarking revealed that packing these particular - * members into a separate array as tightly as possible sped up GetSnapshotData - * considerably on systems with many CPU cores, by reducing the number of - * cache lines needing to be fetched. Thus, think very carefully before adding - * anything else here. - */ -typedef struct PGXACT -{ - bool overflowed; - - uint8 nxids; -} PGXACT; /* * There is one ProcGlobal struct for the whole database cluster. @@ -310,12 +304,16 @@ typedef struct PROC_HDR { /* Array of PGPROC structures (not including dummies for prepared txns) */ PGPROC *allProcs; - /* Array of PGXACT structures (not including dummies for prepared txns) */ - PGXACT *allPgXact; /* Array mirroring PGPROC.xid for each PGPROC currently in the procarray */ TransactionId *xids; + /* + * Array mirroring PGPROC.subxidStatus for each PGPROC currently in the + * procarray. + */ + XidCacheStatus *subxidStates; + /* * Array mirroring PGPROC.vacuumFlags for each PGPROC currently in the * procarray. diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index b4948ac675..3d990463ce 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -1536,7 +1536,6 @@ PGSetenvStatusType PGShmemHeader PGTransactionStatusType PGVerbosity -PGXACT PG_Locale_Strategy PG_Lock_Status PG_init_t