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Start rewriting multimaster to 2PC
1 parent 9972466 commit ed8b893

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4 files changed

+51
-151
lines changed

4 files changed

+51
-151
lines changed

‎contrib/mmts/arbiter.c

Lines changed: 14 additions & 112 deletions
Original file line numberDiff line numberDiff line change
@@ -458,7 +458,7 @@ static void MtmAppendBuffer(MtmBuffer* txBuffer, TransactionId xid, int node, Mt
458458
MTM_TRACE("Send message %s CSN=%ld to node %d from node %d for global transaction %d/local transaction %d\n",
459459
messageText[ts->cmd], ts->csn, node+1, MtmNodeId, ts->gtid.xid, ts->xid);
460460
Assert(ts->cmd != MSG_INVALID);
461-
buf->data[buf->used].code = ts->cmd;
461+
buf->data[buf->used].code = ts->status == TRANSACTION_STATUS_ABORTED ? MSG_ABORTED : MSG_PREPARED;
462462
buf->data[buf->used].dxid = xid;
463463
buf->data[buf->used].sxid = ts->xid;
464464
buf->data[buf->used].csn = ts->csn;
@@ -467,21 +467,6 @@ static void MtmAppendBuffer(MtmBuffer* txBuffer, TransactionId xid, int node, Mt
467467
buf->used += 1;
468468
}
469469

470-
static void MtmBroadcastMessage(MtmBuffer* txBuffer, MtmTransState* ts)
471-
{
472-
int i;
473-
int n = 1;
474-
for (i = 0; i < MtmNodes; i++)
475-
{
476-
if (TransactionIdIsValid(ts->xids[i])) {
477-
Assert(i+1 != MtmNodeId);
478-
MtmAppendBuffer(txBuffer, ts->xids[i], i, ts);
479-
n += 1;
480-
}
481-
}
482-
Assert(n == ds->nNodes);
483-
}
484-
485470
static void MtmTransSender(Datum arg)
486471
{
487472
int nNodes = MtmNodes;
@@ -508,12 +493,7 @@ static void MtmTransSender(Datum arg)
508493
MtmLock(LW_SHARED);
509494

510495
for (ts = ds->votingTransactions; ts != NULL; ts = ts->nextVoting) {
511-
if (MtmIsCoordinator(ts)) {
512-
MtmBroadcastMessage(txBuffer, ts);
513-
} else {
514-
MtmAppendBuffer(txBuffer, ts->gtid.xid, ts->gtid.node-1, ts);
515-
}
516-
ts->cmd = MSG_INVALID;
496+
MtmAppendBuffer(txBuffer, ts->gtid.xid, ts->gtid.node-1, ts);
517497
}
518498
ds->votingTransactions = NULL;
519499
MtmUnlock();
@@ -634,109 +614,31 @@ static void MtmTransReceiver(Datum arg)
634614
MtmArbiterMessage* msg = &rxBuffer[i].data[j];
635615
MtmTransState* ts = (MtmTransState*)hash_search(xid2state, &msg->dxid, HASH_FIND, NULL);
636616
Assert(ts != NULL);
637-
Assert(ts->cmd == MSG_INVALID);
638617
Assert(msg->node > 0 && msg->node <= nNodes && msg->node != MtmNodeId);
639-
ts->xids[msg->node-1] = msg->sxid;
640-
641-
if (MtmIsCoordinator(ts)) {
642-
switch (msg->code) {
643-
case MSG_READY:
644-
Assert(ts->status == TRANSACTION_STATUS_ABORTED || ts->status == TRANSACTION_STATUS_IN_PROGRESS);
645-
Assert(ts->nVotes < ds->nNodes);
646-
ds->nodeTransDelay[msg->node-1] += MtmGetCurrentTime() - ts->csn;
647-
if (++ts->nVotes == ds->nNodes) {
648-
/* All nodes are finished their transactions */
649-
if (ts->status == TRANSACTION_STATUS_IN_PROGRESS) {
650-
ts->nVotes = 1; /* I voted myself */
651-
ts->cmd = MSG_PREPARE;
652-
} else {
653-
ts->status = TRANSACTION_STATUS_ABORTED;
654-
ts->cmd = MSG_ABORT;
655-
MtmAdjustSubtransactions(ts);
656-
MtmWakeUpBackend(ts);
657-
}
658-
MtmSendNotificationMessage(ts);
659-
}
660-
break;
618+
Assert (MtmIsCoordinator(ts));
619+
switch (msg->code) {
661620
case MSG_PREPARED:
662-
Assert(ts->status == TRANSACTION_STATUS_IN_PROGRESS);
663-
Assert(ts->nVotes < ds->nNodes);
664-
if (msg->csn > ts->csn) {
665-
ts->csn = msg->csn;
666-
MtmSyncClock(ts->csn);
667-
}
668-
if (++ts->nVotes == ds->nNodes) {
669-
/* ts->csn is maximum of CSNs at all nodes */
670-
ts->nVotes = 1; /* I voted myself */
671-
ts->cmd = MSG_COMMIT;
672-
ts->csn = MtmAssignCSN();
673-
ts->status = TRANSACTION_STATUS_UNKNOWN;
674-
MtmAdjustSubtransactions(ts);
675-
MtmSendNotificationMessage(ts);
676-
}
677-
break;
678-
case MSG_COMMITTED:
679-
Assert(ts->status == TRANSACTION_STATUS_UNKNOWN);
680-
Assert(ts->nVotes < ds->nNodes);
681-
if (++ts->nVotes == ds->nNodes) {
682-
/* All nodes have the same CSN */
683-
MtmWakeUpBackend(ts);
621+
if (ts->status == TRANSACTION_STATUS_IN_PROGRESS) {
622+
if (msg->csn > ts->csn) {
623+
ts->csn = msg->csn;
624+
MtmSyncClock(ts->csn);
625+
}
626+
if (++ts->nVotes == ds->nNodes) {
627+
MtmWakeUpBackend(ts);
628+
}
684629
}
685630
break;
686631
case MSG_ABORTED:
687-
Assert(ts->status == TRANSACTION_STATUS_ABORTED || ts->status == TRANSACTION_STATUS_IN_PROGRESS);
688-
Assert(ts->nVotes < ds->nNodes);
689-
ts->status = TRANSACTION_STATUS_ABORTED;
690-
if (++ts->nVotes == ds->nNodes) {
691-
ts->cmd = MSG_ABORT;
692-
MtmAdjustSubtransactions(ts);
693-
MtmSendNotificationMessage(ts);
694-
MtmWakeUpBackend(ts);
695-
}
696-
break;
697-
default:
698-
Assert(false);
699-
}
700-
} else { /* replica */
701-
switch (msg->code) {
702-
case MSG_PREPARE:
703-
Assert(ts->status == TRANSACTION_STATUS_IN_PROGRESS);
704-
if ((msg->disabledNodeMask & ~ds->disabledNodeMask) != 0) {
705-
/* Coordinator's disabled mask is wider than my: so reject such transaction to avoid
706-
commit on smaller subset of nodes */
632+
if (ts->status == TRANSACTION_STATUS_IN_PROGRESS) {
707633
ts->status = TRANSACTION_STATUS_ABORTED;
708-
ts->cmd = MSG_ABORT;
709-
MtmAdjustSubtransactions(ts);
710-
MtmWakeUpBackend(ts);
711-
} else {
712-
ts->status = TRANSACTION_STATUS_UNKNOWN;
713-
ts->csn = MtmAssignCSN();
714-
ts->cmd = MSG_PREPARED;
715-
}
716-
MtmSendNotificationMessage(ts);
717-
break;
718-
case MSG_COMMIT:
719-
Assert(ts->status == TRANSACTION_STATUS_UNKNOWN);
720-
Assert(ts->csn < msg->csn);
721-
ts->csn = msg->csn;
722-
MtmSyncClock(ts->csn);
723-
ts->cmd = MSG_COMMITTED;
724-
MtmAdjustSubtransactions(ts);
725-
MtmSendNotificationMessage(ts);
726-
MtmWakeUpBackend(ts);
727-
break;
728-
case MSG_ABORT:
729-
if (ts->status != TRANSACTION_STATUS_ABORTED) {
730-
Assert(ts->status == TRANSACTION_STATUS_UNKNOWN || ts->status == TRANSACTION_STATUS_IN_PROGRESS);
731-
ts->status = TRANSACTION_STATUS_ABORTED;
732634
MtmAdjustSubtransactions(ts);
733635
MtmWakeUpBackend(ts);
734636
}
735637
break;
736638
default:
737639
Assert(false);
738640
}
739-
}
641+
}
740642
}
741643
MtmUnlock();
742644

‎contrib/mmts/multimaster.c

Lines changed: 33 additions & 31 deletions
Original file line numberDiff line numberDiff line change
@@ -64,7 +64,6 @@ typedef struct {
6464
bool isReplicated; /* transaction on replica */
6565
bool isDistributed; /* transaction performed INSERT/UPDATE/DELETE and has to be replicated to other nodes */
6666
bool containsDML; /* transaction contains DML statements */
67-
bool isPrepared; /* transaction is prepared as part of 2PC */
6867
csn_t snapshot; /* transaction snaphsot */
6968
} MtmCurrentTrans;
7069

@@ -100,8 +99,8 @@ static void MtmSetTransactionStatus(TransactionId xid, int nsubxids, Transaction
10099
static void MtmInitialize(void);
101100
static void MtmXactCallback(XactEvent event, void *arg);
102101
static void MtmBeginTransaction(MtmCurrentTrans* x);
103-
static void MtmPrecommitTransaction(MtmCurrentTrans* x);
104102
static bool MtmCommitTransaction(TransactionId xid, int nsubxids, TransactionId *subxids);
103+
static void MtmPrePrepareTransaction(MtmCurrentTrans* x);
105104
static void MtmPrepareTransaction(MtmCurrentTrans* x);
106105
static void MtmCommitPreparedTransaction(MtmCurrentTrans* x);
107106
static void MtmEndTransaction(MtmCurrentTrans* x, bool commit);
@@ -347,15 +346,6 @@ bool MtmXidInMVCCSnapshot(TransactionId xid, Snapshot snapshot)
347346
return PgXidInMVCCSnapshot(xid, snapshot);
348347
}
349348

350-
static uint32 MtmXidHashFunc(const void *key, Size keysize)
351-
{
352-
return (uint32)*(TransactionId*)key;
353-
}
354-
355-
static int MtmXidMatchFunc(const void *key1, const void *key2, Size keysize)
356-
{
357-
return *(TransactionId*)key1 - *(TransactionId*)key2;
358-
}
359349

360350
static void MtmTransactionListAppend(MtmTransState* ts)
361351
{
@@ -489,8 +479,8 @@ MtmXactCallback(XactEvent event, void *arg)
489479
case XACT_EVENT_START:
490480
MtmBeginTransaction(&dtmTx);
491481
break;
492-
case XACT_EVENT_PRE_COMMIT:
493-
MtmPrecommitTransaction(&dtmTx);
482+
case XACT_EVENT_PRE_PREPARE:
483+
MtmPrePrepareTransaction(&dtmTx);
494484
break;
495485
case XACT_EVENT_PREPARE:
496486
MtmPrepareTransaction(&dtmTx);
@@ -598,16 +588,14 @@ MtmCheckClusterLock()
598588
}
599589

600590
/*
601-
* This functions is called as pre-commit callback.
602-
* We need to pass snapshot to WAL-sender, so create record in transaction status hash table
603-
* before commit
591+
* Prepare transaction for two-phase commit
604592
*/
605-
static void MtmPrecommitTransaction(MtmCurrentTrans* x)
593+
MtmPrePrepareTransaction(MtmCurrentTrans* x)
606594
{
607595
MtmTransState* ts;
608596
int i;
609597

610-
if (!x->isDistributed || x->isPrepared) {
598+
if (!x->isDistributed) {
611599
return;
612600
}
613601

@@ -632,7 +620,6 @@ static void MtmPrecommitTransaction(MtmCurrentTrans* x)
632620
ts->snapshot = x->isReplicated || !x->containsDML ? INVALID_CSN : x->snapshot;
633621
ts->csn = MtmAssignCSN();
634622
ts->gtid = x->gtid;
635-
ts->cmd = MSG_INVALID;
636623
ts->procno = MyProc->pgprocno;
637624
ts->nVotes = 0;
638625
ts->voteCompleted = false;
@@ -644,24 +631,41 @@ static void MtmPrecommitTransaction(MtmCurrentTrans* x)
644631
ts->gtid.xid = x->xid;
645632
ts->gtid.node = MtmNodeId;
646633
}
647-
for (i = 0; i < MtmNodes; i++) {
648-
ts->xids[i] = InvalidTransactionId;
649-
}
650634
MtmTransactionListAppend(ts);
651635

652636
MtmUnlock();
653637

654638
MTM_TRACE("%d: MtmPrepareTransaction prepare commit of %d CSN=%ld\n", MyProcPid, x->xid, ts->csn);
655639
}
656640

657-
static void
658641
MtmPrepareTransaction(MtmCurrentTrans* x)
659-
{
660-
MtmPrecommitTransaction(x);
661-
MTM_TRACE("Prepare transaction %d", x->xid);
662-
x->isPrepared = true;
642+
{
643+
MtmLock(LW_EXCLUSIVE);
644+
if (ts->status = TRANSACTION_STATUS_IN_PROGRESS) {
645+
ts->status = TRANSACTION_STATUS_UNKNOWN;
646+
MtmAdjustSubtransactions(ts);
647+
}
648+
649+
if (!MtmIsCoordinator(ts)) {
650+
MtmSendNotificationMessage(ts); /* send notification to coordinator */
651+
MtmUnlock();
652+
} else {
653+
/* wait N commits or just one ABORT */
654+
ts->nVotes += 1;
655+
while (ts->nVotes != dtm->nNodes && ts->status == TRANSACTION_STATUS_PROGRESS) {
656+
MtmUnlock();
657+
WaitLatch(&MyProc->procLatch, WL_LATCH_SET, -1);
658+
ResetLatch(&MyProc->procLatch);
659+
MtmLock(LW_SHARED);
660+
}
661+
MtmUnlock();
662+
if (ts->status == TRANSACTION_STATUS_ABORTED) {
663+
elog(ERROR, "Distributed transaction %d is rejected by DTM", x->xid);
664+
}
665+
}
663666
}
664667

668+
665669
static void
666670
MtmCommitPreparedTransaction(MtmCurrentTrans* x)
667671
{
@@ -1679,14 +1683,12 @@ HTAB* MtmCreateHash(void)
16791683
Assert(MtmNodes > 0);
16801684
memset(&info, 0, sizeof(info));
16811685
info.keysize = sizeof(TransactionId);
1682-
info.entrysize = sizeof(MtmTransState) + (MtmNodes-1)*sizeof(TransactionId);
1683-
info.hash = MtmXidHashFunc;
1684-
info.match = MtmXidMatchFunc;
1686+
info.entrysize = sizeof(MtmTransState);
16851687
htab = ShmemInitHash(
16861688
"xid2state",
16871689
MTM_HASH_SIZE, MTM_HASH_SIZE,
16881690
&info,
1689-
HASH_ELEM | HASH_FUNCTION | HASH_COMPARE
1691+
HASH_ELEM
16901692
);
16911693
return htab;
16921694
}

‎contrib/mmts/multimaster.h

Lines changed: 2 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -19,6 +19,7 @@
1919
#define MULTIMASTER_SLOT_PATTERN "mtm_slot_%d"
2020
#define MULTIMASTER_MIN_PROTO_VERSION 1
2121
#define MULTIMASTER_MAX_PROTO_VERSION 1
22+
#define MULTIMASTER_MAX_GID 32
2223

2324
#define USEC 1000000
2425

@@ -51,12 +52,7 @@ typedef enum
5152
{
5253
MSG_INVALID,
5354
MSG_HANDSHAKE,
54-
MSG_READY,
55-
MSG_PREPARE,
56-
MSG_COMMIT,
57-
MSG_ABORT,
5855
MSG_PREPARED,
59-
MSG_COMMITTED,
6056
MSG_ABORTED,
6157
MSG_STATUS
6258
} MtmMessageCode;
@@ -88,11 +84,10 @@ typedef struct MtmTransState
8884
finally should be nNodes-1 */
8985
int procno; /* pgprocno of transaction coordinator waiting for responses from replicas,
9086
used to notify coordinator by arbiter */
91-
MtmMessageCode cmd; /* Notification message code to be sent */
87+
bool voteCompleted; /* Responses necessary to make a decision are received by coordinator of transaction */
9288
int nSubxids; /* Number of subtransanctions */
9389
struct MtmTransState* nextVoting; /* Next element in L1-list of voting transactions. */
9490
struct MtmTransState* next; /* Next element in L1 list of all finished transaction present in xid2state hash */
95-
bool voteCompleted; /* Responses necessary to make a decision are received by coordinator of transaction */
9691
TransactionId xids[1]; /* transaction ID at replicas: varying size MtmNodes */
9792
} MtmTransState;
9893

‎src/backend/replication/logical/decode.c

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -289,7 +289,8 @@ DecodeXactOp(LogicalDecodingContext *ctx, XLogRecordBuffer *buf)
289289
* transactions in the changestream allowing for a kind of
290290
* distributed 2PC.
291291
*/
292-
// ReorderBufferProcessXid(reorder, XLogRecGetXid(r), buf->origptr);
292+
elog(WARNING, "DECODE process XLOG_XACT_PREPARE");
293+
//ReorderBufferProcessXid(reorder, XLogRecGetXid(r), buf->origptr);
293294
break;
294295

295296
}

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