Skip to content

Commit 4b5d155

Browse files
kelvichkelvich
committed
merge
2 parents 358204a + 3d6eaab commit 4b5d155

File tree

8 files changed

+142
-107
lines changed

8 files changed

+142
-107
lines changed

‎contrib/pg_xtm/libdtm.h

Lines changed: 12 additions & 26 deletions
Original file line numberDiff line numberDiff line change
@@ -8,42 +8,28 @@
88

99
#define INVALID_XID 0
1010

11-
typedef int NodeId;
12-
typedef unsigned long long xid_t;
13-
14-
typedef struct DTMConnData *DTMConn;
15-
16-
// Connects to the specified DTM.
17-
DTMConn DtmConnect(char *host, int port);
18-
19-
// Disconnects from the DTM. Do not use the 'dtm' pointer after this call, or
20-
// bad things will happen.
21-
void DtmDisconnect(DTMConn dtm);
22-
2311
void DtmInitSnapshot(Snapshot snapshot);
2412

25-
typedef struct {
26-
TransactionId* xids;
27-
NodeId* nodes;
28-
int nNodes;
29-
} GlobalTransactionId;
13+
// Starts new global transaction
14+
TransactionId DtmGlobalStartTransaction(int nParticipants, Snapshot shaposhot);
3015

31-
// Creates an entry for a new global transaction. Returns 'true' on success, or
32-
// 'false' otherwise.
33-
bool DtmGlobalStartTransaction(DTMConn dtm, GlobalTransactionId* gtid);
16+
// Asks DTM for a fresh snapshot.
17+
void DtmGlobalNewSnapshot(TransactionId xid, Snapshot snapshot);
3418

35-
// Asks DTM for a fresh snapshot. Returns 'true' on success, or 'false'
36-
// otherwise.
37-
bool DtmGlobalGetSnapshot(DTMConn dtm, NodeId nodeid, TransactionId xid, Snapshot snapshot);
19+
// Get existed DTM snapshot.
20+
void DtmGlobalGetSnapshot(TransactionId xid, Snapshot snapshot);
3821

3922
// Commits transaction only once all participants have called this function,
40-
// does not change CLOG otherwise. Returns 'true' on success, 'false' if
41-
// something failed on the daemon side.
42-
bool DtmGlobalSetTransStatus(DTMConn dtm, NodeId nodeid, TransactionId xid, XidStatus status, bool wait);
23+
// does not change CLOG otherwise.
24+
void DtmGlobalSetTransStatus(TransactionId xid, XidStatus status, bool wait);
4325

4426
// Gets the status of the transaction identified by 'xid'. Returns the status
4527
// on success, or -1 otherwise. If 'wait' is true, then it does not return
4628
// until the transaction is finished.
4729
XidStatus DtmGlobalGetTransStatus(DTMConn dtm, NodeId nodeid, TransactionId xid, bool wait);
4830

31+
// Reserve XIDs for local transaction
32+
TransactioinId DtmGlobalReserve(int nXids);
33+
34+
4935
#endif

‎contrib/pg_xtm/pg_dtm--1.0.sql

Lines changed: 11 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -1,14 +1,22 @@
11
-- complain if script is sourced in psql, rather than via CREATE EXTENSION
22
\echo Use "CREATE EXTENSION pg_dtm" to load this file. \quit
33

4-
CREATE FUNCTION dtm_begin_transaction(nodes integer[], xids integer[]) RETURNS void
4+
CREATE FUNCTION dtm_begin_transaction(n_participants integer) RETURNS integer
55
AS 'MODULE_PATHNAME','dtm_begin_transaction'
66
LANGUAGE C;
77

8-
CREATE FUNCTION dtm_get_current_snapshot_xmin() RETURNS bigint
8+
CREATE FUNCTION dtm_get_snapshot(xid integer) RETURNS void
9+
AS 'MODULE_PATHNAME','dtm_get_snapshot'
10+
LANGUAGE C;
11+
12+
CREATE FUNCTION dtm_new_snapshot(xid integer) RETURNS void
13+
AS 'MODULE_PATHNAME','dtm_new_snapshot'
14+
LANGUAGE C;
15+
16+
CREATE FUNCTION dtm_get_current_snapshot_xmin() RETURNS integer
917
AS 'MODULE_PATHNAME','dtm_get_current_snapshot_xmin'
1018
LANGUAGE C;
1119

12-
CREATE FUNCTION dtm_get_current_snapshot_xmax() RETURNS bigint
20+
CREATE FUNCTION dtm_get_current_snapshot_xmax() RETURNS integer
1321
AS 'MODULE_PATHNAME','dtm_get_current_snapshot_xmax'
1422
LANGUAGE C;

‎contrib/pg_xtm/pg_dtm.c

Lines changed: 109 additions & 75 deletions
Original file line numberDiff line numberDiff line change
@@ -1,4 +1,4 @@
1-
/*
1+
sisva/*
22
* pg_dtm.c
33
*
44
* Pluggable distributed transaction manager
@@ -36,7 +36,10 @@
3636

3737
typedef struct
3838
{
39-
LWLockId lock; /* protect access to hash table */
39+
LWLockId hashLock;
40+
LWLockId xidLock;
41+
TransactionId nextXid;
42+
size_t nReservedXids;
4043
} DtmState;
4144

4245

@@ -48,15 +51,15 @@ typedef struct
4851
void _PG_init(void);
4952
void _PG_fini(void);
5053

51-
static void DtmEnsureConnection(void);
5254
static Snapshot DtmGetSnapshot(void);
5355
static void DtmMergeSnapshots(Snapshot dst, Snapshot src);
5456
static Snapshot DtmCopySnapshot(Snapshot snapshot);
5557
static XidStatus DtmGetTransactionStatus(TransactionId xid, XLogRecPtr *lsn);
5658
static void DtmSetTransactionStatus(TransactionId xid, int nsubxids, TransactionId *subxids, XidStatus status, XLogRecPtr lsn);
5759
static void DtmUpdateRecentXmin(void);
58-
static void DtmInitialize();
60+
static void DtmInitialize(void);
5961
static void DtmXactCallback(XactEvent event, void *arg);
62+
static void DtmGetNextXid(void);
6063

6164
static bool TransactionIdIsInDtmSnapshot(TransactionId xid);
6265
static bool TransactionIdIsInDoubt(TransactionId xid);
@@ -69,33 +72,18 @@ static DtmState* dtm;
6972
static TransactionId DtmCurrentXid = InvalidTransactionId;
7073
static Snapshot CurrentTransactionSnapshot;
7174

72-
static NodeId DtmNodeId;
73-
static DTMConn DtmConn;
75+
static TransactionId DtmNextXid;
7476
static SnapshotData DtmSnapshot = { HeapTupleSatisfiesMVCC };
7577
static SnapshotData DtmLocalSnapshot = { HeapTupleSatisfiesMVCC };
76-
static bool DtmGlobalTransaction = false;
77-
static TransactionManager DtmTM = { DtmGetTransactionStatus, DtmSetTransactionStatus, DtmGetSnapshot, DtmCopySnapshot };
78-
static DTMConn DtmConn;
78+
static bool DtmIsGlobalTransaction = false;
79+
static int DtmLocalXidReserve;
80+
static TransactionManager DtmTM = { DtmGetTransactionStatus, DtmSetTransactionStatus, DtmGetSnapshot, DtmCopySnapshot, DtmGetNextXid };
81+
7982

8083
#define XTM_TRACE(fmt, ...)
8184
#define XTM_INFO(fmt, ...) fprintf(stderr, fmt, ## __VA_ARGS__)
8285
//#define XTM_INFO(fmt, ...)
8386

84-
static void DtmEnsureConnection(void)
85-
{
86-
int attempt = 0;
87-
XTM_TRACE("XTM: DtmEnsureConnection\n");
88-
while (attempt < XTM_CONNECT_ATTEMPTS) {
89-
if (DtmConn) {
90-
return;
91-
}
92-
XTM_TRACE("XTM: DtmEnsureConnection, attempt #%u\n", attempt);
93-
DtmConn = DtmConnect("127.0.0.1", 5431);
94-
attempt++;
95-
}
96-
elog(ERROR, "Failed to connect to DTMD");
97-
}
98-
9987
static void DumpSnapshot(Snapshot s, char *name)
10088
{
10189
int i;
@@ -247,17 +235,43 @@ static Snapshot DtmCopySnapshot(Snapshot snapshot)
247235
return newsnap;
248236
}
249237

238+
static TransactionId DtmGetNextXid()
239+
{
240+
TransactionId xid;
241+
if (TransactionIdIsValid(DtmNextXid)) {
242+
xid = DtmNextXid;
243+
DtmNextXid = InvalidTransactionId;
244+
} else {
245+
LWLockAcquire(dtm->xidLock, LW_EXCLUSIVE);
246+
if (dtm->nReservedXids == 0) {
247+
xid = DtmGlobalReserve(DtmLocalXidReserve);
248+
dtm->nReservedXids = DtmLocalXidReserve;
249+
ShmemVariableCache->nextXid = xid;
250+
}
251+
Assert(dtm->nextXid == ShmemVariableCache->nextXid);
252+
xid = ShmemVariableCache->nextXid;
253+
dtm->nextXid += 1;
254+
dtm->nReservedXids -= 1;
255+
LWLockRelease(dtm->xidLock);
256+
}
257+
return xid;
258+
}
250259

251260
static Snapshot DtmGetSnapshot()
252261
{
253-
CurrentTransactionSnapshot = GetLocalTransactionSnapshot();
254-
if (DtmGlobalTransaction && !IsolationUsesXactSnapshot()){ /* RU & RC */
255-
DtmEnsureConnection();
256-
DtmGlobalGetSnapshot(DtmConn, DtmNodeId, GetCurrentTransactionId(), &DtmSnapshot);
257-
DtmMergeSnapshots(CurrentTransactionSnapshot, &DtmSnapshot);
262+
Snapshot snapshot = GetLocalTransactionSnapshot();
263+
264+
if (DtmIsGlobalTransaction) {
265+
if (!IsolationUsesXactSnapshot()){ /* RU & RC */
266+
DtmEnsureConnection();
267+
DtmGlobalGetSnapshot(DtmConn, DtmNodeId, GetCurrentTransactionId(), &DtmSnapshot);
268+
}
269+
/* Should we actually perform that for RR & S levels? */
270+
DtmMergeSnapshots(snapshot, &DtmSnapshot);
258271
DtmUpdateRecentXmin();
259272
}
260-
return CurrentTransactionSnapshot;
273+
CurrentTransactionSnapshot = snapshot;
274+
return snapshot;
261275
}
262276

263277

@@ -280,18 +294,16 @@ static void DtmSetTransactionStatus(TransactionId xid, int nsubxids, Transaction
280294
CurrentTransactionSnapshot = NULL;
281295
if (status == TRANSACTION_STATUS_ABORTED) {
282296
CLOGTransactionIdSetTreeStatus(xid, nsubxids, subxids, status, lsn);
283-
DtmEnsureConnection();
284-
DtmGlobalSetTransStatus(DtmConn, DtmNodeId, xid, status, false);
297+
DtmGlobalSetTransStatus(xid, status, false);
285298
XTM_INFO("Abort transaction %d\n", xid);
286299
return;
287300
} else {
288-
DtmEnsureConnection();
289301
XTM_INFO("Begin commit transaction %d\n", xid);
290302
DtmCurrentXid = xid;
291-
LWLockAcquire(dtm->lock, LW_EXCLUSIVE);
303+
LWLockAcquire(dtm->hashLock, LW_EXCLUSIVE);
292304
hash_search(xid_in_doubt, &DtmCurrentXid, HASH_ENTER, NULL);
293-
LWLockRelease(dtm->lock);
294-
if (!DtmGlobalSetTransStatus(DtmConn, DtmNodeId, xid, status, true)) {
305+
LWLockRelease(dtm->hashLock);
306+
if (!DtmGlobalSetTransStatus(xid, status, true)) {
295307
elog(ERROR, "DTMD failed to set transaction status");
296308
}
297309
XTM_INFO("Commit transaction %d\n", xid);
@@ -301,8 +313,7 @@ static void DtmSetTransactionStatus(TransactionId xid, int nsubxids, Transaction
301313
}
302314
} else {
303315
XidStatus gs;
304-
DtmEnsureConnection();
305-
gs = DtmGlobalGetTransStatus(DtmConn, DtmNodeId, xid, false);
316+
gs = DtmGlobalGetTransStatus(xid, false);
306317
if (gs != TRANSACTION_STATUS_UNKNOWN) {
307318
status = gs;
308319
}
@@ -330,7 +341,9 @@ static void DtmInitialize()
330341
dtm = ShmemInitStruct("dtm", sizeof(DtmState), &found);
331342
if (!found)
332343
{
333-
dtm->lock = LWLockAssign();
344+
dtm->hashLock = LWLockAssign();
345+
dtm->xidLock = LWLockAssign();
346+
dtm->nReservedXids = 0;
334347
}
335348
LWLockRelease(AddinShmemInitLock);
336349

@@ -352,9 +365,9 @@ static void
352365
DtmXactCallback(XactEvent event, void *arg)
353366
{
354367
if (event == XACT_EVENT_COMMIT && DtmCurrentXid != InvalidTransactionId) {
355-
LWLockAcquire(dtm->lock, LW_EXCLUSIVE);
368+
LWLockAcquire(dtm->hashLock, LW_EXCLUSIVE);
356369
hash_search(xid_in_doubt, &DtmCurrentXid, HASH_REMOVE, NULL);
357-
LWLockRelease(dtm->lock);
370+
LWLockRelease(dtm->hashLock);
358371
}
359372
}
360373

@@ -383,14 +396,14 @@ _PG_init(void)
383396
* resources in imcs_shmem_startup().
384397
*/
385398
RequestAddinShmemSpace(DTM_SHMEM_SIZE);
386-
RequestAddinLWLocks(1);
399+
RequestAddinLWLocks(2);
387400

388-
DefineCustomIntVariable("dtm.node_id",
389-
"Identifier of node in distributed cluster for DTM",
401+
DefineCustomIntVariable("dtm.local_xid_reserve",
402+
"Number of XIDs reserved by node for local transactions",
390403
NULL,
391-
&DtmNodeId,
392-
0,
393-
0,
404+
&DtmLocalXidReserve,
405+
100,
406+
1,
394407
INT_MAX,
395408
PGC_BACKEND,
396409
0,
@@ -430,45 +443,66 @@ static void dtm_shmem_startup(void)
430443
PG_MODULE_MAGIC;
431444

432445
PG_FUNCTION_INFO_V1(dtm_begin_transaction);
446+
PG_FUNCTION_INFO_V1(dtm_get_snapshot);
447+
PG_FUNCTION_INFO_V1(dtm_new_snapshot);
433448
PG_FUNCTION_INFO_V1(dtm_get_current_snapshot_xmax);
434449
PG_FUNCTION_INFO_V1(dtm_get_current_snapshot_xmin);
435450

436451
Datum
437-
dtm_begin_transaction(PG_FUNCTION_ARGS)
452+
dtm_get_current_snapshot_xmin(PG_FUNCTION_ARGS)
438453
{
439-
GlobalTransactionId gtid;
440-
ArrayType* nodes = PG_GETARG_ARRAYTYPE_P(0);
441-
ArrayType* xids = PG_GETARG_ARRAYTYPE_P(1);
442-
gtid.xids = (TransactionId*)ARR_DATA_PTR(xids);
443-
gtid.nodes = (NodeId*)ARR_DATA_PTR(nodes);
444-
gtid.nNodes = ArrayGetNItems(ARR_NDIM(nodes), ARR_DIMS(nodes));
445-
DtmGlobalTransaction = true;
446-
Assert(gtid.xids[DtmNodeId] == GetCurrentTransactionId());
447-
XTM_INFO("Start transaction {%d,%d} at node %d, iso=%d\n", gtid.xids[0], gtid.xids[1], DtmNodeId, XactIsoLevel);
448-
if (DtmNodeId == gtid.nodes[0]) {
449-
DtmEnsureConnection();
450-
DtmGlobalStartTransaction(DtmConn, &gtid);
451-
}
452-
453-
if (IsolationUsesXactSnapshot()){ /* RR & S */
454-
DtmEnsureConnection();
455-
DtmGlobalGetSnapshot(DtmConn, DtmNodeId, gtid.xids[DtmNodeId], &DtmSnapshot);
456-
Assert(CurrentTransactionSnapshot != NULL);
457-
DtmMergeSnapshots(CurrentTransactionSnapshot, &DtmSnapshot);
458-
DtmUpdateRecentXmin();
459-
}
460-
461-
PG_RETURN_VOID();
454+
// if (IsolationUsesXactSnapshot()){ /* RR & S */
455+
// DtmEnsureConnection();
456+
// DtmGlobalGetSnapshot(DtmConn, DtmNodeId, gtid.xids[DtmNodeId], &DtmSnapshot);
457+
// Assert(CurrentTransactionSnapshot != NULL);
458+
// DtmMergeSnapshots(CurrentTransactionSnapshot, &DtmSnapshot);
459+
// DtmUpdateRecentXmin();
460+
// }
461+
PG_RETURN_INT32(CurrentTransactionSnapshot->xmin);
462462
}
463463

464464
Datum
465-
dtm_get_current_snapshot_xmin(PG_FUNCTION_ARGS)
465+
dtm_get_current_snapshot_xmax(PG_FUNCTION_ARGS)
466466
{
467-
PG_RETURN_INT64(CurrentTransactionSnapshot->xmin);
467+
PG_RETURN_INT32(CurrentTransactionSnapshot->xmax);
468468
}
469469

470+
470471
Datum
471-
dtm_get_current_snapshot_xmax(PG_FUNCTION_ARGS)
472+
dtm_begin_transaction(PG_FUNCTION_ARGS)
473+
{
474+
int nPaticipants = PG_GETARG_INT32(0);
475+
Assert(!TransactionIdIsValid(DtmNextXid));
476+
477+
DtmNextXid = DtmGlobalStartTransaction(nParticipants, &DtmSnapshot);
478+
Assert(TransactionIdIsValid(DtmNextXid));
479+
480+
DtmIsGlobalTransaction = true;
481+
482+
PG_RETURN_INT32(DtmNextXid);
483+
}
484+
485+
Datum dtm_get_snapshot(PG_FUNCTION_ARGS)
472486
{
473-
PG_RETURN_INT64(CurrentTransactionSnapshot->xmax);
487+
Assert(!TransactionIdIsValid(DtmNextXid));
488+
DtmNextXid = PG_GETARG_INT32(0);
489+
Assert(TransactionIdIsValid(DtmNextXid));
490+
491+
DtmNextXid = DtmGlobalGetSnapshot(DtmConn, DtmNextXid, &DtmSnapshot);
492+
493+
DtmIsGlobalTransaction = true;
494+
495+
PG_RETURN_VOID();
474496
}
497+
498+
Datum dtm_new_snapshot(PG_FUNCTION_ARGS)
499+
{
500+
Assert(!TransactionIdIsValid(DtmNextXid));
501+
DtmNextXid = PG_GETARG_INT32(0);
502+
Assert(TransactionIdIsValid(DtmNextXid));
503+
504+
DtmNextXid = DtmGlobalNewSnapshot(DtmConn, DtmNextXid, &DtmSnapshot);
505+
506+
PG_RETURN_VOID();
507+
}
508+

‎src/backend/access/transam/clog.c

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -44,7 +44,7 @@
4444
#include "miscadmin.h"
4545
#include "pg_trace.h"
4646

47-
TransactionManager DefaultTM = { CLOGTransactionIdGetStatus, CLOGTransactionIdSetTreeStatus, GetLocalTransactionSnapshot, CopyLocalSnapshot };
47+
TransactionManager DefaultTM = { CLOGTransactionIdGetStatus, CLOGTransactionIdSetTreeStatus, GetLocalTransactionSnapshot, CopyLocalSnapshot, GetNextTransactionId };
4848
TransactionManager* TM = &DefaultTM;
4949

5050
/*

0 commit comments

Comments
 (0)
pFad - Phonifier reborn

Pfad - The Proxy pFad of © 2024 Garber Painting. All rights reserved.

Note: This service is not intended for secure transactions such as banking, social media, email, or purchasing. Use at your own risk. We assume no liability whatsoever for broken pages.


Alternative Proxies:

Alternative Proxy

pFad Proxy

pFad v3 Proxy

pFad v4 Proxy