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Remove CopySmapshot from XTM API
1 parent 8a9c01b commit 9b44cc6

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8 files changed

+43
-86
lines changed

8 files changed

+43
-86
lines changed

‎contrib/pg_xtm/dtmd/Makefile

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
CC=gcc
2-
CFLAGS=-g -Wall -Iinclude -D_LARGEFILE64_SOURCE -DDEBUG
2+
CFLAGS=-g -Wall -Iinclude -D_LARGEFILE64_SOURCE
33
LIBUV_PREFIX=$(HOME)/libuv-build
44
LIBUV_CFLAGS=-I"$(LIBUV_PREFIX)/include" -L"$(LIBUV_PREFIX)/lib"
55
LIBUV_LDFLAGS=-luv -pthread

‎contrib/pg_xtm/pg_dtm.c

Lines changed: 29 additions & 62 deletions
Original file line numberDiff line numberDiff line change
@@ -51,9 +51,8 @@ typedef struct
5151
void _PG_init(void);
5252
void _PG_fini(void);
5353

54-
static Snapshot DtmGetSnapshot(void);
54+
static Snapshot DtmGetSnapshot(Snapshot snapshot);
5555
static void DtmMergeSnapshots(Snapshot dst, Snapshot src);
56-
static Snapshot DtmCopySnapshot(Snapshot snapshot);
5756
static XidStatus DtmGetTransactionStatus(TransactionId xid, XLogRecPtr *lsn);
5857
static void DtmSetTransactionStatus(TransactionId xid, int nsubxids, TransactionId *subxids, XidStatus status, XLogRecPtr lsn);
5958
static void DtmUpdateRecentXmin(void);
@@ -73,11 +72,10 @@ static Snapshot CurrentTransactionSnapshot;
7372

7473
static TransactionId DtmNextXid;
7574
static SnapshotData DtmSnapshot = { HeapTupleSatisfiesMVCC };
76-
static SnapshotData DtmLocalSnapshot = { HeapTupleSatisfiesMVCC };
7775
static bool DtmHasGlobalSnapshot;
7876
static bool DtmIsGlobalTransaction;
7977
static int DtmLocalXidReserve;
80-
static TransactionManager DtmTM = { DtmGetTransactionStatus, DtmSetTransactionStatus, DtmGetSnapshot, DtmCopySnapshot, DtmGetNextXid };
78+
static TransactionManager DtmTM = { DtmGetTransactionStatus, DtmSetTransactionStatus, DtmGetSnapshot, DtmGetNextXid };
8179

8280

8381
#define XTM_TRACE(fmt, ...)
@@ -136,43 +134,42 @@ static void DtmMergeSnapshots(Snapshot dst, Snapshot src)
136134
{
137135
int i, j, n;
138136
TransactionId xid;
139-
Snapshot local;
140137

141138
Assert(TransactionIdIsValid(src->xmin) && TransactionIdIsValid(src->xmax));
142139

143140
GetLocalSnapshot:
144-
local = GetSnapshotData(&DtmLocalSnapshot);
145-
for (i = 0; i < local->xcnt; i++) {
146-
if (TransactionIdIsInDoubt(local->xip[i])) {
141+
dst = GetLocalSnapshotData(dst);
142+
for (i = 0; i < dst->xcnt; i++) {
143+
if (TransactionIdIsInDoubt(dst->xip[i])) {
147144
goto GetLocalSnapshot;
148145
}
149146
}
150-
for (xid = local->xmax; xid < src->xmax; xid++) {
147+
for (xid = dst->xmax; xid < src->xmax; xid++) {
151148
if (TransactionIdIsInDoubt(xid)) {
152149
goto GetLocalSnapshot;
153150
}
154151
}
155-
DumpSnapshot(local, "local");
152+
DumpSnapshot(dst, "local");
156153
DumpSnapshot(src, "DTM");
157154

158155
/* Merge two snapshots: produce most restrictive snapshots whihc includes running transactions from both of them */
159-
dst->xmin = local->xmin < src->xmin ? local->xmin : src->xmin;
160-
dst->xmax = local->xmax < src->xmax ? local->xmax : src->xmax;
156+
if (src->xmin < dst->xmin) dst->xmin = src->xmin;
157+
if (src->xmax < dst->xmax) dst->xmax = src->xmax;
161158

162-
n = local->xcnt;
163-
for (xid = local->xmax; xid <= src->xmin; xid++) {
164-
local->xip[n++] = xid;
159+
n = dst->xcnt;
160+
for (xid = dst->xmax; xid <= src->xmin; xid++) {
161+
dst->xip[n++] = xid;
165162
}
166-
memcpy(local->xip + n, src->xip, src->xcnt*sizeof(TransactionId));
163+
memcpy(dst->xip + n, src->xip, src->xcnt*sizeof(TransactionId));
167164
n += src->xcnt;
168165
Assert(n <= GetMaxSnapshotXidCount());
169166

170-
qsort(local->xip, n, sizeof(TransactionId), xidComparator);
167+
qsort(dst->xip, n, sizeof(TransactionId), xidComparator);
171168
xid = InvalidTransactionId;
172169

173-
for (i = 0, j = 0; i < n && local->xip[i] < dst->xmax; i++) {
174-
if (local->xip[i] != xid) {
175-
dst->xip[j++] = xid = local->xip[i];
170+
for (i = 0, j = 0; i < n && dst->xip[i] < dst->xmax; i++) {
171+
if (dst->xip[i] != xid) {
172+
dst->xip[j++] = xid = dst->xip[i];
176173
}
177174
}
178175
dst->xcnt = j;
@@ -202,54 +199,23 @@ static void DtmUpdateRecentXmin(void)
202199
}
203200
}
204201

205-
static Snapshot DtmCopySnapshot(Snapshot snapshot)
206-
{
207-
Snapshot newsnap;
208-
Size size = sizeof(SnapshotData) + GetMaxSnapshotXidCount() * sizeof(TransactionId);
209-
Size subxipoff = size;
210-
if (snapshot->subxcnt > 0) {
211-
size += snapshot->subxcnt * sizeof(TransactionId);
212-
}
213-
newsnap = (Snapshot) MemoryContextAlloc(TopTransactionContext, size);
214-
memcpy(newsnap, snapshot, sizeof(SnapshotData));
215-
216-
newsnap->regd_count = 0;
217-
newsnap->active_count = 0;
218-
newsnap->copied = true;
219-
220-
newsnap->xip = (TransactionId *) (newsnap + 1);
221-
if (snapshot->xcnt > 0)
222-
{
223-
memcpy(newsnap->xip, snapshot->xip, snapshot->xcnt * sizeof(TransactionId));
224-
}
225-
if (snapshot->subxcnt > 0 &&
226-
(!snapshot->suboverflowed || snapshot->takenDuringRecovery))
227-
{
228-
newsnap->subxip = (TransactionId *) ((char *) newsnap + subxipoff);
229-
memcpy(newsnap->subxip, snapshot->subxip,
230-
snapshot->subxcnt * sizeof(TransactionId));
231-
}
232-
else
233-
newsnap->subxip = NULL;
234-
235-
return newsnap;
236-
}
237-
238202
static TransactionId DtmGetNextXid()
239203
{
240204
TransactionId xid;
241205
if (TransactionIdIsValid(DtmNextXid)) {
242206
XTM_INFO("Use global XID %d\n", DtmNextXid);
243207
xid = DtmNextXid;
208+
dtm->nReservedXids = 0;
209+
ShmemVariableCache->nextXid = xid;
244210
} else {
245211
LWLockAcquire(dtm->xidLock, LW_EXCLUSIVE);
246212
if (dtm->nReservedXids == 0) {
247213
dtm->nReservedXids = DtmGlobalReserve(ShmemVariableCache->nextXid, DtmLocalXidReserve, &xid);
248-
ShmemVariableCache->nextXid = xid;
249-
dtm->nextXid = xid;
250-
}
251-
Assert(dtm->nextXid == ShmemVariableCache->nextXid);
252-
xid = ShmemVariableCache->nextXid;
214+
ShmemVariableCache->nextXid = dtm->nextXid = xid;
215+
} else {
216+
Assert(dtm->nextXid == ShmemVariableCache->nextXid);
217+
xid = ShmemVariableCache->nextXid;
218+
}
253219
XTM_INFO("Obtain new local XID %d\n", xid);
254220
dtm->nextXid += 1;
255221
dtm->nReservedXids -= 1;
@@ -258,9 +224,9 @@ static TransactionId DtmGetNextXid()
258224
return xid;
259225
}
260226

261-
static Snapshot DtmGetSnapshot()
227+
static Snapshot DtmGetSnapshot(Snapshot snapshot)
262228
{
263-
Snapshot snapshot = GetLocalTransactionSnapshot();
229+
264230
if (TransactionIdIsValid(DtmNextXid)) {
265231
if (!DtmHasGlobalSnapshot) {
266232
DtmGlobalGetSnapshot(DtmNextXid, &DtmSnapshot);
@@ -270,7 +236,9 @@ static Snapshot DtmGetSnapshot()
270236
if (!IsolationUsesXactSnapshot()) {
271237
DtmHasGlobalSnapshot = false;
272238
}
273-
}
239+
} else {
240+
snapshot = GetLocalSnapshotData(snapshot);
241+
}
274242
CurrentTransactionSnapshot = snapshot;
275243
return snapshot;
276244
}
@@ -354,7 +322,6 @@ static void DtmInitialize()
354322
);
355323

356324
RegisterXactCallback(DtmXactCallback, NULL);
357-
DtmInitSnapshot(&DtmLocalSnapshot);
358325

359326
TM = &DtmTM;
360327
}

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

5050
/*

‎src/backend/storage/ipc/procarray.c

Lines changed: 7 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1473,6 +1473,12 @@ GetMaxSnapshotSubxidCount(void)
14731473
return TOTAL_MAX_CACHED_SUBXIDS;
14741474
}
14751475

1476+
Snapshot
1477+
GetSnapshotData(Snapshot snapshot)
1478+
{
1479+
return TM->GetSnapshot(snapshot);
1480+
}
1481+
14761482
/*
14771483
* GetSnapshotData -- returns information about running transactions.
14781484
*
@@ -1509,7 +1515,7 @@ GetMaxSnapshotSubxidCount(void)
15091515
* not statically allocated (see xip allocation below).
15101516
*/
15111517
Snapshot
1512-
GetSnapshotData(Snapshot snapshot)
1518+
GetLocalSnapshotData(Snapshot snapshot)
15131519
{
15141520
ProcArrayStruct *arrayP = procArray;
15151521
TransactionId xmin;

‎src/backend/utils/time/snapmgr.c

Lines changed: 3 additions & 17 deletions
Original file line numberDiff line numberDiff line change
@@ -185,7 +185,7 @@ typedef struct SerializedSnapshotData
185185
* used very long.
186186
*/
187187
Snapshot
188-
GetLocalTransactionSnapshot(void)
188+
GetTransactionSnapshot(void)
189189
{
190190
/*
191191
* Return historic snapshot if doing logical decoding. We'll never need a
@@ -251,13 +251,6 @@ GetLocalTransactionSnapshot(void)
251251
return CurrentSnapshot;
252252
}
253253

254-
Snapshot
255-
GetTransactionSnapshot()
256-
{
257-
return TM->GetSnapshot();
258-
}
259-
260-
261254
/*
262255
* GetLatestSnapshot
263256
* Get a snapshot that is up-to-date as of the current instant,
@@ -466,22 +459,15 @@ SetTransactionSnapshot(Snapshot sourcesnap, TransactionId sourcexid,
466459
FirstSnapshotSet = true;
467460
}
468461

469-
Snapshot
470-
CopySnapshot(Snapshot snapshot)
471-
{
472-
return TM->CopySnapshot(snapshot);
473-
}
474-
475-
476462
/*
477463
* CopySnapshot
478464
* Copy the given snapshot.
479465
*
480466
* The copy is palloc'd in TopTransactionContext and has initial refcounts set
481467
* to 0. The returned snapshot has the copied flag set.
482468
*/
483-
Snapshot
484-
CopyLocalSnapshot(Snapshot snapshot)
469+
static Snapshot
470+
CopySnapshot(Snapshot snapshot)
485471
{
486472
Snapshot newsnap;
487473
Size subxipoff;

‎src/include/access/xtm.h

Lines changed: 1 addition & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -18,8 +18,7 @@ typedef struct
1818
{
1919
XidStatus (*GetTransactionStatus)(TransactionId xid, XLogRecPtr *lsn);
2020
void (*SetTransactionStatus)(TransactionId xid, int nsubxids, TransactionId *subxids, XidStatus status, XLogRecPtr lsn);
21-
Snapshot (*GetSnapshot)();
22-
Snapshot (*CopySnapshot)(Snapshot snapshot);
21+
Snapshot (*GetSnapshot)(Snapshot snapshot);
2322
TransactionId (*GetNextXid)();
2423
} TransactionManager;
2524

‎src/include/storage/procarray.h

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -44,6 +44,7 @@ extern int GetMaxSnapshotXidCount(void);
4444
extern int GetMaxSnapshotSubxidCount(void);
4545

4646
extern Snapshot GetSnapshotData(Snapshot snapshot);
47+
extern Snapshot GetLocalSnapshotData(Snapshot snapshot);
4748

4849
extern bool ProcArrayInstallImportedXmin(TransactionId xmin,
4950
TransactionId sourcexid);

‎src/include/utils/snapmgr.h

Lines changed: 0 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -26,7 +26,6 @@ extern TransactionId RecentGlobalXmin;
2626
extern TransactionId RecentGlobalDataXmin;
2727

2828
extern Snapshot GetTransactionSnapshot(void);
29-
extern Snapshot GetLocalTransactionSnapshot(void);
3029
extern Snapshot GetLatestSnapshot(void);
3130
extern void SnapshotSetCommandId(CommandId curcid);
3231

@@ -41,7 +40,6 @@ extern void PopActiveSnapshot(void);
4140
extern Snapshot GetActiveSnapshot(void);
4241
extern bool ActiveSnapshotSet(void);
4342

44-
extern Snapshot CopyLocalSnapshot(Snapshot snapshot);
4543
extern Snapshot RegisterSnapshot(Snapshot snapshot);
4644
extern void UnregisterSnapshot(Snapshot snapshot);
4745
extern Snapshot RegisterSnapshotOnOwner(Snapshot snapshot, ResourceOwner owner);

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