Age Owner Branch data TLA Line data Source code
1 : : /*-------------------------------------------------------------------------
2 : : *
3 : : * twophase.c
4 : : * Two-phase commit support functions.
5 : : *
6 : : * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
7 : : * Portions Copyright (c) 1994, Regents of the University of California
8 : : *
9 : : * IDENTIFICATION
10 : : * src/backend/access/transam/twophase.c
11 : : *
12 : : * NOTES
13 : : * Each global transaction is associated with a global transaction
14 : : * identifier (GID). The client assigns a GID to a postgres
15 : : * transaction with the PREPARE TRANSACTION command.
16 : : *
17 : : * We keep all active global transactions in a shared memory array.
18 : : * When the PREPARE TRANSACTION command is issued, the GID is
19 : : * reserved for the transaction in the array. This is done before
20 : : * a WAL entry is made, because the reservation checks for duplicate
21 : : * GIDs and aborts the transaction if there already is a global
22 : : * transaction in prepared state with the same GID.
23 : : *
24 : : * A global transaction (gxact) also has dummy PGPROC; this is what keeps
25 : : * the XID considered running by TransactionIdIsInProgress. It is also
26 : : * convenient as a PGPROC to hook the gxact's locks to.
27 : : *
28 : : * Information to recover prepared transactions in case of crash is
29 : : * now stored in WAL for the common case. In some cases there will be
30 : : * an extended period between preparing a GXACT and commit/abort, in
31 : : * which case we need to separately record prepared transaction data
32 : : * in permanent storage. This includes locking information, pending
33 : : * notifications etc. All that state information is written to the
34 : : * per-transaction state file in the pg_twophase directory.
35 : : * All prepared transactions will be written prior to shutdown.
36 : : *
37 : : * Life track of state data is following:
38 : : *
39 : : * * On PREPARE TRANSACTION backend writes state data only to the WAL and
40 : : * stores pointer to the start of the WAL record in
41 : : * gxact->prepare_start_lsn.
42 : : * * If COMMIT occurs before checkpoint then backend reads data from WAL
43 : : * using prepare_start_lsn.
44 : : * * On checkpoint state data copied to files in pg_twophase directory and
45 : : * fsynced
46 : : * * If COMMIT happens after checkpoint then backend reads state data from
47 : : * files
48 : : *
49 : : * During replay and replication, TwoPhaseState also holds information
50 : : * about active prepared transactions that haven't been moved to disk yet.
51 : : *
52 : : * Replay of twophase records happens by the following rules:
53 : : *
54 : : * * At the beginning of recovery, pg_twophase is scanned once, filling
55 : : * TwoPhaseState with entries marked with gxact->inredo and
56 : : * gxact->ondisk. Two-phase file data older than the XID horizon of
57 : : * the redo position are discarded.
58 : : * * On PREPARE redo, the transaction is added to TwoPhaseState->prepXacts.
59 : : * gxact->inredo is set to true for such entries.
60 : : * * On Checkpoint we iterate through TwoPhaseState->prepXacts entries
61 : : * that have gxact->inredo set and are behind the redo_horizon. We
62 : : * save them to disk and then switch gxact->ondisk to true.
63 : : * * On COMMIT/ABORT we delete the entry from TwoPhaseState->prepXacts.
64 : : * If gxact->ondisk is true, the corresponding entry from the disk
65 : : * is additionally deleted.
66 : : * * RecoverPreparedTransactions(), StandbyRecoverPreparedTransactions()
67 : : * and PrescanPreparedTransactions() have been modified to go through
68 : : * gxact->inredo entries that have not made it to disk.
69 : : *
70 : : *-------------------------------------------------------------------------
71 : : */
72 : : #include "postgres.h"
73 : :
74 : : #include <fcntl.h>
75 : : #include <sys/stat.h>
76 : : #include <time.h>
77 : : #include <unistd.h>
78 : :
79 : : #include "access/commit_ts.h"
80 : : #include "access/htup_details.h"
81 : : #include "access/subtrans.h"
82 : : #include "access/transam.h"
83 : : #include "access/twophase.h"
84 : : #include "access/twophase_rmgr.h"
85 : : #include "access/xact.h"
86 : : #include "access/xlog.h"
87 : : #include "access/xloginsert.h"
88 : : #include "access/xlogreader.h"
89 : : #include "access/xlogrecovery.h"
90 : : #include "access/xlogutils.h"
91 : : #include "catalog/pg_type.h"
92 : : #include "catalog/storage.h"
93 : : #include "funcapi.h"
94 : : #include "miscadmin.h"
95 : : #include "pg_trace.h"
96 : : #include "pgstat.h"
97 : : #include "replication/origin.h"
98 : : #include "replication/syncrep.h"
99 : : #include "storage/fd.h"
100 : : #include "storage/ipc.h"
101 : : #include "storage/md.h"
102 : : #include "storage/predicate.h"
103 : : #include "storage/proc.h"
104 : : #include "storage/procarray.h"
105 : : #include "utils/builtins.h"
106 : : #include "utils/memutils.h"
107 : : #include "utils/timestamp.h"
108 : :
109 : : /*
110 : : * Directory where Two-phase commit files reside within PGDATA
111 : : */
112 : : #define TWOPHASE_DIR "pg_twophase"
113 : :
114 : : /* GUC variable, can't be changed after startup */
115 : : int max_prepared_xacts = 0;
116 : :
117 : : /*
118 : : * This struct describes one global transaction that is in prepared state
119 : : * or attempting to become prepared.
120 : : *
121 : : * The lifecycle of a global transaction is:
122 : : *
123 : : * 1. After checking that the requested GID is not in use, set up an entry in
124 : : * the TwoPhaseState->prepXacts array with the correct GID and valid = false,
125 : : * and mark it as locked by my backend.
126 : : *
127 : : * 2. After successfully completing prepare, set valid = true and enter the
128 : : * referenced PGPROC into the global ProcArray.
129 : : *
130 : : * 3. To begin COMMIT PREPARED or ROLLBACK PREPARED, check that the entry is
131 : : * valid and not locked, then mark the entry as locked by storing my current
132 : : * proc number into locking_backend. This prevents concurrent attempts to
133 : : * commit or rollback the same prepared xact.
134 : : *
135 : : * 4. On completion of COMMIT PREPARED or ROLLBACK PREPARED, remove the entry
136 : : * from the ProcArray and the TwoPhaseState->prepXacts array and return it to
137 : : * the freelist.
138 : : *
139 : : * Note that if the preparing transaction fails between steps 1 and 2, the
140 : : * entry must be removed so that the GID and the GlobalTransaction struct
141 : : * can be reused. See AtAbort_Twophase().
142 : : *
143 : : * typedef struct GlobalTransactionData *GlobalTransaction appears in
144 : : * twophase.h
145 : : */
146 : :
147 : : typedef struct GlobalTransactionData
148 : : {
149 : : GlobalTransaction next; /* list link for free list */
150 : : int pgprocno; /* ID of associated dummy PGPROC */
151 : : TimestampTz prepared_at; /* time of preparation */
152 : :
153 : : /*
154 : : * Note that we need to keep track of two LSNs for each GXACT. We keep
155 : : * track of the start LSN because this is the address we must use to read
156 : : * state data back from WAL when committing a prepared GXACT. We keep
157 : : * track of the end LSN because that is the LSN we need to wait for prior
158 : : * to commit.
159 : : */
160 : : XLogRecPtr prepare_start_lsn; /* XLOG offset of prepare record start */
161 : : XLogRecPtr prepare_end_lsn; /* XLOG offset of prepare record end */
162 : : FullTransactionId fxid; /* The GXACT full xid */
163 : :
164 : : Oid owner; /* ID of user that executed the xact */
165 : : ProcNumber locking_backend; /* backend currently working on the xact */
166 : : bool valid; /* true if PGPROC entry is in proc array */
167 : : bool ondisk; /* true if prepare state file is on disk */
168 : : bool inredo; /* true if entry was added via xlog_redo */
169 : : char gid[GIDSIZE]; /* The GID assigned to the prepared xact */
170 : : } GlobalTransactionData;
171 : :
172 : : /*
173 : : * Two Phase Commit shared state. Access to this struct is protected
174 : : * by TwoPhaseStateLock.
175 : : */
176 : : typedef struct TwoPhaseStateData
177 : : {
178 : : /* Head of linked list of free GlobalTransactionData structs */
179 : : GlobalTransaction freeGXacts;
180 : :
181 : : /* Number of valid prepXacts entries. */
182 : : int numPrepXacts;
183 : :
184 : : /* There are max_prepared_xacts items in this array */
185 : : GlobalTransaction prepXacts[FLEXIBLE_ARRAY_MEMBER];
186 : : } TwoPhaseStateData;
187 : :
188 : : static TwoPhaseStateData *TwoPhaseState;
189 : :
190 : : /*
191 : : * Global transaction entry currently locked by us, if any. Note that any
192 : : * access to the entry pointed to by this variable must be protected by
193 : : * TwoPhaseStateLock, though obviously the pointer itself doesn't need to be
194 : : * (since it's just local memory).
195 : : */
196 : : static GlobalTransaction MyLockedGxact = NULL;
197 : :
198 : : static bool twophaseExitRegistered = false;
199 : :
200 : : static void PrepareRedoRemoveFull(FullTransactionId fxid, bool giveWarning);
201 : : static void RecordTransactionCommitPrepared(TransactionId xid,
202 : : int nchildren,
203 : : TransactionId *children,
204 : : int nrels,
205 : : RelFileLocator *rels,
206 : : int nstats,
207 : : xl_xact_stats_item *stats,
208 : : int ninvalmsgs,
209 : : SharedInvalidationMessage *invalmsgs,
210 : : bool initfileinval,
211 : : const char *gid);
212 : : static void RecordTransactionAbortPrepared(TransactionId xid,
213 : : int nchildren,
214 : : TransactionId *children,
215 : : int nrels,
216 : : RelFileLocator *rels,
217 : : int nstats,
218 : : xl_xact_stats_item *stats,
219 : : const char *gid);
220 : : static void ProcessRecords(char *bufptr, FullTransactionId fxid,
221 : : const TwoPhaseCallback callbacks[]);
222 : : static void RemoveGXact(GlobalTransaction gxact);
223 : :
224 : : static void XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len);
225 : : static char *ProcessTwoPhaseBuffer(FullTransactionId fxid,
226 : : XLogRecPtr prepare_start_lsn,
227 : : bool fromdisk, bool setParent, bool setNextXid);
228 : : static void MarkAsPreparingGuts(GlobalTransaction gxact, FullTransactionId fxid,
229 : : const char *gid, TimestampTz prepared_at, Oid owner,
230 : : Oid databaseid);
231 : : static void RemoveTwoPhaseFile(FullTransactionId fxid, bool giveWarning);
232 : : static void RecreateTwoPhaseFile(FullTransactionId fxid, void *content, int len);
233 : :
234 : : /*
235 : : * Initialization of shared memory
236 : : */
237 : : Size
7386 tgl@sss.pgh.pa.us 238 :CBC 2938 : TwoPhaseShmemSize(void)
239 : : {
240 : : Size size;
241 : :
242 : : /* Need the fixed struct, the array of pointers, and the GTD structs */
7322 243 : 2938 : size = offsetof(TwoPhaseStateData, prepXacts);
244 : 2938 : size = add_size(size, mul_size(max_prepared_xacts,
245 : : sizeof(GlobalTransaction)));
246 : 2938 : size = MAXALIGN(size);
247 : 2938 : size = add_size(size, mul_size(max_prepared_xacts,
248 : : sizeof(GlobalTransactionData)));
249 : :
250 : 2938 : return size;
251 : : }
252 : :
253 : : void
7386 254 : 1029 : TwoPhaseShmemInit(void)
255 : : {
256 : : bool found;
257 : :
258 : 1029 : TwoPhaseState = ShmemInitStruct("Prepared Transaction Table",
259 : : TwoPhaseShmemSize(),
260 : : &found);
261 [ + - ]: 1029 : if (!IsUnderPostmaster)
262 : : {
263 : : GlobalTransaction gxacts;
264 : : int i;
265 : :
266 [ - + ]: 1029 : Assert(!found);
6152 267 : 1029 : TwoPhaseState->freeGXacts = NULL;
7386 268 : 1029 : TwoPhaseState->numPrepXacts = 0;
269 : :
270 : : /*
271 : : * Initialize the linked list of free GlobalTransactionData structs
272 : : */
273 : 1029 : gxacts = (GlobalTransaction)
274 : 1029 : ((char *) TwoPhaseState +
7266 bruce@momjian.us 275 : 1029 : MAXALIGN(offsetof(TwoPhaseStateData, prepXacts) +
276 : : sizeof(GlobalTransaction) * max_prepared_xacts));
7386 tgl@sss.pgh.pa.us 277 [ + + ]: 1862 : for (i = 0; i < max_prepared_xacts; i++)
278 : : {
279 : : /* insert into linked list */
5034 rhaas@postgresql.org 280 : 833 : gxacts[i].next = TwoPhaseState->freeGXacts;
6152 tgl@sss.pgh.pa.us 281 : 833 : TwoPhaseState->freeGXacts = &gxacts[i];
282 : :
283 : : /* associate it with a PGPROC assigned by InitProcGlobal */
562 heikki.linnakangas@i 284 : 833 : gxacts[i].pgprocno = GetNumberFromPGProc(&PreparedXactProcs[i]);
285 : : }
286 : : }
287 : : else
7386 tgl@sss.pgh.pa.us 288 [ # # ]:UBC 0 : Assert(found);
7386 tgl@sss.pgh.pa.us 289 :CBC 1029 : }
290 : :
291 : : /*
292 : : * Exit hook to unlock the global transaction entry we're working on.
293 : : */
294 : : static void
4132 heikki.linnakangas@i 295 : 132 : AtProcExit_Twophase(int code, Datum arg)
296 : : {
297 : : /* same logic as abort */
298 : 132 : AtAbort_Twophase();
299 : 132 : }
300 : :
301 : : /*
302 : : * Abort hook to unlock the global transaction entry we're working on.
303 : : */
304 : : void
305 : 25048 : AtAbort_Twophase(void)
306 : : {
307 [ + + ]: 25048 : if (MyLockedGxact == NULL)
308 : 25046 : return;
309 : :
310 : : /*
311 : : * What to do with the locked global transaction entry? If we were in the
312 : : * process of preparing the transaction, but haven't written the WAL
313 : : * record and state file yet, the transaction must not be considered as
314 : : * prepared. Likewise, if we are in the process of finishing an
315 : : * already-prepared transaction, and fail after having already written the
316 : : * 2nd phase commit or rollback record to the WAL, the transaction should
317 : : * not be considered as prepared anymore. In those cases, just remove the
318 : : * entry from shared memory.
319 : : *
320 : : * Otherwise, the entry must be left in place so that the transaction can
321 : : * be finished later, so just unlock it.
322 : : *
323 : : * If we abort during prepare, after having written the WAL record, we
324 : : * might not have transferred all locks and other state to the prepared
325 : : * transaction yet. Likewise, if we abort during commit or rollback,
326 : : * after having written the WAL record, we might not have released all the
327 : : * resources held by the transaction yet. In those cases, the in-memory
328 : : * state can be wrong, but it's too late to back out.
329 : : */
3006 alvherre@alvh.no-ip. 330 : 2 : LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
4132 heikki.linnakangas@i 331 [ + - ]: 2 : if (!MyLockedGxact->valid)
332 : 2 : RemoveGXact(MyLockedGxact);
333 : : else
552 heikki.linnakangas@i 334 :UBC 0 : MyLockedGxact->locking_backend = INVALID_PROC_NUMBER;
3006 alvherre@alvh.no-ip. 335 :CBC 2 : LWLockRelease(TwoPhaseStateLock);
336 : :
4132 heikki.linnakangas@i 337 : 2 : MyLockedGxact = NULL;
338 : : }
339 : :
340 : : /*
341 : : * This is called after we have finished transferring state to the prepared
342 : : * PGPROC entry.
343 : : */
344 : : void
3675 andres@anarazel.de 345 : 320 : PostPrepare_Twophase(void)
346 : : {
4132 heikki.linnakangas@i 347 : 320 : LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
552 348 : 320 : MyLockedGxact->locking_backend = INVALID_PROC_NUMBER;
4132 349 : 320 : LWLockRelease(TwoPhaseStateLock);
350 : :
351 : 320 : MyLockedGxact = NULL;
352 : 320 : }
353 : :
354 : :
355 : : /*
356 : : * MarkAsPreparing
357 : : * Reserve the GID for the given transaction.
358 : : */
359 : : GlobalTransaction
61 michael@paquier.xyz 360 :GNC 301 : MarkAsPreparing(FullTransactionId fxid, const char *gid,
361 : : TimestampTz prepared_at, Oid owner, Oid databaseid)
362 : : {
363 : : GlobalTransaction gxact;
364 : : int i;
365 : :
7386 tgl@sss.pgh.pa.us 366 [ - + ]:CBC 301 : if (strlen(gid) >= GIDSIZE)
7386 tgl@sss.pgh.pa.us 367 [ # # ]:UBC 0 : ereport(ERROR,
368 : : (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
369 : : errmsg("transaction identifier \"%s\" is too long",
370 : : gid)));
371 : :
372 : : /* fail immediately if feature is disabled */
5980 tgl@sss.pgh.pa.us 373 [ + + ]:CBC 301 : if (max_prepared_xacts == 0)
374 [ + - ]: 10 : ereport(ERROR,
375 : : (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
376 : : errmsg("prepared transactions are disabled"),
377 : : errhint("Set \"max_prepared_transactions\" to a nonzero value.")));
378 : :
379 : : /* on first call, register the exit hook */
4132 heikki.linnakangas@i 380 [ + + ]: 291 : if (!twophaseExitRegistered)
381 : : {
382 : 72 : before_shmem_exit(AtProcExit_Twophase, 0);
383 : 72 : twophaseExitRegistered = true;
384 : : }
385 : :
386 : 291 : LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
387 : :
388 : : /* Check for conflicting GID */
7386 tgl@sss.pgh.pa.us 389 [ + + ]: 528 : for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
390 : : {
391 : 239 : gxact = TwoPhaseState->prepXacts[i];
392 [ + + ]: 239 : if (strcmp(gxact->gid, gid) == 0)
393 : : {
394 [ + - ]: 2 : ereport(ERROR,
395 : : (errcode(ERRCODE_DUPLICATE_OBJECT),
396 : : errmsg("transaction identifier \"%s\" is already in use",
397 : : gid)));
398 : : }
399 : : }
400 : :
401 : : /* Get a free gxact from the freelist */
6152 402 [ - + ]: 289 : if (TwoPhaseState->freeGXacts == NULL)
7386 tgl@sss.pgh.pa.us 403 [ # # ]:UBC 0 : ereport(ERROR,
404 : : (errcode(ERRCODE_OUT_OF_MEMORY),
405 : : errmsg("maximum number of prepared transactions reached"),
406 : : errhint("Increase \"max_prepared_transactions\" (currently %d).",
407 : : max_prepared_xacts)));
6152 tgl@sss.pgh.pa.us 408 :CBC 289 : gxact = TwoPhaseState->freeGXacts;
4777 409 : 289 : TwoPhaseState->freeGXacts = gxact->next;
410 : :
61 michael@paquier.xyz 411 :GNC 289 : MarkAsPreparingGuts(gxact, fxid, gid, prepared_at, owner, databaseid);
412 : :
3077 simon@2ndQuadrant.co 413 :CBC 289 : gxact->ondisk = false;
414 : :
415 : : /* And insert it into the active array */
416 [ - + ]: 289 : Assert(TwoPhaseState->numPrepXacts < max_prepared_xacts);
417 : 289 : TwoPhaseState->prepXacts[TwoPhaseState->numPrepXacts++] = gxact;
418 : :
419 : 289 : LWLockRelease(TwoPhaseStateLock);
420 : :
421 : 289 : return gxact;
422 : : }
423 : :
424 : : /*
425 : : * MarkAsPreparingGuts
426 : : *
427 : : * This uses a gxact struct and puts it into the active array.
428 : : * NOTE: this is also used when reloading a gxact after a crash; so avoid
429 : : * assuming that we can use very much backend context.
430 : : *
431 : : * Note: This function should be called with appropriate locks held.
432 : : */
433 : : static void
61 michael@paquier.xyz 434 :GNC 322 : MarkAsPreparingGuts(GlobalTransaction gxact, FullTransactionId fxid,
435 : : const char *gid, TimestampTz prepared_at, Oid owner,
436 : : Oid databaseid)
437 : : {
438 : : PGPROC *proc;
439 : : int i;
440 : 322 : TransactionId xid = XidFromFullTransactionId(fxid);
441 : :
3006 alvherre@alvh.no-ip. 442 [ - + ]:CBC 322 : Assert(LWLockHeldByMeInMode(TwoPhaseStateLock, LW_EXCLUSIVE));
443 : :
3077 simon@2ndQuadrant.co 444 [ - + ]: 322 : Assert(gxact != NULL);
552 heikki.linnakangas@i 445 : 322 : proc = GetPGProcByNumber(gxact->pgprocno);
446 : :
447 : : /* Initialize the PGPROC entry */
5034 rhaas@postgresql.org 448 [ + - + - : 33810 : MemSet(proc, 0, sizeof(PGPROC));
+ - + - +
+ ]
962 andres@anarazel.de 449 : 322 : dlist_node_init(&proc->links);
1907 peter@eisentraut.org 450 : 322 : proc->waitStatus = PROC_WAIT_STATUS_OK;
552 heikki.linnakangas@i 451 [ + + ]: 322 : if (LocalTransactionIdIsValid(MyProc->vxid.lxid))
452 : : {
453 : : /* clone VXID, for TwoPhaseGetXidByVirtualXID() to find */
454 : 289 : proc->vxid.lxid = MyProc->vxid.lxid;
455 : 289 : proc->vxid.procNumber = MyProcNumber;
456 : : }
457 : : else
458 : : {
1414 noah@leadboat.com 459 [ - + - - ]: 33 : Assert(AmStartupProcess() || !IsPostmasterEnvironment);
460 : : /* GetLockConflicts() uses this to specify a wait on the XID */
552 heikki.linnakangas@i 461 : 33 : proc->vxid.lxid = xid;
462 : 33 : proc->vxid.procNumber = INVALID_PROC_NUMBER;
463 : : }
1849 andres@anarazel.de 464 : 322 : proc->xid = xid;
1850 465 [ - + ]: 322 : Assert(proc->xmin == InvalidTransactionId);
1247 rhaas@postgresql.org 466 : 322 : proc->delayChkptFlags = 0;
1755 alvherre@alvh.no-ip. 467 : 322 : proc->statusFlags = 0;
5034 rhaas@postgresql.org 468 : 322 : proc->pid = 0;
469 : 322 : proc->databaseId = databaseid;
470 : 322 : proc->roleId = owner;
2581 michael@paquier.xyz 471 : 322 : proc->tempNamespaceId = InvalidOid;
252 tgl@sss.pgh.pa.us 472 : 322 : proc->isRegularBackend = false;
1021 andres@anarazel.de 473 : 322 : proc->lwWaiting = LW_WS_NOT_WAITING;
4968 heikki.linnakangas@i 474 : 322 : proc->lwWaitMode = 0;
5034 rhaas@postgresql.org 475 : 322 : proc->waitLock = NULL;
476 : 322 : proc->waitProcLock = NULL;
1657 fujii@postgresql.org 477 : 322 : pg_atomic_init_u64(&proc->waitStart, 0);
7209 tgl@sss.pgh.pa.us 478 [ + + ]: 5474 : for (i = 0; i < NUM_LOCK_PARTITIONS; i++)
962 andres@anarazel.de 479 : 5152 : dlist_init(&proc->myProcLocks[i]);
480 : : /* subxid data must be filled later by GXactLoadSubxactData */
1849 481 : 322 : proc->subxidStatus.overflowed = false;
482 : 322 : proc->subxidStatus.count = 0;
483 : :
7385 tgl@sss.pgh.pa.us 484 : 322 : gxact->prepared_at = prepared_at;
61 michael@paquier.xyz 485 :GNC 322 : gxact->fxid = fxid;
7386 tgl@sss.pgh.pa.us 486 :CBC 322 : gxact->owner = owner;
552 heikki.linnakangas@i 487 : 322 : gxact->locking_backend = MyProcNumber;
7386 tgl@sss.pgh.pa.us 488 : 322 : gxact->valid = false;
3077 simon@2ndQuadrant.co 489 : 322 : gxact->inredo = false;
7386 tgl@sss.pgh.pa.us 490 : 322 : strcpy(gxact->gid, gid);
491 : :
492 : : /*
493 : : * Remember that we have this GlobalTransaction entry locked for us. If we
494 : : * abort after this, we must release it.
495 : : */
4132 heikki.linnakangas@i 496 : 322 : MyLockedGxact = gxact;
7386 tgl@sss.pgh.pa.us 497 : 322 : }
498 : :
499 : : /*
500 : : * GXactLoadSubxactData
501 : : *
502 : : * If the transaction being persisted had any subtransactions, this must
503 : : * be called before MarkAsPrepared() to load information into the dummy
504 : : * PGPROC.
505 : : */
506 : : static void
507 : 136 : GXactLoadSubxactData(GlobalTransaction gxact, int nsubxacts,
508 : : TransactionId *children)
509 : : {
552 heikki.linnakangas@i 510 : 136 : PGPROC *proc = GetPGProcByNumber(gxact->pgprocno);
511 : :
512 : : /* We need no extra lock since the GXACT isn't valid yet */
7386 tgl@sss.pgh.pa.us 513 [ + + ]: 136 : if (nsubxacts > PGPROC_MAX_CACHED_SUBXIDS)
514 : : {
1849 andres@anarazel.de 515 : 4 : proc->subxidStatus.overflowed = true;
7386 tgl@sss.pgh.pa.us 516 : 4 : nsubxacts = PGPROC_MAX_CACHED_SUBXIDS;
517 : : }
518 [ + + ]: 136 : if (nsubxacts > 0)
519 : : {
5034 rhaas@postgresql.org 520 : 119 : memcpy(proc->subxids.xids, children,
521 : : nsubxacts * sizeof(TransactionId));
1849 andres@anarazel.de 522 : 119 : proc->subxidStatus.count = nsubxacts;
523 : : }
7386 tgl@sss.pgh.pa.us 524 : 136 : }
525 : :
526 : : /*
527 : : * MarkAsPrepared
528 : : * Mark the GXACT as fully valid, and enter it into the global ProcArray.
529 : : *
530 : : * lock_held indicates whether caller already holds TwoPhaseStateLock.
531 : : */
532 : : static void
3006 alvherre@alvh.no-ip. 533 : 320 : MarkAsPrepared(GlobalTransaction gxact, bool lock_held)
534 : : {
535 : : /* Lock here may be overkill, but I'm not convinced of that ... */
536 [ + + ]: 320 : if (!lock_held)
537 : 287 : LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
7386 tgl@sss.pgh.pa.us 538 [ - + ]: 320 : Assert(!gxact->valid);
539 : 320 : gxact->valid = true;
3006 alvherre@alvh.no-ip. 540 [ + + ]: 320 : if (!lock_held)
541 : 287 : LWLockRelease(TwoPhaseStateLock);
542 : :
543 : : /*
544 : : * Put it into the global ProcArray so TransactionIdIsInProgress considers
545 : : * the XID as still running.
546 : : */
552 heikki.linnakangas@i 547 : 320 : ProcArrayAdd(GetPGProcByNumber(gxact->pgprocno));
7386 tgl@sss.pgh.pa.us 548 : 320 : }
549 : :
550 : : /*
551 : : * LockGXact
552 : : * Locate the prepared transaction and mark it busy for COMMIT or PREPARE.
553 : : */
554 : : static GlobalTransaction
7375 555 : 298 : LockGXact(const char *gid, Oid user)
556 : : {
557 : : int i;
558 : :
559 : : /* on first call, register the exit hook */
4132 heikki.linnakangas@i 560 [ + + ]: 298 : if (!twophaseExitRegistered)
561 : : {
562 : 60 : before_shmem_exit(AtProcExit_Twophase, 0);
563 : 60 : twophaseExitRegistered = true;
564 : : }
565 : :
7386 tgl@sss.pgh.pa.us 566 : 298 : LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
567 : :
568 [ + + ]: 489 : for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
569 : : {
7266 bruce@momjian.us 570 : 483 : GlobalTransaction gxact = TwoPhaseState->prepXacts[i];
552 heikki.linnakangas@i 571 : 483 : PGPROC *proc = GetPGProcByNumber(gxact->pgprocno);
572 : :
573 : : /* Ignore not-yet-valid GIDs */
7386 tgl@sss.pgh.pa.us 574 [ + + ]: 483 : if (!gxact->valid)
7386 tgl@sss.pgh.pa.us 575 :GBC 2 : continue;
7386 tgl@sss.pgh.pa.us 576 [ + + ]:CBC 481 : if (strcmp(gxact->gid, gid) != 0)
577 : 189 : continue;
578 : :
579 : : /* Found it, but has someone else got it locked? */
552 heikki.linnakangas@i 580 [ - + ]: 292 : if (gxact->locking_backend != INVALID_PROC_NUMBER)
4132 heikki.linnakangas@i 581 [ # # ]:UBC 0 : ereport(ERROR,
582 : : (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
583 : : errmsg("prepared transaction with identifier \"%s\" is busy",
584 : : gid)));
585 : :
7386 tgl@sss.pgh.pa.us 586 [ - + - - ]:CBC 292 : if (user != gxact->owner && !superuser_arg(user))
7386 tgl@sss.pgh.pa.us 587 [ # # ]:UBC 0 : ereport(ERROR,
588 : : (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
589 : : errmsg("permission denied to finish prepared transaction"),
590 : : errhint("Must be superuser or the user that prepared the transaction.")));
591 : :
592 : : /*
593 : : * Note: it probably would be possible to allow committing from
594 : : * another database; but at the moment NOTIFY is known not to work and
595 : : * there may be some other issues as well. Hence disallow until
596 : : * someone gets motivated to make it work.
597 : : */
5034 rhaas@postgresql.org 598 [ - + ]:CBC 292 : if (MyDatabaseId != proc->databaseId)
6780 tgl@sss.pgh.pa.us 599 [ # # ]:UBC 0 : ereport(ERROR,
600 : : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
601 : : errmsg("prepared transaction belongs to another database"),
602 : : errhint("Connect to the database where the transaction was prepared to finish it.")));
603 : :
604 : : /* OK for me to lock it */
552 heikki.linnakangas@i 605 :CBC 292 : gxact->locking_backend = MyProcNumber;
4132 606 : 292 : MyLockedGxact = gxact;
607 : :
7386 tgl@sss.pgh.pa.us 608 : 292 : LWLockRelease(TwoPhaseStateLock);
609 : :
610 : 292 : return gxact;
611 : : }
612 : :
613 : 6 : LWLockRelease(TwoPhaseStateLock);
614 : :
615 [ + - ]: 6 : ereport(ERROR,
616 : : (errcode(ERRCODE_UNDEFINED_OBJECT),
617 : : errmsg("prepared transaction with identifier \"%s\" does not exist",
618 : : gid)));
619 : :
620 : : /* NOTREACHED */
621 : : return NULL;
622 : : }
623 : :
624 : : /*
625 : : * RemoveGXact
626 : : * Remove the prepared transaction from the shared memory array.
627 : : *
628 : : * NB: caller should have already removed it from ProcArray
629 : : */
630 : : static void
631 : 350 : RemoveGXact(GlobalTransaction gxact)
632 : : {
633 : : int i;
634 : :
3006 alvherre@alvh.no-ip. 635 [ - + ]: 350 : Assert(LWLockHeldByMeInMode(TwoPhaseStateLock, LW_EXCLUSIVE));
636 : :
7386 tgl@sss.pgh.pa.us 637 [ + - ]: 538 : for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
638 : : {
639 [ + + ]: 538 : if (gxact == TwoPhaseState->prepXacts[i])
640 : : {
641 : : /* remove from the active array */
642 : 350 : TwoPhaseState->numPrepXacts--;
643 : 350 : TwoPhaseState->prepXacts[i] = TwoPhaseState->prepXacts[TwoPhaseState->numPrepXacts];
644 : :
645 : : /* and put it back in the freelist */
5034 rhaas@postgresql.org 646 : 350 : gxact->next = TwoPhaseState->freeGXacts;
6152 tgl@sss.pgh.pa.us 647 : 350 : TwoPhaseState->freeGXacts = gxact;
648 : :
7386 649 : 350 : return;
650 : : }
651 : : }
652 : :
7386 tgl@sss.pgh.pa.us 653 [ # # ]:UBC 0 : elog(ERROR, "failed to find %p in GlobalTransaction array", gxact);
654 : : }
655 : :
656 : : /*
657 : : * Returns an array of all prepared transactions for the user-level
658 : : * function pg_prepared_xact.
659 : : *
660 : : * The returned array and all its elements are copies of internal data
661 : : * structures, to minimize the time we need to hold the TwoPhaseStateLock.
662 : : *
663 : : * WARNING -- we return even those transactions that are not fully prepared
664 : : * yet. The caller should filter them out if he doesn't want them.
665 : : *
666 : : * The returned array is palloc'd.
667 : : */
668 : : static int
7386 tgl@sss.pgh.pa.us 669 :CBC 114 : GetPreparedTransactionList(GlobalTransaction *gxacts)
670 : : {
671 : : GlobalTransaction array;
672 : : int num;
673 : : int i;
674 : :
675 : 114 : LWLockAcquire(TwoPhaseStateLock, LW_SHARED);
676 : :
677 [ + + ]: 114 : if (TwoPhaseState->numPrepXacts == 0)
678 : : {
679 : 73 : LWLockRelease(TwoPhaseStateLock);
680 : :
681 : 73 : *gxacts = NULL;
682 : 73 : return 0;
683 : : }
684 : :
685 : 41 : num = TwoPhaseState->numPrepXacts;
686 : 41 : array = (GlobalTransaction) palloc(sizeof(GlobalTransactionData) * num);
687 : 41 : *gxacts = array;
688 [ + + ]: 87 : for (i = 0; i < num; i++)
689 : 46 : memcpy(array + i, TwoPhaseState->prepXacts[i],
690 : : sizeof(GlobalTransactionData));
691 : :
692 : 41 : LWLockRelease(TwoPhaseStateLock);
693 : :
694 : 41 : return num;
695 : : }
696 : :
697 : :
698 : : /* Working status for pg_prepared_xact */
699 : : typedef struct
700 : : {
701 : : GlobalTransaction array;
702 : : int ngxacts;
703 : : int currIdx;
704 : : } Working_State;
705 : :
706 : : /*
707 : : * pg_prepared_xact
708 : : * Produce a view with one row per prepared transaction.
709 : : *
710 : : * This function is here so we don't have to export the
711 : : * GlobalTransactionData struct definition.
712 : : */
713 : : Datum
714 : 160 : pg_prepared_xact(PG_FUNCTION_ARGS)
715 : : {
716 : : FuncCallContext *funcctx;
717 : : Working_State *status;
718 : :
719 [ + + ]: 160 : if (SRF_IS_FIRSTCALL())
720 : : {
721 : : TupleDesc tupdesc;
722 : : MemoryContext oldcontext;
723 : :
724 : : /* create a function context for cross-call persistence */
725 : 114 : funcctx = SRF_FIRSTCALL_INIT();
726 : :
727 : : /*
728 : : * Switch to memory context appropriate for multiple function calls
729 : : */
730 : 114 : oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
731 : :
732 : : /* build tupdesc for result tuples */
733 : : /* this had better match pg_prepared_xacts view in system_views.sql */
2482 andres@anarazel.de 734 : 114 : tupdesc = CreateTemplateTupleDesc(5);
7386 tgl@sss.pgh.pa.us 735 : 114 : TupleDescInitEntry(tupdesc, (AttrNumber) 1, "transaction",
736 : : XIDOID, -1, 0);
737 : 114 : TupleDescInitEntry(tupdesc, (AttrNumber) 2, "gid",
738 : : TEXTOID, -1, 0);
7385 739 : 114 : TupleDescInitEntry(tupdesc, (AttrNumber) 3, "prepared",
740 : : TIMESTAMPTZOID, -1, 0);
741 : 114 : TupleDescInitEntry(tupdesc, (AttrNumber) 4, "ownerid",
742 : : OIDOID, -1, 0);
743 : 114 : TupleDescInitEntry(tupdesc, (AttrNumber) 5, "dbid",
744 : : OIDOID, -1, 0);
745 : :
7386 746 : 114 : funcctx->tuple_desc = BlessTupleDesc(tupdesc);
747 : :
748 : : /*
749 : : * Collect all the 2PC status information that we will format and send
750 : : * out as a result set.
751 : : */
752 : 114 : status = (Working_State *) palloc(sizeof(Working_State));
282 peter@eisentraut.org 753 : 114 : funcctx->user_fctx = status;
754 : :
7386 tgl@sss.pgh.pa.us 755 : 114 : status->ngxacts = GetPreparedTransactionList(&status->array);
756 : 114 : status->currIdx = 0;
757 : :
758 : 114 : MemoryContextSwitchTo(oldcontext);
759 : : }
760 : :
761 : 160 : funcctx = SRF_PERCALL_SETUP();
762 : 160 : status = (Working_State *) funcctx->user_fctx;
763 : :
764 [ + + + + ]: 160 : while (status->array != NULL && status->currIdx < status->ngxacts)
765 : : {
766 : 46 : GlobalTransaction gxact = &status->array[status->currIdx++];
562 heikki.linnakangas@i 767 : 46 : PGPROC *proc = GetPGProcByNumber(gxact->pgprocno);
1148 peter@eisentraut.org 768 : 46 : Datum values[5] = {0};
769 : 46 : bool nulls[5] = {0};
770 : : HeapTuple tuple;
771 : : Datum result;
772 : :
7386 tgl@sss.pgh.pa.us 773 [ - + ]: 46 : if (!gxact->valid)
7386 tgl@sss.pgh.pa.us 774 :UBC 0 : continue;
775 : :
776 : : /*
777 : : * Form tuple with appropriate data.
778 : : */
779 : :
1849 andres@anarazel.de 780 :CBC 46 : values[0] = TransactionIdGetDatum(proc->xid);
6374 tgl@sss.pgh.pa.us 781 : 46 : values[1] = CStringGetTextDatum(gxact->gid);
7385 782 : 46 : values[2] = TimestampTzGetDatum(gxact->prepared_at);
7375 783 : 46 : values[3] = ObjectIdGetDatum(gxact->owner);
5034 rhaas@postgresql.org 784 : 46 : values[4] = ObjectIdGetDatum(proc->databaseId);
785 : :
7386 tgl@sss.pgh.pa.us 786 : 46 : tuple = heap_form_tuple(funcctx->tuple_desc, values, nulls);
787 : 46 : result = HeapTupleGetDatum(tuple);
788 : 46 : SRF_RETURN_NEXT(funcctx, result);
789 : : }
790 : :
791 : 114 : SRF_RETURN_DONE(funcctx);
792 : : }
793 : :
794 : : /*
795 : : * TwoPhaseGetGXact
796 : : * Get the GlobalTransaction struct for a prepared transaction
797 : : * specified by XID
798 : : *
799 : : * If lock_held is set to true, TwoPhaseStateLock will not be taken, so the
800 : : * caller had better hold it.
801 : : */
802 : : static GlobalTransaction
61 michael@paquier.xyz 803 :GNC 1196 : TwoPhaseGetGXact(FullTransactionId fxid, bool lock_held)
804 : : {
4777 tgl@sss.pgh.pa.us 805 :CBC 1196 : GlobalTransaction result = NULL;
806 : : int i;
807 : :
808 : : static FullTransactionId cached_fxid = {InvalidTransactionId};
809 : : static GlobalTransaction cached_gxact = NULL;
810 : :
2385 michael@paquier.xyz 811 [ + + - + ]: 1196 : Assert(!lock_held || LWLockHeldByMe(TwoPhaseStateLock));
812 : :
813 : : /*
814 : : * During a recovery, COMMIT PREPARED, or ABORT PREPARED, we'll be called
815 : : * repeatedly for the same XID. We can save work with a simple cache.
816 : : */
61 michael@paquier.xyz 817 [ + + ]:GNC 1196 : if (FullTransactionIdEquals(fxid, cached_fxid))
4777 tgl@sss.pgh.pa.us 818 :CBC 807 : return cached_gxact;
819 : :
2385 michael@paquier.xyz 820 [ + + ]: 389 : if (!lock_held)
821 : 320 : LWLockAcquire(TwoPhaseStateLock, LW_SHARED);
822 : :
7386 tgl@sss.pgh.pa.us 823 [ + - ]: 627 : for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
824 : : {
7266 bruce@momjian.us 825 : 627 : GlobalTransaction gxact = TwoPhaseState->prepXacts[i];
826 : :
61 michael@paquier.xyz 827 [ + + ]:GNC 627 : if (FullTransactionIdEquals(gxact->fxid, fxid))
828 : : {
4777 tgl@sss.pgh.pa.us 829 :CBC 389 : result = gxact;
7386 830 : 389 : break;
831 : : }
832 : : }
833 : :
2385 michael@paquier.xyz 834 [ + + ]: 389 : if (!lock_held)
835 : 320 : LWLockRelease(TwoPhaseStateLock);
836 : :
7386 tgl@sss.pgh.pa.us 837 [ - + ]: 389 : if (result == NULL) /* should not happen */
61 michael@paquier.xyz 838 [ # # ]:UNC 0 : elog(ERROR, "failed to find GlobalTransaction for xid %u",
839 : : XidFromFullTransactionId(fxid));
840 : :
61 michael@paquier.xyz 841 :GNC 389 : cached_fxid = fxid;
4777 tgl@sss.pgh.pa.us 842 :CBC 389 : cached_gxact = result;
843 : :
7386 844 : 389 : return result;
845 : : }
846 : :
847 : : /*
848 : : * TwoPhaseGetXidByVirtualXID
849 : : * Lookup VXID among xacts prepared since last startup.
850 : : *
851 : : * (This won't find recovered xacts.) If more than one matches, return any
852 : : * and set "have_more" to true. To witness multiple matches, a single
853 : : * proc number must consume 2^32 LXIDs, with no intervening database restart.
854 : : */
855 : : TransactionId
1414 noah@leadboat.com 856 : 81 : TwoPhaseGetXidByVirtualXID(VirtualTransactionId vxid,
857 : : bool *have_more)
858 : : {
859 : : int i;
860 : 81 : TransactionId result = InvalidTransactionId;
861 : :
862 [ - + ]: 81 : Assert(VirtualTransactionIdIsValid(vxid));
863 : 81 : LWLockAcquire(TwoPhaseStateLock, LW_SHARED);
864 : :
865 [ + + ]: 123 : for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
866 : : {
867 : 42 : GlobalTransaction gxact = TwoPhaseState->prepXacts[i];
868 : : PGPROC *proc;
869 : : VirtualTransactionId proc_vxid;
870 : :
871 [ + + ]: 42 : if (!gxact->valid)
1414 noah@leadboat.com 872 :GBC 2 : continue;
552 heikki.linnakangas@i 873 :CBC 40 : proc = GetPGProcByNumber(gxact->pgprocno);
1414 noah@leadboat.com 874 : 40 : GET_VXID_FROM_PGPROC(proc_vxid, *proc);
875 [ + + + - ]: 40 : if (VirtualTransactionIdEquals(vxid, proc_vxid))
876 : : {
877 : : /*
878 : : * Startup process sets proc->vxid.procNumber to
879 : : * INVALID_PROC_NUMBER.
880 : : */
881 [ - + ]: 6 : Assert(!gxact->inredo);
882 : :
883 [ - + ]: 6 : if (result != InvalidTransactionId)
884 : : {
1414 noah@leadboat.com 885 :UBC 0 : *have_more = true;
886 : 0 : break;
887 : : }
61 michael@paquier.xyz 888 :GNC 6 : result = XidFromFullTransactionId(gxact->fxid);
889 : : }
890 : : }
891 : :
1414 noah@leadboat.com 892 :CBC 81 : LWLockRelease(TwoPhaseStateLock);
893 : :
894 : 81 : return result;
895 : : }
896 : :
897 : : /*
898 : : * TwoPhaseGetDummyProcNumber
899 : : * Get the dummy proc number for prepared transaction
900 : : *
901 : : * Dummy proc numbers are similar to proc numbers of real backends. They
902 : : * start at MaxBackends, and are unique across all currently active real
903 : : * backends and prepared transactions. If lock_held is set to true,
904 : : * TwoPhaseStateLock will not be taken, so the caller had better hold it.
905 : : */
906 : : ProcNumber
61 michael@paquier.xyz 907 :GNC 110 : TwoPhaseGetDummyProcNumber(FullTransactionId fxid, bool lock_held)
908 : : {
909 : 110 : GlobalTransaction gxact = TwoPhaseGetGXact(fxid, lock_held);
910 : :
552 heikki.linnakangas@i 911 :CBC 110 : return gxact->pgprocno;
912 : : }
913 : :
914 : : /*
915 : : * TwoPhaseGetDummyProc
916 : : * Get the PGPROC that represents a prepared transaction
917 : : *
918 : : * If lock_held is set to true, TwoPhaseStateLock will not be taken, so the
919 : : * caller had better hold it.
920 : : */
921 : : PGPROC *
61 michael@paquier.xyz 922 :GNC 1086 : TwoPhaseGetDummyProc(FullTransactionId fxid, bool lock_held)
923 : : {
924 : 1086 : GlobalTransaction gxact = TwoPhaseGetGXact(fxid, lock_held);
925 : :
562 heikki.linnakangas@i 926 :CBC 1086 : return GetPGProcByNumber(gxact->pgprocno);
927 : : }
928 : :
929 : : /************************************************************************/
930 : : /* State file support */
931 : : /************************************************************************/
932 : :
933 : : /*
934 : : * Compute the FullTransactionId for the given TransactionId.
935 : : *
936 : : * This is safe if the xid has not yet reached COMMIT PREPARED or ROLLBACK
937 : : * PREPARED. After those commands, concurrent vac_truncate_clog() may make
938 : : * the xid cease to qualify as allowable. XXX Not all callers limit their
939 : : * calls accordingly.
940 : : */
941 : : static inline FullTransactionId
232 michael@paquier.xyz 942 : 303 : AdjustToFullTransactionId(TransactionId xid)
943 : : {
944 [ - + ]: 303 : Assert(TransactionIdIsValid(xid));
224 noah@leadboat.com 945 : 303 : return FullTransactionIdFromAllowableAt(ReadNextFullTransactionId(), xid);
946 : : }
947 : :
948 : : static inline int
61 michael@paquier.xyz 949 :GNC 502 : TwoPhaseFilePath(char *path, FullTransactionId fxid)
950 : : {
647 akorotkov@postgresql 951 :CBC 1004 : return snprintf(path, MAXPGPATH, TWOPHASE_DIR "/%08X%08X",
952 : 502 : EpochFromFullTransactionId(fxid),
953 : 502 : XidFromFullTransactionId(fxid));
954 : : }
955 : :
956 : : /*
957 : : * 2PC state file format:
958 : : *
959 : : * 1. TwoPhaseFileHeader
960 : : * 2. TransactionId[] (subtransactions)
961 : : * 3. RelFileLocator[] (files to be deleted at commit)
962 : : * 4. RelFileLocator[] (files to be deleted at abort)
963 : : * 5. SharedInvalidationMessage[] (inval messages to be sent at commit)
964 : : * 6. TwoPhaseRecordOnDisk
965 : : * 7. ...
966 : : * 8. TwoPhaseRecordOnDisk (end sentinel, rmid == TWOPHASE_RM_END_ID)
967 : : * 9. checksum (CRC-32C)
968 : : *
969 : : * Each segment except the final checksum is MAXALIGN'd.
970 : : */
971 : :
972 : : /*
973 : : * Header for a 2PC state file
974 : : */
975 : : #define TWOPHASE_MAGIC 0x57F94534 /* format identifier */
976 : :
977 : : typedef xl_xact_prepare TwoPhaseFileHeader;
978 : :
979 : : /*
980 : : * Header for each record in a state file
981 : : *
982 : : * NOTE: len counts only the rmgr data, not the TwoPhaseRecordOnDisk header.
983 : : * The rmgr data will be stored starting on a MAXALIGN boundary.
984 : : */
985 : : typedef struct TwoPhaseRecordOnDisk
986 : : {
987 : : uint32 len; /* length of rmgr data */
988 : : TwoPhaseRmgrId rmid; /* resource manager for this record */
989 : : uint16 info; /* flag bits for use by rmgr */
990 : : } TwoPhaseRecordOnDisk;
991 : :
992 : : /*
993 : : * During prepare, the state file is assembled in memory before writing it
994 : : * to WAL and the actual state file. We use a chain of StateFileChunk blocks
995 : : * for that.
996 : : */
997 : : typedef struct StateFileChunk
998 : : {
999 : : char *data;
1000 : : uint32 len;
1001 : : struct StateFileChunk *next;
1002 : : } StateFileChunk;
1003 : :
1004 : : static struct xllist
1005 : : {
1006 : : StateFileChunk *head; /* first data block in the chain */
1007 : : StateFileChunk *tail; /* last block in chain */
1008 : : uint32 num_chunks;
1009 : : uint32 bytes_free; /* free bytes left in tail block */
1010 : : uint32 total_len; /* total data bytes in chain */
1011 : : } records;
1012 : :
1013 : :
1014 : : /*
1015 : : * Append a block of data to records data structure.
1016 : : *
1017 : : * NB: each block is padded to a MAXALIGN multiple. This must be
1018 : : * accounted for when the file is later read!
1019 : : *
1020 : : * The data is copied, so the caller is free to modify it afterwards.
1021 : : */
1022 : : static void
7386 tgl@sss.pgh.pa.us 1023 : 3265 : save_state_data(const void *data, uint32 len)
1024 : : {
7266 bruce@momjian.us 1025 : 3265 : uint32 padlen = MAXALIGN(len);
1026 : :
7386 tgl@sss.pgh.pa.us 1027 [ + + ]: 3265 : if (padlen > records.bytes_free)
1028 : : {
3943 heikki.linnakangas@i 1029 : 43 : records.tail->next = palloc0(sizeof(StateFileChunk));
7386 tgl@sss.pgh.pa.us 1030 : 43 : records.tail = records.tail->next;
1031 : 43 : records.tail->len = 0;
1032 : 43 : records.tail->next = NULL;
3943 heikki.linnakangas@i 1033 : 43 : records.num_chunks++;
1034 : :
7386 tgl@sss.pgh.pa.us 1035 : 43 : records.bytes_free = Max(padlen, 512);
1036 : 43 : records.tail->data = palloc(records.bytes_free);
1037 : : }
1038 : :
1039 : 3265 : memcpy(((char *) records.tail->data) + records.tail->len, data, len);
1040 : 3265 : records.tail->len += padlen;
1041 : 3265 : records.bytes_free -= padlen;
1042 : 3265 : records.total_len += padlen;
1043 : 3265 : }
1044 : :
1045 : : /*
1046 : : * Start preparing a state file.
1047 : : *
1048 : : * Initializes data structure and inserts the 2PC file header record.
1049 : : */
1050 : : void
1051 : 289 : StartPrepare(GlobalTransaction gxact)
1052 : : {
562 heikki.linnakangas@i 1053 : 289 : PGPROC *proc = GetPGProcByNumber(gxact->pgprocno);
61 michael@paquier.xyz 1054 :GNC 289 : TransactionId xid = XidFromFullTransactionId(gxact->fxid);
1055 : : TwoPhaseFileHeader hdr;
1056 : : TransactionId *children;
1057 : : RelFileLocator *commitrels;
1058 : : RelFileLocator *abortrels;
1249 andres@anarazel.de 1059 :CBC 289 : xl_xact_stats_item *abortstats = NULL;
1060 : 289 : xl_xact_stats_item *commitstats = NULL;
1061 : : SharedInvalidationMessage *invalmsgs;
1062 : :
1063 : : /* Initialize linked list */
3943 heikki.linnakangas@i 1064 : 289 : records.head = palloc0(sizeof(StateFileChunk));
7386 tgl@sss.pgh.pa.us 1065 : 289 : records.head->len = 0;
1066 : 289 : records.head->next = NULL;
1067 : :
1068 : 289 : records.bytes_free = Max(sizeof(TwoPhaseFileHeader), 512);
1069 : 289 : records.head->data = palloc(records.bytes_free);
1070 : :
1071 : 289 : records.tail = records.head;
3943 heikki.linnakangas@i 1072 : 289 : records.num_chunks = 1;
1073 : :
7386 tgl@sss.pgh.pa.us 1074 : 289 : records.total_len = 0;
1075 : :
1076 : : /* Create header */
1077 : 289 : hdr.magic = TWOPHASE_MAGIC;
1078 : 289 : hdr.total_len = 0; /* EndPrepare will fill this in */
1079 : 289 : hdr.xid = xid;
5034 rhaas@postgresql.org 1080 : 289 : hdr.database = proc->databaseId;
7385 tgl@sss.pgh.pa.us 1081 : 289 : hdr.prepared_at = gxact->prepared_at;
1082 : 289 : hdr.owner = gxact->owner;
7386 1083 : 289 : hdr.nsubxacts = xactGetCommittedChildren(&children);
5503 rhaas@postgresql.org 1084 : 289 : hdr.ncommitrels = smgrGetPendingDeletes(true, &commitrels);
1085 : 289 : hdr.nabortrels = smgrGetPendingDeletes(false, &abortrels);
1249 andres@anarazel.de 1086 : 289 : hdr.ncommitstats =
1087 : 289 : pgstat_get_transactional_drops(true, &commitstats);
1088 : 289 : hdr.nabortstats =
1089 : 289 : pgstat_get_transactional_drops(false, &abortstats);
5740 simon@2ndQuadrant.co 1090 : 289 : hdr.ninvalmsgs = xactGetCommittedInvalidationMessages(&invalmsgs,
1091 : : &hdr.initfileinval);
2999 tgl@sss.pgh.pa.us 1092 : 289 : hdr.gidlen = strlen(gxact->gid) + 1; /* Include '\0' */
1093 : : /* EndPrepare will fill the origin data, if necessary */
1300 michael@paquier.xyz 1094 : 289 : hdr.origin_lsn = InvalidXLogRecPtr;
1095 : 289 : hdr.origin_timestamp = 0;
1096 : :
7386 tgl@sss.pgh.pa.us 1097 : 289 : save_state_data(&hdr, sizeof(TwoPhaseFileHeader));
3467 simon@2ndQuadrant.co 1098 : 289 : save_state_data(gxact->gid, hdr.gidlen);
1099 : :
1100 : : /*
1101 : : * Add the additional info about subxacts, deletable files and cache
1102 : : * invalidation messages.
1103 : : */
7386 tgl@sss.pgh.pa.us 1104 [ + + ]: 289 : if (hdr.nsubxacts > 0)
1105 : : {
1106 : 103 : save_state_data(children, hdr.nsubxacts * sizeof(TransactionId));
1107 : : /* While we have the child-xact data, stuff it in the gxact too */
1108 : 103 : GXactLoadSubxactData(gxact, hdr.nsubxacts, children);
1109 : : }
1110 [ + + ]: 289 : if (hdr.ncommitrels > 0)
1111 : : {
1158 rhaas@postgresql.org 1112 : 9 : save_state_data(commitrels, hdr.ncommitrels * sizeof(RelFileLocator));
7386 tgl@sss.pgh.pa.us 1113 : 9 : pfree(commitrels);
1114 : : }
1115 [ + + ]: 289 : if (hdr.nabortrels > 0)
1116 : : {
1158 rhaas@postgresql.org 1117 : 17 : save_state_data(abortrels, hdr.nabortrels * sizeof(RelFileLocator));
7386 tgl@sss.pgh.pa.us 1118 : 17 : pfree(abortrels);
1119 : : }
1249 andres@anarazel.de 1120 [ + + ]: 289 : if (hdr.ncommitstats > 0)
1121 : : {
1122 : 9 : save_state_data(commitstats,
1123 : 9 : hdr.ncommitstats * sizeof(xl_xact_stats_item));
1124 : 9 : pfree(commitstats);
1125 : : }
1126 [ + + ]: 289 : if (hdr.nabortstats > 0)
1127 : : {
1128 : 13 : save_state_data(abortstats,
1213 tgl@sss.pgh.pa.us 1129 : 13 : hdr.nabortstats * sizeof(xl_xact_stats_item));
1249 andres@anarazel.de 1130 : 13 : pfree(abortstats);
1131 : : }
5740 simon@2ndQuadrant.co 1132 [ + + ]: 289 : if (hdr.ninvalmsgs > 0)
1133 : : {
1134 : 23 : save_state_data(invalmsgs,
1135 : 23 : hdr.ninvalmsgs * sizeof(SharedInvalidationMessage));
1136 : 23 : pfree(invalmsgs);
1137 : : }
7386 tgl@sss.pgh.pa.us 1138 : 289 : }
1139 : :
1140 : : /*
1141 : : * Finish preparing state data and writing it to WAL.
1142 : : */
1143 : : void
1144 : 287 : EndPrepare(GlobalTransaction gxact)
1145 : : {
1146 : : TwoPhaseFileHeader *hdr;
1147 : : StateFileChunk *record;
1148 : : bool replorigin;
1149 : :
1150 : : /* Add the end sentinel to the list of 2PC records */
1151 : 287 : RegisterTwoPhaseRecord(TWOPHASE_RM_END_ID, 0,
1152 : : NULL, 0);
1153 : :
1154 : : /* Go back and fill in total_len in the file header record */
1155 : 287 : hdr = (TwoPhaseFileHeader *) records.head->data;
1156 [ - + ]: 287 : Assert(hdr->magic == TWOPHASE_MAGIC);
3798 heikki.linnakangas@i 1157 : 287 : hdr->total_len = records.total_len + sizeof(pg_crc32c);
1158 : :
2719 simon@2ndQuadrant.co 1159 [ + + ]: 311 : replorigin = (replorigin_session_origin != InvalidRepOriginId &&
1160 [ + - ]: 24 : replorigin_session_origin != DoNotReplicateId);
1161 : :
1162 [ + + ]: 287 : if (replorigin)
1163 : : {
1164 : 24 : hdr->origin_lsn = replorigin_session_origin_lsn;
1165 : 24 : hdr->origin_timestamp = replorigin_session_origin_timestamp;
1166 : : }
1167 : :
1168 : : /*
1169 : : * If the data size exceeds MaxAllocSize, we won't be able to read it in
1170 : : * ReadTwoPhaseFile. Check for that now, rather than fail in the case
1171 : : * where we write data to file and then re-read at commit time.
1172 : : */
6319 heikki.linnakangas@i 1173 [ - + ]: 287 : if (hdr->total_len > MaxAllocSize)
6319 heikki.linnakangas@i 1174 [ # # ]:UBC 0 : ereport(ERROR,
1175 : : (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
1176 : : errmsg("two-phase state file maximum length exceeded")));
1177 : :
1178 : : /*
1179 : : * Now writing 2PC state data to WAL. We let the WAL's CRC protection
1180 : : * cover us, so no need to calculate a separate CRC.
1181 : : *
1182 : : * We have to set DELAY_CHKPT_START here, too; otherwise a checkpoint
1183 : : * starting immediately after the WAL record is inserted could complete
1184 : : * without fsync'ing our state file. (This is essentially the same kind
1185 : : * of race condition as the COMMIT-to-clog-write case that
1186 : : * RecordTransactionCommit uses DELAY_CHKPT_IN_COMMIT for; see notes
1187 : : * there.) Note that DELAY_CHKPT_IN_COMMIT is used to find transactions in
1188 : : * the critical commit section. We need to know about such transactions
1189 : : * for conflict detection in logical replication. See
1190 : : * GetOldestActiveTransactionId(true, false) and its use.
1191 : : *
1192 : : * We save the PREPARE record's location in the gxact for later use by
1193 : : * CheckPointTwoPhase.
1194 : : */
3943 heikki.linnakangas@i 1195 :CBC 287 : XLogEnsureRecordSpace(0, records.num_chunks);
1196 : :
7386 tgl@sss.pgh.pa.us 1197 : 287 : START_CRIT_SECTION();
1198 : :
1247 rhaas@postgresql.org 1199 [ - + ]: 287 : Assert((MyProc->delayChkptFlags & DELAY_CHKPT_START) == 0);
1200 : 287 : MyProc->delayChkptFlags |= DELAY_CHKPT_START;
1201 : :
3943 heikki.linnakangas@i 1202 : 287 : XLogBeginInsert();
1203 [ + + ]: 617 : for (record = records.head; record != NULL; record = record->next)
1204 : 330 : XLogRegisterData(record->data, record->len);
1205 : :
2719 simon@2ndQuadrant.co 1206 : 287 : XLogSetRecordFlags(XLOG_INCLUDE_ORIGIN);
1207 : :
3517 1208 : 287 : gxact->prepare_end_lsn = XLogInsert(RM_XACT_ID, XLOG_XACT_PREPARE);
1209 : :
2719 1210 [ + + ]: 287 : if (replorigin)
1211 : : {
1212 : : /* Move LSNs forward for this replication origin */
1213 : 24 : replorigin_session_advance(replorigin_session_origin_lsn,
1214 : : gxact->prepare_end_lsn);
1215 : : }
1216 : :
3517 1217 : 287 : XLogFlush(gxact->prepare_end_lsn);
1218 : :
1219 : : /* If we crash now, we have prepared: WAL replay will fix things */
1220 : :
1221 : : /* Store record's start location to read that later on Commit */
1222 : 287 : gxact->prepare_start_lsn = ProcLastRecPtr;
1223 : :
1224 : : /*
1225 : : * Mark the prepared transaction as valid. As soon as xact.c marks MyProc
1226 : : * as not running our XID (which it will do immediately after this
1227 : : * function returns), others can commit/rollback the xact.
1228 : : *
1229 : : * NB: a side effect of this is to make a dummy ProcArray entry for the
1230 : : * prepared XID. This must happen before we clear the XID from MyProc /
1231 : : * ProcGlobal->xids[], else there is a window where the XID is not running
1232 : : * according to TransactionIdIsInProgress, and onlookers would be entitled
1233 : : * to assume the xact crashed. Instead we have a window where the same
1234 : : * XID appears twice in ProcArray, which is OK.
1235 : : */
3006 alvherre@alvh.no-ip. 1236 : 287 : MarkAsPrepared(gxact, false);
1237 : :
1238 : : /*
1239 : : * Now we can mark ourselves as out of the commit critical section: a
1240 : : * checkpoint starting after this will certainly see the gxact as a
1241 : : * candidate for fsyncing.
1242 : : */
1247 rhaas@postgresql.org 1243 : 287 : MyProc->delayChkptFlags &= ~DELAY_CHKPT_START;
1244 : :
1245 : : /*
1246 : : * Remember that we have this GlobalTransaction entry locked for us. If
1247 : : * we crash after this point, it's too late to abort, but we must unlock
1248 : : * it so that the prepared transaction can be committed or rolled back.
1249 : : */
4132 heikki.linnakangas@i 1250 : 287 : MyLockedGxact = gxact;
1251 : :
7386 tgl@sss.pgh.pa.us 1252 [ - + ]: 287 : END_CRIT_SECTION();
1253 : :
1254 : : /*
1255 : : * Wait for synchronous replication, if required.
1256 : : *
1257 : : * Note that at this stage we have marked the prepare, but still show as
1258 : : * running in the procarray (twice!) and continue to hold locks.
1259 : : */
3448 rhaas@postgresql.org 1260 : 287 : SyncRepWaitForLSN(gxact->prepare_end_lsn, false);
1261 : :
7386 tgl@sss.pgh.pa.us 1262 : 287 : records.tail = records.head = NULL;
3943 heikki.linnakangas@i 1263 : 287 : records.num_chunks = 0;
7386 tgl@sss.pgh.pa.us 1264 : 287 : }
1265 : :
1266 : : /*
1267 : : * Register a 2PC record to be written to state file.
1268 : : */
1269 : : void
1270 : 1400 : RegisterTwoPhaseRecord(TwoPhaseRmgrId rmid, uint16 info,
1271 : : const void *data, uint32 len)
1272 : : {
1273 : : TwoPhaseRecordOnDisk record;
1274 : :
1275 : 1400 : record.rmid = rmid;
1276 : 1400 : record.info = info;
1277 : 1400 : record.len = len;
1278 : 1400 : save_state_data(&record, sizeof(TwoPhaseRecordOnDisk));
1279 [ + + ]: 1400 : if (len > 0)
1280 : 1113 : save_state_data(data, len);
1281 : 1400 : }
1282 : :
1283 : :
1284 : : /*
1285 : : * Read and validate the state file for xid.
1286 : : *
1287 : : * If it looks OK (has a valid magic number and CRC), return the palloc'd
1288 : : * contents of the file, issuing an error when finding corrupted data. If
1289 : : * missing_ok is true, which indicates that missing files can be safely
1290 : : * ignored, then return NULL. This state can be reached when doing recovery
1291 : : * after discarding two-phase files from frozen epochs.
1292 : : */
1293 : : static char *
61 michael@paquier.xyz 1294 :GNC 373 : ReadTwoPhaseFile(FullTransactionId fxid, bool missing_ok)
1295 : : {
1296 : : char path[MAXPGPATH];
1297 : : char *buf;
1298 : : TwoPhaseFileHeader *hdr;
1299 : : int fd;
1300 : : struct stat stat;
1301 : : uint32 crc_offset;
1302 : : pg_crc32c calc_crc,
1303 : : file_crc;
1304 : : int r;
1305 : :
1306 : 373 : TwoPhaseFilePath(path, fxid);
1307 : :
2905 peter_e@gmx.net 1308 :CBC 373 : fd = OpenTransientFile(path, O_RDONLY | PG_BINARY);
7386 tgl@sss.pgh.pa.us 1309 [ + + ]: 373 : if (fd < 0)
1310 : : {
2556 michael@paquier.xyz 1311 [ + - + - ]: 303 : if (missing_ok && errno == ENOENT)
1312 : 303 : return NULL;
1313 : :
2556 michael@paquier.xyz 1314 [ # # ]:UBC 0 : ereport(ERROR,
1315 : : (errcode_for_file_access(),
1316 : : errmsg("could not open file \"%s\": %m", path)));
1317 : : }
1318 : :
1319 : : /*
1320 : : * Check file length. We can determine a lower bound pretty easily. We
1321 : : * set an upper bound to avoid palloc() failure on a corrupt file, though
1322 : : * we can't guarantee that we won't get an out of memory error anyway,
1323 : : * even on a valid file.
1324 : : */
7386 tgl@sss.pgh.pa.us 1325 [ - + ]:CBC 70 : if (fstat(fd, &stat))
2556 michael@paquier.xyz 1326 [ # # ]:UBC 0 : ereport(ERROR,
1327 : : (errcode_for_file_access(),
1328 : : errmsg("could not stat file \"%s\": %m", path)));
1329 : :
7386 tgl@sss.pgh.pa.us 1330 [ + - ]:CBC 70 : if (stat.st_size < (MAXALIGN(sizeof(TwoPhaseFileHeader)) +
1331 : : MAXALIGN(sizeof(TwoPhaseRecordOnDisk)) +
3798 heikki.linnakangas@i 1332 : 70 : sizeof(pg_crc32c)) ||
6319 1333 [ - + ]: 70 : stat.st_size > MaxAllocSize)
2556 michael@paquier.xyz 1334 [ # # ]:UBC 0 : ereport(ERROR,
1335 : : (errcode(ERRCODE_DATA_CORRUPTED),
1336 : : errmsg_plural("incorrect size of file \"%s\": %lld byte",
1337 : : "incorrect size of file \"%s\": %lld bytes",
1338 : : (long long int) stat.st_size, path,
1339 : : (long long int) stat.st_size)));
1340 : :
3798 heikki.linnakangas@i 1341 :CBC 70 : crc_offset = stat.st_size - sizeof(pg_crc32c);
7386 tgl@sss.pgh.pa.us 1342 [ - + ]: 70 : if (crc_offset != MAXALIGN(crc_offset))
2556 michael@paquier.xyz 1343 [ # # ]:UBC 0 : ereport(ERROR,
1344 : : (errcode(ERRCODE_DATA_CORRUPTED),
1345 : : errmsg("incorrect alignment of CRC offset for file \"%s\"",
1346 : : path)));
1347 : :
1348 : : /*
1349 : : * OK, slurp in the file.
1350 : : */
7386 tgl@sss.pgh.pa.us 1351 :CBC 70 : buf = (char *) palloc(stat.st_size);
1352 : :
3094 rhaas@postgresql.org 1353 : 70 : pgstat_report_wait_start(WAIT_EVENT_TWOPHASE_FILE_READ);
2607 michael@paquier.xyz 1354 : 70 : r = read(fd, buf, stat.st_size);
1355 [ - + ]: 70 : if (r != stat.st_size)
1356 : : {
2556 michael@paquier.xyz 1357 [ # # ]:UBC 0 : if (r < 0)
1358 [ # # ]: 0 : ereport(ERROR,
1359 : : (errcode_for_file_access(),
1360 : : errmsg("could not read file \"%s\": %m", path)));
1361 : : else
1362 [ # # ]: 0 : ereport(ERROR,
1363 : : (errmsg("could not read file \"%s\": read %d of %lld",
1364 : : path, r, (long long int) stat.st_size)));
1365 : : }
1366 : :
3094 rhaas@postgresql.org 1367 :CBC 70 : pgstat_report_wait_end();
1368 : :
2254 peter@eisentraut.org 1369 [ - + ]: 70 : if (CloseTransientFile(fd) != 0)
2373 michael@paquier.xyz 1370 [ # # ]:UBC 0 : ereport(ERROR,
1371 : : (errcode_for_file_access(),
1372 : : errmsg("could not close file \"%s\": %m", path)));
1373 : :
7386 tgl@sss.pgh.pa.us 1374 :CBC 70 : hdr = (TwoPhaseFileHeader *) buf;
2556 michael@paquier.xyz 1375 [ - + ]: 70 : if (hdr->magic != TWOPHASE_MAGIC)
2556 michael@paquier.xyz 1376 [ # # ]:UBC 0 : ereport(ERROR,
1377 : : (errcode(ERRCODE_DATA_CORRUPTED),
1378 : : errmsg("invalid magic number stored in file \"%s\"",
1379 : : path)));
1380 : :
2556 michael@paquier.xyz 1381 [ - + ]:CBC 70 : if (hdr->total_len != stat.st_size)
2556 michael@paquier.xyz 1382 [ # # ]:UBC 0 : ereport(ERROR,
1383 : : (errcode(ERRCODE_DATA_CORRUPTED),
1384 : : errmsg("invalid size stored in file \"%s\"",
1385 : : path)));
1386 : :
3959 heikki.linnakangas@i 1387 :CBC 70 : INIT_CRC32C(calc_crc);
1388 : 70 : COMP_CRC32C(calc_crc, buf, crc_offset);
1389 : 70 : FIN_CRC32C(calc_crc);
1390 : :
3798 1391 : 70 : file_crc = *((pg_crc32c *) (buf + crc_offset));
1392 : :
3959 1393 [ - + ]: 70 : if (!EQ_CRC32C(calc_crc, file_crc))
2556 michael@paquier.xyz 1394 [ # # ]:UBC 0 : ereport(ERROR,
1395 : : (errcode(ERRCODE_DATA_CORRUPTED),
1396 : : errmsg("calculated CRC checksum does not match value stored in file \"%s\"",
1397 : : path)));
1398 : :
7386 tgl@sss.pgh.pa.us 1399 :CBC 70 : return buf;
1400 : : }
1401 : :
1402 : :
1403 : : /*
1404 : : * Reads 2PC data from xlog. During checkpoint this data will be moved to
1405 : : * twophase files and ReadTwoPhaseFile should be used instead.
1406 : : *
1407 : : * Note clearly that this function can access WAL during normal operation,
1408 : : * similarly to the way WALSender or Logical Decoding would do.
1409 : : */
1410 : : static void
3517 simon@2ndQuadrant.co 1411 : 371 : XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len)
1412 : : {
1413 : : XLogRecord *record;
1414 : : XLogReaderState *xlogreader;
1415 : : char *errormsg;
1416 : :
1580 tmunro@postgresql.or 1417 : 371 : xlogreader = XLogReaderAllocate(wal_segment_size, NULL,
1418 : 371 : XL_ROUTINE(.page_read = &read_local_xlog_page,
1419 : : .segment_open = &wal_segment_open,
1420 : : .segment_close = &wal_segment_close),
1421 : : NULL);
3517 simon@2ndQuadrant.co 1422 [ - + ]: 371 : if (!xlogreader)
3517 simon@2ndQuadrant.co 1423 [ # # ]:UBC 0 : ereport(ERROR,
1424 : : (errcode(ERRCODE_OUT_OF_MEMORY),
1425 : : errmsg("out of memory"),
1426 : : errdetail("Failed while allocating a WAL reading processor.")));
1427 : :
2050 heikki.linnakangas@i 1428 :CBC 371 : XLogBeginRead(xlogreader, lsn);
1580 tmunro@postgresql.or 1429 : 371 : record = XLogReadRecord(xlogreader, &errormsg);
1430 : :
3517 simon@2ndQuadrant.co 1431 [ - + ]: 371 : if (record == NULL)
1432 : : {
1395 noah@leadboat.com 1433 [ # # ]:UBC 0 : if (errormsg)
1434 [ # # ]: 0 : ereport(ERROR,
1435 : : (errcode_for_file_access(),
1436 : : errmsg("could not read two-phase state from WAL at %X/%08X: %s",
1437 : : LSN_FORMAT_ARGS(lsn), errormsg)));
1438 : : else
1439 [ # # ]: 0 : ereport(ERROR,
1440 : : (errcode_for_file_access(),
1441 : : errmsg("could not read two-phase state from WAL at %X/%08X",
1442 : : LSN_FORMAT_ARGS(lsn))));
1443 : : }
1444 : :
3517 simon@2ndQuadrant.co 1445 [ + - ]:CBC 371 : if (XLogRecGetRmid(xlogreader) != RM_XACT_ID ||
1446 [ - + ]: 371 : (XLogRecGetInfo(xlogreader) & XLOG_XACT_OPMASK) != XLOG_XACT_PREPARE)
3517 simon@2ndQuadrant.co 1447 [ # # ]:UBC 0 : ereport(ERROR,
1448 : : (errcode_for_file_access(),
1449 : : errmsg("expected two-phase state data is not present in WAL at %X/%08X",
1450 : : LSN_FORMAT_ARGS(lsn))));
1451 : :
3517 simon@2ndQuadrant.co 1452 [ + + ]:CBC 371 : if (len != NULL)
1453 : 25 : *len = XLogRecGetDataLen(xlogreader);
1454 : :
3376 rhaas@postgresql.org 1455 : 371 : *buf = palloc(sizeof(char) * XLogRecGetDataLen(xlogreader));
3517 simon@2ndQuadrant.co 1456 : 371 : memcpy(*buf, XLogRecGetData(xlogreader), sizeof(char) * XLogRecGetDataLen(xlogreader));
1457 : :
1458 : 371 : XLogReaderFree(xlogreader);
1459 : 371 : }
1460 : :
1461 : :
1462 : : /*
1463 : : * Confirms an xid is prepared, during recovery
1464 : : */
1465 : : bool
5740 1466 : 303 : StandbyTransactionIdIsPrepared(TransactionId xid)
1467 : : {
1468 : : char *buf;
1469 : : TwoPhaseFileHeader *hdr;
1470 : : bool result;
1471 : : FullTransactionId fxid;
1472 : :
1473 [ - + ]: 303 : Assert(TransactionIdIsValid(xid));
1474 : :
5610 tgl@sss.pgh.pa.us 1475 [ - + ]: 303 : if (max_prepared_xacts <= 0)
5541 bruce@momjian.us 1476 :UBC 0 : return false; /* nothing to do */
1477 : :
1478 : : /* Read and validate file */
61 michael@paquier.xyz 1479 :GNC 303 : fxid = AdjustToFullTransactionId(xid);
1480 : 303 : buf = ReadTwoPhaseFile(fxid, true);
5740 simon@2ndQuadrant.co 1481 [ + - ]:CBC 303 : if (buf == NULL)
1482 : 303 : return false;
1483 : :
1484 : : /* Check header also */
5740 simon@2ndQuadrant.co 1485 :UBC 0 : hdr = (TwoPhaseFileHeader *) buf;
1486 : 0 : result = TransactionIdEquals(hdr->xid, xid);
1487 : 0 : pfree(buf);
1488 : :
1489 : 0 : return result;
1490 : : }
1491 : :
1492 : : /*
1493 : : * FinishPreparedTransaction: execute COMMIT PREPARED or ROLLBACK PREPARED
1494 : : */
1495 : : void
7385 tgl@sss.pgh.pa.us 1496 :CBC 298 : FinishPreparedTransaction(const char *gid, bool isCommit)
1497 : : {
1498 : : GlobalTransaction gxact;
1499 : : PGPROC *proc;
1500 : : FullTransactionId fxid;
1501 : : TransactionId xid;
1502 : : bool ondisk;
1503 : : char *buf;
1504 : : char *bufptr;
1505 : : TwoPhaseFileHeader *hdr;
1506 : : TransactionId latestXid;
1507 : : TransactionId *children;
1508 : : RelFileLocator *commitrels;
1509 : : RelFileLocator *abortrels;
1510 : : RelFileLocator *delrels;
1511 : : int ndelrels;
1512 : : xl_xact_stats_item *commitstats;
1513 : : xl_xact_stats_item *abortstats;
1514 : : SharedInvalidationMessage *invalmsgs;
1515 : :
1516 : : /*
1517 : : * Validate the GID, and lock the GXACT to ensure that two backends do not
1518 : : * try to commit the same GID at once.
1519 : : */
7386 1520 : 298 : gxact = LockGXact(gid, GetUserId());
562 heikki.linnakangas@i 1521 : 292 : proc = GetPGProcByNumber(gxact->pgprocno);
61 michael@paquier.xyz 1522 :GNC 292 : fxid = gxact->fxid;
1523 : 292 : xid = XidFromFullTransactionId(fxid);
1524 : :
1525 : : /*
1526 : : * Read and validate 2PC state data. State data will typically be stored
1527 : : * in WAL files if the LSN is after the last checkpoint record, or moved
1528 : : * to disk if for some reason they have lived for a long time.
1529 : : */
3517 simon@2ndQuadrant.co 1530 [ + + ]:CBC 292 : if (gxact->ondisk)
61 michael@paquier.xyz 1531 :GNC 23 : buf = ReadTwoPhaseFile(fxid, false);
1532 : : else
3517 simon@2ndQuadrant.co 1533 :CBC 269 : XlogReadTwoPhaseData(gxact->prepare_start_lsn, &buf, NULL);
1534 : :
1535 : :
1536 : : /*
1537 : : * Disassemble the header area
1538 : : */
7386 tgl@sss.pgh.pa.us 1539 : 292 : hdr = (TwoPhaseFileHeader *) buf;
1540 [ - + ]: 292 : Assert(TransactionIdEquals(hdr->xid, xid));
1541 : 292 : bufptr = buf + MAXALIGN(sizeof(TwoPhaseFileHeader));
3467 simon@2ndQuadrant.co 1542 : 292 : bufptr += MAXALIGN(hdr->gidlen);
7386 tgl@sss.pgh.pa.us 1543 : 292 : children = (TransactionId *) bufptr;
1544 : 292 : bufptr += MAXALIGN(hdr->nsubxacts * sizeof(TransactionId));
1158 rhaas@postgresql.org 1545 : 292 : commitrels = (RelFileLocator *) bufptr;
1546 : 292 : bufptr += MAXALIGN(hdr->ncommitrels * sizeof(RelFileLocator));
1547 : 292 : abortrels = (RelFileLocator *) bufptr;
1548 : 292 : bufptr += MAXALIGN(hdr->nabortrels * sizeof(RelFileLocator));
1213 tgl@sss.pgh.pa.us 1549 : 292 : commitstats = (xl_xact_stats_item *) bufptr;
1249 andres@anarazel.de 1550 : 292 : bufptr += MAXALIGN(hdr->ncommitstats * sizeof(xl_xact_stats_item));
1213 tgl@sss.pgh.pa.us 1551 : 292 : abortstats = (xl_xact_stats_item *) bufptr;
1249 andres@anarazel.de 1552 : 292 : bufptr += MAXALIGN(hdr->nabortstats * sizeof(xl_xact_stats_item));
5740 simon@2ndQuadrant.co 1553 : 292 : invalmsgs = (SharedInvalidationMessage *) bufptr;
1554 : 292 : bufptr += MAXALIGN(hdr->ninvalmsgs * sizeof(SharedInvalidationMessage));
1555 : :
1556 : : /* compute latestXid among all children */
6573 tgl@sss.pgh.pa.us 1557 : 292 : latestXid = TransactionIdLatest(xid, hdr->nsubxacts, children);
1558 : :
1559 : : /* Prevent cancel/die interrupt while cleaning up */
2683 teodor@sigaev.ru 1560 : 292 : HOLD_INTERRUPTS();
1561 : :
1562 : : /*
1563 : : * The order of operations here is critical: make the XLOG entry for
1564 : : * commit or abort, then mark the transaction committed or aborted in
1565 : : * pg_xact, then remove its PGPROC from the global ProcArray (which means
1566 : : * TransactionIdIsInProgress will stop saying the prepared xact is in
1567 : : * progress), then run the post-commit or post-abort callbacks. The
1568 : : * callbacks will release the locks the transaction held.
1569 : : */
7386 tgl@sss.pgh.pa.us 1570 [ + + ]: 292 : if (isCommit)
1571 : 254 : RecordTransactionCommitPrepared(xid,
1572 : : hdr->nsubxacts, children,
1573 : : hdr->ncommitrels, commitrels,
1574 : : hdr->ncommitstats,
1575 : : commitstats,
1576 : : hdr->ninvalmsgs, invalmsgs,
2719 simon@2ndQuadrant.co 1577 : 254 : hdr->initfileinval, gid);
1578 : : else
7386 tgl@sss.pgh.pa.us 1579 : 38 : RecordTransactionAbortPrepared(xid,
1580 : : hdr->nsubxacts, children,
1581 : : hdr->nabortrels, abortrels,
1582 : : hdr->nabortstats,
1583 : : abortstats,
1584 : : gid);
1585 : :
5034 rhaas@postgresql.org 1586 : 292 : ProcArrayRemove(proc, latestXid);
1587 : :
1588 : : /*
1589 : : * In case we fail while running the callbacks, mark the gxact invalid so
1590 : : * no one else will try to commit/rollback, and so it will be recycled if
1591 : : * we fail after this point. It is still locked by our backend so it
1592 : : * won't go away yet.
1593 : : *
1594 : : * (We assume it's safe to do this without taking TwoPhaseStateLock.)
1595 : : */
7386 tgl@sss.pgh.pa.us 1596 : 292 : gxact->valid = false;
1597 : :
1598 : : /*
1599 : : * We have to remove any files that were supposed to be dropped. For
1600 : : * consistency with the regular xact.c code paths, must do this before
1601 : : * releasing locks, so do it before running the callbacks.
1602 : : *
1603 : : * NB: this code knows that we couldn't be dropping any temp rels ...
1604 : : */
1605 [ + + ]: 292 : if (isCommit)
1606 : : {
6135 heikki.linnakangas@i 1607 : 254 : delrels = commitrels;
1608 : 254 : ndelrels = hdr->ncommitrels;
1609 : : }
1610 : : else
1611 : : {
1612 : 38 : delrels = abortrels;
1613 : 38 : ndelrels = hdr->nabortrels;
1614 : : }
1615 : :
1616 : : /* Make sure files supposed to be dropped are dropped */
2620 fujii@postgresql.org 1617 : 292 : DropRelationFiles(delrels, ndelrels, false);
1618 : :
1249 andres@anarazel.de 1619 [ + + ]: 292 : if (isCommit)
1620 : 254 : pgstat_execute_transactional_drops(hdr->ncommitstats, commitstats, false);
1621 : : else
1622 : 38 : pgstat_execute_transactional_drops(hdr->nabortstats, abortstats, false);
1623 : :
1624 : : /*
1625 : : * Handle cache invalidation messages.
1626 : : *
1627 : : * Relcache init file invalidation requires processing both before and
1628 : : * after we send the SI messages, only when committing. See
1629 : : * AtEOXact_Inval().
1630 : : */
1486 michael@paquier.xyz 1631 [ + + ]: 292 : if (isCommit)
1632 : : {
1633 [ - + ]: 254 : if (hdr->initfileinval)
1486 michael@paquier.xyz 1634 :UBC 0 : RelationCacheInitFilePreInvalidate();
1486 michael@paquier.xyz 1635 :CBC 254 : SendSharedInvalidMessages(invalmsgs, hdr->ninvalmsgs);
1636 [ - + ]: 254 : if (hdr->initfileinval)
1486 michael@paquier.xyz 1637 :UBC 0 : RelationCacheInitFilePostInvalidate();
1638 : : }
1639 : :
1640 : : /*
1641 : : * Acquire the two-phase lock. We want to work on the two-phase callbacks
1642 : : * while holding it to avoid potential conflicts with other transactions
1643 : : * attempting to use the same GID, so the lock is released once the shared
1644 : : * memory state is cleared.
1645 : : */
2385 michael@paquier.xyz 1646 :CBC 292 : LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
1647 : :
1648 : : /* And now do the callbacks */
7385 tgl@sss.pgh.pa.us 1649 [ + + ]: 292 : if (isCommit)
61 michael@paquier.xyz 1650 :GNC 254 : ProcessRecords(bufptr, fxid, twophase_postcommit_callbacks);
1651 : : else
1652 : 38 : ProcessRecords(bufptr, fxid, twophase_postabort_callbacks);
1653 : :
1654 : 292 : PredicateLockTwoPhaseFinish(fxid, isCommit);
1655 : :
1656 : : /*
1657 : : * Read this value while holding the two-phase lock, as the on-disk 2PC
1658 : : * file is physically removed after the lock is released.
1659 : : */
340 michael@paquier.xyz 1660 :CBC 292 : ondisk = gxact->ondisk;
1661 : :
1662 : : /* Clear shared memory state */
2385 1663 : 292 : RemoveGXact(gxact);
1664 : :
1665 : : /*
1666 : : * Release the lock as all callbacks are called and shared memory cleanup
1667 : : * is done.
1668 : : */
1669 : 292 : LWLockRelease(TwoPhaseStateLock);
1670 : :
1671 : : /* Count the prepared xact as committed or aborted */
2341 akapila@postgresql.o 1672 : 292 : AtEOXact_PgStat(isCommit, false);
1673 : :
1674 : : /*
1675 : : * And now we can clean up any files we may have left.
1676 : : */
340 michael@paquier.xyz 1677 [ + + ]: 292 : if (ondisk)
61 michael@paquier.xyz 1678 :GNC 24 : RemoveTwoPhaseFile(fxid, true);
1679 : :
4132 heikki.linnakangas@i 1680 :CBC 292 : MyLockedGxact = NULL;
1681 : :
2683 teodor@sigaev.ru 1682 [ - + ]: 292 : RESUME_INTERRUPTS();
1683 : :
7386 tgl@sss.pgh.pa.us 1684 : 292 : pfree(buf);
1685 : 292 : }
1686 : :
1687 : : /*
1688 : : * Scan 2PC state data in memory and call the indicated callbacks for each 2PC record.
1689 : : */
1690 : : static void
61 michael@paquier.xyz 1691 :GNC 325 : ProcessRecords(char *bufptr, FullTransactionId fxid,
1692 : : const TwoPhaseCallback callbacks[])
1693 : : {
1694 : : for (;;)
7386 tgl@sss.pgh.pa.us 1695 :CBC 1303 : {
1696 : 1628 : TwoPhaseRecordOnDisk *record = (TwoPhaseRecordOnDisk *) bufptr;
1697 : :
1698 [ - + ]: 1628 : Assert(record->rmid <= TWOPHASE_RM_MAX_ID);
1699 [ + + ]: 1628 : if (record->rmid == TWOPHASE_RM_END_ID)
1700 : 325 : break;
1701 : :
1702 : 1303 : bufptr += MAXALIGN(sizeof(TwoPhaseRecordOnDisk));
1703 : :
1704 [ + + ]: 1303 : if (callbacks[record->rmid] != NULL)
61 michael@paquier.xyz 1705 :GNC 1224 : callbacks[record->rmid] (fxid, record->info, bufptr, record->len);
1706 : :
7386 tgl@sss.pgh.pa.us 1707 :CBC 1303 : bufptr += MAXALIGN(record->len);
1708 : : }
1709 : 325 : }
1710 : :
1711 : : /*
1712 : : * Remove the 2PC file.
1713 : : *
1714 : : * If giveWarning is false, do not complain about file-not-present;
1715 : : * this is an expected case during WAL replay.
1716 : : *
1717 : : * This routine is used at early stages at recovery where future and
1718 : : * past orphaned files are checked, hence the FullTransactionId to build
1719 : : * a complete file name fit for the removal.
1720 : : */
1721 : : static void
61 michael@paquier.xyz 1722 :GNC 28 : RemoveTwoPhaseFile(FullTransactionId fxid, bool giveWarning)
1723 : : {
1724 : : char path[MAXPGPATH];
1725 : :
1726 : 28 : TwoPhaseFilePath(path, fxid);
7386 tgl@sss.pgh.pa.us 1727 [ - + ]:CBC 28 : if (unlink(path))
7386 tgl@sss.pgh.pa.us 1728 [ # # # # ]:UBC 0 : if (errno != ENOENT || giveWarning)
1729 [ # # ]: 0 : ereport(WARNING,
1730 : : (errcode_for_file_access(),
1731 : : errmsg("could not remove file \"%s\": %m", path)));
7386 tgl@sss.pgh.pa.us 1732 :CBC 28 : }
1733 : :
1734 : : /*
1735 : : * Recreates a state file. This is used in WAL replay and during
1736 : : * checkpoint creation.
1737 : : *
1738 : : * Note: content and len don't include CRC.
1739 : : */
1740 : : static void
61 michael@paquier.xyz 1741 :GNC 25 : RecreateTwoPhaseFile(FullTransactionId fxid, void *content, int len)
1742 : : {
1743 : : char path[MAXPGPATH];
1744 : : pg_crc32c statefile_crc;
1745 : : int fd;
1746 : :
1747 : : /* Recompute CRC */
3959 heikki.linnakangas@i 1748 :CBC 25 : INIT_CRC32C(statefile_crc);
1749 : 25 : COMP_CRC32C(statefile_crc, content, len);
1750 : 25 : FIN_CRC32C(statefile_crc);
1751 : :
61 michael@paquier.xyz 1752 :GNC 25 : TwoPhaseFilePath(path, fxid);
1753 : :
4666 heikki.linnakangas@i 1754 :CBC 25 : fd = OpenTransientFile(path,
1755 : : O_CREAT | O_TRUNC | O_WRONLY | PG_BINARY);
7386 tgl@sss.pgh.pa.us 1756 [ - + ]: 25 : if (fd < 0)
7386 tgl@sss.pgh.pa.us 1757 [ # # ]:UBC 0 : ereport(ERROR,
1758 : : (errcode_for_file_access(),
1759 : : errmsg("could not recreate file \"%s\": %m", path)));
1760 : :
1761 : : /* Write content and CRC */
2589 michael@paquier.xyz 1762 :CBC 25 : errno = 0;
3094 rhaas@postgresql.org 1763 : 25 : pgstat_report_wait_start(WAIT_EVENT_TWOPHASE_FILE_WRITE);
7386 tgl@sss.pgh.pa.us 1764 [ - + ]: 25 : if (write(fd, content, len) != len)
1765 : : {
1766 : : /* if write didn't set errno, assume problem is no disk space */
2334 michael@paquier.xyz 1767 [ # # ]:UBC 0 : if (errno == 0)
1768 : 0 : errno = ENOSPC;
7386 tgl@sss.pgh.pa.us 1769 [ # # ]: 0 : ereport(ERROR,
1770 : : (errcode_for_file_access(),
1771 : : errmsg("could not write file \"%s\": %m", path)));
1772 : : }
3798 heikki.linnakangas@i 1773 [ - + ]:CBC 25 : if (write(fd, &statefile_crc, sizeof(pg_crc32c)) != sizeof(pg_crc32c))
1774 : : {
1775 : : /* if write didn't set errno, assume problem is no disk space */
2334 michael@paquier.xyz 1776 [ # # ]:UBC 0 : if (errno == 0)
1777 : 0 : errno = ENOSPC;
7386 tgl@sss.pgh.pa.us 1778 [ # # ]: 0 : ereport(ERROR,
1779 : : (errcode_for_file_access(),
1780 : : errmsg("could not write file \"%s\": %m", path)));
1781 : : }
3094 rhaas@postgresql.org 1782 :CBC 25 : pgstat_report_wait_end();
1783 : :
1784 : : /*
1785 : : * We must fsync the file because the end-of-replay checkpoint will not do
1786 : : * so, there being no GXACT in shared memory yet to tell it to.
1787 : : */
1788 : 25 : pgstat_report_wait_start(WAIT_EVENT_TWOPHASE_FILE_SYNC);
7386 tgl@sss.pgh.pa.us 1789 [ - + ]: 25 : if (pg_fsync(fd) != 0)
7386 tgl@sss.pgh.pa.us 1790 [ # # ]:UBC 0 : ereport(ERROR,
1791 : : (errcode_for_file_access(),
1792 : : errmsg("could not fsync file \"%s\": %m", path)));
3094 rhaas@postgresql.org 1793 :CBC 25 : pgstat_report_wait_end();
1794 : :
4666 heikki.linnakangas@i 1795 [ - + ]: 25 : if (CloseTransientFile(fd) != 0)
7386 tgl@sss.pgh.pa.us 1796 [ # # ]:UBC 0 : ereport(ERROR,
1797 : : (errcode_for_file_access(),
1798 : : errmsg("could not close file \"%s\": %m", path)));
7386 tgl@sss.pgh.pa.us 1799 :CBC 25 : }
1800 : :
1801 : : /*
1802 : : * CheckPointTwoPhase -- handle 2PC component of checkpointing.
1803 : : *
1804 : : * We must fsync the state file of any GXACT that is valid or has been
1805 : : * generated during redo and has a PREPARE LSN <= the checkpoint's redo
1806 : : * horizon. (If the gxact isn't valid yet, has not been generated in
1807 : : * redo, or has a later LSN, this checkpoint is not responsible for
1808 : : * fsyncing it.)
1809 : : *
1810 : : * This is deliberately run as late as possible in the checkpoint sequence,
1811 : : * because GXACTs ordinarily have short lifespans, and so it is quite
1812 : : * possible that GXACTs that were valid at checkpoint start will no longer
1813 : : * exist if we wait a little bit. With typical checkpoint settings this
1814 : : * will be about 3 minutes for an online checkpoint, so as a result we
1815 : : * expect that there will be no GXACTs that need to be copied to disk.
1816 : : *
1817 : : * If a GXACT remains valid across multiple checkpoints, it will already
1818 : : * be on disk so we don't bother to repeat that write.
1819 : : */
1820 : : void
7384 1821 : 1677 : CheckPointTwoPhase(XLogRecPtr redo_horizon)
1822 : : {
1823 : : int i;
3517 simon@2ndQuadrant.co 1824 : 1677 : int serialized_xacts = 0;
1825 : :
7384 tgl@sss.pgh.pa.us 1826 [ + + ]: 1677 : if (max_prepared_xacts <= 0)
1827 : 1160 : return; /* nothing to do */
1828 : :
1829 : : TRACE_POSTGRESQL_TWOPHASE_CHECKPOINT_START();
1830 : :
1831 : : /*
1832 : : * We are expecting there to be zero GXACTs that need to be copied to
1833 : : * disk, so we perform all I/O while holding TwoPhaseStateLock for
1834 : : * simplicity. This prevents any new xacts from preparing while this
1835 : : * occurs, which shouldn't be a problem since the presence of long-lived
1836 : : * prepared xacts indicates the transaction manager isn't active.
1837 : : *
1838 : : * It's also possible to move I/O out of the lock, but on every error we
1839 : : * should check whether somebody committed our transaction in different
1840 : : * backend. Let's leave this optimization for future, if somebody will
1841 : : * spot that this place cause bottleneck.
1842 : : *
1843 : : * Note that it isn't possible for there to be a GXACT with a
1844 : : * prepare_end_lsn set prior to the last checkpoint yet is marked invalid,
1845 : : * because of the efforts with delayChkptFlags.
1846 : : */
1847 : 517 : LWLockAcquire(TwoPhaseStateLock, LW_SHARED);
1848 [ + + ]: 550 : for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
1849 : : {
1850 : : /*
1851 : : * Note that we are using gxact not PGPROC so this works in recovery
1852 : : * also
1853 : : */
7266 bruce@momjian.us 1854 : 33 : GlobalTransaction gxact = TwoPhaseState->prepXacts[i];
1855 : :
3077 simon@2ndQuadrant.co 1856 [ + + + - ]: 33 : if ((gxact->valid || gxact->inredo) &&
3517 1857 [ + + ]: 33 : !gxact->ondisk &&
1858 [ + + ]: 29 : gxact->prepare_end_lsn <= redo_horizon)
1859 : : {
1860 : : char *buf;
1861 : : int len;
1862 : :
1863 : 25 : XlogReadTwoPhaseData(gxact->prepare_start_lsn, &buf, &len);
61 michael@paquier.xyz 1864 :GNC 25 : RecreateTwoPhaseFile(gxact->fxid, buf, len);
3517 simon@2ndQuadrant.co 1865 :CBC 25 : gxact->ondisk = true;
3077 1866 : 25 : gxact->prepare_start_lsn = InvalidXLogRecPtr;
1867 : 25 : gxact->prepare_end_lsn = InvalidXLogRecPtr;
3517 1868 : 25 : pfree(buf);
1869 : 25 : serialized_xacts++;
1870 : : }
1871 : : }
1872 : 517 : LWLockRelease(TwoPhaseStateLock);
1873 : :
1874 : : /*
1875 : : * Flush unconditionally the parent directory to make any information
1876 : : * durable on disk. Two-phase files could have been removed and those
1877 : : * removals need to be made persistent as well as any files newly created
1878 : : * previously since the last checkpoint.
1879 : : */
3085 teodor@sigaev.ru 1880 : 517 : fsync_fname(TWOPHASE_DIR, true);
1881 : :
1882 : : TRACE_POSTGRESQL_TWOPHASE_CHECKPOINT_DONE();
1883 : :
3517 simon@2ndQuadrant.co 1884 [ + - + + ]: 517 : if (log_checkpoints && serialized_xacts > 0)
1885 [ + - ]: 21 : ereport(LOG,
1886 : : (errmsg_plural("%u two-phase state file was written "
1887 : : "for a long-running prepared transaction",
1888 : : "%u two-phase state files were written "
1889 : : "for long-running prepared transactions",
1890 : : serialized_xacts,
1891 : : serialized_xacts)));
1892 : : }
1893 : :
1894 : : /*
1895 : : * restoreTwoPhaseData
1896 : : *
1897 : : * Scan pg_twophase and fill TwoPhaseState depending on the on-disk data.
1898 : : * This is called once at the beginning of recovery, saving any extra
1899 : : * lookups in the future. Two-phase files that are newer than the
1900 : : * minimum XID horizon are discarded on the way.
1901 : : */
1902 : : void
3077 1903 : 887 : restoreTwoPhaseData(void)
1904 : : {
1905 : : DIR *cldir;
1906 : : struct dirent *clde;
1907 : :
3006 alvherre@alvh.no-ip. 1908 : 887 : LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
2833 tgl@sss.pgh.pa.us 1909 : 887 : cldir = AllocateDir(TWOPHASE_DIR);
3077 simon@2ndQuadrant.co 1910 [ + + ]: 2676 : while ((clde = ReadDir(cldir, TWOPHASE_DIR)) != NULL)
1911 : : {
647 akorotkov@postgresql 1912 [ + + ]: 1789 : if (strlen(clde->d_name) == 16 &&
1913 [ + - ]: 15 : strspn(clde->d_name, "0123456789ABCDEF") == 16)
1914 : : {
1915 : : FullTransactionId fxid;
1916 : : char *buf;
1917 : :
1918 : 15 : fxid = FullTransactionIdFromU64(strtou64(clde->d_name, NULL, 16));
1919 : :
61 michael@paquier.xyz 1920 :GNC 15 : buf = ProcessTwoPhaseBuffer(fxid, InvalidXLogRecPtr,
1921 : : true, false, false);
3077 simon@2ndQuadrant.co 1922 [ - + ]:CBC 15 : if (buf == NULL)
3077 simon@2ndQuadrant.co 1923 :UBC 0 : continue;
1924 : :
61 michael@paquier.xyz 1925 :GNC 15 : PrepareRedoAdd(fxid, buf, InvalidXLogRecPtr,
1926 : : InvalidXLogRecPtr, InvalidRepOriginId);
1927 : : }
1928 : : }
3006 alvherre@alvh.no-ip. 1929 :CBC 887 : LWLockRelease(TwoPhaseStateLock);
3077 simon@2ndQuadrant.co 1930 : 887 : FreeDir(cldir);
1931 : 887 : }
1932 : :
1933 : : /*
1934 : : * PrescanPreparedTransactions
1935 : : *
1936 : : * Scan the shared memory entries of TwoPhaseState and determine the range
1937 : : * of valid XIDs present. This is run during database startup, after we
1938 : : * have completed reading WAL. TransamVariables->nextXid has been set to
1939 : : * one more than the highest XID for which evidence exists in WAL.
1940 : : *
1941 : : * We throw away any prepared xacts with main XID beyond nextXid --- if any
1942 : : * are present, it suggests that the DBA has done a PITR recovery to an
1943 : : * earlier point in time without cleaning out pg_twophase. We dare not
1944 : : * try to recover such prepared xacts since they likely depend on database
1945 : : * state that doesn't exist now.
1946 : : *
1947 : : * However, we will advance nextXid beyond any subxact XIDs belonging to
1948 : : * valid prepared xacts. We need to do this since subxact commit doesn't
1949 : : * write a WAL entry, and so there might be no evidence in WAL of those
1950 : : * subxact XIDs.
1951 : : *
1952 : : * On corrupted two-phase files, fail immediately. Keeping around broken
1953 : : * entries and let replay continue causes harm on the system, and a new
1954 : : * backup should be rolled in.
1955 : : *
1956 : : * Our other responsibility is to determine and return the oldest valid XID
1957 : : * among the prepared xacts (if none, return TransamVariables->nextXid).
1958 : : * This is needed to synchronize pg_subtrans startup properly.
1959 : : *
1960 : : * If xids_p and nxids_p are not NULL, pointer to a palloc'd array of all
1961 : : * top-level xids is stored in *xids_p. The number of entries in the array
1962 : : * is returned in *nxids_p.
1963 : : */
1964 : : TransactionId
5740 1965 : 886 : PrescanPreparedTransactions(TransactionId **xids_p, int *nxids_p)
1966 : : {
638 heikki.linnakangas@i 1967 : 886 : FullTransactionId nextXid = TransamVariables->nextXid;
1852 andres@anarazel.de 1968 : 886 : TransactionId origNextXid = XidFromFullTransactionId(nextXid);
7386 tgl@sss.pgh.pa.us 1969 : 886 : TransactionId result = origNextXid;
5740 simon@2ndQuadrant.co 1970 : 886 : TransactionId *xids = NULL;
1971 : 886 : int nxids = 0;
1972 : 886 : int allocsize = 0;
1973 : : int i;
1974 : :
3006 alvherre@alvh.no-ip. 1975 : 886 : LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
3077 simon@2ndQuadrant.co 1976 [ + + ]: 938 : for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
1977 : : {
1978 : : TransactionId xid;
1979 : : char *buf;
1980 : 52 : GlobalTransaction gxact = TwoPhaseState->prepXacts[i];
1981 : :
1982 [ - + ]: 52 : Assert(gxact->inredo);
1983 : :
61 michael@paquier.xyz 1984 :GNC 52 : buf = ProcessTwoPhaseBuffer(gxact->fxid,
1985 : : gxact->prepare_start_lsn,
3034 bruce@momjian.us 1986 :CBC 52 : gxact->ondisk, false, true);
1987 : :
3077 simon@2ndQuadrant.co 1988 [ - + ]: 52 : if (buf == NULL)
3077 simon@2ndQuadrant.co 1989 :UBC 0 : continue;
1990 : :
1991 : : /*
1992 : : * OK, we think this file is valid. Incorporate xid into the
1993 : : * running-minimum result.
1994 : : */
61 michael@paquier.xyz 1995 :GNC 52 : xid = XidFromFullTransactionId(gxact->fxid);
3063 simon@2ndQuadrant.co 1996 [ + + ]:CBC 52 : if (TransactionIdPrecedes(xid, result))
1997 : 44 : result = xid;
1998 : :
3077 1999 [ + + ]: 52 : if (xids_p)
2000 : : {
2001 [ + + ]: 19 : if (nxids == allocsize)
2002 : : {
2003 [ + - ]: 15 : if (nxids == 0)
2004 : : {
2005 : 15 : allocsize = 10;
2006 : 15 : xids = palloc(allocsize * sizeof(TransactionId));
2007 : : }
2008 : : else
2009 : : {
3077 simon@2ndQuadrant.co 2010 :UBC 0 : allocsize = allocsize * 2;
2011 : 0 : xids = repalloc(xids, allocsize * sizeof(TransactionId));
2012 : : }
2013 : : }
3077 simon@2ndQuadrant.co 2014 :CBC 19 : xids[nxids++] = xid;
2015 : : }
2016 : :
2017 : 52 : pfree(buf);
2018 : : }
2019 : 886 : LWLockRelease(TwoPhaseStateLock);
2020 : :
5740 2021 [ + + ]: 886 : if (xids_p)
2022 : : {
2023 : 54 : *xids_p = xids;
2024 : 54 : *nxids_p = nxids;
2025 : : }
2026 : :
7386 tgl@sss.pgh.pa.us 2027 : 886 : return result;
2028 : : }
2029 : :
2030 : : /*
2031 : : * StandbyRecoverPreparedTransactions
2032 : : *
2033 : : * Scan the shared memory entries of TwoPhaseState and setup all the required
2034 : : * information to allow standby queries to treat prepared transactions as still
2035 : : * active.
2036 : : *
2037 : : * This is never called at the end of recovery - we use
2038 : : * RecoverPreparedTransactions() at that point.
2039 : : *
2040 : : * This updates pg_subtrans, so that any subtransactions will be correctly
2041 : : * seen as in-progress in snapshots taken during recovery.
2042 : : */
2043 : : void
3054 simon@2ndQuadrant.co 2044 : 54 : StandbyRecoverPreparedTransactions(void)
2045 : : {
2046 : : int i;
2047 : :
3006 alvherre@alvh.no-ip. 2048 : 54 : LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
3077 simon@2ndQuadrant.co 2049 [ + + ]: 73 : for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
2050 : : {
2051 : : char *buf;
2052 : 19 : GlobalTransaction gxact = TwoPhaseState->prepXacts[i];
2053 : :
2054 [ - + ]: 19 : Assert(gxact->inredo);
2055 : :
61 michael@paquier.xyz 2056 :GNC 19 : buf = ProcessTwoPhaseBuffer(gxact->fxid,
2057 : : gxact->prepare_start_lsn,
436 heikki.linnakangas@i 2058 :CBC 19 : gxact->ondisk, true, false);
3077 simon@2ndQuadrant.co 2059 [ + - ]: 19 : if (buf != NULL)
3285 2060 : 19 : pfree(buf);
2061 : : }
3077 2062 : 54 : LWLockRelease(TwoPhaseStateLock);
5625 heikki.linnakangas@i 2063 : 54 : }
2064 : :
2065 : : /*
2066 : : * RecoverPreparedTransactions
2067 : : *
2068 : : * Scan the shared memory entries of TwoPhaseState and reload the state for
2069 : : * each prepared transaction (reacquire locks, etc).
2070 : : *
2071 : : * This is run at the end of recovery, but before we allow backends to write
2072 : : * WAL.
2073 : : *
2074 : : * At the end of recovery the way we take snapshots will change. We now need
2075 : : * to mark all running transactions with their full SubTransSetParent() info
2076 : : * to allow normal snapshots to work correctly if snapshots overflow.
2077 : : * We do this here because by definition prepared transactions are the only
2078 : : * type of write transaction still running, so this is necessary and
2079 : : * complete.
2080 : : */
2081 : : void
7386 tgl@sss.pgh.pa.us 2082 : 832 : RecoverPreparedTransactions(void)
2083 : : {
2084 : : int i;
2085 : :
3006 alvherre@alvh.no-ip. 2086 : 832 : LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
3077 simon@2ndQuadrant.co 2087 [ + + ]: 865 : for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
2088 : : {
2089 : : char *buf;
2090 : 33 : GlobalTransaction gxact = TwoPhaseState->prepXacts[i];
61 michael@paquier.xyz 2091 :GNC 33 : FullTransactionId fxid = gxact->fxid;
2092 : : char *bufptr;
2093 : : TwoPhaseFileHeader *hdr;
2094 : : TransactionId *subxids;
2095 : : const char *gid;
2096 : :
2097 : : /*
2098 : : * Reconstruct subtrans state for the transaction --- needed because
2099 : : * pg_subtrans is not preserved over a restart. Note that we are
2100 : : * linking all the subtransactions directly to the top-level XID;
2101 : : * there may originally have been a more complex hierarchy, but
2102 : : * there's no need to restore that exactly. It's possible that
2103 : : * SubTransSetParent has been set before, if the prepared transaction
2104 : : * generated xid assignment records.
2105 : : */
2106 : 33 : buf = ProcessTwoPhaseBuffer(gxact->fxid,
2107 : : gxact->prepare_start_lsn,
3034 bruce@momjian.us 2108 :CBC 33 : gxact->ondisk, true, false);
3077 simon@2ndQuadrant.co 2109 [ - + ]: 33 : if (buf == NULL)
3077 simon@2ndQuadrant.co 2110 :UBC 0 : continue;
2111 : :
3077 simon@2ndQuadrant.co 2112 [ + - ]:CBC 33 : ereport(LOG,
2113 : : (errmsg("recovering prepared transaction %u of epoch %u from shared memory",
2114 : : XidFromFullTransactionId(gxact->fxid),
2115 : : EpochFromFullTransactionId(gxact->fxid))));
2116 : :
2117 : 33 : hdr = (TwoPhaseFileHeader *) buf;
61 michael@paquier.xyz 2118 [ - + ]:GNC 33 : Assert(TransactionIdEquals(hdr->xid,
2119 : : XidFromFullTransactionId(gxact->fxid)));
3077 simon@2ndQuadrant.co 2120 :CBC 33 : bufptr = buf + MAXALIGN(sizeof(TwoPhaseFileHeader));
2121 : 33 : gid = (const char *) bufptr;
2122 : 33 : bufptr += MAXALIGN(hdr->gidlen);
2123 : 33 : subxids = (TransactionId *) bufptr;
2124 : 33 : bufptr += MAXALIGN(hdr->nsubxacts * sizeof(TransactionId));
1158 rhaas@postgresql.org 2125 : 33 : bufptr += MAXALIGN(hdr->ncommitrels * sizeof(RelFileLocator));
2126 : 33 : bufptr += MAXALIGN(hdr->nabortrels * sizeof(RelFileLocator));
1249 andres@anarazel.de 2127 : 33 : bufptr += MAXALIGN(hdr->ncommitstats * sizeof(xl_xact_stats_item));
2128 : 33 : bufptr += MAXALIGN(hdr->nabortstats * sizeof(xl_xact_stats_item));
3077 simon@2ndQuadrant.co 2129 : 33 : bufptr += MAXALIGN(hdr->ninvalmsgs * sizeof(SharedInvalidationMessage));
2130 : :
2131 : : /*
2132 : : * Recreate its GXACT and dummy PGPROC. But, check whether it was
2133 : : * added in redo and already has a shmem entry for it.
2134 : : */
61 michael@paquier.xyz 2135 :GNC 33 : MarkAsPreparingGuts(gxact, gxact->fxid, gid,
2136 : : hdr->prepared_at,
2137 : : hdr->owner, hdr->database);
2138 : :
2139 : : /* recovered, so reset the flag for entries generated by redo */
3077 simon@2ndQuadrant.co 2140 :CBC 33 : gxact->inredo = false;
2141 : :
2142 : 33 : GXactLoadSubxactData(gxact, hdr->nsubxacts, subxids);
3006 alvherre@alvh.no-ip. 2143 : 33 : MarkAsPrepared(gxact, true);
2144 : :
2145 : 33 : LWLockRelease(TwoPhaseStateLock);
2146 : :
2147 : : /*
2148 : : * Recover other state (notably locks) using resource managers.
2149 : : */
61 michael@paquier.xyz 2150 :GNC 33 : ProcessRecords(bufptr, fxid, twophase_recover_callbacks);
2151 : :
2152 : : /*
2153 : : * Release locks held by the standby process after we process each
2154 : : * prepared transaction. As a result, we don't need too many
2155 : : * additional locks at any one time.
2156 : : */
3077 simon@2ndQuadrant.co 2157 [ + + ]:CBC 33 : if (InHotStandby)
61 michael@paquier.xyz 2158 :GNC 7 : StandbyReleaseLockTree(hdr->xid, hdr->nsubxacts, subxids);
2159 : :
2160 : : /*
2161 : : * We're done with recovering this transaction. Clear MyLockedGxact,
2162 : : * like we do in PrepareTransaction() during normal operation.
2163 : : */
3077 simon@2ndQuadrant.co 2164 :CBC 33 : PostPrepare_Twophase();
2165 : :
2166 : 33 : pfree(buf);
2167 : :
3006 alvherre@alvh.no-ip. 2168 : 33 : LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
2169 : : }
2170 : :
2171 : 832 : LWLockRelease(TwoPhaseStateLock);
3077 simon@2ndQuadrant.co 2172 : 832 : }
2173 : :
2174 : : /*
2175 : : * ProcessTwoPhaseBuffer
2176 : : *
2177 : : * Given a FullTransactionId, read it either from disk or read it directly
2178 : : * via shmem xlog record pointer using the provided "prepare_start_lsn".
2179 : : *
2180 : : * If setParent is true, set up subtransaction parent linkages.
2181 : : *
2182 : : * If setNextXid is true, set TransamVariables->nextXid to the newest
2183 : : * value scanned.
2184 : : */
2185 : : static char *
61 michael@paquier.xyz 2186 :GNC 119 : ProcessTwoPhaseBuffer(FullTransactionId fxid,
2187 : : XLogRecPtr prepare_start_lsn,
2188 : : bool fromdisk,
2189 : : bool setParent, bool setNextXid)
2190 : : {
638 heikki.linnakangas@i 2191 :CBC 119 : FullTransactionId nextXid = TransamVariables->nextXid;
2192 : : TransactionId *subxids;
2193 : : char *buf;
2194 : : TwoPhaseFileHeader *hdr;
2195 : : int i;
2196 : :
3006 alvherre@alvh.no-ip. 2197 [ - + ]: 119 : Assert(LWLockHeldByMeInMode(TwoPhaseStateLock, LW_EXCLUSIVE));
2198 : :
3077 simon@2ndQuadrant.co 2199 [ + + ]: 119 : if (!fromdisk)
2200 [ - + ]: 72 : Assert(prepare_start_lsn != InvalidXLogRecPtr);
2201 : :
2202 : : /* Already processed? */
61 michael@paquier.xyz 2203 [ + - - + ]:GNC 238 : if (TransactionIdDidCommit(XidFromFullTransactionId(fxid)) ||
2204 : 119 : TransactionIdDidAbort(XidFromFullTransactionId(fxid)))
2205 : : {
3077 simon@2ndQuadrant.co 2206 [ # # ]:UBC 0 : if (fromdisk)
2207 : : {
2208 [ # # ]: 0 : ereport(WARNING,
2209 : : (errmsg("removing stale two-phase state file for transaction %u of epoch %u",
2210 : : XidFromFullTransactionId(fxid),
2211 : : EpochFromFullTransactionId(fxid))));
61 michael@paquier.xyz 2212 :UNC 0 : RemoveTwoPhaseFile(fxid, true);
2213 : : }
2214 : : else
2215 : : {
250 michael@paquier.xyz 2216 [ # # ]:UBC 0 : ereport(WARNING,
2217 : : (errmsg("removing stale two-phase state from memory for transaction %u of epoch %u",
2218 : : XidFromFullTransactionId(fxid),
2219 : : EpochFromFullTransactionId(fxid))));
61 michael@paquier.xyz 2220 :UNC 0 : PrepareRedoRemoveFull(fxid, true);
2221 : : }
250 michael@paquier.xyz 2222 :UBC 0 : return NULL;
2223 : : }
2224 : :
2225 : : /* Reject XID if too new */
61 michael@paquier.xyz 2226 [ - + ]:GNC 119 : if (FullTransactionIdFollowsOrEquals(fxid, nextXid))
2227 : : {
3077 simon@2ndQuadrant.co 2228 [ # # ]:UBC 0 : if (fromdisk)
2229 : : {
2230 [ # # ]: 0 : ereport(WARNING,
2231 : : (errmsg("removing future two-phase state file for transaction %u of epoch %u",
2232 : : XidFromFullTransactionId(fxid),
2233 : : EpochFromFullTransactionId(fxid))));
61 michael@paquier.xyz 2234 :UNC 0 : RemoveTwoPhaseFile(fxid, true);
2235 : : }
2236 : : else
2237 : : {
3077 simon@2ndQuadrant.co 2238 [ # # ]:UBC 0 : ereport(WARNING,
2239 : : (errmsg("removing future two-phase state from memory for transaction %u of epoch %u",
2240 : : XidFromFullTransactionId(fxid),
2241 : : EpochFromFullTransactionId(fxid))));
61 michael@paquier.xyz 2242 :UNC 0 : PrepareRedoRemoveFull(fxid, true);
2243 : : }
3077 simon@2ndQuadrant.co 2244 :UBC 0 : return NULL;
2245 : : }
2246 : :
3077 simon@2ndQuadrant.co 2247 [ + + ]:CBC 119 : if (fromdisk)
2248 : : {
2249 : : /* Read and validate file */
61 michael@paquier.xyz 2250 :GNC 47 : buf = ReadTwoPhaseFile(fxid, false);
2251 : : }
2252 : : else
2253 : : {
2254 : : /* Read xlog data */
3077 simon@2ndQuadrant.co 2255 :CBC 72 : XlogReadTwoPhaseData(prepare_start_lsn, &buf, NULL);
2256 : : }
2257 : :
2258 : : /* Deconstruct header */
2259 : 119 : hdr = (TwoPhaseFileHeader *) buf;
61 michael@paquier.xyz 2260 [ - + ]:GNC 119 : if (!TransactionIdEquals(hdr->xid, XidFromFullTransactionId(fxid)))
2261 : : {
3077 simon@2ndQuadrant.co 2262 [ # # ]:UBC 0 : if (fromdisk)
2556 michael@paquier.xyz 2263 [ # # ]: 0 : ereport(ERROR,
2264 : : (errcode(ERRCODE_DATA_CORRUPTED),
2265 : : errmsg("corrupted two-phase state file for transaction %u of epoch %u",
2266 : : XidFromFullTransactionId(fxid),
2267 : : EpochFromFullTransactionId(fxid))));
2268 : : else
2269 [ # # ]: 0 : ereport(ERROR,
2270 : : (errcode(ERRCODE_DATA_CORRUPTED),
2271 : : errmsg("corrupted two-phase state in memory for transaction %u of epoch %u",
2272 : : XidFromFullTransactionId(fxid),
2273 : : EpochFromFullTransactionId(fxid))));
2274 : : }
2275 : :
2276 : : /*
2277 : : * Examine subtransaction XIDs ... they should all follow main XID, and
2278 : : * they may force us to advance nextXid.
2279 : : */
3077 simon@2ndQuadrant.co 2280 :CBC 119 : subxids = (TransactionId *) (buf +
2281 : 119 : MAXALIGN(sizeof(TwoPhaseFileHeader)) +
2282 : 119 : MAXALIGN(hdr->gidlen));
2283 [ + + ]: 1901 : for (i = 0; i < hdr->nsubxacts; i++)
2284 : : {
2285 : 1782 : TransactionId subxid = subxids[i];
2286 : :
61 michael@paquier.xyz 2287 [ - + ]:GNC 1782 : Assert(TransactionIdFollows(subxid, XidFromFullTransactionId(fxid)));
2288 : :
2289 : : /* update nextXid if needed */
2354 tmunro@postgresql.or 2290 [ + + ]:CBC 1782 : if (setNextXid)
2291 : 821 : AdvanceNextFullTransactionIdPastXid(subxid);
2292 : :
3077 simon@2ndQuadrant.co 2293 [ + + ]: 1782 : if (setParent)
61 michael@paquier.xyz 2294 :GNC 821 : SubTransSetParent(subxid, XidFromFullTransactionId(fxid));
2295 : : }
2296 : :
3077 simon@2ndQuadrant.co 2297 :CBC 119 : return buf;
2298 : : }
2299 : :
2300 : :
2301 : : /*
2302 : : * RecordTransactionCommitPrepared
2303 : : *
2304 : : * This is basically the same as RecordTransactionCommit (q.v. if you change
2305 : : * this function): in particular, we must set DELAY_CHKPT_IN_COMMIT to avoid a
2306 : : * race condition.
2307 : : *
2308 : : * We know the transaction made at least one XLOG entry (its PREPARE),
2309 : : * so it is never possible to optimize out the commit record.
2310 : : */
2311 : : static void
7386 tgl@sss.pgh.pa.us 2312 : 254 : RecordTransactionCommitPrepared(TransactionId xid,
2313 : : int nchildren,
2314 : : TransactionId *children,
2315 : : int nrels,
2316 : : RelFileLocator *rels,
2317 : : int nstats,
2318 : : xl_xact_stats_item *stats,
2319 : : int ninvalmsgs,
2320 : : SharedInvalidationMessage *invalmsgs,
2321 : : bool initfileinval,
2322 : : const char *gid)
2323 : : {
2324 : : XLogRecPtr recptr;
2325 : : TimestampTz committs;
2326 : : bool replorigin;
2327 : :
2328 : : /*
2329 : : * Are we using the replication origins feature? Or, in other words, are
2330 : : * we replaying remote actions?
2331 : : */
3630 alvherre@alvh.no-ip. 2332 [ + + ]: 275 : replorigin = (replorigin_session_origin != InvalidRepOriginId &&
2333 [ + - ]: 21 : replorigin_session_origin != DoNotReplicateId);
2334 : :
7386 tgl@sss.pgh.pa.us 2335 : 254 : START_CRIT_SECTION();
2336 : :
2337 : : /* See notes in RecordTransactionCommit */
45 akapila@postgresql.o 2338 [ - + ]:GNC 254 : Assert((MyProc->delayChkptFlags & DELAY_CHKPT_IN_COMMIT) == 0);
2339 : 254 : MyProc->delayChkptFlags |= DELAY_CHKPT_IN_COMMIT;
2340 : :
2341 : : /*
2342 : : * Ensures the DELAY_CHKPT_IN_COMMIT flag write is globally visible before
2343 : : * commit time is written.
2344 : : */
2345 : 254 : pg_write_barrier();
2346 : :
2347 : : /*
2348 : : * Note it is important to set committs value after marking ourselves as
2349 : : * in the commit critical section (DELAY_CHKPT_IN_COMMIT). This is because
2350 : : * we want to ensure all transactions that have acquired commit timestamp
2351 : : * are finished before we allow the logical replication client to advance
2352 : : * its xid which is used to hold back dead rows for conflict detection.
2353 : : * See comments atop worker.c.
2354 : : */
2355 : 254 : committs = GetCurrentTimestamp();
2356 : :
2357 : : /*
2358 : : * Emit the XLOG commit record. Note that we mark 2PC commits as
2359 : : * potentially having AccessExclusiveLocks since we don't know whether or
2360 : : * not they do.
2361 : : */
3630 alvherre@alvh.no-ip. 2362 :CBC 254 : recptr = XactLogCommitRecord(committs,
2363 : : nchildren, children, nrels, rels,
2364 : : nstats, stats,
2365 : : ninvalmsgs, invalmsgs,
2366 : : initfileinval,
2999 tgl@sss.pgh.pa.us 2367 : 254 : MyXactFlags | XACT_FLAGS_ACQUIREDACCESSEXCLUSIVELOCK,
2368 : : xid, gid);
2369 : :
2370 : :
3630 alvherre@alvh.no-ip. 2371 [ + + ]: 254 : if (replorigin)
2372 : : /* Move LSNs forward for this replication origin */
2373 : 21 : replorigin_session_advance(replorigin_session_origin_lsn,
2374 : : XactLastRecEnd);
2375 : :
2376 : : /*
2377 : : * Record commit timestamp. The value comes from plain commit timestamp
2378 : : * if replorigin is not enabled, or replorigin already set a value for us
2379 : : * in replorigin_session_origin_timestamp otherwise.
2380 : : *
2381 : : * We don't need to WAL-log anything here, as the commit record written
2382 : : * above already contains the data.
2383 : : */
2384 [ + + - + ]: 254 : if (!replorigin || replorigin_session_origin_timestamp == 0)
2385 : 233 : replorigin_session_origin_timestamp = committs;
2386 : :
2387 : 254 : TransactionTreeSetCommitTsData(xid, nchildren, children,
2388 : : replorigin_session_origin_timestamp,
2389 : : replorigin_session_origin);
2390 : :
2391 : : /*
2392 : : * We don't currently try to sleep before flush here ... nor is there any
2393 : : * support for async commit of a prepared xact (the very idea is probably
2394 : : * a contradiction)
2395 : : */
2396 : :
2397 : : /* Flush XLOG to disk */
7386 tgl@sss.pgh.pa.us 2398 : 254 : XLogFlush(recptr);
2399 : :
2400 : : /* Mark the transaction committed in pg_xact */
6165 alvherre@alvh.no-ip. 2401 : 254 : TransactionIdCommitTree(xid, nchildren, children);
2402 : :
2403 : : /* Checkpoint can proceed now */
45 akapila@postgresql.o 2404 :GNC 254 : MyProc->delayChkptFlags &= ~DELAY_CHKPT_IN_COMMIT;
2405 : :
7386 tgl@sss.pgh.pa.us 2406 [ - + ]:CBC 254 : END_CRIT_SECTION();
2407 : :
2408 : : /*
2409 : : * Wait for synchronous replication, if required.
2410 : : *
2411 : : * Note that at this stage we have marked clog, but still show as running
2412 : : * in the procarray and continue to hold locks.
2413 : : */
3448 rhaas@postgresql.org 2414 : 254 : SyncRepWaitForLSN(recptr, true);
7386 tgl@sss.pgh.pa.us 2415 : 254 : }
2416 : :
2417 : : /*
2418 : : * RecordTransactionAbortPrepared
2419 : : *
2420 : : * This is basically the same as RecordTransactionAbort.
2421 : : *
2422 : : * We know the transaction made at least one XLOG entry (its PREPARE),
2423 : : * so it is never possible to optimize out the abort record.
2424 : : */
2425 : : static void
2426 : 38 : RecordTransactionAbortPrepared(TransactionId xid,
2427 : : int nchildren,
2428 : : TransactionId *children,
2429 : : int nrels,
2430 : : RelFileLocator *rels,
2431 : : int nstats,
2432 : : xl_xact_stats_item *stats,
2433 : : const char *gid)
2434 : : {
2435 : : XLogRecPtr recptr;
2436 : : bool replorigin;
2437 : :
2438 : : /*
2439 : : * Are we using the replication origins feature? Or, in other words, are
2440 : : * we replaying remote actions?
2441 : : */
1643 akapila@postgresql.o 2442 [ + + ]: 44 : replorigin = (replorigin_session_origin != InvalidRepOriginId &&
2443 [ + - ]: 6 : replorigin_session_origin != DoNotReplicateId);
2444 : :
2445 : : /*
2446 : : * Catch the scenario where we aborted partway through
2447 : : * RecordTransactionCommitPrepared ...
2448 : : */
7386 tgl@sss.pgh.pa.us 2449 [ - + ]: 38 : if (TransactionIdDidCommit(xid))
7386 tgl@sss.pgh.pa.us 2450 [ # # ]:UBC 0 : elog(PANIC, "cannot abort transaction %u, it was already committed",
2451 : : xid);
2452 : :
7386 tgl@sss.pgh.pa.us 2453 :CBC 38 : START_CRIT_SECTION();
2454 : :
2455 : : /*
2456 : : * Emit the XLOG commit record. Note that we mark 2PC aborts as
2457 : : * potentially having AccessExclusiveLocks since we don't know whether or
2458 : : * not they do.
2459 : : */
3828 andres@anarazel.de 2460 : 38 : recptr = XactLogAbortRecord(GetCurrentTimestamp(),
2461 : : nchildren, children,
2462 : : nrels, rels,
2463 : : nstats, stats,
2999 tgl@sss.pgh.pa.us 2464 : 38 : MyXactFlags | XACT_FLAGS_ACQUIREDACCESSEXCLUSIVELOCK,
2465 : : xid, gid);
2466 : :
1643 akapila@postgresql.o 2467 [ + + ]: 38 : if (replorigin)
2468 : : /* Move LSNs forward for this replication origin */
2469 : 6 : replorigin_session_advance(replorigin_session_origin_lsn,
2470 : : XactLastRecEnd);
2471 : :
2472 : : /* Always flush, since we're about to remove the 2PC state file */
7386 tgl@sss.pgh.pa.us 2473 : 38 : XLogFlush(recptr);
2474 : :
2475 : : /*
2476 : : * Mark the transaction aborted in clog. This is not absolutely necessary
2477 : : * but we may as well do it while we are here.
2478 : : */
6165 alvherre@alvh.no-ip. 2479 : 38 : TransactionIdAbortTree(xid, nchildren, children);
2480 : :
7386 tgl@sss.pgh.pa.us 2481 [ - + ]: 38 : END_CRIT_SECTION();
2482 : :
2483 : : /*
2484 : : * Wait for synchronous replication, if required.
2485 : : *
2486 : : * Note that at this stage we have marked clog, but still show as running
2487 : : * in the procarray and continue to hold locks.
2488 : : */
3448 rhaas@postgresql.org 2489 : 38 : SyncRepWaitForLSN(recptr, false);
7386 tgl@sss.pgh.pa.us 2490 : 38 : }
2491 : :
2492 : : /*
2493 : : * PrepareRedoAdd
2494 : : *
2495 : : * Store pointers to the start/end of the WAL record along with the xid in
2496 : : * a gxact entry in shared memory TwoPhaseState structure. If caller
2497 : : * specifies InvalidXLogRecPtr as WAL location to fetch the two-phase
2498 : : * data, the entry is marked as located on disk.
2499 : : */
2500 : : void
61 michael@paquier.xyz 2501 :GNC 91 : PrepareRedoAdd(FullTransactionId fxid, char *buf,
2502 : : XLogRecPtr start_lsn, XLogRecPtr end_lsn,
2503 : : RepOriginId origin_id)
2504 : : {
3077 simon@2ndQuadrant.co 2505 :CBC 91 : TwoPhaseFileHeader *hdr = (TwoPhaseFileHeader *) buf;
2506 : : char *bufptr;
2507 : : const char *gid;
2508 : : GlobalTransaction gxact;
2509 : :
3006 alvherre@alvh.no-ip. 2510 [ - + ]: 91 : Assert(LWLockHeldByMeInMode(TwoPhaseStateLock, LW_EXCLUSIVE));
3077 simon@2ndQuadrant.co 2511 [ - + ]: 91 : Assert(RecoveryInProgress());
2512 : :
61 michael@paquier.xyz 2513 [ + + ]:GNC 91 : if (!FullTransactionIdIsValid(fxid))
2514 : : {
2515 [ - + ]: 76 : Assert(InRecovery);
2516 : 76 : fxid = FullTransactionIdFromAllowableAt(TransamVariables->nextXid,
2517 : : hdr->xid);
2518 : : }
2519 : :
3077 simon@2ndQuadrant.co 2520 :CBC 91 : bufptr = buf + MAXALIGN(sizeof(TwoPhaseFileHeader));
2521 : 91 : gid = (const char *) bufptr;
2522 : :
2523 : : /*
2524 : : * Reserve the GID for the given transaction in the redo code path.
2525 : : *
2526 : : * This creates a gxact struct and puts it into the active array.
2527 : : *
2528 : : * In redo, this struct is mainly used to track PREPARE/COMMIT entries in
2529 : : * shared memory. Hence, we only fill up the bare minimum contents here.
2530 : : * The gxact also gets marked with gxact->inredo set to true to indicate
2531 : : * that it got added in the redo phase
2532 : : */
2533 : :
2534 : : /*
2535 : : * In the event of a crash while a checkpoint was running, it may be
2536 : : * possible that some two-phase data found its way to disk while its
2537 : : * corresponding record needs to be replayed in the follow-up recovery. As
2538 : : * the 2PC data was on disk, it has already been restored at the beginning
2539 : : * of recovery with restoreTwoPhaseData(), so skip this record to avoid
2540 : : * duplicates in TwoPhaseState. If a consistent state has been reached,
2541 : : * the record is added to TwoPhaseState and it should have no
2542 : : * corresponding file in pg_twophase.
2543 : : */
781 michael@paquier.xyz 2544 [ + + ]: 91 : if (!XLogRecPtrIsInvalid(start_lsn))
2545 : : {
2546 : : char path[MAXPGPATH];
2547 : :
61 michael@paquier.xyz 2548 [ - + ]:GNC 76 : Assert(InRecovery);
2549 : 76 : TwoPhaseFilePath(path, fxid);
2550 : :
781 michael@paquier.xyz 2551 [ - + ]:CBC 76 : if (access(path, F_OK) == 0)
2552 : : {
781 michael@paquier.xyz 2553 [ # # # # ]:UBC 0 : ereport(reachedConsistency ? ERROR : WARNING,
2554 : : (errmsg("could not recover two-phase state file for transaction %u",
2555 : : hdr->xid),
2556 : : errdetail("Two-phase state file has been found in WAL record %X/%08X, but this transaction has already been restored from disk.",
2557 : : LSN_FORMAT_ARGS(start_lsn))));
2558 : 0 : return;
2559 : : }
2560 : :
781 michael@paquier.xyz 2561 [ - + ]:CBC 76 : if (errno != ENOENT)
781 michael@paquier.xyz 2562 [ # # ]:UBC 0 : ereport(ERROR,
2563 : : (errcode_for_file_access(),
2564 : : errmsg("could not access file \"%s\": %m", path)));
2565 : : }
2566 : :
2567 : : /* Get a free gxact from the freelist */
3077 simon@2ndQuadrant.co 2568 [ - + ]:CBC 91 : if (TwoPhaseState->freeGXacts == NULL)
3077 simon@2ndQuadrant.co 2569 [ # # ]:UBC 0 : ereport(ERROR,
2570 : : (errcode(ERRCODE_OUT_OF_MEMORY),
2571 : : errmsg("maximum number of prepared transactions reached"),
2572 : : errhint("Increase \"max_prepared_transactions\" (currently %d).",
2573 : : max_prepared_xacts)));
3077 simon@2ndQuadrant.co 2574 :CBC 91 : gxact = TwoPhaseState->freeGXacts;
2575 : 91 : TwoPhaseState->freeGXacts = gxact->next;
2576 : :
2577 : 91 : gxact->prepared_at = hdr->prepared_at;
2578 : 91 : gxact->prepare_start_lsn = start_lsn;
2579 : 91 : gxact->prepare_end_lsn = end_lsn;
61 michael@paquier.xyz 2580 :GNC 91 : gxact->fxid = fxid;
3077 simon@2ndQuadrant.co 2581 :CBC 91 : gxact->owner = hdr->owner;
552 heikki.linnakangas@i 2582 : 91 : gxact->locking_backend = INVALID_PROC_NUMBER;
3077 simon@2ndQuadrant.co 2583 : 91 : gxact->valid = false;
2584 : 91 : gxact->ondisk = XLogRecPtrIsInvalid(start_lsn);
3034 bruce@momjian.us 2585 : 91 : gxact->inredo = true; /* yes, added in redo */
3077 simon@2ndQuadrant.co 2586 : 91 : strcpy(gxact->gid, gid);
2587 : :
2588 : : /* And insert it into the active array */
2589 [ - + ]: 91 : Assert(TwoPhaseState->numPrepXacts < max_prepared_xacts);
2590 : 91 : TwoPhaseState->prepXacts[TwoPhaseState->numPrepXacts++] = gxact;
2591 : :
2719 2592 [ + + ]: 91 : if (origin_id != InvalidRepOriginId)
2593 : : {
2594 : : /* recover apply progress */
2595 : 13 : replorigin_advance(origin_id, hdr->origin_lsn, end_lsn,
2596 : : false /* backward */ , false /* WAL */ );
2597 : : }
2598 : :
61 michael@paquier.xyz 2599 [ - + ]:GNC 91 : elog(DEBUG2, "added 2PC data in shared memory for transaction %u of epoch %u",
2600 : : XidFromFullTransactionId(gxact->fxid),
2601 : : EpochFromFullTransactionId(gxact->fxid));
2602 : : }
2603 : :
2604 : : /*
2605 : : * PrepareRedoRemoveFull
2606 : : *
2607 : : * Remove the corresponding gxact entry from TwoPhaseState. Also remove
2608 : : * the 2PC file if a prepared transaction was saved via an earlier checkpoint.
2609 : : *
2610 : : * Caller must hold TwoPhaseStateLock in exclusive mode, because TwoPhaseState
2611 : : * is updated.
2612 : : */
2613 : : static void
2614 : 65 : PrepareRedoRemoveFull(FullTransactionId fxid, bool giveWarning)
2615 : : {
3077 simon@2ndQuadrant.co 2616 :CBC 65 : GlobalTransaction gxact = NULL;
2617 : : int i;
3063 2618 : 65 : bool found = false;
2619 : :
3006 alvherre@alvh.no-ip. 2620 [ - + ]: 65 : Assert(LWLockHeldByMeInMode(TwoPhaseStateLock, LW_EXCLUSIVE));
3077 simon@2ndQuadrant.co 2621 [ - + ]: 65 : Assert(RecoveryInProgress());
2622 : :
2623 [ + + ]: 65 : for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
2624 : : {
2625 : 56 : gxact = TwoPhaseState->prepXacts[i];
2626 : :
61 michael@paquier.xyz 2627 [ + - ]:GNC 56 : if (FullTransactionIdEquals(gxact->fxid, fxid))
2628 : : {
3077 simon@2ndQuadrant.co 2629 [ - + ]:CBC 56 : Assert(gxact->inredo);
3063 2630 : 56 : found = true;
3077 2631 : 56 : break;
2632 : : }
2633 : : }
2634 : :
2635 : : /*
2636 : : * Just leave if there is nothing, this is expected during WAL replay.
2637 : : */
3063 2638 [ + + ]: 65 : if (!found)
3077 2639 : 9 : return;
2640 : :
2641 : : /*
2642 : : * And now we can clean up any files we may have left.
2643 : : */
61 michael@paquier.xyz 2644 [ - + ]:GNC 56 : elog(DEBUG2, "removing 2PC data for transaction %u of epoch %u ",
2645 : : XidFromFullTransactionId(fxid),
2646 : : EpochFromFullTransactionId(fxid));
2647 : :
3077 simon@2ndQuadrant.co 2648 [ + + ]:CBC 56 : if (gxact->ondisk)
61 michael@paquier.xyz 2649 :GNC 4 : RemoveTwoPhaseFile(fxid, giveWarning);
2650 : :
3077 simon@2ndQuadrant.co 2651 :CBC 56 : RemoveGXact(gxact);
2652 : : }
2653 : :
2654 : : /*
2655 : : * Wrapper of PrepareRedoRemoveFull(), for TransactionIds.
2656 : : */
2657 : : void
61 michael@paquier.xyz 2658 :GNC 65 : PrepareRedoRemove(TransactionId xid, bool giveWarning)
2659 : : {
2660 : : FullTransactionId fxid =
2661 : 65 : FullTransactionIdFromAllowableAt(TransamVariables->nextXid, xid);
2662 : :
2663 : 65 : PrepareRedoRemoveFull(fxid, giveWarning);
2664 : 65 : }
2665 : :
2666 : : /*
2667 : : * LookupGXact
2668 : : * Check if the prepared transaction with the given GID, lsn and timestamp
2669 : : * exists.
2670 : : *
2671 : : * Note that we always compare with the LSN where prepare ends because that is
2672 : : * what is stored as origin_lsn in the 2PC file.
2673 : : *
2674 : : * This function is primarily used to check if the prepared transaction
2675 : : * received from the upstream (remote node) already exists. Checking only GID
2676 : : * is not sufficient because a different prepared xact with the same GID can
2677 : : * exist on the same node. So, we are ensuring to match origin_lsn and
2678 : : * origin_timestamp of prepared xact to avoid the possibility of a match of
2679 : : * prepared xact from two different nodes.
2680 : : */
2681 : : bool
1515 akapila@postgresql.o 2682 :CBC 5 : LookupGXact(const char *gid, XLogRecPtr prepare_end_lsn,
2683 : : TimestampTz origin_prepare_timestamp)
2684 : : {
2685 : : int i;
2686 : 5 : bool found = false;
2687 : :
2688 : 5 : LWLockAcquire(TwoPhaseStateLock, LW_SHARED);
2689 [ + - ]: 5 : for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
2690 : : {
2691 : 5 : GlobalTransaction gxact = TwoPhaseState->prepXacts[i];
2692 : :
2693 : : /* Ignore not-yet-valid GIDs. */
2694 [ + - + - ]: 5 : if (gxact->valid && strcmp(gxact->gid, gid) == 0)
2695 : : {
2696 : : char *buf;
2697 : : TwoPhaseFileHeader *hdr;
2698 : :
2699 : : /*
2700 : : * We are not expecting collisions of GXACTs (same gid) between
2701 : : * publisher and subscribers, so we perform all I/O while holding
2702 : : * TwoPhaseStateLock for simplicity.
2703 : : *
2704 : : * To move the I/O out of the lock, we need to ensure that no
2705 : : * other backend commits the prepared xact in the meantime. We can
2706 : : * do this optimization if we encounter many collisions in GID
2707 : : * between publisher and subscriber.
2708 : : */
2709 [ - + ]: 5 : if (gxact->ondisk)
61 michael@paquier.xyz 2710 :UNC 0 : buf = ReadTwoPhaseFile(gxact->fxid, false);
2711 : : else
2712 : : {
1515 akapila@postgresql.o 2713 [ - + ]:CBC 5 : Assert(gxact->prepare_start_lsn);
2714 : 5 : XlogReadTwoPhaseData(gxact->prepare_start_lsn, &buf, NULL);
2715 : : }
2716 : :
2717 : 5 : hdr = (TwoPhaseFileHeader *) buf;
2718 : :
2719 [ + - ]: 5 : if (hdr->origin_lsn == prepare_end_lsn &&
2720 [ + - ]: 5 : hdr->origin_timestamp == origin_prepare_timestamp)
2721 : : {
2722 : 5 : found = true;
2723 : 5 : pfree(buf);
2724 : 5 : break;
2725 : : }
2726 : :
1515 akapila@postgresql.o 2727 :UBC 0 : pfree(buf);
2728 : : }
2729 : : }
1515 akapila@postgresql.o 2730 :CBC 5 : LWLockRelease(TwoPhaseStateLock);
2731 : 5 : return found;
2732 : : }
2733 : :
2734 : : /*
2735 : : * TwoPhaseTransactionGid
2736 : : * Form the prepared transaction GID for two_phase transactions.
2737 : : *
2738 : : * Return the GID in the supplied buffer.
2739 : : */
2740 : : void
409 2741 : 48 : TwoPhaseTransactionGid(Oid subid, TransactionId xid, char *gid_res, int szgid)
2742 : : {
2743 [ - + ]: 48 : Assert(OidIsValid(subid));
2744 : :
2745 [ - + ]: 48 : if (!TransactionIdIsValid(xid))
409 akapila@postgresql.o 2746 [ # # ]:UBC 0 : ereport(ERROR,
2747 : : (errcode(ERRCODE_PROTOCOL_VIOLATION),
2748 : : errmsg_internal("invalid two-phase transaction ID")));
2749 : :
409 akapila@postgresql.o 2750 :CBC 48 : snprintf(gid_res, szgid, "pg_gid_%u_%u", subid, xid);
2751 : 48 : }
2752 : :
2753 : : /*
2754 : : * IsTwoPhaseTransactionGidForSubid
2755 : : * Check whether the given GID (as formed by TwoPhaseTransactionGid) is
2756 : : * for the specified 'subid'.
2757 : : */
2758 : : static bool
409 akapila@postgresql.o 2759 :UBC 0 : IsTwoPhaseTransactionGidForSubid(Oid subid, char *gid)
2760 : : {
2761 : : int ret;
2762 : : Oid subid_from_gid;
2763 : : TransactionId xid_from_gid;
2764 : : char gid_tmp[GIDSIZE];
2765 : :
2766 : : /* Extract the subid and xid from the given GID */
2767 : 0 : ret = sscanf(gid, "pg_gid_%u_%u", &subid_from_gid, &xid_from_gid);
2768 : :
2769 : : /*
2770 : : * Check that the given GID has expected format, and at least the subid
2771 : : * matches.
2772 : : */
2773 [ # # # # ]: 0 : if (ret != 2 || subid != subid_from_gid)
2774 : 0 : return false;
2775 : :
2776 : : /*
2777 : : * Reconstruct a temporary GID based on the subid and xid extracted from
2778 : : * the given GID and check whether the temporary GID and the given GID
2779 : : * match.
2780 : : */
2781 : 0 : TwoPhaseTransactionGid(subid, xid_from_gid, gid_tmp, sizeof(gid_tmp));
2782 : :
2783 : 0 : return strcmp(gid, gid_tmp) == 0;
2784 : : }
2785 : :
2786 : : /*
2787 : : * LookupGXactBySubid
2788 : : * Check if the prepared transaction done by apply worker exists.
2789 : : */
2790 : : bool
409 akapila@postgresql.o 2791 :CBC 1 : LookupGXactBySubid(Oid subid)
2792 : : {
2793 : 1 : bool found = false;
2794 : :
2795 : 1 : LWLockAcquire(TwoPhaseStateLock, LW_SHARED);
2796 [ - + ]: 1 : for (int i = 0; i < TwoPhaseState->numPrepXacts; i++)
2797 : : {
409 akapila@postgresql.o 2798 :UBC 0 : GlobalTransaction gxact = TwoPhaseState->prepXacts[i];
2799 : :
2800 : : /* Ignore not-yet-valid GIDs. */
2801 [ # # # # ]: 0 : if (gxact->valid &&
2802 : 0 : IsTwoPhaseTransactionGidForSubid(subid, gxact->gid))
2803 : : {
2804 : 0 : found = true;
2805 : 0 : break;
2806 : : }
2807 : : }
409 akapila@postgresql.o 2808 :CBC 1 : LWLockRelease(TwoPhaseStateLock);
2809 : :
2810 : 1 : return found;
2811 : : }
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