PostgreSQL Source Code  git master
twophase.h File Reference
#include "access/xact.h"
#include "access/xlogdefs.h"
#include "datatype/timestamp.h"
#include "storage/lock.h"
Include dependency graph for twophase.h:
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Typedefs

typedef struct GlobalTransactionDataGlobalTransaction
 

Functions

Size TwoPhaseShmemSize (void)
 
void TwoPhaseShmemInit (void)
 
void AtAbort_Twophase (void)
 
void PostPrepare_Twophase (void)
 
PGPROCTwoPhaseGetDummyProc (TransactionId xid, bool lock_held)
 
BackendId TwoPhaseGetDummyBackendId (TransactionId xid, bool lock_held)
 
GlobalTransaction MarkAsPreparing (TransactionId xid, const char *gid, TimestampTz prepared_at, Oid owner, Oid databaseid)
 
void StartPrepare (GlobalTransaction gxact)
 
void EndPrepare (GlobalTransaction gxact)
 
bool StandbyTransactionIdIsPrepared (TransactionId xid)
 
TransactionId PrescanPreparedTransactions (TransactionId **xids_p, int *nxids_p)
 
void StandbyRecoverPreparedTransactions (void)
 
void RecoverPreparedTransactions (void)
 
void CheckPointTwoPhase (XLogRecPtr redo_horizon)
 
void FinishPreparedTransaction (const char *gid, bool isCommit)
 
void PrepareRedoAdd (char *buf, XLogRecPtr start_lsn, XLogRecPtr end_lsn, RepOriginId origin_id)
 
void PrepareRedoRemove (TransactionId xid, bool giveWarning)
 
void restoreTwoPhaseData (void)
 

Variables

PGDLLIMPORT int max_prepared_xacts
 

Typedef Documentation

◆ GlobalTransaction

Definition at line 26 of file twophase.h.

Function Documentation

◆ AtAbort_Twophase()

void AtAbort_Twophase ( void  )

Definition at line 317 of file twophase.c.

References InvalidBackendId, GlobalTransactionData::locking_backend, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), RemoveGXact(), and GlobalTransactionData::valid.

Referenced by AbortTransaction(), and AtProcExit_Twophase().

318 {
319  if (MyLockedGxact == NULL)
320  return;
321 
322  /*
323  * What to do with the locked global transaction entry? If we were in the
324  * process of preparing the transaction, but haven't written the WAL
325  * record and state file yet, the transaction must not be considered as
326  * prepared. Likewise, if we are in the process of finishing an
327  * already-prepared transaction, and fail after having already written the
328  * 2nd phase commit or rollback record to the WAL, the transaction should
329  * not be considered as prepared anymore. In those cases, just remove the
330  * entry from shared memory.
331  *
332  * Otherwise, the entry must be left in place so that the transaction can
333  * be finished later, so just unlock it.
334  *
335  * If we abort during prepare, after having written the WAL record, we
336  * might not have transferred all locks and other state to the prepared
337  * transaction yet. Likewise, if we abort during commit or rollback,
338  * after having written the WAL record, we might not have released all the
339  * resources held by the transaction yet. In those cases, the in-memory
340  * state can be wrong, but it's too late to back out.
341  */
342  LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
343  if (!MyLockedGxact->valid)
345  else
347  LWLockRelease(TwoPhaseStateLock);
348 
349  MyLockedGxact = NULL;
350 }
BackendId locking_backend
Definition: twophase.c:168
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1812
static void RemoveGXact(GlobalTransaction gxact)
Definition: twophase.c:631
#define InvalidBackendId
Definition: backendid.h:23
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1208
static GlobalTransaction MyLockedGxact
Definition: twophase.c:199

◆ CheckPointTwoPhase()

void CheckPointTwoPhase ( XLogRecPtr  redo_horizon)

Definition at line 1691 of file twophase.c.

References buf, ereport, errmsg_plural(), fsync_fname(), i, GlobalTransactionData::inredo, InvalidXLogRecPtr, LOG, log_checkpoints, LW_SHARED, LWLockAcquire(), LWLockRelease(), max_prepared_xacts, TwoPhaseStateData::numPrepXacts, GlobalTransactionData::ondisk, pfree(), GlobalTransactionData::prepare_end_lsn, GlobalTransactionData::prepare_start_lsn, TwoPhaseStateData::prepXacts, RecreateTwoPhaseFile(), TWOPHASE_DIR, GlobalTransactionData::valid, GlobalTransactionData::xid, and XlogReadTwoPhaseData().

Referenced by CheckPointGuts().

1692 {
1693  int i;
1694  int serialized_xacts = 0;
1695 
1696  if (max_prepared_xacts <= 0)
1697  return; /* nothing to do */
1698 
1699  TRACE_POSTGRESQL_TWOPHASE_CHECKPOINT_START();
1700 
1701  /*
1702  * We are expecting there to be zero GXACTs that need to be copied to
1703  * disk, so we perform all I/O while holding TwoPhaseStateLock for
1704  * simplicity. This prevents any new xacts from preparing while this
1705  * occurs, which shouldn't be a problem since the presence of long-lived
1706  * prepared xacts indicates the transaction manager isn't active.
1707  *
1708  * It's also possible to move I/O out of the lock, but on every error we
1709  * should check whether somebody committed our transaction in different
1710  * backend. Let's leave this optimization for future, if somebody will
1711  * spot that this place cause bottleneck.
1712  *
1713  * Note that it isn't possible for there to be a GXACT with a
1714  * prepare_end_lsn set prior to the last checkpoint yet is marked invalid,
1715  * because of the efforts with delayChkpt.
1716  */
1717  LWLockAcquire(TwoPhaseStateLock, LW_SHARED);
1718  for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
1719  {
1720  /*
1721  * Note that we are using gxact not PGPROC so this works in recovery
1722  * also
1723  */
1725 
1726  if ((gxact->valid || gxact->inredo) &&
1727  !gxact->ondisk &&
1728  gxact->prepare_end_lsn <= redo_horizon)
1729  {
1730  char *buf;
1731  int len;
1732 
1733  XlogReadTwoPhaseData(gxact->prepare_start_lsn, &buf, &len);
1734  RecreateTwoPhaseFile(gxact->xid, buf, len);
1735  gxact->ondisk = true;
1738  pfree(buf);
1739  serialized_xacts++;
1740  }
1741  }
1742  LWLockRelease(TwoPhaseStateLock);
1743 
1744  /*
1745  * Flush unconditionally the parent directory to make any information
1746  * durable on disk. Two-phase files could have been removed and those
1747  * removals need to be made persistent as well as any files newly created
1748  * previously since the last checkpoint.
1749  */
1750  fsync_fname(TWOPHASE_DIR, true);
1751 
1752  TRACE_POSTGRESQL_TWOPHASE_CHECKPOINT_DONE();
1753 
1754  if (log_checkpoints && serialized_xacts > 0)
1755  ereport(LOG,
1756  (errmsg_plural("%u two-phase state file was written "
1757  "for a long-running prepared transaction",
1758  "%u two-phase state files were written "
1759  "for long-running prepared transactions",
1760  serialized_xacts,
1761  serialized_xacts)));
1762 }
bool log_checkpoints
Definition: xlog.c:105
#define InvalidXLogRecPtr
Definition: xlogdefs.h:28
static TwoPhaseStateData * TwoPhaseState
Definition: twophase.c:191
int errmsg_plural(const char *fmt_singular, const char *fmt_plural, unsigned long n,...)
Definition: elog.c:934
void fsync_fname(const char *fname, bool isdir)
Definition: fd.c:633
#define LOG
Definition: elog.h:26
XLogRecPtr prepare_start_lsn
Definition: twophase.c:163
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1812
void pfree(void *pointer)
Definition: mcxt.c:1057
int max_prepared_xacts
Definition: twophase.c:117
static char * buf
Definition: pg_test_fsync.c:68
GlobalTransaction prepXacts[FLEXIBLE_ARRAY_MEMBER]
Definition: twophase.c:188
static void RecreateTwoPhaseFile(TransactionId xid, void *content, int len)
Definition: twophase.c:1611
#define ereport(elevel,...)
Definition: elog.h:144
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1208
#define TWOPHASE_DIR
Definition: twophase.c:114
TransactionId xid
Definition: twophase.c:165
static void XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len)
Definition: twophase.c:1321
int i
XLogRecPtr prepare_end_lsn
Definition: twophase.c:164

◆ EndPrepare()

void EndPrepare ( GlobalTransaction  gxact)

Definition at line 1054 of file twophase.c.

References Assert, StateFileChunk::data, PGPROC::delayChkpt, DoNotReplicateId, END_CRIT_SECTION, ereport, errcode(), errmsg(), ERROR, xllist::head, InvalidRepOriginId, InvalidXLogRecPtr, StateFileChunk::len, xl_xact_prepare::magic, MarkAsPrepared(), MaxAllocSize, MyProc, StateFileChunk::next, xllist::num_chunks, xl_xact_prepare::origin_lsn, xl_xact_prepare::origin_timestamp, GlobalTransactionData::prepare_end_lsn, GlobalTransactionData::prepare_start_lsn, ProcLastRecPtr, records, RegisterTwoPhaseRecord(), replorigin_session_advance(), replorigin_session_origin, replorigin_session_origin_lsn, replorigin_session_origin_timestamp, START_CRIT_SECTION, SyncRepWaitForLSN(), xllist::tail, xl_xact_prepare::total_len, xllist::total_len, TWOPHASE_MAGIC, TWOPHASE_RM_END_ID, XLOG_INCLUDE_ORIGIN, XLOG_XACT_PREPARE, XLogBeginInsert(), XLogEnsureRecordSpace(), XLogFlush(), XLogInsert(), XLogRegisterData(), and XLogSetRecordFlags().

Referenced by PrepareTransaction().

1055 {
1056  TwoPhaseFileHeader *hdr;
1057  StateFileChunk *record;
1058  bool replorigin;
1059 
1060  /* Add the end sentinel to the list of 2PC records */
1062  NULL, 0);
1063 
1064  /* Go back and fill in total_len in the file header record */
1065  hdr = (TwoPhaseFileHeader *) records.head->data;
1066  Assert(hdr->magic == TWOPHASE_MAGIC);
1067  hdr->total_len = records.total_len + sizeof(pg_crc32c);
1068 
1069  replorigin = (replorigin_session_origin != InvalidRepOriginId &&
1071 
1072  if (replorigin)
1073  {
1077  }
1078  else
1079  {
1081  hdr->origin_timestamp = 0;
1082  }
1083 
1084  /*
1085  * If the data size exceeds MaxAllocSize, we won't be able to read it in
1086  * ReadTwoPhaseFile. Check for that now, rather than fail in the case
1087  * where we write data to file and then re-read at commit time.
1088  */
1089  if (hdr->total_len > MaxAllocSize)
1090  ereport(ERROR,
1091  (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
1092  errmsg("two-phase state file maximum length exceeded")));
1093 
1094  /*
1095  * Now writing 2PC state data to WAL. We let the WAL's CRC protection
1096  * cover us, so no need to calculate a separate CRC.
1097  *
1098  * We have to set delayChkpt here, too; otherwise a checkpoint starting
1099  * immediately after the WAL record is inserted could complete without
1100  * fsync'ing our state file. (This is essentially the same kind of race
1101  * condition as the COMMIT-to-clog-write case that RecordTransactionCommit
1102  * uses delayChkpt for; see notes there.)
1103  *
1104  * We save the PREPARE record's location in the gxact for later use by
1105  * CheckPointTwoPhase.
1106  */
1108 
1110 
1111  MyProc->delayChkpt = true;
1112 
1113  XLogBeginInsert();
1114  for (record = records.head; record != NULL; record = record->next)
1115  XLogRegisterData(record->data, record->len);
1116 
1118 
1119  gxact->prepare_end_lsn = XLogInsert(RM_XACT_ID, XLOG_XACT_PREPARE);
1120 
1121  if (replorigin)
1122  {
1123  /* Move LSNs forward for this replication origin */
1125  gxact->prepare_end_lsn);
1126  }
1127 
1128  XLogFlush(gxact->prepare_end_lsn);
1129 
1130  /* If we crash now, we have prepared: WAL replay will fix things */
1131 
1132  /* Store record's start location to read that later on Commit */
1134 
1135  /*
1136  * Mark the prepared transaction as valid. As soon as xact.c marks
1137  * MyProc as not running our XID (which it will do immediately after
1138  * this function returns), others can commit/rollback the xact.
1139  *
1140  * NB: a side effect of this is to make a dummy ProcArray entry for the
1141  * prepared XID. This must happen before we clear the XID from MyProc /
1142  * ProcGlobal->xids[], else there is a window where the XID is not running
1143  * according to TransactionIdIsInProgress, and onlookers would be entitled
1144  * to assume the xact crashed. Instead we have a window where the same
1145  * XID appears twice in ProcArray, which is OK.
1146  */
1147  MarkAsPrepared(gxact, false);
1148 
1149  /*
1150  * Now we can mark ourselves as out of the commit critical section: a
1151  * checkpoint starting after this will certainly see the gxact as a
1152  * candidate for fsyncing.
1153  */
1154  MyProc->delayChkpt = false;
1155 
1156  /*
1157  * Remember that we have this GlobalTransaction entry locked for us. If
1158  * we crash after this point, it's too late to abort, but we must unlock
1159  * it so that the prepared transaction can be committed or rolled back.
1160  */
1161  MyLockedGxact = gxact;
1162 
1163  END_CRIT_SECTION();
1164 
1165  /*
1166  * Wait for synchronous replication, if required.
1167  *
1168  * Note that at this stage we have marked the prepare, but still show as
1169  * running in the procarray (twice!) and continue to hold locks.
1170  */
1171  SyncRepWaitForLSN(gxact->prepare_end_lsn, false);
1172 
1173  records.tail = records.head = NULL;
1174  records.num_chunks = 0;
1175 }
#define InvalidXLogRecPtr
Definition: xlogdefs.h:28
#define XLOG_XACT_PREPARE
Definition: xact.h:148
#define DoNotReplicateId
Definition: origin.h:34
PGPROC * MyProc
Definition: proc.c:67
StateFileChunk * tail
Definition: twophase.c:938
uint32 pg_crc32c
Definition: pg_crc32c.h:38
XLogRecPtr ProcLastRecPtr
Definition: xlog.c:360
void SyncRepWaitForLSN(XLogRecPtr lsn, bool commit)
Definition: syncrep.c:148
#define END_CRIT_SECTION()
Definition: miscadmin.h:134
#define START_CRIT_SECTION()
Definition: miscadmin.h:132
int errcode(int sqlerrcode)
Definition: elog.c:610
#define TWOPHASE_RM_END_ID
Definition: twophase_rmgr.h:24
#define XLOG_INCLUDE_ORIGIN
Definition: xlog.h:238
uint32 num_chunks
Definition: twophase.c:939
void XLogFlush(XLogRecPtr record)
Definition: xlog.c:2845
void RegisterTwoPhaseRecord(TwoPhaseRmgrId rmid, uint16 info, const void *data, uint32 len)
Definition: twophase.c:1181
XLogRecPtr prepare_start_lsn
Definition: twophase.c:163
char * data
Definition: twophase.c:930
#define ERROR
Definition: elog.h:43
bool delayChkpt
Definition: proc.h:176
XLogRecPtr replorigin_session_origin_lsn
Definition: origin.c:155
TimestampTz replorigin_session_origin_timestamp
Definition: origin.c:156
XLogRecPtr origin_lsn
Definition: xact.h:313
uint32 total_len
Definition: xact.h:302
uint32 len
Definition: twophase.c:931
void XLogSetRecordFlags(uint8 flags)
Definition: xloginsert.c:404
static struct xllist records
uint32 total_len
Definition: twophase.c:941
#define MaxAllocSize
Definition: memutils.h:40
struct StateFileChunk * next
Definition: twophase.c:932
void XLogRegisterData(char *data, int len)
Definition: xloginsert.c:330
XLogRecPtr XLogInsert(RmgrId rmid, uint8 info)
Definition: xloginsert.c:422
#define TWOPHASE_MAGIC
Definition: twophase.c:906
#define ereport(elevel,...)
Definition: elog.h:144
StateFileChunk * head
Definition: twophase.c:937
#define Assert(condition)
Definition: c.h:745
RepOriginId replorigin_session_origin
Definition: origin.c:154
TimestampTz origin_timestamp
Definition: xact.h:314
void XLogEnsureRecordSpace(int max_block_id, int ndatas)
Definition: xloginsert.c:149
void replorigin_session_advance(XLogRecPtr remote_commit, XLogRecPtr local_commit)
Definition: origin.c:1168
static void MarkAsPrepared(GlobalTransaction gxact, bool lock_held)
Definition: twophase.c:533
#define InvalidRepOriginId
Definition: origin.h:33
uint32 magic
Definition: xact.h:301
int errmsg(const char *fmt,...)
Definition: elog.c:824
static GlobalTransaction MyLockedGxact
Definition: twophase.c:199
void XLogBeginInsert(void)
Definition: xloginsert.c:123
XLogRecPtr prepare_end_lsn
Definition: twophase.c:164

◆ FinishPreparedTransaction()

void FinishPreparedTransaction ( const char *  gid,
bool  isCommit 
)

Definition at line 1397 of file twophase.c.

References PROC_HDR::allProcs, Assert, AtEOXact_PgStat(), buf, DropRelationFiles(), GetUserId(), xl_xact_prepare::gidlen, HOLD_INTERRUPTS, xl_xact_prepare::initfileinval, LockGXact(), LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MAXALIGN, xl_xact_prepare::nabortrels, xl_xact_prepare::ncommitrels, xl_xact_prepare::ninvalmsgs, xl_xact_prepare::nsubxacts, GlobalTransactionData::ondisk, pfree(), GlobalTransactionData::pgprocno, PredicateLockTwoPhaseFinish(), GlobalTransactionData::prepare_start_lsn, ProcArrayRemove(), ProcessRecords(), ProcGlobal, ReadTwoPhaseFile(), RecordTransactionAbortPrepared(), RecordTransactionCommitPrepared(), RelationCacheInitFilePostInvalidate(), RelationCacheInitFilePreInvalidate(), RemoveGXact(), RemoveTwoPhaseFile(), RESUME_INTERRUPTS, SendSharedInvalidMessages(), TransactionIdEquals, TransactionIdLatest(), twophase_postabort_callbacks, twophase_postcommit_callbacks, GlobalTransactionData::valid, GlobalTransactionData::xid, xl_xact_prepare::xid, and XlogReadTwoPhaseData().

Referenced by standard_ProcessUtility().

1398 {
1399  GlobalTransaction gxact;
1400  PGPROC *proc;
1401  TransactionId xid;
1402  char *buf;
1403  char *bufptr;
1404  TwoPhaseFileHeader *hdr;
1405  TransactionId latestXid;
1406  TransactionId *children;
1407  RelFileNode *commitrels;
1408  RelFileNode *abortrels;
1409  RelFileNode *delrels;
1410  int ndelrels;
1411  SharedInvalidationMessage *invalmsgs;
1412 
1413  /*
1414  * Validate the GID, and lock the GXACT to ensure that two backends do not
1415  * try to commit the same GID at once.
1416  */
1417  gxact = LockGXact(gid, GetUserId());
1418  proc = &ProcGlobal->allProcs[gxact->pgprocno];
1419  xid = gxact->xid;
1420 
1421  /*
1422  * Read and validate 2PC state data. State data will typically be stored
1423  * in WAL files if the LSN is after the last checkpoint record, or moved
1424  * to disk if for some reason they have lived for a long time.
1425  */
1426  if (gxact->ondisk)
1427  buf = ReadTwoPhaseFile(xid, false);
1428  else
1429  XlogReadTwoPhaseData(gxact->prepare_start_lsn, &buf, NULL);
1430 
1431 
1432  /*
1433  * Disassemble the header area
1434  */
1435  hdr = (TwoPhaseFileHeader *) buf;
1436  Assert(TransactionIdEquals(hdr->xid, xid));
1437  bufptr = buf + MAXALIGN(sizeof(TwoPhaseFileHeader));
1438  bufptr += MAXALIGN(hdr->gidlen);
1439  children = (TransactionId *) bufptr;
1440  bufptr += MAXALIGN(hdr->nsubxacts * sizeof(TransactionId));
1441  commitrels = (RelFileNode *) bufptr;
1442  bufptr += MAXALIGN(hdr->ncommitrels * sizeof(RelFileNode));
1443  abortrels = (RelFileNode *) bufptr;
1444  bufptr += MAXALIGN(hdr->nabortrels * sizeof(RelFileNode));
1445  invalmsgs = (SharedInvalidationMessage *) bufptr;
1446  bufptr += MAXALIGN(hdr->ninvalmsgs * sizeof(SharedInvalidationMessage));
1447 
1448  /* compute latestXid among all children */
1449  latestXid = TransactionIdLatest(xid, hdr->nsubxacts, children);
1450 
1451  /* Prevent cancel/die interrupt while cleaning up */
1452  HOLD_INTERRUPTS();
1453 
1454  /*
1455  * The order of operations here is critical: make the XLOG entry for
1456  * commit or abort, then mark the transaction committed or aborted in
1457  * pg_xact, then remove its PGPROC from the global ProcArray (which means
1458  * TransactionIdIsInProgress will stop saying the prepared xact is in
1459  * progress), then run the post-commit or post-abort callbacks. The
1460  * callbacks will release the locks the transaction held.
1461  */
1462  if (isCommit)
1464  hdr->nsubxacts, children,
1465  hdr->ncommitrels, commitrels,
1466  hdr->ninvalmsgs, invalmsgs,
1467  hdr->initfileinval, gid);
1468  else
1470  hdr->nsubxacts, children,
1471  hdr->nabortrels, abortrels,
1472  gid);
1473 
1474  ProcArrayRemove(proc, latestXid);
1475 
1476  /*
1477  * In case we fail while running the callbacks, mark the gxact invalid so
1478  * no one else will try to commit/rollback, and so it will be recycled if
1479  * we fail after this point. It is still locked by our backend so it
1480  * won't go away yet.
1481  *
1482  * (We assume it's safe to do this without taking TwoPhaseStateLock.)
1483  */
1484  gxact->valid = false;
1485 
1486  /*
1487  * We have to remove any files that were supposed to be dropped. For
1488  * consistency with the regular xact.c code paths, must do this before
1489  * releasing locks, so do it before running the callbacks.
1490  *
1491  * NB: this code knows that we couldn't be dropping any temp rels ...
1492  */
1493  if (isCommit)
1494  {
1495  delrels = commitrels;
1496  ndelrels = hdr->ncommitrels;
1497  }
1498  else
1499  {
1500  delrels = abortrels;
1501  ndelrels = hdr->nabortrels;
1502  }
1503 
1504  /* Make sure files supposed to be dropped are dropped */
1505  DropRelationFiles(delrels, ndelrels, false);
1506 
1507  /*
1508  * Handle cache invalidation messages.
1509  *
1510  * Relcache init file invalidation requires processing both before and
1511  * after we send the SI messages. See AtEOXact_Inval()
1512  */
1513  if (hdr->initfileinval)
1515  SendSharedInvalidMessages(invalmsgs, hdr->ninvalmsgs);
1516  if (hdr->initfileinval)
1518 
1519  /*
1520  * Acquire the two-phase lock. We want to work on the two-phase callbacks
1521  * while holding it to avoid potential conflicts with other transactions
1522  * attempting to use the same GID, so the lock is released once the shared
1523  * memory state is cleared.
1524  */
1525  LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
1526 
1527  /* And now do the callbacks */
1528  if (isCommit)
1530  else
1532 
1533  PredicateLockTwoPhaseFinish(xid, isCommit);
1534 
1535  /* Clear shared memory state */
1536  RemoveGXact(gxact);
1537 
1538  /*
1539  * Release the lock as all callbacks are called and shared memory cleanup
1540  * is done.
1541  */
1542  LWLockRelease(TwoPhaseStateLock);
1543 
1544  /* Count the prepared xact as committed or aborted */
1545  AtEOXact_PgStat(isCommit, false);
1546 
1547  /*
1548  * And now we can clean up any files we may have left.
1549  */
1550  if (gxact->ondisk)
1551  RemoveTwoPhaseFile(xid, true);
1552 
1553  MyLockedGxact = NULL;
1554 
1556 
1557  pfree(buf);
1558 }
int32 ninvalmsgs
Definition: xact.h:310
static void RecordTransactionAbortPrepared(TransactionId xid, int nchildren, TransactionId *children, int nrels, RelFileNode *rels, const char *gid)
Definition: twophase.c:2272
int32 nsubxacts
Definition: xact.h:307
#define TransactionIdEquals(id1, id2)
Definition: transam.h:43
uint32 TransactionId
Definition: c.h:520
int32 ncommitrels
Definition: xact.h:308
Oid GetUserId(void)
Definition: miscinit.c:476
TransactionId TransactionIdLatest(TransactionId mainxid, int nxids, const TransactionId *xids)
Definition: transam.c:365
static void ProcessRecords(char *bufptr, TransactionId xid, const TwoPhaseCallback callbacks[])
Definition: twophase.c:1564
const TwoPhaseCallback twophase_postcommit_callbacks[TWOPHASE_RM_MAX_ID+1]
Definition: twophase_rmgr.c:33
PROC_HDR * ProcGlobal
Definition: proc.c:79
static char * ReadTwoPhaseFile(TransactionId xid, bool missing_ok)
Definition: twophase.c:1204
uint16 gidlen
Definition: xact.h:312
XLogRecPtr prepare_start_lsn
Definition: twophase.c:163
int32 nabortrels
Definition: xact.h:309
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1812
#define RESUME_INTERRUPTS()
Definition: miscadmin.h:118
void pfree(void *pointer)
Definition: mcxt.c:1057
static GlobalTransaction LockGXact(const char *gid, Oid user)
Definition: twophase.c:555
void ProcArrayRemove(PGPROC *proc, TransactionId latestXid)
Definition: procarray.c:514
static void RemoveGXact(GlobalTransaction gxact)
Definition: twophase.c:631
void DropRelationFiles(RelFileNode *delrels, int ndelrels, bool isRedo)
Definition: md.c:1022
void AtEOXact_PgStat(bool isCommit, bool parallel)
Definition: pgstat.c:2143
void PredicateLockTwoPhaseFinish(TransactionId xid, bool isCommit)
Definition: predicate.c:4952
static char * buf
Definition: pg_test_fsync.c:68
const TwoPhaseCallback twophase_postabort_callbacks[TWOPHASE_RM_MAX_ID+1]
Definition: twophase_rmgr.c:42
void RelationCacheInitFilePostInvalidate(void)
Definition: relcache.c:6323
static void RemoveTwoPhaseFile(TransactionId xid, bool giveWarning)
Definition: twophase.c:1592
bool initfileinval
Definition: xact.h:311
void RelationCacheInitFilePreInvalidate(void)
Definition: relcache.c:6298
#define Assert(condition)
Definition: c.h:745
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1208
#define MAXALIGN(LEN)
Definition: c.h:698
void SendSharedInvalidMessages(const SharedInvalidationMessage *msgs, int n)
Definition: sinval.c:49
TransactionId xid
Definition: xact.h:303
TransactionId xid
Definition: twophase.c:165
static void XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len)
Definition: twophase.c:1321
static GlobalTransaction MyLockedGxact
Definition: twophase.c:199
#define HOLD_INTERRUPTS()
Definition: miscadmin.h:116
PGPROC * allProcs
Definition: proc.h:306
Definition: proc.h:112
static void RecordTransactionCommitPrepared(TransactionId xid, int nchildren, TransactionId *children, int nrels, RelFileNode *rels, int ninvalmsgs, SharedInvalidationMessage *invalmsgs, bool initfileinval, const char *gid)
Definition: twophase.c:2178

◆ MarkAsPreparing()

GlobalTransaction MarkAsPreparing ( TransactionId  xid,
const char *  gid,
TimestampTz  prepared_at,
Oid  owner,
Oid  databaseid 
)

Definition at line 372 of file twophase.c.

References Assert, AtProcExit_Twophase(), before_shmem_exit(), ereport, errcode(), ERRCODE_DUPLICATE_OBJECT, errhint(), errmsg(), ERROR, TwoPhaseStateData::freeGXacts, GlobalTransactionData::gid, GIDSIZE, i, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MarkAsPreparingGuts(), max_prepared_xacts, GlobalTransactionData::next, TwoPhaseStateData::numPrepXacts, GlobalTransactionData::ondisk, TwoPhaseStateData::prepXacts, and twophaseExitRegistered.

Referenced by PrepareTransaction().

374 {
375  GlobalTransaction gxact;
376  int i;
377 
378  if (strlen(gid) >= GIDSIZE)
379  ereport(ERROR,
380  (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
381  errmsg("transaction identifier \"%s\" is too long",
382  gid)));
383 
384  /* fail immediately if feature is disabled */
385  if (max_prepared_xacts == 0)
386  ereport(ERROR,
387  (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
388  errmsg("prepared transactions are disabled"),
389  errhint("Set max_prepared_transactions to a nonzero value.")));
390 
391  /* on first call, register the exit hook */
393  {
395  twophaseExitRegistered = true;
396  }
397 
398  LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
399 
400  /* Check for conflicting GID */
401  for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
402  {
403  gxact = TwoPhaseState->prepXacts[i];
404  if (strcmp(gxact->gid, gid) == 0)
405  {
406  ereport(ERROR,
408  errmsg("transaction identifier \"%s\" is already in use",
409  gid)));
410  }
411  }
412 
413  /* Get a free gxact from the freelist */
414  if (TwoPhaseState->freeGXacts == NULL)
415  ereport(ERROR,
416  (errcode(ERRCODE_OUT_OF_MEMORY),
417  errmsg("maximum number of prepared transactions reached"),
418  errhint("Increase max_prepared_transactions (currently %d).",
420  gxact = TwoPhaseState->freeGXacts;
421  TwoPhaseState->freeGXacts = gxact->next;
422 
423  MarkAsPreparingGuts(gxact, xid, gid, prepared_at, owner, databaseid);
424 
425  gxact->ondisk = false;
426 
427  /* And insert it into the active array */
430 
431  LWLockRelease(TwoPhaseStateLock);
432 
433  return gxact;
434 }
int errhint(const char *fmt,...)
Definition: elog.c:1071
static TwoPhaseStateData * TwoPhaseState
Definition: twophase.c:191
GlobalTransaction freeGXacts
Definition: twophase.c:182
int errcode(int sqlerrcode)
Definition: elog.c:610
static bool twophaseExitRegistered
Definition: twophase.c:201
GlobalTransaction next
Definition: twophase.c:151
char gid[GIDSIZE]
Definition: twophase.c:172
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1812
static void MarkAsPreparingGuts(GlobalTransaction gxact, TransactionId xid, const char *gid, TimestampTz prepared_at, Oid owner, Oid databaseid)
Definition: twophase.c:446
#define ERROR
Definition: elog.h:43
int max_prepared_xacts
Definition: twophase.c:117
#define GIDSIZE
Definition: xact.h:31
void before_shmem_exit(pg_on_exit_callback function, Datum arg)
Definition: ipc.c:333
GlobalTransaction prepXacts[FLEXIBLE_ARRAY_MEMBER]
Definition: twophase.c:188
#define ereport(elevel,...)
Definition: elog.h:144
#define Assert(condition)
Definition: c.h:745
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1208
int errmsg(const char *fmt,...)
Definition: elog.c:824
int i
static void AtProcExit_Twophase(int code, Datum arg)
Definition: twophase.c:307
#define ERRCODE_DUPLICATE_OBJECT
Definition: streamutil.c:32

◆ PostPrepare_Twophase()

void PostPrepare_Twophase ( void  )

Definition at line 357 of file twophase.c.

References InvalidBackendId, GlobalTransactionData::locking_backend, LW_EXCLUSIVE, LWLockAcquire(), and LWLockRelease().

Referenced by PrepareTransaction(), and RecoverPreparedTransactions().

358 {
359  LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
361  LWLockRelease(TwoPhaseStateLock);
362 
363  MyLockedGxact = NULL;
364 }
BackendId locking_backend
Definition: twophase.c:168
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1812
#define InvalidBackendId
Definition: backendid.h:23
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1208
static GlobalTransaction MyLockedGxact
Definition: twophase.c:199

◆ PrepareRedoAdd()

void PrepareRedoAdd ( char *  buf,
XLogRecPtr  start_lsn,
XLogRecPtr  end_lsn,
RepOriginId  origin_id 
)

Definition at line 2331 of file twophase.c.

References Assert, DEBUG2, elog, ereport, errcode(), errhint(), errmsg(), ERROR, TwoPhaseStateData::freeGXacts, GlobalTransactionData::gid, GlobalTransactionData::inredo, InvalidBackendId, InvalidRepOriginId, GlobalTransactionData::locking_backend, LW_EXCLUSIVE, LWLockHeldByMeInMode(), max_prepared_xacts, MAXALIGN, GlobalTransactionData::next, TwoPhaseStateData::numPrepXacts, GlobalTransactionData::ondisk, xl_xact_prepare::origin_lsn, GlobalTransactionData::owner, xl_xact_prepare::owner, GlobalTransactionData::prepare_end_lsn, GlobalTransactionData::prepare_start_lsn, GlobalTransactionData::prepared_at, xl_xact_prepare::prepared_at, TwoPhaseStateData::prepXacts, RecoveryInProgress(), replorigin_advance(), GlobalTransactionData::valid, GlobalTransactionData::xid, xl_xact_prepare::xid, and XLogRecPtrIsInvalid.

Referenced by restoreTwoPhaseData(), and xact_redo().

2333 {
2335  char *bufptr;
2336  const char *gid;
2337  GlobalTransaction gxact;
2338 
2339  Assert(LWLockHeldByMeInMode(TwoPhaseStateLock, LW_EXCLUSIVE));
2341 
2342  bufptr = buf + MAXALIGN(sizeof(TwoPhaseFileHeader));
2343  gid = (const char *) bufptr;
2344 
2345  /*
2346  * Reserve the GID for the given transaction in the redo code path.
2347  *
2348  * This creates a gxact struct and puts it into the active array.
2349  *
2350  * In redo, this struct is mainly used to track PREPARE/COMMIT entries in
2351  * shared memory. Hence, we only fill up the bare minimum contents here.
2352  * The gxact also gets marked with gxact->inredo set to true to indicate
2353  * that it got added in the redo phase
2354  */
2355 
2356  /* Get a free gxact from the freelist */
2357  if (TwoPhaseState->freeGXacts == NULL)
2358  ereport(ERROR,
2359  (errcode(ERRCODE_OUT_OF_MEMORY),
2360  errmsg("maximum number of prepared transactions reached"),
2361  errhint("Increase max_prepared_transactions (currently %d).",
2362  max_prepared_xacts)));
2363  gxact = TwoPhaseState->freeGXacts;
2364  TwoPhaseState->freeGXacts = gxact->next;
2365 
2366  gxact->prepared_at = hdr->prepared_at;
2367  gxact->prepare_start_lsn = start_lsn;
2368  gxact->prepare_end_lsn = end_lsn;
2369  gxact->xid = hdr->xid;
2370  gxact->owner = hdr->owner;
2372  gxact->valid = false;
2373  gxact->ondisk = XLogRecPtrIsInvalid(start_lsn);
2374  gxact->inredo = true; /* yes, added in redo */
2375  strcpy(gxact->gid, gid);
2376 
2377  /* And insert it into the active array */
2380 
2381  if (origin_id != InvalidRepOriginId)
2382  {
2383  /* recover apply progress */
2384  replorigin_advance(origin_id, hdr->origin_lsn, end_lsn,
2385  false /* backward */ , false /* WAL */ );
2386  }
2387 
2388  elog(DEBUG2, "added 2PC data in shared memory for transaction %u", gxact->xid);
2389 }
bool LWLockHeldByMeInMode(LWLock *l, LWLockMode mode)
Definition: lwlock.c:1946
int errhint(const char *fmt,...)
Definition: elog.c:1071
static TwoPhaseStateData * TwoPhaseState
Definition: twophase.c:191
GlobalTransaction freeGXacts
Definition: twophase.c:182
int errcode(int sqlerrcode)
Definition: elog.c:610
void replorigin_advance(RepOriginId node, XLogRecPtr remote_commit, XLogRecPtr local_commit, bool go_backward, bool wal_log)
Definition: origin.c:855
GlobalTransaction next
Definition: twophase.c:151
bool RecoveryInProgress(void)
Definition: xlog.c:8074
char gid[GIDSIZE]
Definition: twophase.c:172
BackendId locking_backend
Definition: twophase.c:168
XLogRecPtr prepare_start_lsn
Definition: twophase.c:163
#define ERROR
Definition: elog.h:43
int max_prepared_xacts
Definition: twophase.c:117
#define DEBUG2
Definition: elog.h:24
static char * buf
Definition: pg_test_fsync.c:68
XLogRecPtr origin_lsn
Definition: xact.h:313
GlobalTransaction prepXacts[FLEXIBLE_ARRAY_MEMBER]
Definition: twophase.c:188
#define XLogRecPtrIsInvalid(r)
Definition: xlogdefs.h:29
#define InvalidBackendId
Definition: backendid.h:23
#define ereport(elevel,...)
Definition: elog.h:144
#define Assert(condition)
Definition: c.h:745
#define MAXALIGN(LEN)
Definition: c.h:698
TransactionId xid
Definition: xact.h:303
#define InvalidRepOriginId
Definition: origin.h:33
TransactionId xid
Definition: twophase.c:165
TimestampTz prepared_at
Definition: twophase.c:154
int errmsg(const char *fmt,...)
Definition: elog.c:824
#define elog(elevel,...)
Definition: elog.h:214
TimestampTz prepared_at
Definition: xact.h:305
XLogRecPtr prepare_end_lsn
Definition: twophase.c:164

◆ PrepareRedoRemove()

void PrepareRedoRemove ( TransactionId  xid,
bool  giveWarning 
)

Definition at line 2401 of file twophase.c.

References Assert, DEBUG2, elog, i, GlobalTransactionData::inredo, LW_EXCLUSIVE, LWLockHeldByMeInMode(), TwoPhaseStateData::numPrepXacts, GlobalTransactionData::ondisk, TwoPhaseStateData::prepXacts, RecoveryInProgress(), RemoveGXact(), RemoveTwoPhaseFile(), and GlobalTransactionData::xid.

Referenced by ProcessTwoPhaseBuffer(), and xact_redo().

2402 {
2403  GlobalTransaction gxact = NULL;
2404  int i;
2405  bool found = false;
2406 
2407  Assert(LWLockHeldByMeInMode(TwoPhaseStateLock, LW_EXCLUSIVE));
2409 
2410  for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
2411  {
2412  gxact = TwoPhaseState->prepXacts[i];
2413 
2414  if (gxact->xid == xid)
2415  {
2416  Assert(gxact->inredo);
2417  found = true;
2418  break;
2419  }
2420  }
2421 
2422  /*
2423  * Just leave if there is nothing, this is expected during WAL replay.
2424  */
2425  if (!found)
2426  return;
2427 
2428  /*
2429  * And now we can clean up any files we may have left.
2430  */
2431  elog(DEBUG2, "removing 2PC data for transaction %u", xid);
2432  if (gxact->ondisk)
2433  RemoveTwoPhaseFile(xid, giveWarning);
2434  RemoveGXact(gxact);
2435 }
bool LWLockHeldByMeInMode(LWLock *l, LWLockMode mode)
Definition: lwlock.c:1946
static TwoPhaseStateData * TwoPhaseState
Definition: twophase.c:191
bool RecoveryInProgress(void)
Definition: xlog.c:8074
static void RemoveGXact(GlobalTransaction gxact)
Definition: twophase.c:631
#define DEBUG2
Definition: elog.h:24
GlobalTransaction prepXacts[FLEXIBLE_ARRAY_MEMBER]
Definition: twophase.c:188
static void RemoveTwoPhaseFile(TransactionId xid, bool giveWarning)
Definition: twophase.c:1592
#define Assert(condition)
Definition: c.h:745
TransactionId xid
Definition: twophase.c:165
#define elog(elevel,...)
Definition: elog.h:214
int i

◆ PrescanPreparedTransactions()

TransactionId PrescanPreparedTransactions ( TransactionId **  xids_p,
int *  nxids_p 
)

Definition at line 1835 of file twophase.c.

References Assert, buf, i, GlobalTransactionData::inredo, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), VariableCacheData::nextXid, TwoPhaseStateData::numPrepXacts, GlobalTransactionData::ondisk, palloc(), pfree(), GlobalTransactionData::prepare_start_lsn, TwoPhaseStateData::prepXacts, ProcessTwoPhaseBuffer(), repalloc(), ShmemVariableCache, TransactionIdPrecedes(), GlobalTransactionData::xid, and XidFromFullTransactionId.

Referenced by StartupXLOG(), and xlog_redo().

1836 {
1838  TransactionId origNextXid = XidFromFullTransactionId(nextXid);
1839  TransactionId result = origNextXid;
1840  TransactionId *xids = NULL;
1841  int nxids = 0;
1842  int allocsize = 0;
1843  int i;
1844 
1845  LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
1846  for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
1847  {
1848  TransactionId xid;
1849  char *buf;
1851 
1852  Assert(gxact->inredo);
1853 
1854  xid = gxact->xid;
1855 
1856  buf = ProcessTwoPhaseBuffer(xid,
1857  gxact->prepare_start_lsn,
1858  gxact->ondisk, false, true);
1859 
1860  if (buf == NULL)
1861  continue;
1862 
1863  /*
1864  * OK, we think this file is valid. Incorporate xid into the
1865  * running-minimum result.
1866  */
1867  if (TransactionIdPrecedes(xid, result))
1868  result = xid;
1869 
1870  if (xids_p)
1871  {
1872  if (nxids == allocsize)
1873  {
1874  if (nxids == 0)
1875  {
1876  allocsize = 10;
1877  xids = palloc(allocsize * sizeof(TransactionId));
1878  }
1879  else
1880  {
1881  allocsize = allocsize * 2;
1882  xids = repalloc(xids, allocsize * sizeof(TransactionId));
1883  }
1884  }
1885  xids[nxids++] = xid;
1886  }
1887 
1888  pfree(buf);
1889  }
1890  LWLockRelease(TwoPhaseStateLock);
1891 
1892  if (xids_p)
1893  {
1894  *xids_p = xids;
1895  *nxids_p = nxids;
1896  }
1897 
1898  return result;
1899 }
static TwoPhaseStateData * TwoPhaseState
Definition: twophase.c:191
uint32 TransactionId
Definition: c.h:520
FullTransactionId nextXid
Definition: transam.h:213
XLogRecPtr prepare_start_lsn
Definition: twophase.c:163
#define XidFromFullTransactionId(x)
Definition: transam.h:48
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1812
void pfree(void *pointer)
Definition: mcxt.c:1057
static char * buf
Definition: pg_test_fsync.c:68
VariableCache ShmemVariableCache
Definition: varsup.c:34
GlobalTransaction prepXacts[FLEXIBLE_ARRAY_MEMBER]
Definition: twophase.c:188
bool TransactionIdPrecedes(TransactionId id1, TransactionId id2)
Definition: transam.c:300
static char * ProcessTwoPhaseBuffer(TransactionId xid, XLogRecPtr prepare_start_lsn, bool fromdisk, bool setParent, bool setNextXid)
Definition: twophase.c:2058
#define Assert(condition)
Definition: c.h:745
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1208
void * repalloc(void *pointer, Size size)
Definition: mcxt.c:1070
TransactionId xid
Definition: twophase.c:165
void * palloc(Size size)
Definition: mcxt.c:950
int i

◆ RecoverPreparedTransactions()

void RecoverPreparedTransactions ( void  )

Definition at line 1957 of file twophase.c.

References Assert, buf, xl_xact_prepare::database, ereport, errmsg(), GlobalTransactionData::gid, xl_xact_prepare::gidlen, GXactLoadSubxactData(), i, InHotStandby, GlobalTransactionData::inredo, LOG, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MarkAsPrepared(), MarkAsPreparingGuts(), MAXALIGN, xl_xact_prepare::nabortrels, xl_xact_prepare::ncommitrels, xl_xact_prepare::ninvalmsgs, xl_xact_prepare::nsubxacts, TwoPhaseStateData::numPrepXacts, GlobalTransactionData::ondisk, xl_xact_prepare::owner, pfree(), PostPrepare_Twophase(), GlobalTransactionData::prepare_start_lsn, xl_xact_prepare::prepared_at, TwoPhaseStateData::prepXacts, ProcessRecords(), ProcessTwoPhaseBuffer(), StandbyReleaseLockTree(), TransactionIdEquals, twophase_recover_callbacks, GlobalTransactionData::xid, and xl_xact_prepare::xid.

Referenced by StartupXLOG().

1958 {
1959  int i;
1960 
1961  LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
1962  for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
1963  {
1964  TransactionId xid;
1965  char *buf;
1967  char *bufptr;
1968  TwoPhaseFileHeader *hdr;
1969  TransactionId *subxids;
1970  const char *gid;
1971 
1972  xid = gxact->xid;
1973 
1974  /*
1975  * Reconstruct subtrans state for the transaction --- needed because
1976  * pg_subtrans is not preserved over a restart. Note that we are
1977  * linking all the subtransactions directly to the top-level XID;
1978  * there may originally have been a more complex hierarchy, but
1979  * there's no need to restore that exactly. It's possible that
1980  * SubTransSetParent has been set before, if the prepared transaction
1981  * generated xid assignment records.
1982  */
1983  buf = ProcessTwoPhaseBuffer(xid,
1984  gxact->prepare_start_lsn,
1985  gxact->ondisk, true, false);
1986  if (buf == NULL)
1987  continue;
1988 
1989  ereport(LOG,
1990  (errmsg("recovering prepared transaction %u from shared memory", xid)));
1991 
1992  hdr = (TwoPhaseFileHeader *) buf;
1993  Assert(TransactionIdEquals(hdr->xid, xid));
1994  bufptr = buf + MAXALIGN(sizeof(TwoPhaseFileHeader));
1995  gid = (const char *) bufptr;
1996  bufptr += MAXALIGN(hdr->gidlen);
1997  subxids = (TransactionId *) bufptr;
1998  bufptr += MAXALIGN(hdr->nsubxacts * sizeof(TransactionId));
1999  bufptr += MAXALIGN(hdr->ncommitrels * sizeof(RelFileNode));
2000  bufptr += MAXALIGN(hdr->nabortrels * sizeof(RelFileNode));
2001  bufptr += MAXALIGN(hdr->ninvalmsgs * sizeof(SharedInvalidationMessage));
2002 
2003  /*
2004  * Recreate its GXACT and dummy PGPROC. But, check whether it was
2005  * added in redo and already has a shmem entry for it.
2006  */
2007  MarkAsPreparingGuts(gxact, xid, gid,
2008  hdr->prepared_at,
2009  hdr->owner, hdr->database);
2010 
2011  /* recovered, so reset the flag for entries generated by redo */
2012  gxact->inredo = false;
2013 
2014  GXactLoadSubxactData(gxact, hdr->nsubxacts, subxids);
2015  MarkAsPrepared(gxact, true);
2016 
2017  LWLockRelease(TwoPhaseStateLock);
2018 
2019  /*
2020  * Recover other state (notably locks) using resource managers.
2021  */
2023 
2024  /*
2025  * Release locks held by the standby process after we process each
2026  * prepared transaction. As a result, we don't need too many
2027  * additional locks at any one time.
2028  */
2029  if (InHotStandby)
2030  StandbyReleaseLockTree(xid, hdr->nsubxacts, subxids);
2031 
2032  /*
2033  * We're done with recovering this transaction. Clear MyLockedGxact,
2034  * like we do in PrepareTransaction() during normal operation.
2035  */
2037 
2038  pfree(buf);
2039 
2040  LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
2041  }
2042 
2043  LWLockRelease(TwoPhaseStateLock);
2044 }
int32 ninvalmsgs
Definition: xact.h:310
int32 nsubxacts
Definition: xact.h:307
static TwoPhaseStateData * TwoPhaseState
Definition: twophase.c:191
#define TransactionIdEquals(id1, id2)
Definition: transam.h:43
uint32 TransactionId
Definition: c.h:520
int32 ncommitrels
Definition: xact.h:308
static void ProcessRecords(char *bufptr, TransactionId xid, const TwoPhaseCallback callbacks[])
Definition: twophase.c:1564
const TwoPhaseCallback twophase_recover_callbacks[TWOPHASE_RM_MAX_ID+1]
Definition: twophase_rmgr.c:24
#define InHotStandby
Definition: xlog.h:74
uint16 gidlen
Definition: xact.h:312
#define LOG
Definition: elog.h:26
Oid database
Definition: xact.h:304
XLogRecPtr prepare_start_lsn
Definition: twophase.c:163
int32 nabortrels
Definition: xact.h:309
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1812
void pfree(void *pointer)
Definition: mcxt.c:1057
static void MarkAsPreparingGuts(GlobalTransaction gxact, TransactionId xid, const char *gid, TimestampTz prepared_at, Oid owner, Oid databaseid)
Definition: twophase.c:446
static void GXactLoadSubxactData(GlobalTransaction gxact, int nsubxacts, TransactionId *children)
Definition: twophase.c:507
static char * buf
Definition: pg_test_fsync.c:68
void StandbyReleaseLockTree(TransactionId xid, int nsubxids, TransactionId *subxids)
Definition: standby.c:738
GlobalTransaction prepXacts[FLEXIBLE_ARRAY_MEMBER]
Definition: twophase.c:188
static char * ProcessTwoPhaseBuffer(TransactionId xid, XLogRecPtr prepare_start_lsn, bool fromdisk, bool setParent, bool setNextXid)
Definition: twophase.c:2058
#define ereport(elevel,...)
Definition: elog.h:144
#define Assert(condition)
Definition: c.h:745
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1208
#define MAXALIGN(LEN)
Definition: c.h:698
static void MarkAsPrepared(GlobalTransaction gxact, bool lock_held)
Definition: twophase.c:533
TransactionId xid
Definition: xact.h:303
TransactionId xid
Definition: twophase.c:165
int errmsg(const char *fmt,...)
Definition: elog.c:824
void PostPrepare_Twophase(void)
Definition: twophase.c:357
int i
TimestampTz prepared_at
Definition: xact.h:305

◆ restoreTwoPhaseData()

void restoreTwoPhaseData ( void  )

Definition at line 1773 of file twophase.c.

References AllocateDir(), buf, dirent::d_name, FreeDir(), InvalidRepOriginId, InvalidXLogRecPtr, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), PrepareRedoAdd(), ProcessTwoPhaseBuffer(), ReadDir(), TWOPHASE_DIR, and GlobalTransactionData::xid.

Referenced by StartupXLOG().

1774 {
1775  DIR *cldir;
1776  struct dirent *clde;
1777 
1778  LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
1779  cldir = AllocateDir(TWOPHASE_DIR);
1780  while ((clde = ReadDir(cldir, TWOPHASE_DIR)) != NULL)
1781  {
1782  if (strlen(clde->d_name) == 8 &&
1783  strspn(clde->d_name, "0123456789ABCDEF") == 8)
1784  {
1785  TransactionId xid;
1786  char *buf;
1787 
1788  xid = (TransactionId) strtoul(clde->d_name, NULL, 16);
1789 
1791  true, false, false);
1792  if (buf == NULL)
1793  continue;
1794 
1797  }
1798  }
1799  LWLockRelease(TwoPhaseStateLock);
1800  FreeDir(cldir);
1801 }
#define InvalidXLogRecPtr
Definition: xlogdefs.h:28
uint32 TransactionId
Definition: c.h:520
Definition: dirent.h:9
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1812
Definition: dirent.c:25
static char * buf
Definition: pg_test_fsync.c:68
DIR * AllocateDir(const char *dirname)
Definition: fd.c:2583
static char * ProcessTwoPhaseBuffer(TransactionId xid, XLogRecPtr prepare_start_lsn, bool fromdisk, bool setParent, bool setNextXid)
Definition: twophase.c:2058
void PrepareRedoAdd(char *buf, XLogRecPtr start_lsn, XLogRecPtr end_lsn, RepOriginId origin_id)
Definition: twophase.c:2331
struct dirent * ReadDir(DIR *dir, const char *dirname)
Definition: fd.c:2649
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1208
#define InvalidRepOriginId
Definition: origin.h:33
#define TWOPHASE_DIR
Definition: twophase.c:114
char d_name[MAX_PATH]
Definition: dirent.h:15
int FreeDir(DIR *dir)
Definition: fd.c:2701

◆ StandbyRecoverPreparedTransactions()

void StandbyRecoverPreparedTransactions ( void  )

Definition at line 1916 of file twophase.c.

References Assert, buf, i, GlobalTransactionData::inredo, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), TwoPhaseStateData::numPrepXacts, GlobalTransactionData::ondisk, pfree(), GlobalTransactionData::prepare_start_lsn, TwoPhaseStateData::prepXacts, ProcessTwoPhaseBuffer(), and GlobalTransactionData::xid.

Referenced by StartupXLOG(), and xlog_redo().

1917 {
1918  int i;
1919 
1920  LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
1921  for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
1922  {
1923  TransactionId xid;
1924  char *buf;
1926 
1927  Assert(gxact->inredo);
1928 
1929  xid = gxact->xid;
1930 
1931  buf = ProcessTwoPhaseBuffer(xid,
1932  gxact->prepare_start_lsn,
1933  gxact->ondisk, false, false);
1934  if (buf != NULL)
1935  pfree(buf);
1936  }
1937  LWLockRelease(TwoPhaseStateLock);
1938 }
static TwoPhaseStateData * TwoPhaseState
Definition: twophase.c:191
uint32 TransactionId
Definition: c.h:520
XLogRecPtr prepare_start_lsn
Definition: twophase.c:163
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1812
void pfree(void *pointer)
Definition: mcxt.c:1057
static char * buf
Definition: pg_test_fsync.c:68
GlobalTransaction prepXacts[FLEXIBLE_ARRAY_MEMBER]
Definition: twophase.c:188
static char * ProcessTwoPhaseBuffer(TransactionId xid, XLogRecPtr prepare_start_lsn, bool fromdisk, bool setParent, bool setNextXid)
Definition: twophase.c:2058
#define Assert(condition)
Definition: c.h:745
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1208
TransactionId xid
Definition: twophase.c:165
int i

◆ StandbyTransactionIdIsPrepared()

bool StandbyTransactionIdIsPrepared ( TransactionId  xid)

Definition at line 1369 of file twophase.c.

References Assert, buf, max_prepared_xacts, pfree(), ReadTwoPhaseFile(), TransactionIdEquals, TransactionIdIsValid, and xl_xact_prepare::xid.

Referenced by KnownAssignedXidsRemovePreceding(), and StandbyReleaseOldLocks().

1370 {
1371  char *buf;
1372  TwoPhaseFileHeader *hdr;
1373  bool result;
1374 
1376 
1377  if (max_prepared_xacts <= 0)
1378  return false; /* nothing to do */
1379 
1380  /* Read and validate file */
1381  buf = ReadTwoPhaseFile(xid, true);
1382  if (buf == NULL)
1383  return false;
1384 
1385  /* Check header also */
1386  hdr = (TwoPhaseFileHeader *) buf;
1387  result = TransactionIdEquals(hdr->xid, xid);
1388  pfree(buf);
1389 
1390  return result;
1391 }
#define TransactionIdEquals(id1, id2)
Definition: transam.h:43
static char * ReadTwoPhaseFile(TransactionId xid, bool missing_ok)
Definition: twophase.c:1204
void pfree(void *pointer)
Definition: mcxt.c:1057
int max_prepared_xacts
Definition: twophase.c:117
static char * buf
Definition: pg_test_fsync.c:68
#define Assert(condition)
Definition: c.h:745
TransactionId xid
Definition: xact.h:303
#define TransactionIdIsValid(xid)
Definition: transam.h:41

◆ StartPrepare()

void StartPrepare ( GlobalTransaction  gxact)

Definition at line 982 of file twophase.c.

References PROC_HDR::allProcs, xllist::bytes_free, StateFileChunk::data, xl_xact_prepare::database, PGPROC::databaseId, GlobalTransactionData::gid, xl_xact_prepare::gidlen, GXactLoadSubxactData(), xllist::head, xl_xact_prepare::initfileinval, StateFileChunk::len, xl_xact_prepare::magic, Max, xl_xact_prepare::nabortrels, xl_xact_prepare::ncommitrels, StateFileChunk::next, xl_xact_prepare::ninvalmsgs, xl_xact_prepare::nsubxacts, xllist::num_chunks, GlobalTransactionData::owner, xl_xact_prepare::owner, palloc(), palloc0(), pfree(), GlobalTransactionData::pgprocno, GlobalTransactionData::prepared_at, xl_xact_prepare::prepared_at, ProcGlobal, records, save_state_data(), smgrGetPendingDeletes(), xllist::tail, xl_xact_prepare::total_len, xllist::total_len, TWOPHASE_MAGIC, xactGetCommittedChildren(), xactGetCommittedInvalidationMessages(), GlobalTransactionData::xid, and xl_xact_prepare::xid.

Referenced by PrepareTransaction().

983 {
984  PGPROC *proc = &ProcGlobal->allProcs[gxact->pgprocno];
985  TransactionId xid = gxact->xid;
986  TwoPhaseFileHeader hdr;
987  TransactionId *children;
988  RelFileNode *commitrels;
989  RelFileNode *abortrels;
990  SharedInvalidationMessage *invalmsgs;
991 
992  /* Initialize linked list */
993  records.head = palloc0(sizeof(StateFileChunk));
994  records.head->len = 0;
995  records.head->next = NULL;
996 
997  records.bytes_free = Max(sizeof(TwoPhaseFileHeader), 512);
999 
1001  records.num_chunks = 1;
1002 
1003  records.total_len = 0;
1004 
1005  /* Create header */
1006  hdr.magic = TWOPHASE_MAGIC;
1007  hdr.total_len = 0; /* EndPrepare will fill this in */
1008  hdr.xid = xid;
1009  hdr.database = proc->databaseId;
1010  hdr.prepared_at = gxact->prepared_at;
1011  hdr.owner = gxact->owner;
1012  hdr.nsubxacts = xactGetCommittedChildren(&children);
1013  hdr.ncommitrels = smgrGetPendingDeletes(true, &commitrels);
1014  hdr.nabortrels = smgrGetPendingDeletes(false, &abortrels);
1016  &hdr.initfileinval);
1017  hdr.gidlen = strlen(gxact->gid) + 1; /* Include '\0' */
1018 
1019  save_state_data(&hdr, sizeof(TwoPhaseFileHeader));
1020  save_state_data(gxact->gid, hdr.gidlen);
1021 
1022  /*
1023  * Add the additional info about subxacts, deletable files and cache
1024  * invalidation messages.
1025  */
1026  if (hdr.nsubxacts > 0)
1027  {
1028  save_state_data(children, hdr.nsubxacts * sizeof(TransactionId));
1029  /* While we have the child-xact data, stuff it in the gxact too */
1030  GXactLoadSubxactData(gxact, hdr.nsubxacts, children);
1031  }
1032  if (hdr.ncommitrels > 0)
1033  {
1034  save_state_data(commitrels, hdr.ncommitrels * sizeof(RelFileNode));
1035  pfree(commitrels);
1036  }
1037  if (hdr.nabortrels > 0)
1038  {
1039  save_state_data(abortrels, hdr.nabortrels * sizeof(RelFileNode));
1040  pfree(abortrels);
1041  }
1042  if (hdr.ninvalmsgs > 0)
1043  {
1044  save_state_data(invalmsgs,
1045  hdr.ninvalmsgs * sizeof(SharedInvalidationMessage));
1046  pfree(invalmsgs);
1047  }
1048 }
int32 ninvalmsgs
Definition: xact.h:310
int xactGetCommittedChildren(TransactionId **ptr)
Definition: xact.c:5477
int32 nsubxacts
Definition: xact.h:307
uint32 TransactionId
Definition: c.h:520
int32 ncommitrels
Definition: xact.h:308
StateFileChunk * tail
Definition: twophase.c:938
PROC_HDR * ProcGlobal
Definition: proc.c:79
uint16 gidlen
Definition: xact.h:312
uint32 num_chunks
Definition: twophase.c:939
char gid[GIDSIZE]
Definition: twophase.c:172
Oid database
Definition: xact.h:304
char * data
Definition: twophase.c:930
int32 nabortrels
Definition: xact.h:309
void pfree(void *pointer)
Definition: mcxt.c:1057
static void GXactLoadSubxactData(GlobalTransaction gxact, int nsubxacts, TransactionId *children)
Definition: twophase.c:507
uint32 bytes_free
Definition: twophase.c:940
int smgrGetPendingDeletes(bool forCommit, RelFileNode **ptr)
Definition: storage.c:815
uint32 total_len
Definition: xact.h:302
uint32 len
Definition: twophase.c:931
Oid databaseId
Definition: proc.h:145
static struct xllist records
uint32 total_len
Definition: twophase.c:941
struct StateFileChunk * next
Definition: twophase.c:932
void * palloc0(Size size)
Definition: mcxt.c:981
#define TWOPHASE_MAGIC
Definition: twophase.c:906
bool initfileinval
Definition: xact.h:311
#define Max(x, y)
Definition: c.h:921
StateFileChunk * head
Definition: twophase.c:937
static void save_state_data(const void *data, uint32 len)
Definition: twophase.c:954
TransactionId xid
Definition: xact.h:303
TransactionId xid
Definition: twophase.c:165
TimestampTz prepared_at
Definition: twophase.c:154
uint32 magic
Definition: xact.h:301
void * palloc(Size size)
Definition: mcxt.c:950
int xactGetCommittedInvalidationMessages(SharedInvalidationMessage **msgs, bool *RelcacheInitFileInval)
Definition: inval.c:831
TimestampTz prepared_at
Definition: xact.h:305
PGPROC * allProcs
Definition: proc.h:306
Definition: proc.h:112

◆ TwoPhaseGetDummyBackendId()

BackendId TwoPhaseGetDummyBackendId ( TransactionId  xid,
bool  lock_held 
)

Definition at line 858 of file twophase.c.

References GlobalTransactionData::dummyBackendId, and TwoPhaseGetGXact().

Referenced by multixact_twophase_postcommit(), multixact_twophase_recover(), and PostPrepare_MultiXact().

859 {
860  GlobalTransaction gxact = TwoPhaseGetGXact(xid, lock_held);
861 
862  return gxact->dummyBackendId;
863 }
static GlobalTransaction TwoPhaseGetGXact(TransactionId xid, bool lock_held)
Definition: twophase.c:805
BackendId dummyBackendId
Definition: twophase.c:153

◆ TwoPhaseGetDummyProc()

PGPROC* TwoPhaseGetDummyProc ( TransactionId  xid,
bool  lock_held 
)

Definition at line 873 of file twophase.c.

References PROC_HDR::allProcs, GlobalTransactionData::pgprocno, ProcGlobal, and TwoPhaseGetGXact().

Referenced by lock_twophase_postcommit(), lock_twophase_recover(), and PostPrepare_Locks().

874 {
875  GlobalTransaction gxact = TwoPhaseGetGXact(xid, lock_held);
876 
877  return &ProcGlobal->allProcs[gxact->pgprocno];
878 }
PROC_HDR * ProcGlobal
Definition: proc.c:79
static GlobalTransaction TwoPhaseGetGXact(TransactionId xid, bool lock_held)
Definition: twophase.c:805
PGPROC * allProcs
Definition: proc.h:306

◆ TwoPhaseShmemInit()

void TwoPhaseShmemInit ( void  )

Definition at line 252 of file twophase.c.

References Assert, GlobalTransactionData::dummyBackendId, TwoPhaseStateData::freeGXacts, i, IsUnderPostmaster, max_prepared_xacts, MAXALIGN, MaxBackends, GlobalTransactionData::next, TwoPhaseStateData::numPrepXacts, offsetof, PGPROC::pgprocno, GlobalTransactionData::pgprocno, PreparedXactProcs, ShmemInitStruct(), and TwoPhaseShmemSize().

Referenced by CreateSharedMemoryAndSemaphores().

253 {
254  bool found;
255 
256  TwoPhaseState = ShmemInitStruct("Prepared Transaction Table",
258  &found);
259  if (!IsUnderPostmaster)
260  {
261  GlobalTransaction gxacts;
262  int i;
263 
264  Assert(!found);
265  TwoPhaseState->freeGXacts = NULL;
267 
268  /*
269  * Initialize the linked list of free GlobalTransactionData structs
270  */
271  gxacts = (GlobalTransaction)
272  ((char *) TwoPhaseState +
273  MAXALIGN(offsetof(TwoPhaseStateData, prepXacts) +
275  for (i = 0; i < max_prepared_xacts; i++)
276  {
277  /* insert into linked list */
278  gxacts[i].next = TwoPhaseState->freeGXacts;
279  TwoPhaseState->freeGXacts = &gxacts[i];
280 
281  /* associate it with a PGPROC assigned by InitProcGlobal */
283 
284  /*
285  * Assign a unique ID for each dummy proc, so that the range of
286  * dummy backend IDs immediately follows the range of normal
287  * backend IDs. We don't dare to assign a real backend ID to dummy
288  * procs, because prepared transactions don't take part in cache
289  * invalidation like a real backend ID would imply, but having a
290  * unique ID for them is nevertheless handy. This arrangement
291  * allows you to allocate an array of size (MaxBackends +
292  * max_prepared_xacts + 1), and have a slot for every backend and
293  * prepared transaction. Currently multixact.c uses that
294  * technique.
295  */
296  gxacts[i].dummyBackendId = MaxBackends + 1 + i;
297  }
298  }
299  else
300  Assert(found);
301 }
static TwoPhaseStateData * TwoPhaseState
Definition: twophase.c:191
GlobalTransaction freeGXacts
Definition: twophase.c:182
PGPROC * PreparedXactProcs
Definition: proc.c:81
Size TwoPhaseShmemSize(void)
Definition: twophase.c:236
GlobalTransaction next
Definition: twophase.c:151
struct GlobalTransactionData * GlobalTransaction
Definition: twophase.h:26
int max_prepared_xacts
Definition: twophase.c:117
void * ShmemInitStruct(const char *name, Size size, bool *foundPtr)
Definition: shmem.c:392
int MaxBackends
Definition: globals.c:136
bool IsUnderPostmaster
Definition: globals.c:109
#define Assert(condition)
Definition: c.h:745
#define MAXALIGN(LEN)
Definition: c.h:698
int pgprocno
Definition: proc.h:141
int i
#define offsetof(type, field)
Definition: c.h:668
BackendId dummyBackendId
Definition: twophase.c:153

◆ TwoPhaseShmemSize()

Size TwoPhaseShmemSize ( void  )

Definition at line 236 of file twophase.c.

References add_size(), max_prepared_xacts, MAXALIGN, mul_size(), and offsetof.

Referenced by CreateSharedMemoryAndSemaphores(), and TwoPhaseShmemInit().

237 {
238  Size size;
239 
240  /* Need the fixed struct, the array of pointers, and the GTD structs */
241  size = offsetof(TwoPhaseStateData, prepXacts);
242  size = add_size(size, mul_size(max_prepared_xacts,
243  sizeof(GlobalTransaction)));
244  size = MAXALIGN(size);
245  size = add_size(size, mul_size(max_prepared_xacts,
246  sizeof(GlobalTransactionData)));
247 
248  return size;
249 }
int max_prepared_xacts
Definition: twophase.c:117
Size mul_size(Size s1, Size s2)
Definition: shmem.c:515
Size add_size(Size s1, Size s2)
Definition: shmem.c:498
size_t Size
Definition: c.h:473
#define MAXALIGN(LEN)
Definition: c.h:698
#define offsetof(type, field)
Definition: c.h:668

Variable Documentation

◆ max_prepared_xacts