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)
 
TransactionId TwoPhaseGetXidByVirtualXID (VirtualTransactionId vxid, bool *have_more)
 
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)
 
bool LookupGXact (const char *gid, XLogRecPtr prepare_end_lsn, TimestampTz origin_prepare_timestamp)
 

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 322 of file twophase.c.

323 {
324  if (MyLockedGxact == NULL)
325  return;
326 
327  /*
328  * What to do with the locked global transaction entry? If we were in the
329  * process of preparing the transaction, but haven't written the WAL
330  * record and state file yet, the transaction must not be considered as
331  * prepared. Likewise, if we are in the process of finishing an
332  * already-prepared transaction, and fail after having already written the
333  * 2nd phase commit or rollback record to the WAL, the transaction should
334  * not be considered as prepared anymore. In those cases, just remove the
335  * entry from shared memory.
336  *
337  * Otherwise, the entry must be left in place so that the transaction can
338  * be finished later, so just unlock it.
339  *
340  * If we abort during prepare, after having written the WAL record, we
341  * might not have transferred all locks and other state to the prepared
342  * transaction yet. Likewise, if we abort during commit or rollback,
343  * after having written the WAL record, we might not have released all the
344  * resources held by the transaction yet. In those cases, the in-memory
345  * state can be wrong, but it's too late to back out.
346  */
347  LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
348  if (!MyLockedGxact->valid)
350  else
352  LWLockRelease(TwoPhaseStateLock);
353 
354  MyLockedGxact = NULL;
355 }
#define InvalidBackendId
Definition: backendid.h:23
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1195
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1808
@ LW_EXCLUSIVE
Definition: lwlock.h:116
BackendId locking_backend
Definition: twophase.c:169
static void RemoveGXact(GlobalTransaction gxact)
Definition: twophase.c:647
static GlobalTransaction MyLockedGxact
Definition: twophase.c:200

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

Referenced by AbortTransaction(), and AtProcExit_Twophase().

◆ CheckPointTwoPhase()

void CheckPointTwoPhase ( XLogRecPtr  redo_horizon)

Definition at line 1794 of file twophase.c.

1795 {
1796  int i;
1797  int serialized_xacts = 0;
1798 
1799  if (max_prepared_xacts <= 0)
1800  return; /* nothing to do */
1801 
1802  TRACE_POSTGRESQL_TWOPHASE_CHECKPOINT_START();
1803 
1804  /*
1805  * We are expecting there to be zero GXACTs that need to be copied to
1806  * disk, so we perform all I/O while holding TwoPhaseStateLock for
1807  * simplicity. This prevents any new xacts from preparing while this
1808  * occurs, which shouldn't be a problem since the presence of long-lived
1809  * prepared xacts indicates the transaction manager isn't active.
1810  *
1811  * It's also possible to move I/O out of the lock, but on every error we
1812  * should check whether somebody committed our transaction in different
1813  * backend. Let's leave this optimization for future, if somebody will
1814  * spot that this place cause bottleneck.
1815  *
1816  * Note that it isn't possible for there to be a GXACT with a
1817  * prepare_end_lsn set prior to the last checkpoint yet is marked invalid,
1818  * because of the efforts with delayChkptFlags.
1819  */
1820  LWLockAcquire(TwoPhaseStateLock, LW_SHARED);
1821  for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
1822  {
1823  /*
1824  * Note that we are using gxact not PGPROC so this works in recovery
1825  * also
1826  */
1828 
1829  if ((gxact->valid || gxact->inredo) &&
1830  !gxact->ondisk &&
1831  gxact->prepare_end_lsn <= redo_horizon)
1832  {
1833  char *buf;
1834  int len;
1835 
1837  RecreateTwoPhaseFile(gxact->xid, buf, len);
1838  gxact->ondisk = true;
1841  pfree(buf);
1842  serialized_xacts++;
1843  }
1844  }
1845  LWLockRelease(TwoPhaseStateLock);
1846 
1847  /*
1848  * Flush unconditionally the parent directory to make any information
1849  * durable on disk. Two-phase files could have been removed and those
1850  * removals need to be made persistent as well as any files newly created
1851  * previously since the last checkpoint.
1852  */
1853  fsync_fname(TWOPHASE_DIR, true);
1854 
1855  TRACE_POSTGRESQL_TWOPHASE_CHECKPOINT_DONE();
1856 
1857  if (log_checkpoints && serialized_xacts > 0)
1858  ereport(LOG,
1859  (errmsg_plural("%u two-phase state file was written "
1860  "for a long-running prepared transaction",
1861  "%u two-phase state files were written "
1862  "for long-running prepared transactions",
1863  serialized_xacts,
1864  serialized_xacts)));
1865 }
int errmsg_plural(const char *fmt_singular, const char *fmt_plural, unsigned long n,...)
Definition: elog.c:1179
#define LOG
Definition: elog.h:31
#define ereport(elevel,...)
Definition: elog.h:149
void fsync_fname(const char *fname, bool isdir)
Definition: fd.c:708
int i
Definition: isn.c:73
@ LW_SHARED
Definition: lwlock.h:117
void pfree(void *pointer)
Definition: mcxt.c:1456
const void size_t len
static char * buf
Definition: pg_test_fsync.c:67
TransactionId xid
Definition: twophase.c:166
XLogRecPtr prepare_start_lsn
Definition: twophase.c:164
XLogRecPtr prepare_end_lsn
Definition: twophase.c:165
GlobalTransaction prepXacts[FLEXIBLE_ARRAY_MEMBER]
Definition: twophase.c:189
static void XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len)
Definition: twophase.c:1398
#define TWOPHASE_DIR
Definition: twophase.c:115
int max_prepared_xacts
Definition: twophase.c:118
static TwoPhaseStateData * TwoPhaseState
Definition: twophase.c:192
static void RecreateTwoPhaseFile(TransactionId xid, void *content, int len)
Definition: twophase.c:1714
bool log_checkpoints
Definition: xlog.c:132
#define InvalidXLogRecPtr
Definition: xlogdefs.h:28

References buf, ereport, errmsg_plural(), fsync_fname(), i, GlobalTransactionData::inredo, InvalidXLogRecPtr, len, 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, TwoPhaseState, GlobalTransactionData::valid, GlobalTransactionData::xid, and XlogReadTwoPhaseData().

Referenced by CheckPointGuts().

◆ EndPrepare()

void EndPrepare ( GlobalTransaction  gxact)

Definition at line 1136 of file twophase.c.

1137 {
1138  TwoPhaseFileHeader *hdr;
1139  StateFileChunk *record;
1140  bool replorigin;
1141 
1142  /* Add the end sentinel to the list of 2PC records */
1144  NULL, 0);
1145 
1146  /* Go back and fill in total_len in the file header record */
1147  hdr = (TwoPhaseFileHeader *) records.head->data;
1148  Assert(hdr->magic == TWOPHASE_MAGIC);
1149  hdr->total_len = records.total_len + sizeof(pg_crc32c);
1150 
1151  replorigin = (replorigin_session_origin != InvalidRepOriginId &&
1153 
1154  if (replorigin)
1155  {
1158  }
1159 
1160  /*
1161  * If the data size exceeds MaxAllocSize, we won't be able to read it in
1162  * ReadTwoPhaseFile. Check for that now, rather than fail in the case
1163  * where we write data to file and then re-read at commit time.
1164  */
1165  if (hdr->total_len > MaxAllocSize)
1166  ereport(ERROR,
1167  (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
1168  errmsg("two-phase state file maximum length exceeded")));
1169 
1170  /*
1171  * Now writing 2PC state data to WAL. We let the WAL's CRC protection
1172  * cover us, so no need to calculate a separate CRC.
1173  *
1174  * We have to set DELAY_CHKPT_START here, too; otherwise a checkpoint
1175  * starting immediately after the WAL record is inserted could complete
1176  * without fsync'ing our state file. (This is essentially the same kind
1177  * of race condition as the COMMIT-to-clog-write case that
1178  * RecordTransactionCommit uses DELAY_CHKPT_START for; see notes there.)
1179  *
1180  * We save the PREPARE record's location in the gxact for later use by
1181  * CheckPointTwoPhase.
1182  */
1184 
1186 
1189 
1190  XLogBeginInsert();
1191  for (record = records.head; record != NULL; record = record->next)
1192  XLogRegisterData(record->data, record->len);
1193 
1195 
1196  gxact->prepare_end_lsn = XLogInsert(RM_XACT_ID, XLOG_XACT_PREPARE);
1197 
1198  if (replorigin)
1199  {
1200  /* Move LSNs forward for this replication origin */
1202  gxact->prepare_end_lsn);
1203  }
1204 
1205  XLogFlush(gxact->prepare_end_lsn);
1206 
1207  /* If we crash now, we have prepared: WAL replay will fix things */
1208 
1209  /* Store record's start location to read that later on Commit */
1211 
1212  /*
1213  * Mark the prepared transaction as valid. As soon as xact.c marks MyProc
1214  * as not running our XID (which it will do immediately after this
1215  * function returns), others can commit/rollback the xact.
1216  *
1217  * NB: a side effect of this is to make a dummy ProcArray entry for the
1218  * prepared XID. This must happen before we clear the XID from MyProc /
1219  * ProcGlobal->xids[], else there is a window where the XID is not running
1220  * according to TransactionIdIsInProgress, and onlookers would be entitled
1221  * to assume the xact crashed. Instead we have a window where the same
1222  * XID appears twice in ProcArray, which is OK.
1223  */
1224  MarkAsPrepared(gxact, false);
1225 
1226  /*
1227  * Now we can mark ourselves as out of the commit critical section: a
1228  * checkpoint starting after this will certainly see the gxact as a
1229  * candidate for fsyncing.
1230  */
1232 
1233  /*
1234  * Remember that we have this GlobalTransaction entry locked for us. If
1235  * we crash after this point, it's too late to abort, but we must unlock
1236  * it so that the prepared transaction can be committed or rolled back.
1237  */
1238  MyLockedGxact = gxact;
1239 
1240  END_CRIT_SECTION();
1241 
1242  /*
1243  * Wait for synchronous replication, if required.
1244  *
1245  * Note that at this stage we have marked the prepare, but still show as
1246  * running in the procarray (twice!) and continue to hold locks.
1247  */
1248  SyncRepWaitForLSN(gxact->prepare_end_lsn, false);
1249 
1250  records.tail = records.head = NULL;
1251  records.num_chunks = 0;
1252 }
int errcode(int sqlerrcode)
Definition: elog.c:858
int errmsg(const char *fmt,...)
Definition: elog.c:1069
#define ERROR
Definition: elog.h:39
Assert(fmt[strlen(fmt) - 1] !='\n')
#define MaxAllocSize
Definition: memutils.h:40
#define START_CRIT_SECTION()
Definition: miscadmin.h:148
#define END_CRIT_SECTION()
Definition: miscadmin.h:150
TimestampTz replorigin_session_origin_timestamp
Definition: origin.c:158
void replorigin_session_advance(XLogRecPtr remote_commit, XLogRecPtr local_commit)
Definition: origin.c:1216
RepOriginId replorigin_session_origin
Definition: origin.c:156
XLogRecPtr replorigin_session_origin_lsn
Definition: origin.c:157
#define DoNotReplicateId
Definition: origin.h:34
#define InvalidRepOriginId
Definition: origin.h:33
uint32 pg_crc32c
Definition: pg_crc32c.h:38
#define DELAY_CHKPT_START
Definition: proc.h:119
PGPROC * MyProc
Definition: proc.c:66
int delayChkptFlags
Definition: proc.h:231
struct StateFileChunk * next
Definition: twophase.c:993
uint32 len
Definition: twophase.c:992
char * data
Definition: twophase.c:991
TimestampTz origin_timestamp
Definition: xact.h:363
uint32 total_len
Definition: xact.h:349
XLogRecPtr origin_lsn
Definition: xact.h:362
uint32 magic
Definition: xact.h:348
uint32 total_len
Definition: twophase.c:1002
uint32 num_chunks
Definition: twophase.c:1000
StateFileChunk * head
Definition: twophase.c:998
StateFileChunk * tail
Definition: twophase.c:999
void SyncRepWaitForLSN(XLogRecPtr lsn, bool commit)
Definition: syncrep.c:149
void RegisterTwoPhaseRecord(TwoPhaseRmgrId rmid, uint16 info, const void *data, uint32 len)
Definition: twophase.c:1258
#define TWOPHASE_MAGIC
Definition: twophase.c:967
static void MarkAsPrepared(GlobalTransaction gxact, bool lock_held)
Definition: twophase.c:549
static struct xllist records
#define TWOPHASE_RM_END_ID
Definition: twophase_rmgr.h:24
#define XLOG_XACT_PREPARE
Definition: xact.h:170
XLogRecPtr ProcLastRecPtr
Definition: xlog.c:256
void XLogFlush(XLogRecPtr record)
Definition: xlog.c:2535
#define XLOG_INCLUDE_ORIGIN
Definition: xlog.h:149
void XLogRegisterData(char *data, uint32 len)
Definition: xloginsert.c:351
XLogRecPtr XLogInsert(RmgrId rmid, uint8 info)
Definition: xloginsert.c:461
void XLogSetRecordFlags(uint8 flags)
Definition: xloginsert.c:443
void XLogBeginInsert(void)
Definition: xloginsert.c:150
void XLogEnsureRecordSpace(int max_block_id, int ndatas)
Definition: xloginsert.c:176

References Assert(), StateFileChunk::data, DELAY_CHKPT_START, PGPROC::delayChkptFlags, DoNotReplicateId, END_CRIT_SECTION, ereport, errcode(), errmsg(), ERROR, xllist::head, InvalidRepOriginId, StateFileChunk::len, xl_xact_prepare::magic, MarkAsPrepared(), MaxAllocSize, MyLockedGxact, 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, xllist::total_len, xl_xact_prepare::total_len, TWOPHASE_MAGIC, TWOPHASE_RM_END_ID, XLOG_INCLUDE_ORIGIN, XLOG_XACT_PREPARE, XLogBeginInsert(), XLogEnsureRecordSpace(), XLogFlush(), XLogInsert(), XLogRegisterData(), and XLogSetRecordFlags().

Referenced by PrepareTransaction().

◆ FinishPreparedTransaction()

void FinishPreparedTransaction ( const char *  gid,
bool  isCommit 
)

Definition at line 1481 of file twophase.c.

1482 {
1483  GlobalTransaction gxact;
1484  PGPROC *proc;
1485  TransactionId xid;
1486  char *buf;
1487  char *bufptr;
1488  TwoPhaseFileHeader *hdr;
1489  TransactionId latestXid;
1490  TransactionId *children;
1491  RelFileLocator *commitrels;
1492  RelFileLocator *abortrels;
1493  RelFileLocator *delrels;
1494  int ndelrels;
1495  xl_xact_stats_item *commitstats;
1496  xl_xact_stats_item *abortstats;
1497  SharedInvalidationMessage *invalmsgs;
1498 
1499  /*
1500  * Validate the GID, and lock the GXACT to ensure that two backends do not
1501  * try to commit the same GID at once.
1502  */
1503  gxact = LockGXact(gid, GetUserId());
1504  proc = &ProcGlobal->allProcs[gxact->pgprocno];
1505  xid = gxact->xid;
1506 
1507  /*
1508  * Read and validate 2PC state data. State data will typically be stored
1509  * in WAL files if the LSN is after the last checkpoint record, or moved
1510  * to disk if for some reason they have lived for a long time.
1511  */
1512  if (gxact->ondisk)
1513  buf = ReadTwoPhaseFile(xid, false);
1514  else
1515  XlogReadTwoPhaseData(gxact->prepare_start_lsn, &buf, NULL);
1516 
1517 
1518  /*
1519  * Disassemble the header area
1520  */
1521  hdr = (TwoPhaseFileHeader *) buf;
1522  Assert(TransactionIdEquals(hdr->xid, xid));
1523  bufptr = buf + MAXALIGN(sizeof(TwoPhaseFileHeader));
1524  bufptr += MAXALIGN(hdr->gidlen);
1525  children = (TransactionId *) bufptr;
1526  bufptr += MAXALIGN(hdr->nsubxacts * sizeof(TransactionId));
1527  commitrels = (RelFileLocator *) bufptr;
1528  bufptr += MAXALIGN(hdr->ncommitrels * sizeof(RelFileLocator));
1529  abortrels = (RelFileLocator *) bufptr;
1530  bufptr += MAXALIGN(hdr->nabortrels * sizeof(RelFileLocator));
1531  commitstats = (xl_xact_stats_item *) bufptr;
1532  bufptr += MAXALIGN(hdr->ncommitstats * sizeof(xl_xact_stats_item));
1533  abortstats = (xl_xact_stats_item *) bufptr;
1534  bufptr += MAXALIGN(hdr->nabortstats * sizeof(xl_xact_stats_item));
1535  invalmsgs = (SharedInvalidationMessage *) bufptr;
1536  bufptr += MAXALIGN(hdr->ninvalmsgs * sizeof(SharedInvalidationMessage));
1537 
1538  /* compute latestXid among all children */
1539  latestXid = TransactionIdLatest(xid, hdr->nsubxacts, children);
1540 
1541  /* Prevent cancel/die interrupt while cleaning up */
1542  HOLD_INTERRUPTS();
1543 
1544  /*
1545  * The order of operations here is critical: make the XLOG entry for
1546  * commit or abort, then mark the transaction committed or aborted in
1547  * pg_xact, then remove its PGPROC from the global ProcArray (which means
1548  * TransactionIdIsInProgress will stop saying the prepared xact is in
1549  * progress), then run the post-commit or post-abort callbacks. The
1550  * callbacks will release the locks the transaction held.
1551  */
1552  if (isCommit)
1554  hdr->nsubxacts, children,
1555  hdr->ncommitrels, commitrels,
1556  hdr->ncommitstats,
1557  commitstats,
1558  hdr->ninvalmsgs, invalmsgs,
1559  hdr->initfileinval, gid);
1560  else
1562  hdr->nsubxacts, children,
1563  hdr->nabortrels, abortrels,
1564  hdr->nabortstats,
1565  abortstats,
1566  gid);
1567 
1568  ProcArrayRemove(proc, latestXid);
1569 
1570  /*
1571  * In case we fail while running the callbacks, mark the gxact invalid so
1572  * no one else will try to commit/rollback, and so it will be recycled if
1573  * we fail after this point. It is still locked by our backend so it
1574  * won't go away yet.
1575  *
1576  * (We assume it's safe to do this without taking TwoPhaseStateLock.)
1577  */
1578  gxact->valid = false;
1579 
1580  /*
1581  * We have to remove any files that were supposed to be dropped. For
1582  * consistency with the regular xact.c code paths, must do this before
1583  * releasing locks, so do it before running the callbacks.
1584  *
1585  * NB: this code knows that we couldn't be dropping any temp rels ...
1586  */
1587  if (isCommit)
1588  {
1589  delrels = commitrels;
1590  ndelrels = hdr->ncommitrels;
1591  }
1592  else
1593  {
1594  delrels = abortrels;
1595  ndelrels = hdr->nabortrels;
1596  }
1597 
1598  /* Make sure files supposed to be dropped are dropped */
1599  DropRelationFiles(delrels, ndelrels, false);
1600 
1601  if (isCommit)
1602  pgstat_execute_transactional_drops(hdr->ncommitstats, commitstats, false);
1603  else
1604  pgstat_execute_transactional_drops(hdr->nabortstats, abortstats, false);
1605 
1606  /*
1607  * Handle cache invalidation messages.
1608  *
1609  * Relcache init file invalidation requires processing both before and
1610  * after we send the SI messages, only when committing. See
1611  * AtEOXact_Inval().
1612  */
1613  if (isCommit)
1614  {
1615  if (hdr->initfileinval)
1617  SendSharedInvalidMessages(invalmsgs, hdr->ninvalmsgs);
1618  if (hdr->initfileinval)
1620  }
1621 
1622  /*
1623  * Acquire the two-phase lock. We want to work on the two-phase callbacks
1624  * while holding it to avoid potential conflicts with other transactions
1625  * attempting to use the same GID, so the lock is released once the shared
1626  * memory state is cleared.
1627  */
1628  LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
1629 
1630  /* And now do the callbacks */
1631  if (isCommit)
1633  else
1635 
1636  PredicateLockTwoPhaseFinish(xid, isCommit);
1637 
1638  /* Clear shared memory state */
1639  RemoveGXact(gxact);
1640 
1641  /*
1642  * Release the lock as all callbacks are called and shared memory cleanup
1643  * is done.
1644  */
1645  LWLockRelease(TwoPhaseStateLock);
1646 
1647  /* Count the prepared xact as committed or aborted */
1648  AtEOXact_PgStat(isCommit, false);
1649 
1650  /*
1651  * And now we can clean up any files we may have left.
1652  */
1653  if (gxact->ondisk)
1654  RemoveTwoPhaseFile(xid, true);
1655 
1656  MyLockedGxact = NULL;
1657 
1659 
1660  pfree(buf);
1661 }
#define MAXALIGN(LEN)
Definition: c.h:800
uint32 TransactionId
Definition: c.h:641
void DropRelationFiles(RelFileLocator *delrels, int ndelrels, bool isRedo)
Definition: md.c:1252
#define RESUME_INTERRUPTS()
Definition: miscadmin.h:134
#define HOLD_INTERRUPTS()
Definition: miscadmin.h:132
Oid GetUserId(void)
Definition: miscinit.c:509
void pgstat_execute_transactional_drops(int ndrops, struct xl_xact_stats_item *items, bool is_redo)
Definition: pgstat_xact.c:313
void AtEOXact_PgStat(bool isCommit, bool parallel)
Definition: pgstat_xact.c:41
void PredicateLockTwoPhaseFinish(TransactionId xid, bool isCommit)
Definition: predicate.c:4816
void ProcArrayRemove(PGPROC *proc, TransactionId latestXid)
Definition: procarray.c:565
void RelationCacheInitFilePostInvalidate(void)
Definition: relcache.c:6761
void RelationCacheInitFilePreInvalidate(void)
Definition: relcache.c:6736
void SendSharedInvalidMessages(const SharedInvalidationMessage *msgs, int n)
Definition: sinval.c:49
PROC_HDR * ProcGlobal
Definition: proc.c:78
Definition: proc.h:162
PGPROC * allProcs
Definition: proc.h:362
int32 nabortrels
Definition: xact.h:356
int32 ninvalmsgs
Definition: xact.h:359
bool initfileinval
Definition: xact.h:360
int32 ncommitstats
Definition: xact.h:357
uint16 gidlen
Definition: xact.h:361
int32 nabortstats
Definition: xact.h:358
int32 ncommitrels
Definition: xact.h:355
TransactionId xid
Definition: xact.h:350
int32 nsubxacts
Definition: xact.h:354
TransactionId TransactionIdLatest(TransactionId mainxid, int nxids, const TransactionId *xids)
Definition: transam.c:345
#define TransactionIdEquals(id1, id2)
Definition: transam.h:43
static void RecordTransactionAbortPrepared(TransactionId xid, int nchildren, TransactionId *children, int nrels, RelFileLocator *rels, int nstats, xl_xact_stats_item *stats, const char *gid)
Definition: twophase.c:2381
static void RecordTransactionCommitPrepared(TransactionId xid, int nchildren, TransactionId *children, int nrels, RelFileLocator *rels, int nstats, xl_xact_stats_item *stats, int ninvalmsgs, SharedInvalidationMessage *invalmsgs, bool initfileinval, const char *gid)
Definition: twophase.c:2283
static void ProcessRecords(char *bufptr, TransactionId xid, const TwoPhaseCallback callbacks[])
Definition: twophase.c:1667
static void RemoveTwoPhaseFile(TransactionId xid, bool giveWarning)
Definition: twophase.c:1695
static char * ReadTwoPhaseFile(TransactionId xid, bool missing_ok)
Definition: twophase.c:1281
static GlobalTransaction LockGXact(const char *gid, Oid user)
Definition: twophase.c:571
const TwoPhaseCallback twophase_postcommit_callbacks[TWOPHASE_RM_MAX_ID+1]
Definition: twophase_rmgr.c:33
const TwoPhaseCallback twophase_postabort_callbacks[TWOPHASE_RM_MAX_ID+1]
Definition: twophase_rmgr.c:42

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, MyLockedGxact, xl_xact_prepare::nabortrels, xl_xact_prepare::nabortstats, xl_xact_prepare::ncommitrels, xl_xact_prepare::ncommitstats, xl_xact_prepare::ninvalmsgs, xl_xact_prepare::nsubxacts, GlobalTransactionData::ondisk, pfree(), GlobalTransactionData::pgprocno, pgstat_execute_transactional_drops(), 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 apply_handle_commit_prepared(), apply_handle_rollback_prepared(), and standard_ProcessUtility().

◆ LookupGXact()

bool LookupGXact ( const char *  gid,
XLogRecPtr  prepare_end_lsn,
TimestampTz  origin_prepare_timestamp 
)

Definition at line 2610 of file twophase.c.

2612 {
2613  int i;
2614  bool found = false;
2615 
2616  LWLockAcquire(TwoPhaseStateLock, LW_SHARED);
2617  for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
2618  {
2620 
2621  /* Ignore not-yet-valid GIDs. */
2622  if (gxact->valid && strcmp(gxact->gid, gid) == 0)
2623  {
2624  char *buf;
2625  TwoPhaseFileHeader *hdr;
2626 
2627  /*
2628  * We are not expecting collisions of GXACTs (same gid) between
2629  * publisher and subscribers, so we perform all I/O while holding
2630  * TwoPhaseStateLock for simplicity.
2631  *
2632  * To move the I/O out of the lock, we need to ensure that no
2633  * other backend commits the prepared xact in the meantime. We can
2634  * do this optimization if we encounter many collisions in GID
2635  * between publisher and subscriber.
2636  */
2637  if (gxact->ondisk)
2638  buf = ReadTwoPhaseFile(gxact->xid, false);
2639  else
2640  {
2641  Assert(gxact->prepare_start_lsn);
2642  XlogReadTwoPhaseData(gxact->prepare_start_lsn, &buf, NULL);
2643  }
2644 
2645  hdr = (TwoPhaseFileHeader *) buf;
2646 
2647  if (hdr->origin_lsn == prepare_end_lsn &&
2648  hdr->origin_timestamp == origin_prepare_timestamp)
2649  {
2650  found = true;
2651  pfree(buf);
2652  break;
2653  }
2654 
2655  pfree(buf);
2656  }
2657  }
2658  LWLockRelease(TwoPhaseStateLock);
2659  return found;
2660 }
char gid[GIDSIZE]
Definition: twophase.c:173

References Assert(), buf, GlobalTransactionData::gid, i, LW_SHARED, LWLockAcquire(), LWLockRelease(), TwoPhaseStateData::numPrepXacts, GlobalTransactionData::ondisk, xl_xact_prepare::origin_lsn, xl_xact_prepare::origin_timestamp, pfree(), GlobalTransactionData::prepare_start_lsn, TwoPhaseStateData::prepXacts, ReadTwoPhaseFile(), TwoPhaseState, GlobalTransactionData::valid, GlobalTransactionData::xid, and XlogReadTwoPhaseData().

Referenced by apply_handle_rollback_prepared().

◆ MarkAsPreparing()

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

Definition at line 377 of file twophase.c.

379 {
380  GlobalTransaction gxact;
381  int i;
382 
383  if (strlen(gid) >= GIDSIZE)
384  ereport(ERROR,
385  (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
386  errmsg("transaction identifier \"%s\" is too long",
387  gid)));
388 
389  /* fail immediately if feature is disabled */
390  if (max_prepared_xacts == 0)
391  ereport(ERROR,
392  (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
393  errmsg("prepared transactions are disabled"),
394  errhint("Set max_prepared_transactions to a nonzero value.")));
395 
396  /* on first call, register the exit hook */
398  {
400  twophaseExitRegistered = true;
401  }
402 
403  LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
404 
405  /* Check for conflicting GID */
406  for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
407  {
408  gxact = TwoPhaseState->prepXacts[i];
409  if (strcmp(gxact->gid, gid) == 0)
410  {
411  ereport(ERROR,
413  errmsg("transaction identifier \"%s\" is already in use",
414  gid)));
415  }
416  }
417 
418  /* Get a free gxact from the freelist */
419  if (TwoPhaseState->freeGXacts == NULL)
420  ereport(ERROR,
421  (errcode(ERRCODE_OUT_OF_MEMORY),
422  errmsg("maximum number of prepared transactions reached"),
423  errhint("Increase max_prepared_transactions (currently %d).",
425  gxact = TwoPhaseState->freeGXacts;
426  TwoPhaseState->freeGXacts = gxact->next;
427 
428  MarkAsPreparingGuts(gxact, xid, gid, prepared_at, owner, databaseid);
429 
430  gxact->ondisk = false;
431 
432  /* And insert it into the active array */
435 
436  LWLockRelease(TwoPhaseStateLock);
437 
438  return gxact;
439 }
int errhint(const char *fmt,...)
Definition: elog.c:1316
void before_shmem_exit(pg_on_exit_callback function, Datum arg)
Definition: ipc.c:333
#define ERRCODE_DUPLICATE_OBJECT
Definition: streamutil.c:32
GlobalTransaction next
Definition: twophase.c:152
GlobalTransaction freeGXacts
Definition: twophase.c:183
static bool twophaseExitRegistered
Definition: twophase.c:202
static void MarkAsPreparingGuts(GlobalTransaction gxact, TransactionId xid, const char *gid, TimestampTz prepared_at, Oid owner, Oid databaseid)
Definition: twophase.c:451
static void AtProcExit_Twophase(int code, Datum arg)
Definition: twophase.c:312
#define GIDSIZE
Definition: xact.h:31

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, twophaseExitRegistered, and TwoPhaseState.

Referenced by PrepareTransaction().

◆ PostPrepare_Twophase()

void PostPrepare_Twophase ( void  )

Definition at line 362 of file twophase.c.

363 {
364  LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
366  LWLockRelease(TwoPhaseStateLock);
367 
368  MyLockedGxact = NULL;
369 }

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

Referenced by PrepareTransaction(), and RecoverPreparedTransactions().

◆ PrepareRedoAdd()

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

Definition at line 2456 of file twophase.c.

2458 {
2460  char *bufptr;
2461  const char *gid;
2462  GlobalTransaction gxact;
2463 
2464  Assert(LWLockHeldByMeInMode(TwoPhaseStateLock, LW_EXCLUSIVE));
2466 
2467  bufptr = buf + MAXALIGN(sizeof(TwoPhaseFileHeader));
2468  gid = (const char *) bufptr;
2469 
2470  /*
2471  * Reserve the GID for the given transaction in the redo code path.
2472  *
2473  * This creates a gxact struct and puts it into the active array.
2474  *
2475  * In redo, this struct is mainly used to track PREPARE/COMMIT entries in
2476  * shared memory. Hence, we only fill up the bare minimum contents here.
2477  * The gxact also gets marked with gxact->inredo set to true to indicate
2478  * that it got added in the redo phase
2479  */
2480 
2481  /*
2482  * In the event of a crash while a checkpoint was running, it may be
2483  * possible that some two-phase data found its way to disk while its
2484  * corresponding record needs to be replayed in the follow-up recovery. As
2485  * the 2PC data was on disk, it has already been restored at the beginning
2486  * of recovery with restoreTwoPhaseData(), so skip this record to avoid
2487  * duplicates in TwoPhaseState. If a consistent state has been reached,
2488  * the record is added to TwoPhaseState and it should have no
2489  * corresponding file in pg_twophase.
2490  */
2491  if (!XLogRecPtrIsInvalid(start_lsn))
2492  {
2493  char path[MAXPGPATH];
2494 
2495  TwoPhaseFilePath(path, hdr->xid);
2496 
2497  if (access(path, F_OK) == 0)
2498  {
2500  (errmsg("could not recover two-phase state file for transaction %u",
2501  hdr->xid),
2502  errdetail("Two-phase state file has been found in WAL record %X/%X, but this transaction has already been restored from disk.",
2503  LSN_FORMAT_ARGS(start_lsn))));
2504  return;
2505  }
2506 
2507  if (errno != ENOENT)
2508  ereport(ERROR,
2510  errmsg("could not access file \"%s\": %m", path)));
2511  }
2512 
2513  /* Get a free gxact from the freelist */
2514  if (TwoPhaseState->freeGXacts == NULL)
2515  ereport(ERROR,
2516  (errcode(ERRCODE_OUT_OF_MEMORY),
2517  errmsg("maximum number of prepared transactions reached"),
2518  errhint("Increase max_prepared_transactions (currently %d).",
2519  max_prepared_xacts)));
2520  gxact = TwoPhaseState->freeGXacts;
2521  TwoPhaseState->freeGXacts = gxact->next;
2522 
2523  gxact->prepared_at = hdr->prepared_at;
2524  gxact->prepare_start_lsn = start_lsn;
2525  gxact->prepare_end_lsn = end_lsn;
2526  gxact->xid = hdr->xid;
2527  gxact->owner = hdr->owner;
2529  gxact->valid = false;
2530  gxact->ondisk = XLogRecPtrIsInvalid(start_lsn);
2531  gxact->inredo = true; /* yes, added in redo */
2532  strcpy(gxact->gid, gid);
2533 
2534  /* And insert it into the active array */
2537 
2538  if (origin_id != InvalidRepOriginId)
2539  {
2540  /* recover apply progress */
2541  replorigin_advance(origin_id, hdr->origin_lsn, end_lsn,
2542  false /* backward */ , false /* WAL */ );
2543  }
2544 
2545  elog(DEBUG2, "added 2PC data in shared memory for transaction %u", gxact->xid);
2546 }
int errcode_for_file_access(void)
Definition: elog.c:881
int errdetail(const char *fmt,...)
Definition: elog.c:1202
#define WARNING
Definition: elog.h:36
#define DEBUG2
Definition: elog.h:29
bool LWLockHeldByMeInMode(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1964
void replorigin_advance(RepOriginId node, XLogRecPtr remote_commit, XLogRecPtr local_commit, bool go_backward, bool wal_log)
Definition: origin.c:888
#define MAXPGPATH
short access
Definition: preproc-type.c:36
TimestampTz prepared_at
Definition: twophase.c:155
TimestampTz prepared_at
Definition: xact.h:352
#define TwoPhaseFilePath(path, xid)
Definition: twophase.c:945
bool RecoveryInProgress(void)
Definition: xlog.c:5948
#define LSN_FORMAT_ARGS(lsn)
Definition: xlogdefs.h:43
#define XLogRecPtrIsInvalid(r)
Definition: xlogdefs.h:29
bool reachedConsistency
Definition: xlogrecovery.c:294

References Assert(), buf, DEBUG2, elog(), ereport, errcode(), errcode_for_file_access(), errdetail(), errhint(), errmsg(), ERROR, TwoPhaseStateData::freeGXacts, GlobalTransactionData::gid, GlobalTransactionData::inredo, InvalidBackendId, InvalidRepOriginId, GlobalTransactionData::locking_backend, LSN_FORMAT_ARGS, LW_EXCLUSIVE, LWLockHeldByMeInMode(), max_prepared_xacts, MAXALIGN, MAXPGPATH, 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, reachedConsistency, RecoveryInProgress(), replorigin_advance(), TwoPhaseFilePath, TwoPhaseState, GlobalTransactionData::valid, WARNING, GlobalTransactionData::xid, xl_xact_prepare::xid, and XLogRecPtrIsInvalid.

Referenced by restoreTwoPhaseData(), and xact_redo().

◆ PrepareRedoRemove()

void PrepareRedoRemove ( TransactionId  xid,
bool  giveWarning 
)

Definition at line 2558 of file twophase.c.

2559 {
2560  GlobalTransaction gxact = NULL;
2561  int i;
2562  bool found = false;
2563 
2564  Assert(LWLockHeldByMeInMode(TwoPhaseStateLock, LW_EXCLUSIVE));
2566 
2567  for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
2568  {
2569  gxact = TwoPhaseState->prepXacts[i];
2570 
2571  if (gxact->xid == xid)
2572  {
2573  Assert(gxact->inredo);
2574  found = true;
2575  break;
2576  }
2577  }
2578 
2579  /*
2580  * Just leave if there is nothing, this is expected during WAL replay.
2581  */
2582  if (!found)
2583  return;
2584 
2585  /*
2586  * And now we can clean up any files we may have left.
2587  */
2588  elog(DEBUG2, "removing 2PC data for transaction %u", xid);
2589  if (gxact->ondisk)
2590  RemoveTwoPhaseFile(xid, giveWarning);
2591  RemoveGXact(gxact);
2592 }

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

Referenced by ProcessTwoPhaseBuffer(), and xact_redo().

◆ PrescanPreparedTransactions()

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

Definition at line 1938 of file twophase.c.

1939 {
1941  TransactionId origNextXid = XidFromFullTransactionId(nextXid);
1942  TransactionId result = origNextXid;
1943  TransactionId *xids = NULL;
1944  int nxids = 0;
1945  int allocsize = 0;
1946  int i;
1947 
1948  LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
1949  for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
1950  {
1951  TransactionId xid;
1952  char *buf;
1954 
1955  Assert(gxact->inredo);
1956 
1957  xid = gxact->xid;
1958 
1959  buf = ProcessTwoPhaseBuffer(xid,
1960  gxact->prepare_start_lsn,
1961  gxact->ondisk, false, true);
1962 
1963  if (buf == NULL)
1964  continue;
1965 
1966  /*
1967  * OK, we think this file is valid. Incorporate xid into the
1968  * running-minimum result.
1969  */
1970  if (TransactionIdPrecedes(xid, result))
1971  result = xid;
1972 
1973  if (xids_p)
1974  {
1975  if (nxids == allocsize)
1976  {
1977  if (nxids == 0)
1978  {
1979  allocsize = 10;
1980  xids = palloc(allocsize * sizeof(TransactionId));
1981  }
1982  else
1983  {
1984  allocsize = allocsize * 2;
1985  xids = repalloc(xids, allocsize * sizeof(TransactionId));
1986  }
1987  }
1988  xids[nxids++] = xid;
1989  }
1990 
1991  pfree(buf);
1992  }
1993  LWLockRelease(TwoPhaseStateLock);
1994 
1995  if (xids_p)
1996  {
1997  *xids_p = xids;
1998  *nxids_p = nxids;
1999  }
2000 
2001  return result;
2002 }
void * repalloc(void *pointer, Size size)
Definition: mcxt.c:1476
void * palloc(Size size)
Definition: mcxt.c:1226
FullTransactionId nextXid
Definition: transam.h:220
bool TransactionIdPrecedes(TransactionId id1, TransactionId id2)
Definition: transam.c:280
#define XidFromFullTransactionId(x)
Definition: transam.h:48
static char * ProcessTwoPhaseBuffer(TransactionId xid, XLogRecPtr prepare_start_lsn, bool fromdisk, bool setParent, bool setNextXid)
Definition: twophase.c:2163
VariableCache ShmemVariableCache
Definition: varsup.c:34

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(), TwoPhaseState, GlobalTransactionData::xid, and XidFromFullTransactionId.

Referenced by StartupXLOG(), and xlog_redo().

◆ RecoverPreparedTransactions()

void RecoverPreparedTransactions ( void  )

Definition at line 2060 of file twophase.c.

2061 {
2062  int i;
2063 
2064  LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
2065  for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
2066  {
2067  TransactionId xid;
2068  char *buf;
2070  char *bufptr;
2071  TwoPhaseFileHeader *hdr;
2072  TransactionId *subxids;
2073  const char *gid;
2074 
2075  xid = gxact->xid;
2076 
2077  /*
2078  * Reconstruct subtrans state for the transaction --- needed because
2079  * pg_subtrans is not preserved over a restart. Note that we are
2080  * linking all the subtransactions directly to the top-level XID;
2081  * there may originally have been a more complex hierarchy, but
2082  * there's no need to restore that exactly. It's possible that
2083  * SubTransSetParent has been set before, if the prepared transaction
2084  * generated xid assignment records.
2085  */
2086  buf = ProcessTwoPhaseBuffer(xid,
2087  gxact->prepare_start_lsn,
2088  gxact->ondisk, true, false);
2089  if (buf == NULL)
2090  continue;
2091 
2092  ereport(LOG,
2093  (errmsg("recovering prepared transaction %u from shared memory", xid)));
2094 
2095  hdr = (TwoPhaseFileHeader *) buf;
2096  Assert(TransactionIdEquals(hdr->xid, xid));
2097  bufptr = buf + MAXALIGN(sizeof(TwoPhaseFileHeader));
2098  gid = (const char *) bufptr;
2099  bufptr += MAXALIGN(hdr->gidlen);
2100  subxids = (TransactionId *) bufptr;
2101  bufptr += MAXALIGN(hdr->nsubxacts * sizeof(TransactionId));
2102  bufptr += MAXALIGN(hdr->ncommitrels * sizeof(RelFileLocator));
2103  bufptr += MAXALIGN(hdr->nabortrels * sizeof(RelFileLocator));
2104  bufptr += MAXALIGN(hdr->ncommitstats * sizeof(xl_xact_stats_item));
2105  bufptr += MAXALIGN(hdr->nabortstats * sizeof(xl_xact_stats_item));
2106  bufptr += MAXALIGN(hdr->ninvalmsgs * sizeof(SharedInvalidationMessage));
2107 
2108  /*
2109  * Recreate its GXACT and dummy PGPROC. But, check whether it was
2110  * added in redo and already has a shmem entry for it.
2111  */
2112  MarkAsPreparingGuts(gxact, xid, gid,
2113  hdr->prepared_at,
2114  hdr->owner, hdr->database);
2115 
2116  /* recovered, so reset the flag for entries generated by redo */
2117  gxact->inredo = false;
2118 
2119  GXactLoadSubxactData(gxact, hdr->nsubxacts, subxids);
2120  MarkAsPrepared(gxact, true);
2121 
2122  LWLockRelease(TwoPhaseStateLock);
2123 
2124  /*
2125  * Recover other state (notably locks) using resource managers.
2126  */
2128 
2129  /*
2130  * Release locks held by the standby process after we process each
2131  * prepared transaction. As a result, we don't need too many
2132  * additional locks at any one time.
2133  */
2134  if (InHotStandby)
2135  StandbyReleaseLockTree(xid, hdr->nsubxacts, subxids);
2136 
2137  /*
2138  * We're done with recovering this transaction. Clear MyLockedGxact,
2139  * like we do in PrepareTransaction() during normal operation.
2140  */
2142 
2143  pfree(buf);
2144 
2145  LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
2146  }
2147 
2148  LWLockRelease(TwoPhaseStateLock);
2149 }
void StandbyReleaseLockTree(TransactionId xid, int nsubxids, TransactionId *subxids)
Definition: standby.c:1093
Oid database
Definition: xact.h:351
static void GXactLoadSubxactData(GlobalTransaction gxact, int nsubxacts, TransactionId *children)
Definition: twophase.c:523
void PostPrepare_Twophase(void)
Definition: twophase.c:362
const TwoPhaseCallback twophase_recover_callbacks[TWOPHASE_RM_MAX_ID+1]
Definition: twophase_rmgr.c:24
#define InHotStandby
Definition: xlogutils.h:57

References Assert(), buf, xl_xact_prepare::database, ereport, errmsg(), xl_xact_prepare::gidlen, GXactLoadSubxactData(), i, InHotStandby, GlobalTransactionData::inredo, LOG, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MarkAsPrepared(), MarkAsPreparingGuts(), MAXALIGN, xl_xact_prepare::nabortrels, xl_xact_prepare::nabortstats, xl_xact_prepare::ncommitrels, xl_xact_prepare::ncommitstats, 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, TwoPhaseState, GlobalTransactionData::xid, and xl_xact_prepare::xid.

Referenced by StartupXLOG().

◆ restoreTwoPhaseData()

void restoreTwoPhaseData ( void  )

Definition at line 1876 of file twophase.c.

1877 {
1878  DIR *cldir;
1879  struct dirent *clde;
1880 
1881  LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
1882  cldir = AllocateDir(TWOPHASE_DIR);
1883  while ((clde = ReadDir(cldir, TWOPHASE_DIR)) != NULL)
1884  {
1885  if (strlen(clde->d_name) == 8 &&
1886  strspn(clde->d_name, "0123456789ABCDEF") == 8)
1887  {
1888  TransactionId xid;
1889  char *buf;
1890 
1891  xid = (TransactionId) strtoul(clde->d_name, NULL, 16);
1892 
1894  true, false, false);
1895  if (buf == NULL)
1896  continue;
1897 
1900  }
1901  }
1902  LWLockRelease(TwoPhaseStateLock);
1903  FreeDir(cldir);
1904 }
struct dirent * ReadDir(DIR *dir, const char *dirname)
Definition: fd.c:2854
int FreeDir(DIR *dir)
Definition: fd.c:2906
DIR * AllocateDir(const char *dirname)
Definition: fd.c:2788
Definition: dirent.c:26
Definition: dirent.h:10
char d_name[MAX_PATH]
Definition: dirent.h:15
void PrepareRedoAdd(char *buf, XLogRecPtr start_lsn, XLogRecPtr end_lsn, RepOriginId origin_id)
Definition: twophase.c:2456

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

Referenced by StartupXLOG().

◆ StandbyRecoverPreparedTransactions()

void StandbyRecoverPreparedTransactions ( void  )

Definition at line 2019 of file twophase.c.

2020 {
2021  int i;
2022 
2023  LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
2024  for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
2025  {
2026  TransactionId xid;
2027  char *buf;
2029 
2030  Assert(gxact->inredo);
2031 
2032  xid = gxact->xid;
2033 
2034  buf = ProcessTwoPhaseBuffer(xid,
2035  gxact->prepare_start_lsn,
2036  gxact->ondisk, false, false);
2037  if (buf != NULL)
2038  pfree(buf);
2039  }
2040  LWLockRelease(TwoPhaseStateLock);
2041 }

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

Referenced by StartupXLOG(), and xlog_redo().

◆ StandbyTransactionIdIsPrepared()

bool StandbyTransactionIdIsPrepared ( TransactionId  xid)

Definition at line 1453 of file twophase.c.

1454 {
1455  char *buf;
1456  TwoPhaseFileHeader *hdr;
1457  bool result;
1458 
1460 
1461  if (max_prepared_xacts <= 0)
1462  return false; /* nothing to do */
1463 
1464  /* Read and validate file */
1465  buf = ReadTwoPhaseFile(xid, true);
1466  if (buf == NULL)
1467  return false;
1468 
1469  /* Check header also */
1470  hdr = (TwoPhaseFileHeader *) buf;
1471  result = TransactionIdEquals(hdr->xid, xid);
1472  pfree(buf);
1473 
1474  return result;
1475 }
#define TransactionIdIsValid(xid)
Definition: transam.h:41

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

Referenced by KnownAssignedXidsRemovePreceding(), and StandbyReleaseOldLocks().

◆ StartPrepare()

void StartPrepare ( GlobalTransaction  gxact)

Definition at line 1043 of file twophase.c.

1044 {
1045  PGPROC *proc = &ProcGlobal->allProcs[gxact->pgprocno];
1046  TransactionId xid = gxact->xid;
1047  TwoPhaseFileHeader hdr;
1048  TransactionId *children;
1049  RelFileLocator *commitrels;
1050  RelFileLocator *abortrels;
1051  xl_xact_stats_item *abortstats = NULL;
1052  xl_xact_stats_item *commitstats = NULL;
1053  SharedInvalidationMessage *invalmsgs;
1054 
1055  /* Initialize linked list */
1056  records.head = palloc0(sizeof(StateFileChunk));
1057  records.head->len = 0;
1058  records.head->next = NULL;
1059 
1060  records.bytes_free = Max(sizeof(TwoPhaseFileHeader), 512);
1062 
1064  records.num_chunks = 1;
1065 
1066  records.total_len = 0;
1067 
1068  /* Create header */
1069  hdr.magic = TWOPHASE_MAGIC;
1070  hdr.total_len = 0; /* EndPrepare will fill this in */
1071  hdr.xid = xid;
1072  hdr.database = proc->databaseId;
1073  hdr.prepared_at = gxact->prepared_at;
1074  hdr.owner = gxact->owner;
1075  hdr.nsubxacts = xactGetCommittedChildren(&children);
1076  hdr.ncommitrels = smgrGetPendingDeletes(true, &commitrels);
1077  hdr.nabortrels = smgrGetPendingDeletes(false, &abortrels);
1078  hdr.ncommitstats =
1079  pgstat_get_transactional_drops(true, &commitstats);
1080  hdr.nabortstats =
1081  pgstat_get_transactional_drops(false, &abortstats);
1083  &hdr.initfileinval);
1084  hdr.gidlen = strlen(gxact->gid) + 1; /* Include '\0' */
1085  /* EndPrepare will fill the origin data, if necessary */
1087  hdr.origin_timestamp = 0;
1088 
1089  save_state_data(&hdr, sizeof(TwoPhaseFileHeader));
1090  save_state_data(gxact->gid, hdr.gidlen);
1091 
1092  /*
1093  * Add the additional info about subxacts, deletable files and cache
1094  * invalidation messages.
1095  */
1096  if (hdr.nsubxacts > 0)
1097  {
1098  save_state_data(children, hdr.nsubxacts * sizeof(TransactionId));
1099  /* While we have the child-xact data, stuff it in the gxact too */
1100  GXactLoadSubxactData(gxact, hdr.nsubxacts, children);
1101  }
1102  if (hdr.ncommitrels > 0)
1103  {
1104  save_state_data(commitrels, hdr.ncommitrels * sizeof(RelFileLocator));
1105  pfree(commitrels);
1106  }
1107  if (hdr.nabortrels > 0)
1108  {
1109  save_state_data(abortrels, hdr.nabortrels * sizeof(RelFileLocator));
1110  pfree(abortrels);
1111  }
1112  if (hdr.ncommitstats > 0)
1113  {
1114  save_state_data(commitstats,
1115  hdr.ncommitstats * sizeof(xl_xact_stats_item));
1116  pfree(commitstats);
1117  }
1118  if (hdr.nabortstats > 0)
1119  {
1120  save_state_data(abortstats,
1121  hdr.nabortstats * sizeof(xl_xact_stats_item));
1122  pfree(abortstats);
1123  }
1124  if (hdr.ninvalmsgs > 0)
1125  {
1126  save_state_data(invalmsgs,
1127  hdr.ninvalmsgs * sizeof(SharedInvalidationMessage));
1128  pfree(invalmsgs);
1129  }
1130 }
#define Max(x, y)
Definition: c.h:987
int xactGetCommittedInvalidationMessages(SharedInvalidationMessage **msgs, bool *RelcacheInitFileInval)
Definition: inval.c:884
void * palloc0(Size size)
Definition: mcxt.c:1257
int pgstat_get_transactional_drops(bool isCommit, xl_xact_stats_item **items)
Definition: pgstat_xact.c:271
int smgrGetPendingDeletes(bool forCommit, RelFileLocator **ptr)
Definition: storage.c:870
Oid databaseId
Definition: proc.h:198
uint32 bytes_free
Definition: twophase.c:1001
static void save_state_data(const void *data, uint32 len)
Definition: twophase.c:1015
int xactGetCommittedChildren(TransactionId **ptr)
Definition: xact.c:5612

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, InvalidXLogRecPtr, StateFileChunk::len, xl_xact_prepare::magic, Max, xl_xact_prepare::nabortrels, xl_xact_prepare::nabortstats, xl_xact_prepare::ncommitrels, xl_xact_prepare::ncommitstats, StateFileChunk::next, xl_xact_prepare::ninvalmsgs, xl_xact_prepare::nsubxacts, xllist::num_chunks, xl_xact_prepare::origin_lsn, xl_xact_prepare::origin_timestamp, GlobalTransactionData::owner, xl_xact_prepare::owner, palloc(), palloc0(), pfree(), GlobalTransactionData::pgprocno, pgstat_get_transactional_drops(), GlobalTransactionData::prepared_at, xl_xact_prepare::prepared_at, ProcGlobal, records, save_state_data(), smgrGetPendingDeletes(), xllist::tail, xllist::total_len, xl_xact_prepare::total_len, TWOPHASE_MAGIC, xactGetCommittedChildren(), xactGetCommittedInvalidationMessages(), GlobalTransactionData::xid, and xl_xact_prepare::xid.

Referenced by PrepareTransaction().

◆ TwoPhaseGetDummyBackendId()

BackendId TwoPhaseGetDummyBackendId ( TransactionId  xid,
bool  lock_held 
)

Definition at line 919 of file twophase.c.

920 {
921  GlobalTransaction gxact = TwoPhaseGetGXact(xid, lock_held);
922 
923  return gxact->dummyBackendId;
924 }
BackendId dummyBackendId
Definition: twophase.c:154
static GlobalTransaction TwoPhaseGetGXact(TransactionId xid, bool lock_held)
Definition: twophase.c:819

References GlobalTransactionData::dummyBackendId, and TwoPhaseGetGXact().

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

◆ TwoPhaseGetDummyProc()

PGPROC* TwoPhaseGetDummyProc ( TransactionId  xid,
bool  lock_held 
)

Definition at line 934 of file twophase.c.

935 {
936  GlobalTransaction gxact = TwoPhaseGetGXact(xid, lock_held);
937 
938  return &ProcGlobal->allProcs[gxact->pgprocno];
939 }

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

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

◆ TwoPhaseGetXidByVirtualXID()

TransactionId TwoPhaseGetXidByVirtualXID ( VirtualTransactionId  vxid,
bool have_more 
)

Definition at line 871 of file twophase.c.

873 {
874  int i;
876 
878  LWLockAcquire(TwoPhaseStateLock, LW_SHARED);
879 
880  for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
881  {
883  PGPROC *proc;
884  VirtualTransactionId proc_vxid;
885 
886  if (!gxact->valid)
887  continue;
888  proc = &ProcGlobal->allProcs[gxact->pgprocno];
889  GET_VXID_FROM_PGPROC(proc_vxid, *proc);
890  if (VirtualTransactionIdEquals(vxid, proc_vxid))
891  {
892  /* Startup process sets proc->backendId to InvalidBackendId. */
893  Assert(!gxact->inredo);
894 
895  if (result != InvalidTransactionId)
896  {
897  *have_more = true;
898  break;
899  }
900  result = gxact->xid;
901  }
902  }
903 
904  LWLockRelease(TwoPhaseStateLock);
905 
906  return result;
907 }
#define VirtualTransactionIdIsValid(vxid)
Definition: lock.h:67
#define VirtualTransactionIdEquals(vxid1, vxid2)
Definition: lock.h:71
#define GET_VXID_FROM_PGPROC(vxid, proc)
Definition: lock.h:77
#define InvalidTransactionId
Definition: transam.h:31

References PROC_HDR::allProcs, Assert(), GET_VXID_FROM_PGPROC, i, GlobalTransactionData::inredo, InvalidTransactionId, LW_SHARED, LWLockAcquire(), LWLockRelease(), TwoPhaseStateData::numPrepXacts, GlobalTransactionData::pgprocno, TwoPhaseStateData::prepXacts, ProcGlobal, TwoPhaseState, GlobalTransactionData::valid, VirtualTransactionIdEquals, VirtualTransactionIdIsValid, and GlobalTransactionData::xid.

Referenced by XactLockForVirtualXact().

◆ TwoPhaseShmemInit()

void TwoPhaseShmemInit ( void  )

Definition at line 257 of file twophase.c.

258 {
259  bool found;
260 
261  TwoPhaseState = ShmemInitStruct("Prepared Transaction Table",
263  &found);
264  if (!IsUnderPostmaster)
265  {
266  GlobalTransaction gxacts;
267  int i;
268 
269  Assert(!found);
270  TwoPhaseState->freeGXacts = NULL;
272 
273  /*
274  * Initialize the linked list of free GlobalTransactionData structs
275  */
276  gxacts = (GlobalTransaction)
277  ((char *) TwoPhaseState +
278  MAXALIGN(offsetof(TwoPhaseStateData, prepXacts) +
280  for (i = 0; i < max_prepared_xacts; i++)
281  {
282  /* insert into linked list */
283  gxacts[i].next = TwoPhaseState->freeGXacts;
284  TwoPhaseState->freeGXacts = &gxacts[i];
285 
286  /* associate it with a PGPROC assigned by InitProcGlobal */
288 
289  /*
290  * Assign a unique ID for each dummy proc, so that the range of
291  * dummy backend IDs immediately follows the range of normal
292  * backend IDs. We don't dare to assign a real backend ID to dummy
293  * procs, because prepared transactions don't take part in cache
294  * invalidation like a real backend ID would imply, but having a
295  * unique ID for them is nevertheless handy. This arrangement
296  * allows you to allocate an array of size (MaxBackends +
297  * max_prepared_xacts + 1), and have a slot for every backend and
298  * prepared transaction. Currently multixact.c uses that
299  * technique.
300  */
301  gxacts[i].dummyBackendId = MaxBackends + 1 + i;
302  }
303  }
304  else
305  Assert(found);
306 }
bool IsUnderPostmaster
Definition: globals.c:113
int MaxBackends
Definition: globals.c:140
void * ShmemInitStruct(const char *name, Size size, bool *foundPtr)
Definition: shmem.c:396
PGPROC * PreparedXactProcs
Definition: proc.c:80
int pgprocno
Definition: proc.h:191
Size TwoPhaseShmemSize(void)
Definition: twophase.c:241
struct GlobalTransactionData * GlobalTransaction
Definition: twophase.h:26

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

Referenced by CreateSharedMemoryAndSemaphores().

◆ TwoPhaseShmemSize()

Size TwoPhaseShmemSize ( void  )

Definition at line 241 of file twophase.c.

242 {
243  Size size;
244 
245  /* Need the fixed struct, the array of pointers, and the GTD structs */
246  size = offsetof(TwoPhaseStateData, prepXacts);
247  size = add_size(size, mul_size(max_prepared_xacts,
248  sizeof(GlobalTransaction)));
249  size = MAXALIGN(size);
250  size = add_size(size, mul_size(max_prepared_xacts,
251  sizeof(GlobalTransactionData)));
252 
253  return size;
254 }
size_t Size
Definition: c.h:594
Size add_size(Size s1, Size s2)
Definition: shmem.c:502
Size mul_size(Size s1, Size s2)
Definition: shmem.c:519

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

Referenced by CalculateShmemSize(), and TwoPhaseShmemInit().

Variable Documentation

◆ max_prepared_xacts