PostgreSQL Source Code  git master
twophase.h File Reference
#include "access/xlogdefs.h"
#include "access/xact.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)
 
BackendId TwoPhaseGetDummyBackendId (TransactionId xid)
 
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 ParsePrepareRecord (uint8 info, char *xlrec, xl_xact_parsed_prepare *parsed)
 
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:1725
static void RemoveGXact(GlobalTransaction gxact)
Definition: twophase.c:633
#define InvalidBackendId
Definition: backendid.h:23
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1121
static GlobalTransaction MyLockedGxact
Definition: twophase.c:199

◆ CheckPointTwoPhase()

void CheckPointTwoPhase ( XLogRecPtr  redo_horizon)

Definition at line 1744 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().

1745 {
1746  int i;
1747  int serialized_xacts = 0;
1748 
1749  if (max_prepared_xacts <= 0)
1750  return; /* nothing to do */
1751 
1752  TRACE_POSTGRESQL_TWOPHASE_CHECKPOINT_START();
1753 
1754  /*
1755  * We are expecting there to be zero GXACTs that need to be copied to
1756  * disk, so we perform all I/O while holding TwoPhaseStateLock for
1757  * simplicity. This prevents any new xacts from preparing while this
1758  * occurs, which shouldn't be a problem since the presence of long-lived
1759  * prepared xacts indicates the transaction manager isn't active.
1760  *
1761  * It's also possible to move I/O out of the lock, but on every error we
1762  * should check whether somebody committed our transaction in different
1763  * backend. Let's leave this optimization for future, if somebody will
1764  * spot that this place cause bottleneck.
1765  *
1766  * Note that it isn't possible for there to be a GXACT with a
1767  * prepare_end_lsn set prior to the last checkpoint yet is marked invalid,
1768  * because of the efforts with delayChkpt.
1769  */
1770  LWLockAcquire(TwoPhaseStateLock, LW_SHARED);
1771  for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
1772  {
1773  /*
1774  * Note that we are using gxact not pgxact so this works in recovery
1775  * also
1776  */
1778 
1779  if ((gxact->valid || gxact->inredo) &&
1780  !gxact->ondisk &&
1781  gxact->prepare_end_lsn <= redo_horizon)
1782  {
1783  char *buf;
1784  int len;
1785 
1786  XlogReadTwoPhaseData(gxact->prepare_start_lsn, &buf, &len);
1787  RecreateTwoPhaseFile(gxact->xid, buf, len);
1788  gxact->ondisk = true;
1791  pfree(buf);
1792  serialized_xacts++;
1793  }
1794  }
1795  LWLockRelease(TwoPhaseStateLock);
1796 
1797  /*
1798  * Flush unconditionally the parent directory to make any information
1799  * durable on disk. Two-phase files could have been removed and those
1800  * removals need to be made persistent as well as any files newly created
1801  * previously since the last checkpoint.
1802  */
1803  fsync_fname(TWOPHASE_DIR, true);
1804 
1805  TRACE_POSTGRESQL_TWOPHASE_CHECKPOINT_DONE();
1806 
1807  if (log_checkpoints && serialized_xacts > 0)
1808  ereport(LOG,
1809  (errmsg_plural("%u two-phase state file was written "
1810  "for a long-running prepared transaction",
1811  "%u two-phase state files were written "
1812  "for long-running prepared transactions",
1813  serialized_xacts,
1814  serialized_xacts)));
1815 }
bool log_checkpoints
Definition: xlog.c:102
#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:850
void fsync_fname(const char *fname, bool isdir)
Definition: fd.c:575
#define LOG
Definition: elog.h:26
XLogRecPtr prepare_start_lsn
Definition: twophase.c:163
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1725
void pfree(void *pointer)
Definition: mcxt.c:1031
int max_prepared_xacts
Definition: twophase.c:117
static char * buf
Definition: pg_test_fsync.c:67
#define ereport(elevel, rest)
Definition: elog.h:122
GlobalTransaction prepXacts[FLEXIBLE_ARRAY_MEMBER]
Definition: twophase.c:188
static void RecreateTwoPhaseFile(TransactionId xid, void *content, int len)
Definition: twophase.c:1651
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1121
#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:1377
int i
XLogRecPtr prepare_end_lsn
Definition: twophase.c:164

◆ EndPrepare()

void EndPrepare ( GlobalTransaction  gxact)

Definition at line 1064 of file twophase.c.

References Assert, StateFileChunk::data, PGXACT::delayChkpt, DoNotReplicateId, END_CRIT_SECTION, ereport, errcode(), errmsg(), ERROR, xllist::head, InvalidRepOriginId, InvalidXLogRecPtr, StateFileChunk::len, TwoPhaseFileHeader::magic, MarkAsPrepared(), MaxAllocSize, MyPgXact, StateFileChunk::next, xllist::num_chunks, TwoPhaseFileHeader::origin_lsn, TwoPhaseFileHeader::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, TwoPhaseFileHeader::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().

1065 {
1066  TwoPhaseFileHeader *hdr;
1067  StateFileChunk *record;
1068  bool replorigin;
1069 
1070  /* Add the end sentinel to the list of 2PC records */
1072  NULL, 0);
1073 
1074  /* Go back and fill in total_len in the file header record */
1075  hdr = (TwoPhaseFileHeader *) records.head->data;
1076  Assert(hdr->magic == TWOPHASE_MAGIC);
1077  hdr->total_len = records.total_len + sizeof(pg_crc32c);
1078 
1079  replorigin = (replorigin_session_origin != InvalidRepOriginId &&
1081 
1082  if (replorigin)
1083  {
1087  }
1088  else
1089  {
1091  hdr->origin_timestamp = 0;
1092  }
1093 
1094  /*
1095  * If the data size exceeds MaxAllocSize, we won't be able to read it in
1096  * ReadTwoPhaseFile. Check for that now, rather than fail in the case
1097  * where we write data to file and then re-read at commit time.
1098  */
1099  if (hdr->total_len > MaxAllocSize)
1100  ereport(ERROR,
1101  (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
1102  errmsg("two-phase state file maximum length exceeded")));
1103 
1104  /*
1105  * Now writing 2PC state data to WAL. We let the WAL's CRC protection
1106  * cover us, so no need to calculate a separate CRC.
1107  *
1108  * We have to set delayChkpt here, too; otherwise a checkpoint starting
1109  * immediately after the WAL record is inserted could complete without
1110  * fsync'ing our state file. (This is essentially the same kind of race
1111  * condition as the COMMIT-to-clog-write case that RecordTransactionCommit
1112  * uses delayChkpt for; see notes there.)
1113  *
1114  * We save the PREPARE record's location in the gxact for later use by
1115  * CheckPointTwoPhase.
1116  */
1118 
1120 
1121  MyPgXact->delayChkpt = true;
1122 
1123  XLogBeginInsert();
1124  for (record = records.head; record != NULL; record = record->next)
1125  XLogRegisterData(record->data, record->len);
1126 
1128 
1129  gxact->prepare_end_lsn = XLogInsert(RM_XACT_ID, XLOG_XACT_PREPARE);
1130 
1131  if (replorigin)
1132  {
1133  /* Move LSNs forward for this replication origin */
1135  gxact->prepare_end_lsn);
1136  }
1137 
1138  XLogFlush(gxact->prepare_end_lsn);
1139 
1140  /* If we crash now, we have prepared: WAL replay will fix things */
1141 
1142  /* Store record's start location to read that later on Commit */
1144 
1145  /*
1146  * Mark the prepared transaction as valid. As soon as xact.c marks
1147  * MyPgXact as not running our XID (which it will do immediately after
1148  * this function returns), others can commit/rollback the xact.
1149  *
1150  * NB: a side effect of this is to make a dummy ProcArray entry for the
1151  * prepared XID. This must happen before we clear the XID from MyPgXact,
1152  * else there is a window where the XID is not running according to
1153  * TransactionIdIsInProgress, and onlookers would be entitled to assume
1154  * the xact crashed. Instead we have a window where the same XID appears
1155  * twice in ProcArray, which is OK.
1156  */
1157  MarkAsPrepared(gxact, false);
1158 
1159  /*
1160  * Now we can mark ourselves as out of the commit critical section: a
1161  * checkpoint starting after this will certainly see the gxact as a
1162  * candidate for fsyncing.
1163  */
1164  MyPgXact->delayChkpt = false;
1165 
1166  /*
1167  * Remember that we have this GlobalTransaction entry locked for us. If
1168  * we crash after this point, it's too late to abort, but we must unlock
1169  * it so that the prepared transaction can be committed or rolled back.
1170  */
1171  MyLockedGxact = gxact;
1172 
1173  END_CRIT_SECTION();
1174 
1175  /*
1176  * Wait for synchronous replication, if required.
1177  *
1178  * Note that at this stage we have marked the prepare, but still show as
1179  * running in the procarray (twice!) and continue to hold locks.
1180  */
1181  SyncRepWaitForLSN(gxact->prepare_end_lsn, false);
1182 
1183  records.tail = records.head = NULL;
1184  records.num_chunks = 0;
1185 }
#define InvalidXLogRecPtr
Definition: xlogdefs.h:28
#define XLOG_XACT_PREPARE
Definition: xact.h:141
#define DoNotReplicateId
Definition: origin.h:35
StateFileChunk * tail
Definition: twophase.c:947
uint32 pg_crc32c
Definition: pg_crc32c.h:38
XLogRecPtr ProcLastRecPtr
Definition: xlog.c:338
void SyncRepWaitForLSN(XLogRecPtr lsn, bool commit)
Definition: syncrep.c:146
#define END_CRIT_SECTION()
Definition: miscadmin.h:133
#define START_CRIT_SECTION()
Definition: miscadmin.h:131
int errcode(int sqlerrcode)
Definition: elog.c:575
#define TWOPHASE_RM_END_ID
Definition: twophase_rmgr.h:24
#define XLOG_INCLUDE_ORIGIN
Definition: xlog.h:192
uint32 num_chunks
Definition: twophase.c:948
void XLogFlush(XLogRecPtr record)
Definition: xlog.c:2796
void RegisterTwoPhaseRecord(TwoPhaseRmgrId rmid, uint16 info, const void *data, uint32 len)
Definition: twophase.c:1191
PGXACT * MyPgXact
Definition: proc.c:68
XLogRecPtr prepare_start_lsn
Definition: twophase.c:163
char * data
Definition: twophase.c:939
#define ERROR
Definition: elog.h:43
TimestampTz origin_timestamp
Definition: twophase.c:916
XLogRecPtr replorigin_session_origin_lsn
Definition: origin.c:156
TimestampTz replorigin_session_origin_timestamp
Definition: origin.c:157
uint32 len
Definition: twophase.c:940
void XLogSetRecordFlags(uint8 flags)
Definition: xloginsert.c:397
#define ereport(elevel, rest)
Definition: elog.h:122
bool delayChkpt
Definition: proc.h:232
static struct xllist records
uint32 total_len
Definition: twophase.c:950
#define MaxAllocSize
Definition: memutils.h:40
struct StateFileChunk * next
Definition: twophase.c:941
void XLogRegisterData(char *data, int len)
Definition: xloginsert.c:323
XLogRecPtr XLogInsert(RmgrId rmid, uint8 info)
Definition: xloginsert.c:415
#define TWOPHASE_MAGIC
Definition: twophase.c:899
StateFileChunk * head
Definition: twophase.c:946
#define Assert(condition)
Definition: c.h:699
RepOriginId replorigin_session_origin
Definition: origin.c:155
void XLogEnsureRecordSpace(int max_block_id, int ndatas)
Definition: xloginsert.c:146
void replorigin_session_advance(XLogRecPtr remote_commit, XLogRecPtr local_commit)
Definition: origin.c:1169
static void MarkAsPrepared(GlobalTransaction gxact, bool lock_held)
Definition: twophase.c:535
#define InvalidRepOriginId
Definition: origin.h:34
int errmsg(const char *fmt,...)
Definition: elog.c:797
static GlobalTransaction MyLockedGxact
Definition: twophase.c:199
XLogRecPtr origin_lsn
Definition: twophase.c:915
void XLogBeginInsert(void)
Definition: xloginsert.c:120
XLogRecPtr prepare_end_lsn
Definition: twophase.c:164

◆ FinishPreparedTransaction()

void FinishPreparedTransaction ( const char *  gid,
bool  isCommit 
)

Definition at line 1449 of file twophase.c.

References PROC_HDR::allPgXact, PROC_HDR::allProcs, Assert, AtEOXact_PgStat(), buf, DropRelationFiles(), GetUserId(), TwoPhaseFileHeader::gidlen, HOLD_INTERRUPTS, TwoPhaseFileHeader::initfileinval, LockGXact(), LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MAXALIGN, TwoPhaseFileHeader::nabortrels, TwoPhaseFileHeader::ncommitrels, TwoPhaseFileHeader::ninvalmsgs, TwoPhaseFileHeader::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, PGXACT::xid, TwoPhaseFileHeader::xid, and XlogReadTwoPhaseData().

Referenced by standard_ProcessUtility().

1450 {
1451  GlobalTransaction gxact;
1452  PGPROC *proc;
1453  PGXACT *pgxact;
1454  TransactionId xid;
1455  char *buf;
1456  char *bufptr;
1457  TwoPhaseFileHeader *hdr;
1458  TransactionId latestXid;
1459  TransactionId *children;
1460  RelFileNode *commitrels;
1461  RelFileNode *abortrels;
1462  RelFileNode *delrels;
1463  int ndelrels;
1464  SharedInvalidationMessage *invalmsgs;
1465 
1466  /*
1467  * Validate the GID, and lock the GXACT to ensure that two backends do not
1468  * try to commit the same GID at once.
1469  */
1470  gxact = LockGXact(gid, GetUserId());
1471  proc = &ProcGlobal->allProcs[gxact->pgprocno];
1472  pgxact = &ProcGlobal->allPgXact[gxact->pgprocno];
1473  xid = pgxact->xid;
1474 
1475  /*
1476  * Read and validate 2PC state data. State data will typically be stored
1477  * in WAL files if the LSN is after the last checkpoint record, or moved
1478  * to disk if for some reason they have lived for a long time.
1479  */
1480  if (gxact->ondisk)
1481  buf = ReadTwoPhaseFile(xid, true);
1482  else
1483  XlogReadTwoPhaseData(gxact->prepare_start_lsn, &buf, NULL);
1484 
1485 
1486  /*
1487  * Disassemble the header area
1488  */
1489  hdr = (TwoPhaseFileHeader *) buf;
1490  Assert(TransactionIdEquals(hdr->xid, xid));
1491  bufptr = buf + MAXALIGN(sizeof(TwoPhaseFileHeader));
1492  bufptr += MAXALIGN(hdr->gidlen);
1493  children = (TransactionId *) bufptr;
1494  bufptr += MAXALIGN(hdr->nsubxacts * sizeof(TransactionId));
1495  commitrels = (RelFileNode *) bufptr;
1496  bufptr += MAXALIGN(hdr->ncommitrels * sizeof(RelFileNode));
1497  abortrels = (RelFileNode *) bufptr;
1498  bufptr += MAXALIGN(hdr->nabortrels * sizeof(RelFileNode));
1499  invalmsgs = (SharedInvalidationMessage *) bufptr;
1500  bufptr += MAXALIGN(hdr->ninvalmsgs * sizeof(SharedInvalidationMessage));
1501 
1502  /* compute latestXid among all children */
1503  latestXid = TransactionIdLatest(xid, hdr->nsubxacts, children);
1504 
1505  /* Prevent cancel/die interrupt while cleaning up */
1506  HOLD_INTERRUPTS();
1507 
1508  /*
1509  * The order of operations here is critical: make the XLOG entry for
1510  * commit or abort, then mark the transaction committed or aborted in
1511  * pg_xact, then remove its PGPROC from the global ProcArray (which means
1512  * TransactionIdIsInProgress will stop saying the prepared xact is in
1513  * progress), then run the post-commit or post-abort callbacks. The
1514  * callbacks will release the locks the transaction held.
1515  */
1516  if (isCommit)
1518  hdr->nsubxacts, children,
1519  hdr->ncommitrels, commitrels,
1520  hdr->ninvalmsgs, invalmsgs,
1521  hdr->initfileinval, gid);
1522  else
1524  hdr->nsubxacts, children,
1525  hdr->nabortrels, abortrels,
1526  gid);
1527 
1528  ProcArrayRemove(proc, latestXid);
1529 
1530  /*
1531  * In case we fail while running the callbacks, mark the gxact invalid so
1532  * no one else will try to commit/rollback, and so it will be recycled if
1533  * we fail after this point. It is still locked by our backend so it
1534  * won't go away yet.
1535  *
1536  * (We assume it's safe to do this without taking TwoPhaseStateLock.)
1537  */
1538  gxact->valid = false;
1539 
1540  /*
1541  * We have to remove any files that were supposed to be dropped. For
1542  * consistency with the regular xact.c code paths, must do this before
1543  * releasing locks, so do it before running the callbacks.
1544  *
1545  * NB: this code knows that we couldn't be dropping any temp rels ...
1546  */
1547  if (isCommit)
1548  {
1549  delrels = commitrels;
1550  ndelrels = hdr->ncommitrels;
1551  }
1552  else
1553  {
1554  delrels = abortrels;
1555  ndelrels = hdr->nabortrels;
1556  }
1557 
1558  /* Make sure files supposed to be dropped are dropped */
1559  DropRelationFiles(delrels, ndelrels, false);
1560 
1561  /*
1562  * Handle cache invalidation messages.
1563  *
1564  * Relcache init file invalidation requires processing both before and
1565  * after we send the SI messages. See AtEOXact_Inval()
1566  */
1567  if (hdr->initfileinval)
1569  SendSharedInvalidMessages(invalmsgs, hdr->ninvalmsgs);
1570  if (hdr->initfileinval)
1572 
1573  /* And now do the callbacks */
1574  if (isCommit)
1576  else
1578 
1579  PredicateLockTwoPhaseFinish(xid, isCommit);
1580 
1581  /* Count the prepared xact as committed or aborted */
1582  AtEOXact_PgStat(isCommit);
1583 
1584  /*
1585  * And now we can clean up any files we may have left.
1586  */
1587  if (gxact->ondisk)
1588  RemoveTwoPhaseFile(xid, true);
1589 
1590  LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
1591  RemoveGXact(gxact);
1592  LWLockRelease(TwoPhaseStateLock);
1593  MyLockedGxact = NULL;
1594 
1596 
1597  pfree(buf);
1598 }
static void RecordTransactionAbortPrepared(TransactionId xid, int nchildren, TransactionId *children, int nrels, RelFileNode *rels, const char *gid)
Definition: twophase.c:2349
#define TransactionIdEquals(id1, id2)
Definition: transam.h:43
uint32 TransactionId
Definition: c.h:474
Definition: proc.h:219
Oid GetUserId(void)
Definition: miscinit.c:384
PGXACT * allPgXact
Definition: proc.h:246
TransactionId xid
Definition: proc.h:221
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:1604
const TwoPhaseCallback twophase_postcommit_callbacks[TWOPHASE_RM_MAX_ID+1]
Definition: twophase_rmgr.c:33
PROC_HDR * ProcGlobal
Definition: proc.c:80
TransactionId xid
Definition: twophase.c:905
XLogRecPtr prepare_start_lsn
Definition: twophase.c:163
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1725
#define RESUME_INTERRUPTS()
Definition: miscadmin.h:117
void pfree(void *pointer)
Definition: mcxt.c:1031
static GlobalTransaction LockGXact(const char *gid, Oid user)
Definition: twophase.c:557
void ProcArrayRemove(PGPROC *proc, TransactionId latestXid)
Definition: procarray.c:333
static void RemoveGXact(GlobalTransaction gxact)
Definition: twophase.c:633
void DropRelationFiles(RelFileNode *delrels, int ndelrels, bool isRedo)
Definition: md.c:1711
void PredicateLockTwoPhaseFinish(TransactionId xid, bool isCommit)
Definition: predicate.c:4850
static char * buf
Definition: pg_test_fsync.c:67
const TwoPhaseCallback twophase_postabort_callbacks[TWOPHASE_RM_MAX_ID+1]
Definition: twophase_rmgr.c:42
static char * ReadTwoPhaseFile(TransactionId xid, bool give_warnings)
Definition: twophase.c:1212
void RelationCacheInitFilePostInvalidate(void)
Definition: relcache.c:6096
static void RemoveTwoPhaseFile(TransactionId xid, bool giveWarning)
Definition: twophase.c:1632
void RelationCacheInitFilePreInvalidate(void)
Definition: relcache.c:6071
#define Assert(condition)
Definition: c.h:699
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1121
#define MAXALIGN(LEN)
Definition: c.h:652
void SendSharedInvalidMessages(const SharedInvalidationMessage *msgs, int n)
Definition: sinval.c:49
static void XlogReadTwoPhaseData(XLogRecPtr lsn, char **buf, int *len)
Definition: twophase.c:1377
static GlobalTransaction MyLockedGxact
Definition: twophase.c:199
#define HOLD_INTERRUPTS()
Definition: miscadmin.h:115
PGPROC * allProcs
Definition: proc.h:244
Definition: proc.h:95
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:2255
void AtEOXact_PgStat(bool isCommit)
Definition: pgstat.c:2053

◆ 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:987
static TwoPhaseStateData * TwoPhaseState
Definition: twophase.c:191
GlobalTransaction freeGXacts
Definition: twophase.c:182
int errcode(int sqlerrcode)
Definition: elog.c:575
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:1725
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:30
void before_shmem_exit(pg_on_exit_callback function, Datum arg)
Definition: ipc.c:333
#define ereport(elevel, rest)
Definition: elog.h:122
GlobalTransaction prepXacts[FLEXIBLE_ARRAY_MEMBER]
Definition: twophase.c:188
#define Assert(condition)
Definition: c.h:699
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1121
int errmsg(const char *fmt,...)
Definition: elog.c:797
int i
static void AtProcExit_Twophase(int code, Datum arg)
Definition: twophase.c:307
#define ERRCODE_DUPLICATE_OBJECT
Definition: streamutil.c:32

◆ ParsePrepareRecord()

void ParsePrepareRecord ( uint8  info,
char *  xlrec,
xl_xact_parsed_prepare parsed 
)

Definition at line 1333 of file twophase.c.

References xl_xact_parsed_commit::abortnodes, TwoPhaseFileHeader::database, xl_xact_parsed_commit::dbId, TwoPhaseFileHeader::gidlen, MAXALIGN, xl_xact_parsed_commit::msgs, xl_xact_parsed_commit::nabortrels, TwoPhaseFileHeader::nabortrels, TwoPhaseFileHeader::ncommitrels, TwoPhaseFileHeader::ninvalmsgs, xl_xact_parsed_commit::nmsgs, xl_xact_parsed_commit::nrels, xl_xact_parsed_commit::nsubxacts, TwoPhaseFileHeader::nsubxacts, xl_xact_parsed_commit::origin_lsn, TwoPhaseFileHeader::origin_lsn, xl_xact_parsed_commit::origin_timestamp, TwoPhaseFileHeader::origin_timestamp, xl_xact_parsed_commit::subxacts, xl_xact_parsed_commit::twophase_gid, xl_xact_parsed_commit::twophase_xid, TwoPhaseFileHeader::xid, and xl_xact_parsed_commit::xnodes.

1334 {
1335  TwoPhaseFileHeader *hdr;
1336  char *bufptr;
1337 
1338  hdr = (TwoPhaseFileHeader *) xlrec;
1339  bufptr = xlrec + MAXALIGN(sizeof(TwoPhaseFileHeader));
1340 
1341  parsed->origin_lsn = hdr->origin_lsn;
1342  parsed->origin_timestamp = hdr->origin_timestamp;
1343  parsed->twophase_xid = hdr->xid;
1344  parsed->dbId = hdr->database;
1345  parsed->nsubxacts = hdr->nsubxacts;
1346  parsed->nrels = hdr->ncommitrels;
1347  parsed->nabortrels = hdr->nabortrels;
1348  parsed->nmsgs = hdr->ninvalmsgs;
1349 
1350  strncpy(parsed->twophase_gid, bufptr, hdr->gidlen);
1351  bufptr += MAXALIGN(hdr->gidlen);
1352 
1353  parsed->subxacts = (TransactionId *) bufptr;
1354  bufptr += MAXALIGN(hdr->nsubxacts * sizeof(TransactionId));
1355 
1356  parsed->xnodes = (RelFileNode *) bufptr;
1357  bufptr += MAXALIGN(hdr->ncommitrels * sizeof(RelFileNode));
1358 
1359  parsed->abortnodes = (RelFileNode *) bufptr;
1360  bufptr += MAXALIGN(hdr->nabortrels * sizeof(RelFileNode));
1361 
1362  parsed->msgs = (SharedInvalidationMessage *) bufptr;
1363  bufptr += MAXALIGN(hdr->ninvalmsgs * sizeof(SharedInvalidationMessage));
1364 }
RelFileNode * xnodes
Definition: xact.h:309
uint32 TransactionId
Definition: c.h:474
TimestampTz origin_timestamp
Definition: xact.h:320
TransactionId twophase_xid
Definition: xact.h:314
TransactionId * subxacts
Definition: xact.h:306
SharedInvalidationMessage * msgs
Definition: xact.h:312
XLogRecPtr origin_lsn
Definition: xact.h:319
TransactionId xid
Definition: twophase.c:905
TimestampTz origin_timestamp
Definition: twophase.c:916
RelFileNode * abortnodes
Definition: xact.h:317
#define MAXALIGN(LEN)
Definition: c.h:652
XLogRecPtr origin_lsn
Definition: twophase.c:915
char twophase_gid[GIDSIZE]
Definition: xact.h:315

◆ 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:1725
#define InvalidBackendId
Definition: backendid.h:23
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1121
static GlobalTransaction MyLockedGxact
Definition: twophase.c:199

◆ PrepareRedoAdd()

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

Definition at line 2408 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, TwoPhaseFileHeader::origin_lsn, GlobalTransactionData::owner, TwoPhaseFileHeader::owner, GlobalTransactionData::prepare_end_lsn, GlobalTransactionData::prepare_start_lsn, GlobalTransactionData::prepared_at, TwoPhaseFileHeader::prepared_at, TwoPhaseStateData::prepXacts, RecoveryInProgress(), replorigin_advance(), GlobalTransactionData::valid, GlobalTransactionData::xid, TwoPhaseFileHeader::xid, and XLogRecPtrIsInvalid.

Referenced by restoreTwoPhaseData(), and xact_redo().

2410 {
2412  char *bufptr;
2413  const char *gid;
2414  GlobalTransaction gxact;
2415 
2416  Assert(LWLockHeldByMeInMode(TwoPhaseStateLock, LW_EXCLUSIVE));
2418 
2419  bufptr = buf + MAXALIGN(sizeof(TwoPhaseFileHeader));
2420  gid = (const char *) bufptr;
2421 
2422  /*
2423  * Reserve the GID for the given transaction in the redo code path.
2424  *
2425  * This creates a gxact struct and puts it into the active array.
2426  *
2427  * In redo, this struct is mainly used to track PREPARE/COMMIT entries in
2428  * shared memory. Hence, we only fill up the bare minimum contents here.
2429  * The gxact also gets marked with gxact->inredo set to true to indicate
2430  * that it got added in the redo phase
2431  */
2432 
2433  /* Get a free gxact from the freelist */
2434  if (TwoPhaseState->freeGXacts == NULL)
2435  ereport(ERROR,
2436  (errcode(ERRCODE_OUT_OF_MEMORY),
2437  errmsg("maximum number of prepared transactions reached"),
2438  errhint("Increase max_prepared_transactions (currently %d).",
2439  max_prepared_xacts)));
2440  gxact = TwoPhaseState->freeGXacts;
2441  TwoPhaseState->freeGXacts = gxact->next;
2442 
2443  gxact->prepared_at = hdr->prepared_at;
2444  gxact->prepare_start_lsn = start_lsn;
2445  gxact->prepare_end_lsn = end_lsn;
2446  gxact->xid = hdr->xid;
2447  gxact->owner = hdr->owner;
2449  gxact->valid = false;
2450  gxact->ondisk = XLogRecPtrIsInvalid(start_lsn);
2451  gxact->inredo = true; /* yes, added in redo */
2452  strcpy(gxact->gid, gid);
2453 
2454  /* And insert it into the active array */
2457 
2458  if (origin_id != InvalidRepOriginId)
2459  {
2460  /* recover apply progress */
2461  replorigin_advance(origin_id, hdr->origin_lsn, end_lsn,
2462  false /* backward */ , false /* WAL */ );
2463  }
2464 
2465  elog(DEBUG2, "added 2PC data in shared memory for transaction %u", gxact->xid);
2466 }
bool LWLockHeldByMeInMode(LWLock *l, LWLockMode mode)
Definition: lwlock.c:1859
int errhint(const char *fmt,...)
Definition: elog.c:987
static TwoPhaseStateData * TwoPhaseState
Definition: twophase.c:191
GlobalTransaction freeGXacts
Definition: twophase.c:182
int errcode(int sqlerrcode)
Definition: elog.c:575
TransactionId xid
Definition: twophase.c:905
void replorigin_advance(RepOriginId node, XLogRecPtr remote_commit, XLogRecPtr local_commit, bool go_backward, bool wal_log)
Definition: origin.c:856
GlobalTransaction next
Definition: twophase.c:151
bool RecoveryInProgress(void)
Definition: xlog.c:8051
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:67
#define ereport(elevel, rest)
Definition: elog.h:122
GlobalTransaction prepXacts[FLEXIBLE_ARRAY_MEMBER]
Definition: twophase.c:188
#define XLogRecPtrIsInvalid(r)
Definition: xlogdefs.h:29
#define InvalidBackendId
Definition: backendid.h:23
#define Assert(condition)
Definition: c.h:699
#define MAXALIGN(LEN)
Definition: c.h:652
#define InvalidRepOriginId
Definition: origin.h:34
TransactionId xid
Definition: twophase.c:165
TimestampTz prepared_at
Definition: twophase.c:154
int errmsg(const char *fmt,...)
Definition: elog.c:797
XLogRecPtr origin_lsn
Definition: twophase.c:915
#define elog
Definition: elog.h:219
TimestampTz prepared_at
Definition: twophase.c:907
XLogRecPtr prepare_end_lsn
Definition: twophase.c:164

◆ PrepareRedoRemove()

void PrepareRedoRemove ( TransactionId  xid,
bool  giveWarning 
)

Definition at line 2478 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().

2479 {
2480  GlobalTransaction gxact = NULL;
2481  int i;
2482  bool found = false;
2483 
2484  Assert(LWLockHeldByMeInMode(TwoPhaseStateLock, LW_EXCLUSIVE));
2486 
2487  for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
2488  {
2489  gxact = TwoPhaseState->prepXacts[i];
2490 
2491  if (gxact->xid == xid)
2492  {
2493  Assert(gxact->inredo);
2494  found = true;
2495  break;
2496  }
2497  }
2498 
2499  /*
2500  * Just leave if there is nothing, this is expected during WAL replay.
2501  */
2502  if (!found)
2503  return;
2504 
2505  /*
2506  * And now we can clean up any files we may have left.
2507  */
2508  elog(DEBUG2, "removing 2PC data for transaction %u", xid);
2509  if (gxact->ondisk)
2510  RemoveTwoPhaseFile(xid, giveWarning);
2511  RemoveGXact(gxact);
2512 
2513  return;
2514 }
bool LWLockHeldByMeInMode(LWLock *l, LWLockMode mode)
Definition: lwlock.c:1859
static TwoPhaseStateData * TwoPhaseState
Definition: twophase.c:191
bool RecoveryInProgress(void)
Definition: xlog.c:8051
static void RemoveGXact(GlobalTransaction gxact)
Definition: twophase.c:633
#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:1632
#define Assert(condition)
Definition: c.h:699
TransactionId xid
Definition: twophase.c:165
int i
#define elog
Definition: elog.h:219

◆ PrescanPreparedTransactions()

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

Definition at line 1884 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(), and GlobalTransactionData::xid.

Referenced by StartupXLOG(), and xlog_redo().

1885 {
1886  TransactionId origNextXid = ShmemVariableCache->nextXid;
1887  TransactionId result = origNextXid;
1888  TransactionId *xids = NULL;
1889  int nxids = 0;
1890  int allocsize = 0;
1891  int i;
1892 
1893  LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
1894  for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
1895  {
1896  TransactionId xid;
1897  char *buf;
1899 
1900  Assert(gxact->inredo);
1901 
1902  xid = gxact->xid;
1903 
1904  buf = ProcessTwoPhaseBuffer(xid,
1905  gxact->prepare_start_lsn,
1906  gxact->ondisk, false, true);
1907 
1908  if (buf == NULL)
1909  continue;
1910 
1911  /*
1912  * OK, we think this file is valid. Incorporate xid into the
1913  * running-minimum result.
1914  */
1915  if (TransactionIdPrecedes(xid, result))
1916  result = xid;
1917 
1918  if (xids_p)
1919  {
1920  if (nxids == allocsize)
1921  {
1922  if (nxids == 0)
1923  {
1924  allocsize = 10;
1925  xids = palloc(allocsize * sizeof(TransactionId));
1926  }
1927  else
1928  {
1929  allocsize = allocsize * 2;
1930  xids = repalloc(xids, allocsize * sizeof(TransactionId));
1931  }
1932  }
1933  xids[nxids++] = xid;
1934  }
1935 
1936  pfree(buf);
1937  }
1938  LWLockRelease(TwoPhaseStateLock);
1939 
1940  if (xids_p)
1941  {
1942  *xids_p = xids;
1943  *nxids_p = nxids;
1944  }
1945 
1946  return result;
1947 }
static TwoPhaseStateData * TwoPhaseState
Definition: twophase.c:191
uint32 TransactionId
Definition: c.h:474
XLogRecPtr prepare_start_lsn
Definition: twophase.c:163
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1725
void pfree(void *pointer)
Definition: mcxt.c:1031
TransactionId nextXid
Definition: transam.h:117
static char * buf
Definition: pg_test_fsync.c:67
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:2106
#define Assert(condition)
Definition: c.h:699
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1121
void * repalloc(void *pointer, Size size)
Definition: mcxt.c:1044
TransactionId xid
Definition: twophase.c:165
void * palloc(Size size)
Definition: mcxt.c:924
int i

◆ RecoverPreparedTransactions()

void RecoverPreparedTransactions ( void  )

Definition at line 2005 of file twophase.c.

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

Referenced by StartupXLOG().

2006 {
2007  int i;
2008 
2009  LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
2010  for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
2011  {
2012  TransactionId xid;
2013  char *buf;
2015  char *bufptr;
2016  TwoPhaseFileHeader *hdr;
2017  TransactionId *subxids;
2018  const char *gid;
2019 
2020  xid = gxact->xid;
2021 
2022  /*
2023  * Reconstruct subtrans state for the transaction --- needed because
2024  * pg_subtrans is not preserved over a restart. Note that we are
2025  * linking all the subtransactions directly to the top-level XID;
2026  * there may originally have been a more complex hierarchy, but
2027  * there's no need to restore that exactly. It's possible that
2028  * SubTransSetParent has been set before, if the prepared transaction
2029  * generated xid assignment records.
2030  */
2031  buf = ProcessTwoPhaseBuffer(xid,
2032  gxact->prepare_start_lsn,
2033  gxact->ondisk, true, false);
2034  if (buf == NULL)
2035  continue;
2036 
2037  ereport(LOG,
2038  (errmsg("recovering prepared transaction %u from shared memory", xid)));
2039 
2040  hdr = (TwoPhaseFileHeader *) buf;
2041  Assert(TransactionIdEquals(hdr->xid, xid));
2042  bufptr = buf + MAXALIGN(sizeof(TwoPhaseFileHeader));
2043  gid = (const char *) bufptr;
2044  bufptr += MAXALIGN(hdr->gidlen);
2045  subxids = (TransactionId *) bufptr;
2046  bufptr += MAXALIGN(hdr->nsubxacts * sizeof(TransactionId));
2047  bufptr += MAXALIGN(hdr->ncommitrels * sizeof(RelFileNode));
2048  bufptr += MAXALIGN(hdr->nabortrels * sizeof(RelFileNode));
2049  bufptr += MAXALIGN(hdr->ninvalmsgs * sizeof(SharedInvalidationMessage));
2050 
2051  /*
2052  * Recreate its GXACT and dummy PGPROC. But, check whether it was
2053  * added in redo and already has a shmem entry for it.
2054  */
2055  MarkAsPreparingGuts(gxact, xid, gid,
2056  hdr->prepared_at,
2057  hdr->owner, hdr->database);
2058 
2059  /* recovered, so reset the flag for entries generated by redo */
2060  gxact->inredo = false;
2061 
2062  GXactLoadSubxactData(gxact, hdr->nsubxacts, subxids);
2063  MarkAsPrepared(gxact, true);
2064 
2065  LWLockRelease(TwoPhaseStateLock);
2066 
2067  /*
2068  * Recover other state (notably locks) using resource managers.
2069  */
2071 
2072  /*
2073  * Release locks held by the standby process after we process each
2074  * prepared transaction. As a result, we don't need too many
2075  * additional locks at any one time.
2076  */
2077  if (InHotStandby)
2078  StandbyReleaseLockTree(xid, hdr->nsubxacts, subxids);
2079 
2080  /*
2081  * We're done with recovering this transaction. Clear MyLockedGxact,
2082  * like we do in PrepareTransaction() during normal operation.
2083  */
2085 
2086  pfree(buf);
2087 
2088  LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
2089  }
2090 
2091  LWLockRelease(TwoPhaseStateLock);
2092 }
static TwoPhaseStateData * TwoPhaseState
Definition: twophase.c:191
#define TransactionIdEquals(id1, id2)
Definition: transam.h:43
uint32 TransactionId
Definition: c.h:474
static void ProcessRecords(char *bufptr, TransactionId xid, const TwoPhaseCallback callbacks[])
Definition: twophase.c:1604
const TwoPhaseCallback twophase_recover_callbacks[TWOPHASE_RM_MAX_ID+1]
Definition: twophase_rmgr.c:24
#define InHotStandby
Definition: xlog.h:74
TransactionId xid
Definition: twophase.c:905
#define LOG
Definition: elog.h:26
XLogRecPtr prepare_start_lsn
Definition: twophase.c:163
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1725
void pfree(void *pointer)
Definition: mcxt.c:1031
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:508
static char * buf
Definition: pg_test_fsync.c:67
void StandbyReleaseLockTree(TransactionId xid, int nsubxids, TransactionId *subxids)
Definition: standby.c:716
#define ereport(elevel, rest)
Definition: elog.h:122
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:2106
#define Assert(condition)
Definition: c.h:699
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1121
#define MAXALIGN(LEN)
Definition: c.h:652
static void MarkAsPrepared(GlobalTransaction gxact, bool lock_held)
Definition: twophase.c:535
TransactionId xid
Definition: twophase.c:165
int errmsg(const char *fmt,...)
Definition: elog.c:797
void PostPrepare_Twophase(void)
Definition: twophase.c:357
int i
TimestampTz prepared_at
Definition: twophase.c:907

◆ restoreTwoPhaseData()

void restoreTwoPhaseData ( void  )

Definition at line 1826 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().

1827 {
1828  DIR *cldir;
1829  struct dirent *clde;
1830 
1831  LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
1832  cldir = AllocateDir(TWOPHASE_DIR);
1833  while ((clde = ReadDir(cldir, TWOPHASE_DIR)) != NULL)
1834  {
1835  if (strlen(clde->d_name) == 8 &&
1836  strspn(clde->d_name, "0123456789ABCDEF") == 8)
1837  {
1838  TransactionId xid;
1839  char *buf;
1840 
1841  xid = (TransactionId) strtoul(clde->d_name, NULL, 16);
1842 
1844  true, false, false);
1845  if (buf == NULL)
1846  continue;
1847 
1850  }
1851  }
1852  LWLockRelease(TwoPhaseStateLock);
1853  FreeDir(cldir);
1854 }
#define InvalidXLogRecPtr
Definition: xlogdefs.h:28
uint32 TransactionId
Definition: c.h:474
Definition: dirent.h:9
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1725
Definition: dirent.c:25
static char * buf
Definition: pg_test_fsync.c:67
DIR * AllocateDir(const char *dirname)
Definition: fd.c:2590
static char * ProcessTwoPhaseBuffer(TransactionId xid, XLogRecPtr prepare_start_lsn, bool fromdisk, bool setParent, bool setNextXid)
Definition: twophase.c:2106
void PrepareRedoAdd(char *buf, XLogRecPtr start_lsn, XLogRecPtr end_lsn, RepOriginId origin_id)
Definition: twophase.c:2408
struct dirent * ReadDir(DIR *dir, const char *dirname)
Definition: fd.c:2656
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1121
#define InvalidRepOriginId
Definition: origin.h:34
#define TWOPHASE_DIR
Definition: twophase.c:114
char d_name[MAX_PATH]
Definition: dirent.h:14
int FreeDir(DIR *dir)
Definition: fd.c:2708

◆ StandbyRecoverPreparedTransactions()

void StandbyRecoverPreparedTransactions ( void  )

Definition at line 1964 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().

1965 {
1966  int i;
1967 
1968  LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
1969  for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
1970  {
1971  TransactionId xid;
1972  char *buf;
1974 
1975  Assert(gxact->inredo);
1976 
1977  xid = gxact->xid;
1978 
1979  buf = ProcessTwoPhaseBuffer(xid,
1980  gxact->prepare_start_lsn,
1981  gxact->ondisk, false, false);
1982  if (buf != NULL)
1983  pfree(buf);
1984  }
1985  LWLockRelease(TwoPhaseStateLock);
1986 }
static TwoPhaseStateData * TwoPhaseState
Definition: twophase.c:191
uint32 TransactionId
Definition: c.h:474
XLogRecPtr prepare_start_lsn
Definition: twophase.c:163
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1725
void pfree(void *pointer)
Definition: mcxt.c:1031
static char * buf
Definition: pg_test_fsync.c:67
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:2106
#define Assert(condition)
Definition: c.h:699
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1121
TransactionId xid
Definition: twophase.c:165
int i

◆ StandbyTransactionIdIsPrepared()

bool StandbyTransactionIdIsPrepared ( TransactionId  xid)

Definition at line 1421 of file twophase.c.

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

Referenced by KnownAssignedXidsRemovePreceding(), and StandbyReleaseOldLocks().

1422 {
1423  char *buf;
1424  TwoPhaseFileHeader *hdr;
1425  bool result;
1426 
1428 
1429  if (max_prepared_xacts <= 0)
1430  return false; /* nothing to do */
1431 
1432  /* Read and validate file */
1433  buf = ReadTwoPhaseFile(xid, false);
1434  if (buf == NULL)
1435  return false;
1436 
1437  /* Check header also */
1438  hdr = (TwoPhaseFileHeader *) buf;
1439  result = TransactionIdEquals(hdr->xid, xid);
1440  pfree(buf);
1441 
1442  return result;
1443 }
#define TransactionIdEquals(id1, id2)
Definition: transam.h:43
TransactionId xid
Definition: twophase.c:905
void pfree(void *pointer)
Definition: mcxt.c:1031
int max_prepared_xacts
Definition: twophase.c:117
static char * buf
Definition: pg_test_fsync.c:67
static char * ReadTwoPhaseFile(TransactionId xid, bool give_warnings)
Definition: twophase.c:1212
#define Assert(condition)
Definition: c.h:699
#define TransactionIdIsValid(xid)
Definition: transam.h:41

◆ StartPrepare()

void StartPrepare ( GlobalTransaction  gxact)

Definition at line 991 of file twophase.c.

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

Referenced by PrepareTransaction().

992 {
993  PGPROC *proc = &ProcGlobal->allProcs[gxact->pgprocno];
994  PGXACT *pgxact = &ProcGlobal->allPgXact[gxact->pgprocno];
995  TransactionId xid = pgxact->xid;
996  TwoPhaseFileHeader hdr;
997  TransactionId *children;
998  RelFileNode *commitrels;
999  RelFileNode *abortrels;
1000  SharedInvalidationMessage *invalmsgs;
1001 
1002  /* Initialize linked list */
1003  records.head = palloc0(sizeof(StateFileChunk));
1004  records.head->len = 0;
1005  records.head->next = NULL;
1006 
1007  records.bytes_free = Max(sizeof(TwoPhaseFileHeader), 512);
1009 
1011  records.num_chunks = 1;
1012 
1013  records.total_len = 0;
1014 
1015  /* Create header */
1016  hdr.magic = TWOPHASE_MAGIC;
1017  hdr.total_len = 0; /* EndPrepare will fill this in */
1018  hdr.xid = xid;
1019  hdr.database = proc->databaseId;
1020  hdr.prepared_at = gxact->prepared_at;
1021  hdr.owner = gxact->owner;
1022  hdr.nsubxacts = xactGetCommittedChildren(&children);
1023  hdr.ncommitrels = smgrGetPendingDeletes(true, &commitrels);
1024  hdr.nabortrels = smgrGetPendingDeletes(false, &abortrels);
1026  &hdr.initfileinval);
1027  hdr.gidlen = strlen(gxact->gid) + 1; /* Include '\0' */
1028 
1029  save_state_data(&hdr, sizeof(TwoPhaseFileHeader));
1030  save_state_data(gxact->gid, hdr.gidlen);
1031 
1032  /*
1033  * Add the additional info about subxacts, deletable files and cache
1034  * invalidation messages.
1035  */
1036  if (hdr.nsubxacts > 0)
1037  {
1038  save_state_data(children, hdr.nsubxacts * sizeof(TransactionId));
1039  /* While we have the child-xact data, stuff it in the gxact too */
1040  GXactLoadSubxactData(gxact, hdr.nsubxacts, children);
1041  }
1042  if (hdr.ncommitrels > 0)
1043  {
1044  save_state_data(commitrels, hdr.ncommitrels * sizeof(RelFileNode));
1045  pfree(commitrels);
1046  }
1047  if (hdr.nabortrels > 0)
1048  {
1049  save_state_data(abortrels, hdr.nabortrels * sizeof(RelFileNode));
1050  pfree(abortrels);
1051  }
1052  if (hdr.ninvalmsgs > 0)
1053  {
1054  save_state_data(invalmsgs,
1055  hdr.ninvalmsgs * sizeof(SharedInvalidationMessage));
1056  pfree(invalmsgs);
1057  }
1058 }
int xactGetCommittedChildren(TransactionId **ptr)
Definition: xact.c:5210
uint32 TransactionId
Definition: c.h:474
Definition: proc.h:219
PGXACT * allPgXact
Definition: proc.h:246
TransactionId xid
Definition: proc.h:221
StateFileChunk * tail
Definition: twophase.c:947
PROC_HDR * ProcGlobal
Definition: proc.c:80
TransactionId xid
Definition: twophase.c:905
uint32 num_chunks
Definition: twophase.c:948
char gid[GIDSIZE]
Definition: twophase.c:172
char * data
Definition: twophase.c:939
void pfree(void *pointer)
Definition: mcxt.c:1031
static void GXactLoadSubxactData(GlobalTransaction gxact, int nsubxacts, TransactionId *children)
Definition: twophase.c:508
uint32 bytes_free
Definition: twophase.c:949
int smgrGetPendingDeletes(bool forCommit, RelFileNode **ptr)
Definition: storage.c:388
uint32 len
Definition: twophase.c:940
Oid databaseId
Definition: proc.h:114
static struct xllist records
uint32 total_len
Definition: twophase.c:950
struct StateFileChunk * next
Definition: twophase.c:941
void * palloc0(Size size)
Definition: mcxt.c:955
#define TWOPHASE_MAGIC
Definition: twophase.c:899
#define Max(x, y)
Definition: c.h:851
StateFileChunk * head
Definition: twophase.c:946
static void save_state_data(const void *data, uint32 len)
Definition: twophase.c:963
TimestampTz prepared_at
Definition: twophase.c:154
void * palloc(Size size)
Definition: mcxt.c:924
int xactGetCommittedInvalidationMessages(SharedInvalidationMessage **msgs, bool *RelcacheInitFileInval)
Definition: inval.c:816
PGPROC * allProcs
Definition: proc.h:244
TimestampTz prepared_at
Definition: twophase.c:907
Definition: proc.h:95

◆ TwoPhaseGetDummyBackendId()

BackendId TwoPhaseGetDummyBackendId ( TransactionId  xid)

Definition at line 854 of file twophase.c.

References GlobalTransactionData::dummyBackendId, and TwoPhaseGetGXact().

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

855 {
856  GlobalTransaction gxact = TwoPhaseGetGXact(xid);
857 
858  return gxact->dummyBackendId;
859 }
static GlobalTransaction TwoPhaseGetGXact(TransactionId xid)
Definition: twophase.c:805
BackendId dummyBackendId
Definition: twophase.c:153

◆ TwoPhaseGetDummyProc()

PGPROC* TwoPhaseGetDummyProc ( TransactionId  xid)

Definition at line 866 of file twophase.c.

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

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

867 {
868  GlobalTransaction gxact = TwoPhaseGetGXact(xid);
869 
870  return &ProcGlobal->allProcs[gxact->pgprocno];
871 }
static GlobalTransaction TwoPhaseGetGXact(TransactionId xid)
Definition: twophase.c:805
PROC_HDR * ProcGlobal
Definition: proc.c:80
PGPROC * allProcs
Definition: proc.h:244

◆ 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:82
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:372
int MaxBackends
Definition: globals.c:134
bool IsUnderPostmaster
Definition: globals.c:108
#define Assert(condition)
Definition: c.h:699
#define MAXALIGN(LEN)
Definition: c.h:652
int pgprocno
Definition: proc.h:110
int i
#define offsetof(type, field)
Definition: c.h:622
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:492
Size add_size(Size s1, Size s2)
Definition: shmem.c:475
size_t Size
Definition: c.h:433
#define MAXALIGN(LEN)
Definition: c.h:652
#define offsetof(type, field)
Definition: c.h:622

Variable Documentation

◆ max_prepared_xacts