twophase.h File Reference

#include "access/xact.h"
#include "access/xlogdefs.h"
#include "datatype/timestamp.h"

Include dependency graph for twophase.h:

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Go to the source code of this file.

Typedefs
typedef struct PGPROC	PGPROC
typedef struct VirtualTransactionId	VirtualTransactionId
typedef struct GlobalTransactionData *	GlobalTransaction

Functions
void	AtAbort_Twophase (void)
void	PostPrepare_Twophase (void)
TransactionId	TwoPhaseGetXidByVirtualXID (VirtualTransactionId vxid, bool *have_more)
PGPROC *	TwoPhaseGetDummyProc (FullTransactionId fxid, bool lock_held)
int	TwoPhaseGetDummyProcNumber (FullTransactionId fxid, bool lock_held)
GlobalTransaction	MarkAsPreparing (FullTransactionId fxid, 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 (FullTransactionId fxid, char *buf, XLogRecPtr start_lsn, XLogRecPtr end_lsn, ReplOriginId origin_id)
void	PrepareRedoRemove (TransactionId xid, bool giveWarning)
void	restoreTwoPhaseData (void)
bool	LookupGXact (const char *gid, XLogRecPtr prepare_end_lsn, TimestampTz origin_prepare_timestamp)
void	TwoPhaseTransactionGid (Oid subid, TransactionId xid, char *gid_res, int szgid)
bool	LookupGXactBySubid (Oid subid)
TransactionId	TwoPhaseGetOldestXidInCommit (void)

Variables
PGDLLIMPORT int	max_prepared_xacts

Typedef Documentation

GlobalTransaction

typedef struct GlobalTransactionData* GlobalTransaction

Definition at line 31 of file twophase.h.

PGPROC

typedef struct PGPROC PGPROC

Definition at line 24 of file twophase.h.

VirtualTransactionId

typedef struct VirtualTransactionId VirtualTransactionId

Definition at line 25 of file twophase.h.

Function Documentation

AtAbort_Twophase()

void AtAbort_Twophase ( void  )

extern

Definition at line 310 of file twophase.c.

{
    if (MyLockedGxact == NULL)
        return;
 
    /*
     * What to do with the locked global transaction entry?  If we were in the
     * process of preparing the transaction, but haven't written the WAL
     * record and state file yet, the transaction must not be considered as
     * prepared.  Likewise, if we are in the process of finishing an
     * already-prepared transaction, and fail after having already written the
     * 2nd phase commit or rollback record to the WAL, the transaction should
     * not be considered as prepared anymore.  In those cases, just remove the
     * entry from shared memory.
     *
     * Otherwise, the entry must be left in place so that the transaction can
     * be finished later, so just unlock it.
     *
     * If we abort during prepare, after having written the WAL record, we
     * might not have transferred all locks and other state to the prepared
     * transaction yet.  Likewise, if we abort during commit or rollback,
     * after having written the WAL record, we might not have released all the
     * resources held by the transaction yet.  In those cases, the in-memory
     * state can be wrong, but it's too late to back out.
     */
    LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
    if (!MyLockedGxact->valid)
        RemoveGXact(MyLockedGxact);
    else
        MyLockedGxact->locking_backend = INVALID_PROC_NUMBER;
    LWLockRelease(TwoPhaseStateLock);
 
    MyLockedGxact = NULL;
}

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

Referenced by AbortTransaction(), and AtProcExit_Twophase().

CheckPointTwoPhase()

void CheckPointTwoPhase ( XLogRecPtr  redo_horizon )

extern

Definition at line 1830 of file twophase.c.

{
    int         i;
    int         serialized_xacts = 0;
 
    if (max_prepared_xacts <= 0)
        return;                 /* nothing to do */
 
    TRACE_POSTGRESQL_TWOPHASE_CHECKPOINT_START();
 
    /*
     * We are expecting there to be zero GXACTs that need to be copied to
     * disk, so we perform all I/O while holding TwoPhaseStateLock for
     * simplicity. This prevents any new xacts from preparing while this
     * occurs, which shouldn't be a problem since the presence of long-lived
     * prepared xacts indicates the transaction manager isn't active.
     *
     * It's also possible to move I/O out of the lock, but on every error we
     * should check whether somebody committed our transaction in different
     * backend. Let's leave this optimization for future, if somebody will
     * spot that this place cause bottleneck.
     *
     * Note that it isn't possible for there to be a GXACT with a
     * prepare_end_lsn set prior to the last checkpoint yet is marked invalid,
     * because of the efforts with delayChkptFlags.
     */
    LWLockAcquire(TwoPhaseStateLock, LW_SHARED);
    for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
    {
        /*
         * Note that we are using gxact not PGPROC so this works in recovery
         * also
         */
        GlobalTransaction gxact = TwoPhaseState->prepXacts[i];
 
        if ((gxact->valid || gxact->inredo) &&
            !gxact->ondisk &&
            gxact->prepare_end_lsn <= redo_horizon)
        {
            char       *buf;
            size_t      len;
 
            XlogReadTwoPhaseData(gxact->prepare_start_lsn, &buf, &len);
            RecreateTwoPhaseFile(gxact->fxid, buf, len);
            gxact->ondisk = true;
            gxact->prepare_start_lsn = InvalidXLogRecPtr;
            gxact->prepare_end_lsn = InvalidXLogRecPtr;
            pfree(buf);
            serialized_xacts++;
        }
    }
    LWLockRelease(TwoPhaseStateLock);
 
    /*
     * Flush unconditionally the parent directory to make any information
     * durable on disk.  Two-phase files could have been removed and those
     * removals need to be made persistent as well as any files newly created
     * previously since the last checkpoint.
     */
    fsync_fname(TWOPHASE_DIR, true);
 
    TRACE_POSTGRESQL_TWOPHASE_CHECKPOINT_DONE();
 
    if (log_checkpoints && serialized_xacts > 0)
        ereport(LOG,
                (errmsg_plural("%u two-phase state file was written "
                               "for a long-running prepared transaction",
                               "%u two-phase state files were written "
                               "for long-running prepared transactions",
                               serialized_xacts,
                               serialized_xacts)));
}

References buf, ereport, errmsg_plural(), fb(), fsync_fname(), i, InvalidXLogRecPtr, len, LOG, log_checkpoints, LW_SHARED, LWLockAcquire(), LWLockRelease(), max_prepared_xacts, TwoPhaseStateData::numPrepXacts, pfree(), TwoPhaseStateData::prepXacts, RecreateTwoPhaseFile(), TWOPHASE_DIR, TwoPhaseState, and XlogReadTwoPhaseData().

Referenced by CheckPointGuts().

EndPrepare()

void EndPrepare ( GlobalTransaction  gxact )

extern

Definition at line 1151 of file twophase.c.

{
    TwoPhaseFileHeader *hdr;
    StateFileChunk *record;
    bool        replorigin;
 
    /* Add the end sentinel to the list of 2PC records */
    RegisterTwoPhaseRecord(TWOPHASE_RM_END_ID, 0,
                           NULL, 0);
 
    /* Go back and fill in total_len in the file header record */
    hdr = (TwoPhaseFileHeader *) records.head->data;
    Assert(hdr->magic == TWOPHASE_MAGIC);
    hdr->total_len = records.total_len + sizeof(pg_crc32c);
 
    replorigin = (replorigin_xact_state.origin != InvalidReplOriginId &&
                  replorigin_xact_state.origin != DoNotReplicateId);
 
    if (replorigin)
    {
        hdr->origin_lsn = replorigin_xact_state.origin_lsn;
        hdr->origin_timestamp = replorigin_xact_state.origin_timestamp;
    }
 
    /*
     * If the data size exceeds MaxAllocSize, we won't be able to read it in
     * ReadTwoPhaseFile. Check for that now, rather than fail in the case
     * where we write data to file and then re-read at commit time.
     */
    if (hdr->total_len > MaxAllocSize)
        ereport(ERROR,
                (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
                 errmsg("two-phase state file maximum length exceeded")));
 
    /*
     * Now writing 2PC state data to WAL. We let the WAL's CRC protection
     * cover us, so no need to calculate a separate CRC.
     *
     * We have to set DELAY_CHKPT_START here, too; otherwise a checkpoint
     * starting immediately after the WAL record is inserted could complete
     * without fsync'ing our state file.  (This is essentially the same kind
     * of race condition as the COMMIT-to-clog-write case that
     * RecordTransactionCommit uses DELAY_CHKPT_IN_COMMIT for; see notes
     * there.) Note that DELAY_CHKPT_IN_COMMIT is used to find transactions in
     * the critical commit section. We need to know about such transactions
     * for conflict detection in logical replication. See
     * GetOldestActiveTransactionId(true, false) and its use.
     *
     * We save the PREPARE record's location in the gxact for later use by
     * CheckPointTwoPhase.
     */
    XLogEnsureRecordSpace(0, records.num_chunks);
 
    START_CRIT_SECTION();
 
    Assert((MyProc->delayChkptFlags & DELAY_CHKPT_START) == 0);
    MyProc->delayChkptFlags |= DELAY_CHKPT_START;
 
    XLogBeginInsert();
    for (record = records.head; record != NULL; record = record->next)
        XLogRegisterData(record->data, record->len);
 
    XLogSetRecordFlags(XLOG_INCLUDE_ORIGIN);
 
    gxact->prepare_end_lsn = XLogInsert(RM_XACT_ID, XLOG_XACT_PREPARE);
 
    if (replorigin)
    {
        /* Move LSNs forward for this replication origin */
        replorigin_session_advance(replorigin_xact_state.origin_lsn,
                                   gxact->prepare_end_lsn);
    }
 
    XLogFlush(gxact->prepare_end_lsn);
 
    /* If we crash now, we have prepared: WAL replay will fix things */
 
    /* Store record's start location to read that later on Commit */
    gxact->prepare_start_lsn = ProcLastRecPtr;
 
    /*
     * Mark the prepared transaction as valid.  As soon as xact.c marks MyProc
     * as not running our XID (which it will do immediately after this
     * function returns), others can commit/rollback the xact.
     *
     * NB: a side effect of this is to make a dummy ProcArray entry for the
     * prepared XID.  This must happen before we clear the XID from MyProc /
     * ProcGlobal->xids[], else there is a window where the XID is not running
     * according to TransactionIdIsInProgress, and onlookers would be entitled
     * to assume the xact crashed.  Instead we have a window where the same
     * XID appears twice in ProcArray, which is OK.
     */
    MarkAsPrepared(gxact, false);
 
    /*
     * Now we can mark ourselves as out of the commit critical section: a
     * checkpoint starting after this will certainly see the gxact as a
     * candidate for fsyncing.
     */
    MyProc->delayChkptFlags &= ~DELAY_CHKPT_START;
 
    /*
     * Remember that we have this GlobalTransaction entry locked for us.  If
     * we crash after this point, it's too late to abort, but we must unlock
     * it so that the prepared transaction can be committed or rolled back.
     */
    MyLockedGxact = gxact;
 
    END_CRIT_SECTION();
 
    /*
     * Wait for synchronous replication, if required.
     *
     * Note that at this stage we have marked the prepare, but still show as
     * running in the procarray (twice!) and continue to hold locks.
     */
    SyncRepWaitForLSN(gxact->prepare_end_lsn, false);
 
    records.tail = records.head = NULL;
    records.num_chunks = 0;
}

References Assert, StateFileChunk::data, DELAY_CHKPT_START, PGPROC::delayChkptFlags, DoNotReplicateId, END_CRIT_SECTION, ereport, errcode(), errmsg, ERROR, fb(), xllist::head, InvalidReplOriginId, StateFileChunk::len, xl_xact_prepare::magic, MarkAsPrepared(), MaxAllocSize, MyLockedGxact, MyProc, StateFileChunk::next, xllist::num_chunks, ReplOriginXactState::origin, xl_xact_prepare::origin_lsn, ReplOriginXactState::origin_lsn, xl_xact_prepare::origin_timestamp, ReplOriginXactState::origin_timestamp, ProcLastRecPtr, records, RegisterTwoPhaseRecord(), replorigin_session_advance(), replorigin_xact_state, 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  )

extern

Definition at line 1505 of file twophase.c.

{
    GlobalTransaction gxact;
    PGPROC     *proc;
    FullTransactionId fxid;
    TransactionId xid;
    bool        ondisk;
    char       *buf;
    char       *bufptr;
    TwoPhaseFileHeader *hdr;
    TransactionId latestXid;
    TransactionId *children;
    RelFileLocator *commitrels;
    RelFileLocator *abortrels;
    RelFileLocator *delrels;
    int         ndelrels;
    xl_xact_stats_item *commitstats;
    xl_xact_stats_item *abortstats;
    SharedInvalidationMessage *invalmsgs;
 
    /*
     * Validate the GID, and lock the GXACT to ensure that two backends do not
     * try to commit the same GID at once.
     */
    gxact = LockGXact(gid, GetUserId());
    proc = GetPGProcByNumber(gxact->pgprocno);
    fxid = gxact->fxid;
    xid = XidFromFullTransactionId(fxid);
 
    /*
     * Read and validate 2PC state data. State data will typically be stored
     * in WAL files if the LSN is after the last checkpoint record, or moved
     * to disk if for some reason they have lived for a long time.
     */
    if (gxact->ondisk)
        buf = ReadTwoPhaseFile(fxid, false);
    else
        XlogReadTwoPhaseData(gxact->prepare_start_lsn, &buf, NULL);
 
 
    /*
     * Disassemble the header area
     */
    hdr = (TwoPhaseFileHeader *) buf;
    Assert(TransactionIdEquals(hdr->xid, xid));
    bufptr = buf + MAXALIGN(sizeof(TwoPhaseFileHeader));
    bufptr += MAXALIGN(hdr->gidlen);
    children = (TransactionId *) bufptr;
    bufptr += MAXALIGN(hdr->nsubxacts * sizeof(TransactionId));
    commitrels = (RelFileLocator *) bufptr;
    bufptr += MAXALIGN(hdr->ncommitrels * sizeof(RelFileLocator));
    abortrels = (RelFileLocator *) bufptr;
    bufptr += MAXALIGN(hdr->nabortrels * sizeof(RelFileLocator));
    commitstats = (xl_xact_stats_item *) bufptr;
    bufptr += MAXALIGN(hdr->ncommitstats * sizeof(xl_xact_stats_item));
    abortstats = (xl_xact_stats_item *) bufptr;
    bufptr += MAXALIGN(hdr->nabortstats * sizeof(xl_xact_stats_item));
    invalmsgs = (SharedInvalidationMessage *) bufptr;
    bufptr += MAXALIGN(hdr->ninvalmsgs * sizeof(SharedInvalidationMessage));
 
    /* compute latestXid among all children */
    latestXid = TransactionIdLatest(xid, hdr->nsubxacts, children);
 
    /* Prevent cancel/die interrupt while cleaning up */
    HOLD_INTERRUPTS();
 
    /*
     * The order of operations here is critical: make the XLOG entry for
     * commit or abort, then mark the transaction committed or aborted in
     * pg_xact, then remove its PGPROC from the global ProcArray (which means
     * TransactionIdIsInProgress will stop saying the prepared xact is in
     * progress), then run the post-commit or post-abort callbacks. The
     * callbacks will release the locks the transaction held.
     */
    if (isCommit)
        RecordTransactionCommitPrepared(xid,
                                        hdr->nsubxacts, children,
                                        hdr->ncommitrels, commitrels,
                                        hdr->ncommitstats,
                                        commitstats,
                                        hdr->ninvalmsgs, invalmsgs,
                                        hdr->initfileinval, gid);
    else
        RecordTransactionAbortPrepared(xid,
                                       hdr->nsubxacts, children,
                                       hdr->nabortrels, abortrels,
                                       hdr->nabortstats,
                                       abortstats,
                                       gid);
 
    ProcArrayRemove(proc, latestXid);
 
    /*
     * In case we fail while running the callbacks, mark the gxact invalid so
     * no one else will try to commit/rollback, and so it will be recycled if
     * we fail after this point.  It is still locked by our backend so it
     * won't go away yet.
     *
     * (We assume it's safe to do this without taking TwoPhaseStateLock.)
     */
    gxact->valid = false;
 
    /*
     * We have to remove any files that were supposed to be dropped. For
     * consistency with the regular xact.c code paths, must do this before
     * releasing locks, so do it before running the callbacks.
     *
     * NB: this code knows that we couldn't be dropping any temp rels ...
     */
    if (isCommit)
    {
        delrels = commitrels;
        ndelrels = hdr->ncommitrels;
    }
    else
    {
        delrels = abortrels;
        ndelrels = hdr->nabortrels;
    }
 
    /* Make sure files supposed to be dropped are dropped */
    DropRelationFiles(delrels, ndelrels, false);
 
    if (isCommit)
        pgstat_execute_transactional_drops(hdr->ncommitstats, commitstats, false);
    else
        pgstat_execute_transactional_drops(hdr->nabortstats, abortstats, false);
 
    /*
     * Handle cache invalidation messages.
     *
     * Relcache init file invalidation requires processing both before and
     * after we send the SI messages, only when committing.  See
     * AtEOXact_Inval().
     */
    if (isCommit)
    {
        if (hdr->initfileinval)
            RelationCacheInitFilePreInvalidate();
        SendSharedInvalidMessages(invalmsgs, hdr->ninvalmsgs);
        if (hdr->initfileinval)
            RelationCacheInitFilePostInvalidate();
    }
 
    /*
     * Acquire the two-phase lock.  We want to work on the two-phase callbacks
     * while holding it to avoid potential conflicts with other transactions
     * attempting to use the same GID, so the lock is released once the shared
     * memory state is cleared.
     */
    LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
 
    /* And now do the callbacks */
    if (isCommit)
        ProcessRecords(bufptr, fxid, twophase_postcommit_callbacks);
    else
        ProcessRecords(bufptr, fxid, twophase_postabort_callbacks);
 
    PredicateLockTwoPhaseFinish(fxid, isCommit);
 
    /*
     * Read this value while holding the two-phase lock, as the on-disk 2PC
     * file is physically removed after the lock is released.
     */
    ondisk = gxact->ondisk;
 
    /* Clear shared memory state */
    RemoveGXact(gxact);
 
    /*
     * Release the lock as all callbacks are called and shared memory cleanup
     * is done.
     */
    LWLockRelease(TwoPhaseStateLock);
 
    /* Count the prepared xact as committed or aborted */
    AtEOXact_PgStat(isCommit, false);
 
    /*
     * And now we can clean up any files we may have left.
     */
    if (ondisk)
        RemoveTwoPhaseFile(fxid, true);
 
    MyLockedGxact = NULL;
 
    RESUME_INTERRUPTS();
 
    pfree(buf);
}

References Assert, AtEOXact_PgStat(), buf, DropRelationFiles(), fb(), GetPGProcByNumber, 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, pfree(), pgstat_execute_transactional_drops(), PredicateLockTwoPhaseFinish(), ProcArrayRemove(), ProcessRecords(), ReadTwoPhaseFile(), RecordTransactionAbortPrepared(), RecordTransactionCommitPrepared(), RelationCacheInitFilePostInvalidate(), RelationCacheInitFilePreInvalidate(), RemoveGXact(), RemoveTwoPhaseFile(), RESUME_INTERRUPTS, SendSharedInvalidMessages(), TransactionIdEquals, TransactionIdLatest(), twophase_postabort_callbacks, twophase_postcommit_callbacks, xl_xact_prepare::xid, XidFromFullTransactionId, 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  )

extern

Definition at line 2696 of file twophase.c.

{
    int         i;
    bool        found = false;
 
    LWLockAcquire(TwoPhaseStateLock, LW_SHARED);
    for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
    {
        GlobalTransaction gxact = TwoPhaseState->prepXacts[i];
 
        /* Ignore not-yet-valid GIDs. */
        if (gxact->valid && strcmp(gxact->gid, gid) == 0)
        {
            char       *buf;
            TwoPhaseFileHeader *hdr;
 
            /*
             * We are not expecting collisions of GXACTs (same gid) between
             * publisher and subscribers, so we perform all I/O while holding
             * TwoPhaseStateLock for simplicity.
             *
             * To move the I/O out of the lock, we need to ensure that no
             * other backend commits the prepared xact in the meantime. We can
             * do this optimization if we encounter many collisions in GID
             * between publisher and subscriber.
             */
            if (gxact->ondisk)
                buf = ReadTwoPhaseFile(gxact->fxid, false);
            else
            {
                Assert(gxact->prepare_start_lsn);
                XlogReadTwoPhaseData(gxact->prepare_start_lsn, &buf, NULL);
            }
 
            hdr = (TwoPhaseFileHeader *) buf;
 
            if (hdr->origin_lsn == prepare_end_lsn &&
                hdr->origin_timestamp == origin_prepare_timestamp)
            {
                found = true;
                pfree(buf);
                break;
            }
 
            pfree(buf);
        }
    }
    LWLockRelease(TwoPhaseStateLock);
    return found;
}

References Assert, buf, fb(), i, LW_SHARED, LWLockAcquire(), LWLockRelease(), TwoPhaseStateData::numPrepXacts, xl_xact_prepare::origin_lsn, xl_xact_prepare::origin_timestamp, pfree(), TwoPhaseStateData::prepXacts, ReadTwoPhaseFile(), TwoPhaseState, and XlogReadTwoPhaseData().

Referenced by apply_handle_rollback_prepared().

LookupGXactBySubid()

bool LookupGXactBySubid ( Oid  subid )

extern

Definition at line 2805 of file twophase.c.

{
    bool        found = false;
 
    LWLockAcquire(TwoPhaseStateLock, LW_SHARED);
    for (int i = 0; i < TwoPhaseState->numPrepXacts; i++)
    {
        GlobalTransaction gxact = TwoPhaseState->prepXacts[i];
 
        /* Ignore not-yet-valid GIDs. */
        if (gxact->valid &&
            IsTwoPhaseTransactionGidForSubid(subid, gxact->gid))
        {
            found = true;
            break;
        }
    }
    LWLockRelease(TwoPhaseStateLock);
 
    return found;
}

References fb(), i, IsTwoPhaseTransactionGidForSubid(), LW_SHARED, LWLockAcquire(), LWLockRelease(), TwoPhaseStateData::numPrepXacts, TwoPhaseStateData::prepXacts, and TwoPhaseState.

Referenced by AlterSubscription().

MarkAsPreparing()

GlobalTransaction MarkAsPreparing ( FullTransactionId  fxid, const char *  gid, TimestampTz  prepared_at, Oid  owner, Oid  databaseid  )

extern

Definition at line 365 of file twophase.c.

{
    GlobalTransaction gxact;
    int         i;
 
    if (strlen(gid) >= GIDSIZE)
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                 errmsg("transaction identifier \"%s\" is too long",
                        gid)));
 
    /* fail immediately if feature is disabled */
    if (max_prepared_xacts == 0)
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("prepared transactions are disabled"),
                 errhint("Set \"max_prepared_transactions\" to a nonzero value.")));
 
    /* on first call, register the exit hook */
    if (!twophaseExitRegistered)
    {
        before_shmem_exit(AtProcExit_Twophase, 0);
        twophaseExitRegistered = true;
    }
 
    LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
 
    /* Check for conflicting GID */
    for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
    {
        gxact = TwoPhaseState->prepXacts[i];
        if (strcmp(gxact->gid, gid) == 0)
        {
            ereport(ERROR,
                    (errcode(ERRCODE_DUPLICATE_OBJECT),
                     errmsg("transaction identifier \"%s\" is already in use",
                            gid)));
        }
    }
 
    /* Get a free gxact from the freelist */
    if (TwoPhaseState->freeGXacts == NULL)
        ereport(ERROR,
                (errcode(ERRCODE_OUT_OF_MEMORY),
                 errmsg("maximum number of prepared transactions reached"),
                 errhint("Increase \"max_prepared_transactions\" (currently %d).",
                         max_prepared_xacts)));
    gxact = TwoPhaseState->freeGXacts;
    TwoPhaseState->freeGXacts = gxact->next;
 
    MarkAsPreparingGuts(gxact, fxid, gid, prepared_at, owner, databaseid);
 
    gxact->ondisk = false;
 
    /* And insert it into the active array */
    Assert(TwoPhaseState->numPrepXacts < max_prepared_xacts);
    TwoPhaseState->prepXacts[TwoPhaseState->numPrepXacts++] = gxact;
 
    LWLockRelease(TwoPhaseStateLock);
 
    return gxact;
}

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

Referenced by PrepareTransaction().

PostPrepare_Twophase()

void PostPrepare_Twophase ( void  )

extern

Definition at line 350 of file twophase.c.

{
    LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
    MyLockedGxact->locking_backend = INVALID_PROC_NUMBER;
    LWLockRelease(TwoPhaseStateLock);
 
    MyLockedGxact = NULL;
}

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

Referenced by PrepareTransaction(), and RecoverPreparedTransactions().

PrepareRedoAdd()

void PrepareRedoAdd ( FullTransactionId  fxid, char *  buf, XLogRecPtr  start_lsn, XLogRecPtr  end_lsn, ReplOriginId  origin_id  )

extern

Definition at line 2515 of file twophase.c.

{
    TwoPhaseFileHeader *hdr = (TwoPhaseFileHeader *) buf;
    char       *bufptr;
    const char *gid;
    GlobalTransaction gxact;
 
    Assert(LWLockHeldByMeInMode(TwoPhaseStateLock, LW_EXCLUSIVE));
    Assert(RecoveryInProgress());
 
    if (!FullTransactionIdIsValid(fxid))
    {
        Assert(InRecovery);
        fxid = FullTransactionIdFromAllowableAt(TransamVariables->nextXid,
                                                hdr->xid);
    }
 
    bufptr = buf + MAXALIGN(sizeof(TwoPhaseFileHeader));
    gid = (const char *) bufptr;
 
    /*
     * Reserve the GID for the given transaction in the redo code path.
     *
     * This creates a gxact struct and puts it into the active array.
     *
     * In redo, this struct is mainly used to track PREPARE/COMMIT entries in
     * shared memory. Hence, we only fill up the bare minimum contents here.
     * The gxact also gets marked with gxact->inredo set to true to indicate
     * that it got added in the redo phase
     */
 
    /*
     * In the event of a crash while a checkpoint was running, it may be
     * possible that some two-phase data found its way to disk while its
     * corresponding record needs to be replayed in the follow-up recovery. As
     * the 2PC data was on disk, it has already been restored at the beginning
     * of recovery with restoreTwoPhaseData(), so skip this record to avoid
     * duplicates in TwoPhaseState.  If a consistent state has been reached,
     * the record is added to TwoPhaseState and it should have no
     * corresponding file in pg_twophase.
     */
    if (XLogRecPtrIsValid(start_lsn))
    {
        char        path[MAXPGPATH];
 
        Assert(InRecovery);
        TwoPhaseFilePath(path, fxid);
 
        if (access(path, F_OK) == 0)
        {
            ereport(reachedConsistency ? ERROR : WARNING,
                    (errmsg("could not recover two-phase state file for transaction %u",
                            hdr->xid),
                     errdetail("Two-phase state file has been found in WAL record %X/%08X, but this transaction has already been restored from disk.",
                               LSN_FORMAT_ARGS(start_lsn))));
            return;
        }
 
        if (errno != ENOENT)
            ereport(ERROR,
                    (errcode_for_file_access(),
                     errmsg("could not access file \"%s\": %m", path)));
    }
 
    /* Get a free gxact from the freelist */
    if (TwoPhaseState->freeGXacts == NULL)
        ereport(ERROR,
                (errcode(ERRCODE_OUT_OF_MEMORY),
                 errmsg("maximum number of prepared transactions reached"),
                 errhint("Increase \"max_prepared_transactions\" (currently %d).",
                         max_prepared_xacts)));
    gxact = TwoPhaseState->freeGXacts;
    TwoPhaseState->freeGXacts = gxact->next;
 
    gxact->prepared_at = hdr->prepared_at;
    gxact->prepare_start_lsn = start_lsn;
    gxact->prepare_end_lsn = end_lsn;
    gxact->fxid = fxid;
    gxact->owner = hdr->owner;
    gxact->locking_backend = INVALID_PROC_NUMBER;
    gxact->valid = false;
    gxact->ondisk = !XLogRecPtrIsValid(start_lsn);
    gxact->inredo = true;       /* yes, added in redo */
    strcpy(gxact->gid, gid);
 
    /* And insert it into the active array */
    Assert(TwoPhaseState->numPrepXacts < max_prepared_xacts);
    TwoPhaseState->prepXacts[TwoPhaseState->numPrepXacts++] = gxact;
 
    if (origin_id != InvalidReplOriginId)
    {
        /* recover apply progress */
        replorigin_advance(origin_id, hdr->origin_lsn, end_lsn,
                           false /* backward */ , false /* WAL */ );
    }
 
    elog(DEBUG2, "added 2PC data in shared memory for transaction %u of epoch %u",
         XidFromFullTransactionId(gxact->fxid),
         EpochFromFullTransactionId(gxact->fxid));
}

References Assert, buf, DEBUG2, elog, EpochFromFullTransactionId, ereport, errcode(), errcode_for_file_access(), errdetail(), errhint(), errmsg, ERROR, fb(), TwoPhaseStateData::freeGXacts, FullTransactionIdFromAllowableAt(), FullTransactionIdIsValid, InRecovery, INVALID_PROC_NUMBER, InvalidReplOriginId, LSN_FORMAT_ARGS, LW_EXCLUSIVE, LWLockHeldByMeInMode(), max_prepared_xacts, MAXALIGN, MAXPGPATH, GlobalTransactionData::next, TransamVariablesData::nextXid, TwoPhaseStateData::numPrepXacts, xl_xact_prepare::origin_lsn, xl_xact_prepare::owner, GlobalTransactionData::prepared_at, xl_xact_prepare::prepared_at, TwoPhaseStateData::prepXacts, reachedConsistency, RecoveryInProgress(), replorigin_advance(), TransamVariables, TwoPhaseFilePath(), TwoPhaseState, WARNING, xl_xact_prepare::xid, XidFromFullTransactionId, and XLogRecPtrIsValid.

Referenced by restoreTwoPhaseData(), and xact_redo().

PrepareRedoRemove()

void PrepareRedoRemove ( TransactionId  xid, bool  giveWarning  )

extern

Definition at line 2672 of file twophase.c.

{
    FullTransactionId fxid =
        FullTransactionIdFromAllowableAt(TransamVariables->nextXid, xid);
 
    PrepareRedoRemoveFull(fxid, giveWarning);
}

References fb(), FullTransactionIdFromAllowableAt(), TransamVariablesData::nextXid, PrepareRedoRemoveFull(), and TransamVariables.

Referenced by xact_redo().

PrescanPreparedTransactions()

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

extern

Definition at line 1974 of file twophase.c.

{
    FullTransactionId nextXid = TransamVariables->nextXid;
    TransactionId origNextXid = XidFromFullTransactionId(nextXid);
    TransactionId result = origNextXid;
    TransactionId *xids = NULL;
    int         nxids = 0;
    int         allocsize = 0;
    int         i;
 
    LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
    for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
    {
        TransactionId xid;
        char       *buf;
        GlobalTransaction gxact = TwoPhaseState->prepXacts[i];
 
        Assert(gxact->inredo);
 
        buf = ProcessTwoPhaseBuffer(gxact->fxid,
                                    gxact->prepare_start_lsn,
                                    gxact->ondisk, false, true);
 
        if (buf == NULL)
            continue;
 
        /*
         * OK, we think this file is valid.  Incorporate xid into the
         * running-minimum result.
         */
        xid = XidFromFullTransactionId(gxact->fxid);
        if (TransactionIdPrecedes(xid, result))
            result = xid;
 
        if (xids_p)
        {
            if (nxids == allocsize)
            {
                if (nxids == 0)
                {
                    allocsize = 10;
                    xids = palloc(allocsize * sizeof(TransactionId));
                }
                else
                {
                    allocsize = allocsize * 2;
                    xids = repalloc(xids, allocsize * sizeof(TransactionId));
                }
            }
            xids[nxids++] = xid;
        }
 
        pfree(buf);
    }
    LWLockRelease(TwoPhaseStateLock);
 
    if (xids_p)
    {
        *xids_p = xids;
        *nxids_p = nxids;
    }
 
    return result;
}

References Assert, buf, fb(), i, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), TransamVariablesData::nextXid, TwoPhaseStateData::numPrepXacts, palloc(), pfree(), TwoPhaseStateData::prepXacts, ProcessTwoPhaseBuffer(), repalloc(), result, TransactionIdPrecedes(), TransamVariables, TwoPhaseState, and XidFromFullTransactionId.

Referenced by StartupXLOG(), and xlog_redo().

RecoverPreparedTransactions()

void RecoverPreparedTransactions ( void  )

extern

Definition at line 2091 of file twophase.c.

{
    int         i;
 
    LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
    for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
    {
        char       *buf;
        GlobalTransaction gxact = TwoPhaseState->prepXacts[i];
        FullTransactionId fxid = gxact->fxid;
        char       *bufptr;
        TwoPhaseFileHeader *hdr;
        TransactionId *subxids;
        const char *gid;
 
        /*
         * Reconstruct subtrans state for the transaction --- needed because
         * pg_subtrans is not preserved over a restart.  Note that we are
         * linking all the subtransactions directly to the top-level XID;
         * there may originally have been a more complex hierarchy, but
         * there's no need to restore that exactly. It's possible that
         * SubTransSetParent has been set before, if the prepared transaction
         * generated xid assignment records.
         */
        buf = ProcessTwoPhaseBuffer(gxact->fxid,
                                    gxact->prepare_start_lsn,
                                    gxact->ondisk, true, false);
        if (buf == NULL)
            continue;
 
        ereport(LOG,
                (errmsg("recovering prepared transaction %u of epoch %u from shared memory",
                        XidFromFullTransactionId(gxact->fxid),
                        EpochFromFullTransactionId(gxact->fxid))));
 
        hdr = (TwoPhaseFileHeader *) buf;
        Assert(TransactionIdEquals(hdr->xid,
                                   XidFromFullTransactionId(gxact->fxid)));
        bufptr = buf + MAXALIGN(sizeof(TwoPhaseFileHeader));
        gid = (const char *) bufptr;
        bufptr += MAXALIGN(hdr->gidlen);
        subxids = (TransactionId *) bufptr;
        bufptr += MAXALIGN(hdr->nsubxacts * sizeof(TransactionId));
        bufptr += MAXALIGN(hdr->ncommitrels * sizeof(RelFileLocator));
        bufptr += MAXALIGN(hdr->nabortrels * sizeof(RelFileLocator));
        bufptr += MAXALIGN(hdr->ncommitstats * sizeof(xl_xact_stats_item));
        bufptr += MAXALIGN(hdr->nabortstats * sizeof(xl_xact_stats_item));
        bufptr += MAXALIGN(hdr->ninvalmsgs * sizeof(SharedInvalidationMessage));
 
        /*
         * Recreate its GXACT and dummy PGPROC. But, check whether it was
         * added in redo and already has a shmem entry for it.
         */
        MarkAsPreparingGuts(gxact, gxact->fxid, gid,
                            hdr->prepared_at,
                            hdr->owner, hdr->database);
 
        /* recovered, so reset the flag for entries generated by redo */
        gxact->inredo = false;
 
        GXactLoadSubxactData(gxact, hdr->nsubxacts, subxids);
        MarkAsPrepared(gxact, true);
 
        LWLockRelease(TwoPhaseStateLock);
 
        /*
         * Recover other state (notably locks) using resource managers.
         */
        ProcessRecords(bufptr, fxid, twophase_recover_callbacks);
 
        /*
         * Release locks held by the standby process after we process each
         * prepared transaction. As a result, we don't need too many
         * additional locks at any one time.
         */
        if (InHotStandby)
            StandbyReleaseLockTree(hdr->xid, hdr->nsubxacts, subxids);
 
        /*
         * We're done with recovering this transaction. Clear MyLockedGxact,
         * like we do in PrepareTransaction() during normal operation.
         */
        PostPrepare_Twophase();
 
        pfree(buf);
 
        LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
    }
 
    LWLockRelease(TwoPhaseStateLock);
}

References Assert, buf, xl_xact_prepare::database, EpochFromFullTransactionId, ereport, errmsg, fb(), xl_xact_prepare::gidlen, GXactLoadSubxactData(), i, InHotStandby, 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, xl_xact_prepare::owner, pfree(), PostPrepare_Twophase(), xl_xact_prepare::prepared_at, TwoPhaseStateData::prepXacts, ProcessRecords(), ProcessTwoPhaseBuffer(), StandbyReleaseLockTree(), TransactionIdEquals, twophase_recover_callbacks, TwoPhaseState, xl_xact_prepare::xid, and XidFromFullTransactionId.

Referenced by StartupXLOG().

restoreTwoPhaseData()

void restoreTwoPhaseData ( void  )

extern

Definition at line 1912 of file twophase.c.

{
    DIR        *cldir;
    struct dirent *clde;
 
    LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
    cldir = AllocateDir(TWOPHASE_DIR);
    while ((clde = ReadDir(cldir, TWOPHASE_DIR)) != NULL)
    {
        if (strlen(clde->d_name) == 16 &&
            strspn(clde->d_name, "0123456789ABCDEF") == 16)
        {
            FullTransactionId fxid;
            char       *buf;
 
            fxid = FullTransactionIdFromU64(strtou64(clde->d_name, NULL, 16));
 
            buf = ProcessTwoPhaseBuffer(fxid, InvalidXLogRecPtr,
                                        true, false, false);
            if (buf == NULL)
                continue;
 
            PrepareRedoAdd(fxid, buf, InvalidXLogRecPtr,
                           InvalidXLogRecPtr, InvalidReplOriginId);
        }
    }
    LWLockRelease(TwoPhaseStateLock);
    FreeDir(cldir);
}

References AllocateDir(), buf, fb(), FreeDir(), FullTransactionIdFromU64(), InvalidReplOriginId, InvalidXLogRecPtr, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), PrepareRedoAdd(), ProcessTwoPhaseBuffer(), ReadDir(), and TWOPHASE_DIR.

Referenced by StartupXLOG().

StandbyRecoverPreparedTransactions()

void StandbyRecoverPreparedTransactions ( void  )

extern

Definition at line 2053 of file twophase.c.

{
    int         i;
 
    LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
    for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
    {
        char       *buf;
        GlobalTransaction gxact = TwoPhaseState->prepXacts[i];
 
        Assert(gxact->inredo);
 
        buf = ProcessTwoPhaseBuffer(gxact->fxid,
                                    gxact->prepare_start_lsn,
                                    gxact->ondisk, true, false);
        if (buf != NULL)
            pfree(buf);
    }
    LWLockRelease(TwoPhaseStateLock);
}

References Assert, buf, fb(), i, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), TwoPhaseStateData::numPrepXacts, pfree(), TwoPhaseStateData::prepXacts, ProcessTwoPhaseBuffer(), and TwoPhaseState.

Referenced by StartupXLOG(), and xlog_redo().

StandbyTransactionIdIsPrepared()

bool StandbyTransactionIdIsPrepared ( TransactionId  xid )

extern

Definition at line 1475 of file twophase.c.

{
    char       *buf;
    TwoPhaseFileHeader *hdr;
    bool        result;
    FullTransactionId fxid;
 
    Assert(TransactionIdIsValid(xid));
 
    if (max_prepared_xacts <= 0)
        return false;           /* nothing to do */
 
    /* Read and validate file */
    fxid = AdjustToFullTransactionId(xid);
    buf = ReadTwoPhaseFile(fxid, true);
    if (buf == NULL)
        return false;
 
    /* Check header also */
    hdr = (TwoPhaseFileHeader *) buf;
    result = TransactionIdEquals(hdr->xid, xid);
    pfree(buf);
 
    return result;
}

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

Referenced by KnownAssignedXidsRemovePreceding(), and StandbyReleaseOldLocks().

StartPrepare()

void StartPrepare ( GlobalTransaction  gxact )

extern

Definition at line 1058 of file twophase.c.

{
    PGPROC     *proc = GetPGProcByNumber(gxact->pgprocno);
    TransactionId xid = XidFromFullTransactionId(gxact->fxid);
    TwoPhaseFileHeader hdr;
    TransactionId *children;
    RelFileLocator *commitrels;
    RelFileLocator *abortrels;
    xl_xact_stats_item *abortstats = NULL;
    xl_xact_stats_item *commitstats = NULL;
    SharedInvalidationMessage *invalmsgs;
 
    /* Initialize linked list */
    records.head = palloc0_object(StateFileChunk);
    records.head->len = 0;
    records.head->next = NULL;
 
    records.bytes_free = Max(sizeof(TwoPhaseFileHeader), 512);
    records.head->data = palloc(records.bytes_free);
 
    records.tail = records.head;
    records.num_chunks = 1;
 
    records.total_len = 0;
 
    /* Create header */
    hdr.magic = TWOPHASE_MAGIC;
    hdr.total_len = 0;          /* EndPrepare will fill this in */
    hdr.xid = xid;
    hdr.database = proc->databaseId;
    hdr.prepared_at = gxact->prepared_at;
    hdr.owner = gxact->owner;
    hdr.nsubxacts = xactGetCommittedChildren(&children);
    hdr.ncommitrels = smgrGetPendingDeletes(true, &commitrels);
    hdr.nabortrels = smgrGetPendingDeletes(false, &abortrels);
    hdr.ncommitstats =
        pgstat_get_transactional_drops(true, &commitstats);
    hdr.nabortstats =
        pgstat_get_transactional_drops(false, &abortstats);
    hdr.ninvalmsgs = xactGetCommittedInvalidationMessages(&invalmsgs,
                                                          &hdr.initfileinval);
    hdr.gidlen = strlen(gxact->gid) + 1;    /* Include '\0' */
    /* EndPrepare will fill the origin data, if necessary */
    hdr.origin_lsn = InvalidXLogRecPtr;
    hdr.origin_timestamp = 0;
 
    save_state_data(&hdr, sizeof(TwoPhaseFileHeader));
    save_state_data(gxact->gid, hdr.gidlen);
 
    /*
     * Add the additional info about subxacts, deletable files and cache
     * invalidation messages.
     */
    if (hdr.nsubxacts > 0)
    {
        save_state_data(children, hdr.nsubxacts * sizeof(TransactionId));
        /* While we have the child-xact data, stuff it in the gxact too */
        GXactLoadSubxactData(gxact, hdr.nsubxacts, children);
    }
    if (hdr.ncommitrels > 0)
    {
        save_state_data(commitrels, hdr.ncommitrels * sizeof(RelFileLocator));
        pfree(commitrels);
    }
    if (hdr.nabortrels > 0)
    {
        save_state_data(abortrels, hdr.nabortrels * sizeof(RelFileLocator));
        pfree(abortrels);
    }
    if (hdr.ncommitstats > 0)
    {
        save_state_data(commitstats,
                        hdr.ncommitstats * sizeof(xl_xact_stats_item));
        pfree(commitstats);
    }
    if (hdr.nabortstats > 0)
    {
        save_state_data(abortstats,
                        hdr.nabortstats * sizeof(xl_xact_stats_item));
        pfree(abortstats);
    }
    if (hdr.ninvalmsgs > 0)
    {
        save_state_data(invalmsgs,
                        hdr.ninvalmsgs * sizeof(SharedInvalidationMessage));
        pfree(invalmsgs);
    }
}

References xllist::bytes_free, StateFileChunk::data, xl_xact_prepare::database, PGPROC::databaseId, fb(), GetPGProcByNumber, 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, xl_xact_prepare::owner, palloc(), palloc0_object, pfree(), pgstat_get_transactional_drops(), xl_xact_prepare::prepared_at, records, save_state_data(), smgrGetPendingDeletes(), xllist::tail, xllist::total_len, xl_xact_prepare::total_len, TWOPHASE_MAGIC, xactGetCommittedChildren(), xactGetCommittedInvalidationMessages(), xl_xact_prepare::xid, and XidFromFullTransactionId.

Referenced by PrepareTransaction().

TwoPhaseGetDummyProc()

PGPROC * TwoPhaseGetDummyProc ( FullTransactionId  fxid, bool  lock_held  )

extern

Definition at line 929 of file twophase.c.

{
    GlobalTransaction gxact = TwoPhaseGetGXact(fxid, lock_held);
 
    return GetPGProcByNumber(gxact->pgprocno);
}

References fb(), GetPGProcByNumber, and TwoPhaseGetGXact().

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

TwoPhaseGetDummyProcNumber()

int TwoPhaseGetDummyProcNumber ( FullTransactionId  fxid, bool  lock_held  )

extern

Definition at line 914 of file twophase.c.

{
    GlobalTransaction gxact = TwoPhaseGetGXact(fxid, lock_held);
 
    return gxact->pgprocno;
}

References fb(), and TwoPhaseGetGXact().

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

TwoPhaseGetOldestXidInCommit()

TransactionId TwoPhaseGetOldestXidInCommit ( void  )

extern

Definition at line 2837 of file twophase.c.

{
    TransactionId oldestRunningXid = InvalidTransactionId;
 
    LWLockAcquire(TwoPhaseStateLock, LW_SHARED);
 
    for (int i = 0; i < TwoPhaseState->numPrepXacts; i++)
    {
        GlobalTransaction gxact = TwoPhaseState->prepXacts[i];
        PGPROC     *commitproc;
        TransactionId xid;
 
        if (!gxact->valid)
            continue;
 
        if (gxact->locking_backend == INVALID_PROC_NUMBER)
            continue;
 
        /*
         * Get the backend that is handling the transaction. It's safe to
         * access this backend while holding TwoPhaseStateLock, as the backend
         * can only be destroyed after either removing or unlocking the
         * current global transaction, both of which require an exclusive
         * TwoPhaseStateLock.
         */
        commitproc = GetPGProcByNumber(gxact->locking_backend);
 
        if (MyDatabaseId != commitproc->databaseId)
            continue;
 
        if ((commitproc->delayChkptFlags & DELAY_CHKPT_IN_COMMIT) == 0)
            continue;
 
        xid = XidFromFullTransactionId(gxact->fxid);
 
        if (!TransactionIdIsValid(oldestRunningXid) ||
            TransactionIdPrecedes(xid, oldestRunningXid))
            oldestRunningXid = xid;
    }
 
    LWLockRelease(TwoPhaseStateLock);
 
    return oldestRunningXid;
}

References DELAY_CHKPT_IN_COMMIT, fb(), GetPGProcByNumber, i, INVALID_PROC_NUMBER, InvalidTransactionId, LW_SHARED, LWLockAcquire(), LWLockRelease(), MyDatabaseId, TwoPhaseStateData::numPrepXacts, TwoPhaseStateData::prepXacts, TransactionIdIsValid, TransactionIdPrecedes(), TwoPhaseState, and XidFromFullTransactionId.

Referenced by ProcessStandbyPSRequestMessage().

TwoPhaseGetXidByVirtualXID()

TransactionId TwoPhaseGetXidByVirtualXID ( VirtualTransactionId  vxid, bool *  have_more  )

extern

Definition at line 862 of file twophase.c.

{
    int         i;
    TransactionId result = InvalidTransactionId;
 
    Assert(VirtualTransactionIdIsValid(vxid));
    LWLockAcquire(TwoPhaseStateLock, LW_SHARED);
 
    for (i = 0; i < TwoPhaseState->numPrepXacts; i++)
    {
        GlobalTransaction gxact = TwoPhaseState->prepXacts[i];
        PGPROC     *proc;
        VirtualTransactionId proc_vxid;
 
        if (!gxact->valid)
            continue;
        proc = GetPGProcByNumber(gxact->pgprocno);
        GET_VXID_FROM_PGPROC(proc_vxid, *proc);
        if (VirtualTransactionIdEquals(vxid, proc_vxid))
        {
            /*
             * Startup process sets proc->vxid.procNumber to
             * INVALID_PROC_NUMBER.
             */
            Assert(!gxact->inredo);
 
            if (result != InvalidTransactionId)
            {
                *have_more = true;
                break;
            }
            result = XidFromFullTransactionId(gxact->fxid);
        }
    }
 
    LWLockRelease(TwoPhaseStateLock);
 
    return result;
}

References Assert, fb(), GET_VXID_FROM_PGPROC, GetPGProcByNumber, i, InvalidTransactionId, LW_SHARED, LWLockAcquire(), LWLockRelease(), TwoPhaseStateData::numPrepXacts, TwoPhaseStateData::prepXacts, result, TwoPhaseState, VirtualTransactionIdEquals, VirtualTransactionIdIsValid, and XidFromFullTransactionId.

Referenced by XactLockForVirtualXact().

TwoPhaseTransactionGid()

void TwoPhaseTransactionGid ( Oid  subid, TransactionId  xid, char *  gid_res, int  szgid  )

extern

Definition at line 2755 of file twophase.c.

{
    Assert(OidIsValid(subid));
 
    if (!TransactionIdIsValid(xid))
        ereport(ERROR,
                (errcode(ERRCODE_PROTOCOL_VIOLATION),
                 errmsg_internal("invalid two-phase transaction ID")));
 
    snprintf(gid_res, szgid, "pg_gid_%u_%u", subid, xid);
}

References Assert, ereport, errcode(), ERRCODE_PROTOCOL_VIOLATION, errmsg_internal(), ERROR, fb(), OidIsValid, snprintf, and TransactionIdIsValid.

Referenced by apply_handle_commit_prepared(), apply_handle_prepare_internal(), apply_handle_rollback_prepared(), and IsTwoPhaseTransactionGidForSubid().

Variable Documentation

max_prepared_xacts

PGDLLIMPORT int max_prepared_xacts

extern

Definition at line 118 of file twophase.c.

Referenced by CheckPointTwoPhase(), CheckRequiredParameterValues(), GetLockConflicts(), GetSerializableTransactionSnapshotInt(), InitControlFile(), MarkAsPreparing(), predicatelock_twophase_recover(), PredicateLockShmemRequest(), PrepareRedoAdd(), ProcGlobalShmemRequest(), StandbyTransactionIdIsPrepared(), TwoPhaseShmemInit(), TwoPhaseShmemRequest(), XactLockForVirtualXact(), and XLogReportParameters().