/*
* FinishPreparedTransaction: execute COMMIT PREPARED or ROLLBACK PREPARED
*/
void
FinishPreparedTransaction(const char *gid, bool isCommit)
{
GlobalTransaction gxact;
TransactionId xid;
char *buf;
char *bufptr;
TwoPhaseFileHeader *hdr;
TransactionId *children;
RelFileNode *commitrels;
RelFileNode *abortrels;
int i;
/*
* 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());
xid = gxact->proc.xid;
/*
* Read and validate the state file
*/
buf = ReadTwoPhaseFile(xid);
if (buf == NULL)
ereport(ERROR,
(errcode(ERRCODE_DATA_CORRUPTED),
errmsg("two-phase state file for transaction %u is corrupt",
xid)));
/*
* Disassemble the header area
*/
hdr = (TwoPhaseFileHeader *) buf;
Assert(TransactionIdEquals(hdr->xid, xid));
bufptr = buf + MAXALIGN(sizeof(TwoPhaseFileHeader));
children = (TransactionId *) bufptr;
bufptr += MAXALIGN(hdr->nsubxacts * sizeof(TransactionId));
commitrels = (RelFileNode *) bufptr;
bufptr += MAXALIGN(hdr->ncommitrels * sizeof(RelFileNode));
abortrels = (RelFileNode *) bufptr;
bufptr += MAXALIGN(hdr->nabortrels * sizeof(RelFileNode));
/*
* The order of operations here is critical: make the XLOG entry for
* commit or abort, then mark the transaction committed or aborted in
* pg_clog, 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);
else
RecordTransactionAbortPrepared(xid,
hdr->nsubxacts, children,
hdr->nabortrels, abortrels);
ProcArrayRemove(&gxact->proc);
/*
* In case we fail while running the callbacks, mark the gxact invalid so
* no one else will try to commit/rollback, and so it can be recycled
* properly later. It is still locked by our XID 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)
{
for (i = 0; i < hdr->ncommitrels; i++)
smgrdounlink(smgropen(commitrels[i]), false, false);
}
else
{
for (i = 0; i < hdr->nabortrels; i++)
smgrdounlink(smgropen(abortrels[i]), false, false);
}
/* And now do the callbacks */
if (isCommit)
ProcessRecords(bufptr, xid, twophase_postcommit_callbacks);
else
ProcessRecords(bufptr, xid, twophase_postabort_callbacks);
pgstat_count_xact_commit();
/*
* And now we can clean up our mess.
*/
RemoveTwoPhaseFile(xid, true);
RemoveGXact(gxact);
pfree(buf);
}
/*
* CommitTransaction
*/
static void
CommitTransaction(void)
{
TransactionState s = CurrentTransactionState;
/*
* check the current transaction state
*/
if (s->state != TRANS_INPROGRESS)
elog(WARNING, "CommitTransaction and not in in-progress state");
/*
* Do pre-commit processing (most of this stuff requires database
* access, and in fact could still cause an error...)
*/
/*
* Tell the trigger manager that this transaction is about to be
* committed. He'll invoke all trigger deferred until XACT before we
* really start on committing the transaction.
*/
DeferredTriggerEndXact();
/* Close open cursors */
AtCommit_Portals();
/*
* Let ON COMMIT management do its thing (must happen after closing
* cursors, to avoid dangling-reference problems)
*/
PreCommit_on_commit_actions();
/* handle commit for large objects [ PA, 7/17/98 ] */
/* XXX probably this does not belong here */
lo_commit(true);
/* NOTIFY commit must come before lower-level cleanup */
AtCommit_Notify();
/* Update the flat password file if we changed pg_shadow or pg_group */
AtEOXact_UpdatePasswordFile(true);
/* Prevent cancel/die interrupt while cleaning up */
HOLD_INTERRUPTS();
/*
* set the current transaction state information appropriately during
* the abort processing
*/
s->state = TRANS_COMMIT;
/*
* Here is where we really truly commit.
*/
RecordTransactionCommit();
/*
* Let others know about no transaction in progress by me. Note that
* this must be done _before_ releasing locks we hold and _after_
* RecordTransactionCommit.
*
* LWLockAcquire(SInvalLock) is required: UPDATE with xid 0 is blocked by
* xid 1' UPDATE, xid 1 is doing commit while xid 2 gets snapshot - if
* xid 2' GetSnapshotData sees xid 1 as running then it must see xid 0
* as running as well or it will see two tuple versions - one deleted
* by xid 1 and one inserted by xid 0. See notes in GetSnapshotData.
*/
if (MyProc != (PGPROC *) NULL)
{
/* Lock SInvalLock because that's what GetSnapshotData uses. */
LWLockAcquire(SInvalLock, LW_EXCLUSIVE);
MyProc->xid = InvalidTransactionId;
MyProc->xmin = InvalidTransactionId;
LWLockRelease(SInvalLock);
}
/*
* This is all post-commit cleanup. Note that if an error is raised
* here, it's too late to abort the transaction. This should be just
* noncritical resource releasing.
*
* The ordering of operations is not entirely random. The idea is:
* release resources visible to other backends (eg, files, buffer
* pins); then release locks; then release backend-local resources. We
* want to release locks at the point where any backend waiting for us
* will see our transaction as being fully cleaned up.
*/
smgrDoPendingDeletes(true);
AtCommit_Cache();
AtEOXact_Buffers(true);
/* smgrcommit already done */
AtCommit_Locks();
CallEOXactCallbacks(true);
AtEOXact_GUC(true);
AtEOXact_SPI();
AtEOXact_gist();
AtEOXact_hash();
AtEOXact_nbtree();
AtEOXact_rtree();
AtEOXact_on_commit_actions(true);
AtEOXact_Namespace(true);
AtEOXact_CatCache(true);
AtEOXact_Files();
pgstat_count_xact_commit();
AtCommit_Memory();
/*
* done with commit processing, set current transaction state back to
* default
*/
s->state = TRANS_DEFAULT;
RESUME_INTERRUPTS();
}
