*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.169 2004/07/01 00:49:42 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.170 2004/07/01 20:11:02 tgl Exp $
*
* NOTES
* Transaction aborts can now occur two ways:
static void CommitSubTransaction(void);
static void AbortSubTransaction(void);
static void CleanupSubTransaction(void);
+static void StartAbortedSubTransaction(void);
static void PushTransaction(void);
static void PopTransaction(void);
TransactionState s = CurrentTransactionState;
if (s->blockState == TBLOCK_ABORT ||
- s->blockState == TBLOCK_SUBABORT)
+ s->blockState == TBLOCK_SUBABORT)
return true;
return false;
break;
/*
- * This is the case when are somewhere in a transaction block
+ * This is the case when we are somewhere in a transaction block
* and about to start a new command. For now we do nothing
- * but someday we may do command-local resource
- * initialization.
+ * but someday we may do command-local resource initialization.
*/
case TBLOCK_INPROGRESS:
case TBLOCK_SUBINPROGRESS:
/*
* We were just issued a BEGIN inside a transaction block.
- * Start a subtransaction.
+ * Start a subtransaction. (BeginTransactionBlock already
+ * did PushTransaction, so as to have someplace to put the
+ * SUBBEGIN state.)
*/
case TBLOCK_SUBBEGIN:
StartSubTransaction();
* Start a subtransaction, and put it in aborted state.
*/
case TBLOCK_SUBBEGINABORT:
- StartSubTransaction();
- AbortSubTransaction();
+ StartAbortedSubTransaction();
s->blockState = TBLOCK_SUBABORT;
break;
break;
/*
- * We where issued a COMMIT command, so we end the current
+ * We were issued a COMMIT command, so we end the current
* subtransaction and return to the parent transaction.
*/
case TBLOCK_SUBEND:
break;
/*
- * We are ending a subtransaction that aborted nicely,
+ * We are ending an aborted subtransaction via ROLLBACK,
* so the parent can be allowed to live.
*/
case TBLOCK_SUBENDABORT_OK:
break;
/*
- * We are ending a subtransaction that aborted in a unclean
- * way (e.g. the user issued COMMIT in an aborted subtrasaction.)
- * Abort the subtransaction, and abort the parent too.
+ * We are ending an aborted subtransaction via COMMIT.
+ * End the subtransaction, and abort the parent too.
*/
case TBLOCK_SUBENDABORT_ERROR:
CleanupSubTransaction();
break;
/*
- * If we are in the TBLOCK_BEGIN it means something screwed up
+ * If we are in TBLOCK_BEGIN it means something screwed up
* right after reading "BEGIN TRANSACTION" so we enter the
* abort state. Eventually an "END TRANSACTION" will fix
* things.
break;
/*
- * This is the case when are somewhere in a transaction block
- * which aborted so we abort the transaction and set the ABORT
- * state. Eventually an "END TRANSACTION" will fix things and
- * restore us to a normal state.
+ * This is the case when we are somewhere in a transaction block
+ * and we've gotten a failure, so we abort the transaction and
+ * set up the persistent ABORT state. We will stay in ABORT
+ * until we get an "END TRANSACTION".
*/
case TBLOCK_INPROGRESS:
AbortTransaction();
/*
* Here, the system was fouled up just after the user wanted
* to end the transaction block so we abort the transaction
- * and put us back into the default state.
+ * and return to the default state.
*/
case TBLOCK_END:
AbortTransaction();
*/
case TBLOCK_SUBBEGIN:
case TBLOCK_SUBBEGINABORT:
- PushTransaction();
- s = CurrentTransactionState; /* changed by push */
- StartSubTransaction();
- AbortSubTransaction();
+ StartAbortedSubTransaction();
s->blockState = TBLOCK_SUBABORT;
break;
* transaction block support
* ----------------------------------------------------------------
*/
+
/*
* BeginTransactionBlock
+ * This executes a BEGIN command.
*/
void
BeginTransactionBlock(void)
switch (s->blockState) {
/*
- * We are inside a transaction, so allow a transaction block
+ * We are not inside a transaction block, so allow one
* to begin.
*/
case TBLOCK_STARTED:
/*
* EndTransactionBlock
+ * This executes a COMMIT command.
*/
void
EndTransactionBlock(void)
break;
/*
- * here, we are in a transaction block which aborted and since the
- * AbortTransaction() was already done, we do whatever is needed
- * and change to the special "END ABORT" state. The upcoming
+ * here, we are in a transaction block which aborted. Since the
+ * AbortTransaction() was already done, we need only
+ * change to the special "END ABORT" state. The upcoming
* CommitTransactionCommand() will recognise this and then put us
* back in the default state.
*/
/*
* here we are in an aborted subtransaction. Signal
* CommitTransactionCommand() to clean up and return to the
- * parent transaction.
+ * parent transaction. Since the user said COMMIT, we must
+ * fail the parent transaction.
*/
case TBLOCK_SUBABORT:
s->blockState = TBLOCK_SUBENDABORT_ERROR;
s->blockState = TBLOCK_ENDABORT;
break;
- /* These cases are invalid. Reject them altogether. */
+ /* these cases are invalid. */
case TBLOCK_DEFAULT:
case TBLOCK_BEGIN:
case TBLOCK_ENDABORT:
/*
* UserAbortTransactionBlock
+ * This executes a ROLLBACK command.
*/
void
UserAbortTransactionBlock(void)
s->blockState = TBLOCK_ENDABORT;
break;
- /* Ditto, for a subtransaction. */
+ /*
+ * Ditto, for a subtransaction. Here it is okay to allow the
+ * parent transaction to continue.
+ */
case TBLOCK_SUBABORT:
s->blockState = TBLOCK_SUBENDABORT_OK;
break;
case TBLOCK_SUBBEGIN:
case TBLOCK_SUBBEGINABORT:
/*
- * Just starting a new transaction -- return to parent.
- * FIXME -- Is this correct?
+ * We didn't get as far as starting the subxact, so there's
+ * nothing to abort. Just pop back to parent.
*/
PopTransaction();
s = CurrentTransactionState; /* changed by pop */
case TBLOCK_SUBABORT:
case TBLOCK_SUBENDABORT_OK:
case TBLOCK_SUBENDABORT_ERROR:
+ /* As above, but AbortSubTransaction already done */
CleanupSubTransaction();
PopTransaction();
s = CurrentTransactionState; /* changed by pop */
AtSubCommit_Portals(s->parent->transactionIdData);
DeferredTriggerEndSubXact(true);
+ s->state = TRANS_COMMIT;
+
/* Mark subtransaction as subcommitted */
CommandCounterIncrement();
RecordSubTransactionCommit();
s->state = TRANS_DEFAULT;
}
+/*
+ * StartAbortedSubTransaction
+ *
+ * This function is used to start a subtransaction and put it immediately
+ * into aborted state. The end result should be equivalent to
+ * StartSubTransaction immediately followed by AbortSubTransaction.
+ * The reason we don't implement it just that way is that many of the backend
+ * modules aren't designed to handle starting a subtransaction when not
+ * inside a valid transaction. Rather than making them all capable of
+ * doing that, we just omit the paired start and abort calls in this path.
+ */
+static void
+StartAbortedSubTransaction(void)
+{
+ TransactionState s = CurrentTransactionState;
+
+ if (s->state != TRANS_DEFAULT)
+ elog(WARNING, "StartAbortedSubTransaction and not in default state");
+
+ s->state = TRANS_START;
+
+ /*
+ * We don't bother to generate a new Xid, so the end state is not
+ * *exactly* like we had done a full Start/AbortSubTransaction...
+ */
+ s->transactionIdData = InvalidTransactionId;
+
+ /* Make sure currentUser is reasonably valid */
+ Assert(s->parent != NULL);
+ s->currentUser = s->parent->currentUser;
+
+ /*
+ * Initialize only what has to be there for CleanupSubTransaction to work.
+ */
+ AtSubStart_Memory();
+
+ s->state = TRANS_ABORT;
+
+ AtSubAbort_Memory();
+
+ ShowTransactionState("StartAbortedSubTransaction");
+}
+
/*
* PushTransaction
* Set up transaction state for a subtransaction
*/
s->transactionIdData = p->transactionIdData;
s->curTransactionContext = p->curTransactionContext;
+ s->currentUser = p->currentUser;
CurrentTransactionState = s;
}
projects / postgresql / commitdiff