diff options
Diffstat (limited to 'src/backend/access/transam/xact.c')
| -rw-r--r-- | src/backend/access/transam/xact.c | 92 |
1 files changed, 61 insertions, 31 deletions
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index 3c6e2ebf5cd..673a34ad034 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -10,7 +10,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.228 2006/11/05 22:42:07 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.229 2006/11/23 01:14:59 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -171,6 +171,12 @@ static TimestampTz stmtStartTimestamp; */ static char *prepareGID; +/* + * Private context for transaction-abort work --- we reserve space for this + * at startup to ensure that AbortTransaction and AbortSubTransaction can work + * when we've run out of memory. + */ +static MemoryContext TransactionAbortContext = NULL; /* * List of add-on start- and end-of-xact callbacks @@ -556,6 +562,21 @@ AtStart_Memory(void) TransactionState s = CurrentTransactionState; /* + * If this is the first time through, create a private context for + * AbortTransaction to work in. By reserving some space now, we can + * insulate AbortTransaction from out-of-memory scenarios. Like + * ErrorContext, we set it up with slow growth rate and a nonzero + * minimum size, so that space will be reserved immediately. + */ + if (TransactionAbortContext == NULL) + TransactionAbortContext = + AllocSetContextCreate(TopMemoryContext, + "TransactionAbortContext", + 32 * 1024, + 32 * 1024, + 32 * 1024); + + /* * We shouldn't have a transaction context already. */ Assert(TopTransactionContext == NULL); @@ -1086,20 +1107,15 @@ static void AtAbort_Memory(void) { /* - * Make sure we are in a valid context (not a child of - * TopTransactionContext...). Note that it is possible for this code to - * be called when we aren't in a transaction at all; go directly to - * TopMemoryContext in that case. + * Switch into TransactionAbortContext, which should have some free + * space even if nothing else does. We'll work in this context until + * we've finished cleaning up. + * + * It is barely possible to get here when we've not been able to create + * TransactionAbortContext yet; if so use TopMemoryContext. */ - if (TopTransactionContext != NULL) - { - MemoryContextSwitchTo(TopTransactionContext); - - /* - * We do not want to destroy the transaction's global state yet, so we - * can't free any memory here. - */ - } + if (TransactionAbortContext != NULL) + MemoryContextSwitchTo(TransactionAbortContext); else MemoryContextSwitchTo(TopMemoryContext); } @@ -1110,9 +1126,9 @@ AtAbort_Memory(void) static void AtSubAbort_Memory(void) { - Assert(TopTransactionContext != NULL); + Assert(TransactionAbortContext != NULL); - MemoryContextSwitchTo(TopTransactionContext); + MemoryContextSwitchTo(TransactionAbortContext); } @@ -1272,13 +1288,19 @@ RecordSubTransactionAbort(void) static void AtCleanup_Memory(void) { + Assert(CurrentTransactionState->parent == NULL); + /* * Now that we're "out" of a transaction, have the system allocate things * in the top memory context instead of per-transaction contexts. */ MemoryContextSwitchTo(TopMemoryContext); - Assert(CurrentTransactionState->parent == NULL); + /* + * Clear the special abort context for next time. + */ + if (TransactionAbortContext != NULL) + MemoryContextResetAndDeleteChildren(TransactionAbortContext); /* * Release all transaction-local memory. @@ -1311,6 +1333,12 @@ AtSubCleanup_Memory(void) CurTransactionContext = s->parent->curTransactionContext; /* + * Clear the special abort context for next time. + */ + if (TransactionAbortContext != NULL) + MemoryContextResetAndDeleteChildren(TransactionAbortContext); + + /* * Delete the subxact local memory contexts. Its CurTransactionContext can * go too (note this also kills CurTransactionContexts from any children * of the subxact). @@ -1849,6 +1877,10 @@ AbortTransaction(void) /* Prevent cancel/die interrupt while cleaning up */ HOLD_INTERRUPTS(); + /* Make sure we have a valid memory context and resource owner */ + AtAbort_Memory(); + AtAbort_ResourceOwner(); + /* * Release any LW locks we might be holding as quickly as possible. * (Regular locks, however, must be held till we finish aborting.) @@ -1881,10 +1913,6 @@ AbortTransaction(void) */ s->state = TRANS_ABORT; - /* Make sure we have a valid memory context and resource owner */ - AtAbort_Memory(); - AtAbort_ResourceOwner(); - /* * Reset user id which might have been changed transiently. We cannot use * s->currentUser, since it may not be set yet; instead rely on internal @@ -3704,15 +3732,12 @@ AbortSubTransaction(void) { TransactionState s = CurrentTransactionState; - ShowTransactionState("AbortSubTransaction"); - - if (s->state != TRANS_INPROGRESS) - elog(WARNING, "AbortSubTransaction while in %s state", - TransStateAsString(s->state)); - + /* Prevent cancel/die interrupt while cleaning up */ HOLD_INTERRUPTS(); - s->state = TRANS_ABORT; + /* Make sure we have a valid memory context and resource owner */ + AtSubAbort_Memory(); + AtSubAbort_ResourceOwner(); /* * Release any LW locks we might be holding as quickly as possible. @@ -3731,10 +3756,15 @@ AbortSubTransaction(void) LockWaitCancel(); /* - * do abort processing + * check the current transaction state */ - AtSubAbort_Memory(); - AtSubAbort_ResourceOwner(); + ShowTransactionState("AbortSubTransaction"); + + if (s->state != TRANS_INPROGRESS) + elog(WARNING, "AbortSubTransaction while in %s state", + TransStateAsString(s->state)); + + s->state = TRANS_ABORT; /* * We can skip all this stuff if the subxact failed before creating a |