diff options
Diffstat (limited to 'src/backend/access/transam/xact.c')
| -rw-r--r-- | src/backend/access/transam/xact.c | 57 |
1 files changed, 50 insertions, 7 deletions
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index fe99ba15f36..17db7dd78d5 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 1.189 2004/09/16 16:58:26 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.190 2004/09/16 20:17:16 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -861,9 +861,6 @@ AtCommit_Memory(void) /* * AtSubCommit_Memory - * - * We do not throw away the child's CurTransactionContext, since the data - * it contains will be needed at upper commit. */ static void AtSubCommit_Memory(void) @@ -875,6 +872,18 @@ AtSubCommit_Memory(void) /* Return to parent transaction level's memory context. */ CurTransactionContext = s->parent->curTransactionContext; MemoryContextSwitchTo(CurTransactionContext); + + /* + * Ordinarily we cannot throw away the child's CurTransactionContext, + * since the data it contains will be needed at upper commit. However, + * if there isn't actually anything in it, we can throw it away. This + * avoids a small memory leak in the common case of "trivial" subxacts. + */ + if (MemoryContextIsEmpty(s->curTransactionContext)) + { + MemoryContextDelete(s->curTransactionContext); + s->curTransactionContext = NULL; + } } /* @@ -890,13 +899,27 @@ AtSubCommit_childXids(void) Assert(s->parent != NULL); - old_cxt = MemoryContextSwitchTo(s->parent->curTransactionContext); + /* + * We keep the child-XID lists in TopTransactionContext; this avoids + * setting up child-transaction contexts for what might be just a few + * bytes of grandchild XIDs. + */ + old_cxt = MemoryContextSwitchTo(TopTransactionContext); s->parent->childXids = lappend_xid(s->parent->childXids, s->transactionId); - s->parent->childXids = list_concat(s->parent->childXids, s->childXids); - s->childXids = NIL; /* ensure list not doubly referenced */ + if (s->childXids != NIL) + { + s->parent->childXids = list_concat(s->parent->childXids, + s->childXids); + /* + * list_concat doesn't free the list header for the second list; + * do so here to avoid memory leakage (kluge) + */ + pfree(s->childXids); + s->childXids = NIL; + } MemoryContextSwitchTo(old_cxt); } @@ -1093,6 +1116,23 @@ AtSubAbort_Memory(void) } /* + * AtSubAbort_childXids + */ +static void +AtSubAbort_childXids(void) +{ + TransactionState s = CurrentTransactionState; + + /* + * We keep the child-XID lists in TopTransactionContext (see + * AtSubCommit_childXids). This means we'd better free the list + * explicitly at abort to avoid leakage. + */ + list_free(s->childXids); + s->childXids = NIL; +} + +/* * RecordSubTransactionAbort */ static void @@ -3317,7 +3357,10 @@ AbortSubTransaction(void) /* Advertise the fact that we aborted in pg_clog. */ if (TransactionIdIsValid(s->transactionId)) + { RecordSubTransactionAbort(); + AtSubAbort_childXids(); + } /* Post-abort cleanup */ CallSubXactCallbacks(SUBXACT_EVENT_ABORT_SUB, s->subTransactionId, |