diff options
Diffstat (limited to 'src/backend/access/transam/xact.c')
| -rw-r--r-- | src/backend/access/transam/xact.c | 30 |
1 files changed, 29 insertions, 1 deletions
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index e000547b327..6ef1f5a7420 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 1.229.2.3 2008/01/03 21:23:45 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.229.2.4 2008/03/04 19:54:23 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -57,6 +57,13 @@ bool XactReadOnly; int CommitDelay = 0; /* precommit delay in microseconds */ int CommitSiblings = 5; /* # concurrent xacts needed to sleep */ +/* + * MyXactAccessedTempRel is set when a temporary relation is accessed. + * We don't allow PREPARE TRANSACTION in that case. (This is global + * so that it can be set from heapam.c.) + */ +bool MyXactAccessedTempRel = false; + /* * transaction states - transaction state from server perspective @@ -1389,6 +1396,7 @@ StartTransaction(void) FreeXactSnapshot(); XactIsoLevel = DefaultXactIsoLevel; XactReadOnly = DefaultXactReadOnly; + MyXactAccessedTempRel = false; /* * reinitialize within-transaction counters @@ -1715,6 +1723,26 @@ PrepareTransaction(void) /* NOTIFY and flatfiles will be handled below */ + /* + * Don't allow PREPARE TRANSACTION if we've accessed a temporary table + * in this transaction. Having the prepared xact hold locks on another + * backend's temp table seems a bad idea --- for instance it would prevent + * the backend from exiting. There are other problems too, such as how + * to clean up the source backend's local buffers and ON COMMIT state + * if the prepared xact includes a DROP of a temp table. + * + * We must check this after executing any ON COMMIT actions, because + * they might still access a temp relation. + * + * XXX In principle this could be relaxed to allow some useful special + * cases, such as a temp table created and dropped all within the + * transaction. That seems to require much more bookkeeping though. + */ + if (MyXactAccessedTempRel) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("cannot PREPARE a transaction that has operated on temporary tables"))); + /* Prevent cancel/die interrupt while cleaning up */ HOLD_INTERRUPTS(); |