Disallow committing a prepared transaction unless we are in the same database

it was executed in.  Someday it might be nice to allow cross-DB commits, but
work would be needed in NOTIFY and perhaps other places.  Per Heikki.

diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c
index ca44e19a8ef462c3c32d4b08f3f6be6fb28cb50f..193fc2b6fbb00b37d19d350fe8c27367027c9980 100644 (file)
--- a/src/backend/access/transam/twophase.c
+++ b/src/backend/access/transam/twophase.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *     $PostgreSQL: pgsql/src/backend/access/transam/twophase.c,v 1.16.2.1 2005/11/22 18:23:05 momjian Exp $
+ *     $PostgreSQL: pgsql/src/backend/access/transam/twophase.c,v 1.16.2.2 2007/02/13 19:39:55 tgl Exp $
  *
  * NOTES
  *     Each global transaction is associated with a global transaction
@@ -390,6 +390,18 @@ LockGXact(const char *gid, Oid user)
                  errmsg("permission denied to finish prepared transaction"),
                     errhint("Must be superuser or the user that prepared the transaction.")));
 
+       /*
+        * Note: it probably would be possible to allow committing from another
+        * database; but at the moment NOTIFY is known not to work and there
+        * may be some other issues as well.  Hence disallow until someone
+        * gets motivated to make it work.
+        */
+       if (MyDatabaseId != gxact->proc.databaseId)
+           ereport(ERROR,
+                   (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+                    errmsg("prepared transaction belongs to another database"),
+                    errhint("Connect to the database where the transaction was prepared to finish it.")));
+
        /* OK for me to lock it */
        gxact->locking_xid = GetTopTransactionId();