Author: gordonsim Date: 2007-11-29 05:19:28 -0500 (Thu, 29 Nov 2007) New Revision: 1386 Modified: store/trunk/cpp/lib/BdbMessageStore.cpp Log: Initial (temporary?) fix for deadlocking in bdbstore. Modified: store/trunk/cpp/lib/BdbMessageStore.cpp =================================================================== --- store/trunk/cpp/lib/BdbMessageStore.cpp 2007-11-29 09:57:11 UTC (rev 1385) +++ store/trunk/cpp/lib/BdbMessageStore.cpp 2007-11-29 10:19:28 UTC (rev 1386) @@ -1130,6 +1130,22 @@ bool BdbMessageStore::dequeue(DbTxn* txn, Dbt& messageId, Dbt& queueId) { + //need to get a lock on the messageDb in case we want to delete + //(to avoid deadlocks with enqueue that acquires locks in this + //order) + Dbt peek; + peek.set_flags(DB_DBT_USERMEM); + peek.set_ulen(0); + try { + int status = messageDb.get(txn, &messageId, &peek, DB_RMW); + if (status != DB_BUFFER_SMALL) { + THROW_STORE_EXCEPTION("Unexpected status code when peeking at message: " + string(DbEnv::strerror(status))); + } + } catch (DbMemoryException& expected) { + //api doc indicates may throw exception instead of status = DB_BUFFER_SMALL; + } + + Cursor cursor; cursor.open(mappingDb, txn);