Find deadlock and send notification

Question

Hi World,
I am looking for trigger to find out the deadlock and send an email to me to kill .
can you help me please

Answer 1

proora, the condition you are speaking about is probably just lock waited task rathter than a deadlock. A deadlock (simple form) is where task_A wants resources held by task_B and task_B want resources held by task_A. Since both process hold resouces needed by the other neighter will ever be able to get the resouces it needs to continue. Oracle will detect this situation and automatically choose a process and kill it so the other process can get the newly freed resources and complete. Oracle records when this occurs.
Your situation is more highly a locked waited task caused by one session performing DML and not issueing a timely commit to release the locks. Oracle provides a lock tree script in the $ORACLE_HOME/rdbms/admin directly named something like utlltree.sql Numerous lock waited scripts have been posted on this and other forumns.
The other possibility is that the entire database is hung, but this situation is unlikely. Oracle support provides articles on what to do in the case of a hung database.
HTH -- Mark D Powell --