If the session was waiting for a buffer during the last wait, then the next wait will be 3 seconds. For us a database restart fixed this issue. The Oracle AQ monitoring process that is responsable for changing the state from 'WAITING' to 'READY' (after the delay is expired) wasn't working properly. Of course, excessive truncate and DDL statement on objects can cause issues in RAC due to global lock activity. Find the object details from the objectid, and understand the activity on that segment. enq: CF - contention) and happens during parallel access 6to the control files. The messages in the queue stayed the state 'WAITING'. If you encounter high number of waits for ‘DFS lock handle’ with CI enqueue, then find the objectid of the event. Prior to release 10.1, all four reasons were covered by "buffer busy waits." In release 10.1, the "gc buffer busy" wait event covered both the "gc buffer busy acquire" and "gc buffer busy release" wait events. There are many types of Oracle enqueues, here is a sample of the most common types: - CF enqueue - The CF enqueue is a Control File enqueue (a.k.a. Well, a lot has changed in 11g including the enqueue waits. ![]() The Oracle AQ monitoring process that is responsable for changing the state from 'WAITING' to 'READY' (after the delay is expired) wasnt working properly. "gc buffer busy release": A session cannot pin the buffer in the buffer cache because another session on another instance is taking the buffer from this cache into its own cache so it can pin it. Oracle 11g R2 enqueue waits Decem Gerald Over 1 and a half year ago I posted the enqueue waits for Oracle 10g. The messages in the queue stayed the state 'WAITING'. Once you have established that you have high waits for enq: TX row lock. "gc buffer busy acquire": A session cannot pin the buffer in the buffer cache because another session is reading the buffer from the cache of another instance. Oracle Enqueues Interview Questions and Answers - STechies WebIn 10g. "read by other session": A session cannot pin the buffer in the buffer cache because another session is reading the buffer from disk. ![]() "buffer busy waits": A session cannot pin the buffer in the buffer cache because another session has the buffer pinned. ![]() There are four reasons that a session cannot pin a buffer in the buffer cache, and a separate wait event exists for each reason:
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