Cause: The number of log files specificied exceeded the maximum number of log files supported in this release. Action: Re-create the control file with the highest number of log files no greater than the maximum supported in this release.
Cause: The instance was started with DML_LOCKS = 0, and the statement being executed needs a full-table lock (S, X, or SSX). Action: Restart the instance with DML_LOCKS not equal to zero, and reexecute the statement.
Cause: The shared instance being started is using DML locks, and the running instances are not, or vice-versa. Action: Ensure that all instances’ INIT.ORA files specify the DML_LOCKS parameter as 0 or all as non-zero.
Cause: Transactions deadlocked one another while waiting for resources. Action: Look at the trace file to see the transactions and resources involved. Retry if necessary.
This event occurs when a session requests a buffer that is currently being read into the buffer cache by another session. Prior to release 10.1, waits for this event were grouped with the other reasons for waiting for buffers under the ‘buffer busy waits’ event. Wait Time: Time waited for the buffer to be read by the…
This event is used to wait for a reply from one of the background processes. Wait Time: The wait time is specified by the user and is indicated by the parameter timeout. Parameter Description from_process The background process for which the session is waiting. The wait is for a reply to an IPC message sent by…
The background processes (LGWR, DBWR, LMS0) use this event to indicate that they are idle and are waiting for the foreground processes to send them an IPC message to do some work. Wait Time: Up to 3 seconds. The parameter timeout shows the true sleep time. Parameter Description timeout The amount of time that the session waits…
Library cache mutexes protect hash buckets within the shared pool. Each hash bucket contains a number of cursors. The mutex must be held in exclusive mode before any of the structures that it protects can be changed. This wait event is often associated with high parse activity.
The session tries to find the load lock for the database object so that it can load the object. The load lock is always obtained in Exclusive mode, so that no other process can load the same object. If the load lock is busy the session will wait on this event until the lock becomes…
Redo copy latches are acquired by sessions in order to write changes into the redo log buffer and by the LGWR process to ensure that there are no current writers before it copies data from the buffer to the redo log.
Oracle Database Internal Mechanism 