This event occurs only if the instance is mounted in shared mode (Oracle Real Application Cluster). During the read of the buffer, the contents changed. This means that either: The version number, dba, or the incarnation and sequence number stored in the block no longer match The checksum on the block does not match the…
The session waits on the buffer hash chain latch. Primarily used in the dump routines. The virtual address in the SGA where this latch is located. Use the following statement to find the name of this latch: select * from v$latch a, v$latchname b where addr = latch addr and a.latch# = b.latch#; chain# The…
Oracle does not really wait on this event; the foreground only yields the CPU. Thus, the chances of catching this event are very low. This is not an application induced deadlock, but an assumed deadlock by the cache layer. The cache layer cannot get a buffer in a certain mode within a certain amount of…
Processes enter “wait for broadcast mesg recovery queue transition” when cleaning up a publisher channel handle to a RELIABLE broadcast channel. The broadcasted message is in the recovery queue of another channel handle (for example, ch2). Process enters this wait, if the message is yet to be removed from the recovery queue of the ch2…
Processes enter “wait for broadcast mesg queue transition” when cleaning up a publisher channel handle to a RELIABLE broadcast channel. The publisher is responsible for moving the message to the free queue, but it cannot do so until the message is in the done queue. If the message is still not in the done queue,…
A session is waiting on another process to allocate a system change number (SCN). If the foreground timed out waiting on a process to get the SCN, the foreground will get the SCN.
Used to track the time (in centiseconds) that ARCn background processes spend blocked waiting for network write operations to complete.
A session has issued a statement ALTER SYSTEM SET DISPATCHER = string and is waiting for the dispatchers to get started. Wait Time: The session will wait 1 / 100 of a second and verify if the new dispatchers have started, else the session will wait again
Cause: The value of the DB_FILES initialization parameter was exceeded. Action: Increase the value of the DB_FILES parameter and warm start.
Cause: DB_BLOCK_SIZE initialization parameter is wrong for the database being mounted. It does not match the value used to create the database. Action: Fix the value of the DB_BLOCK_SIZE parameter or mount a database that matches the value.
Oracle Database Internal Mechanism 