For Oracle9i Release 2 and later systems, Oracle provides multiple redo allocation latches. By simply increasing the instance parameter processes, the number of redo allocation latches is also increased. Sampling from multiple Oracle systems indicates that about one redo allocation latch is created for every eight defined processes. So, if your system has the processes instance parameter set to 2000, you can expect to see around 250 redo allocation latches. By increasing the number of redo allocation latches, redo allocation latch concurrency is increased, reducing the likelihood of sleeping while trying to acquire one of the redo allocation latches.

As with most latches, it is very common for the operating system to be experiencing a raging CPU bottleneck. While increasing CPU capacity is a valid solution and will most likely enable more work to flow through Oracle, simply adding more redo allocation latches to the Oracle system will most likely solve the problem, without requiring any operating system or application-related changes.

If a process must acquire one of the redo copy latches, it needs to have this control structure to copy redo into the redo log buffer. This type of latch contention is unusual, but can occur with very high-concurrency OLTP workloads.