In addition to the sleeps information in v$latch, the v$latch_misses view contains additional information. One key piece of potentially helpful information is the location (column location) of the latch within the kernel code. This can provide useful information when searching MetaLink or Google for solution clues.

Table 3-2. Without wait time details, the impact calculation can be used to determine the offending latch.

The use of another memory serialization control structure was introduced starting with the Oracle Database 10g Release 2 kernel. Called a mutex, it provides more flexibility and potentially lower performance impact than traditional Oracle latches. Oracle continues to more fully make use of mutexes in each release. Currently, the mutex focus has been in the library cache area. As you'll come to understand, the performance possibilities will entice Oracle kernel developers to increasingly take advantage of the mutex.