33.4 Obtaining View Cache Information

To examine a view's cache information, use cleartool getcache -view. The view server prints information about the view cache sizes and hit rates. You can use this information in several ways:

• To determine whether to increase the view cache

• To check the results after changing the view cache

• To analyze other view server processes

Example:

cleartool getcache -view jo_main
Lookup cache: 29% full, 1121 entries ( 56.8K), 15832 requests, 75% hits
Readdir cache: 4% full, 24 entries ( 36.5K), 4159 requests, 83% hits
Fstat cache: 31% full, 281 entries (105.1K), 55164 requests, 100% hits
Object cache: 26% full, 1281 entries (176.6K), 40626 requests, 72% hits
Total memory used for view caches: 375.0Kbytes
The current view server cache limits are:
Lookup cache: 201312 bytes
Readdir cache: 838860 bytes
Fstat cache: 352296 bytes
Object cache: 704592 bytes
Total cache size limit: 2097152 bytes

The view cache includes these types of subcaches:

• Lookup. Stores data used to accelerate the mapping of names to objects in the view.

• Read Directory. Stores data used to accelerate read-directory operations (for example, ls or dir) by the view.

• File Stats. Stores data on file attributes used by the view.

• Object. Stores data pertaining to objects used by the view.

To find the size of the total view cache, sum the sizes of these components.

NOTE: On UNIX computers, you can force a view_server process to write cumulative cache-performance (and other) statistics to its log file, /var/adm/atria/log/view_log then reset all the statistics accumulators to zero, by running the following command on the host where the view_server executes:

kill -HUP view_server-process-ID

Analyzing the Output

getcache -view provides this information:

• Cache type

• Percentage of the view cache being used

• Number of entries in cache

• Number of requests made

• Percentage of cache hit rates

• Amount of view cache memory being used

Here are some suggestions for analyzing this information:

• Check the percentage of view cache being used. This value is very important.

• If the hit rate is 90% or less and the view cache is 100% full, the view cache may be too small. The combination of a hit rate greater than 90% and view cache that is 100% full indicates that the cache size is about right.

• If you are at less than 50% on every portion, your cache is probably too large.

• Check this value more than once to be sure you are not seeing a transitory value, such as for a newly started or restarted view server.

• If you decide to increase the view cache size for a view, use the procedure described in Reconfiguring a View.