Application Caches

Complete

The Application Caches window displays current memory use and statistics for select caches in OpenVPMS.
This is launched by clicking Caches in Administration - System.

The table displays:

  • Name
 The cache name.
  • Elements
 The number of elements currently in the cache.
  • Max Elements
 The maxium number of elements the cache can hold, before old elements are discarded.
  • Use
 The cache use, expressed as a percentage.
  • Cache Hits
 The number of times an element was in the cache when it was requested.
  • Cache Misses
 The number of times an element was not in the cache when it was requested.
  • Size
 An approximate calculation of the cache size.

The buttons are:

  • Edit
 Change the selected cache.
  • Refresh
 Refreshes the statistics.
  • Reset Statistics
 Resets the Cache Hits and Cache Misses to zero. This can be used to help evaluate the effectiveness of a change to the Max Elements of a cache.
  • Clear Cache
 Releases memory allocated to a cache.
  • Close
 Close the window.

 

Changing a Cache

The Edit button displayed a Change Cache window for the selected cache.

This displays the current maximum elements for the cache, and provides options to select a suggested value for the cache size, or enter a new one.

The cache size should be changed if:

  • there are too many cache misses vs cache hits.
    This indicates that the cache is too small and that Max Elements should be increased.
  • memory consumption is too high
    Here Max Elements should be decreased.

 

Note that the suggested size does not take into account memory consumption.