Application Caches

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 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.

 

 

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