Connection Caching

Database Connection Caching

Improving server data refresh performance

Database connection caching is supported by Omniscope. This is mainly of use in Server installations, and should be ignored for typical desktop use as it will provide little benefit. Connection caching allows an Omniscope instance to retain and reuse database connection objects, which can improve performance.  By default, desktop Omniscope installations cache 3 connections for up to 1 minute after use.

Connection caching has the following options:

NameMeaning
Default
visokio.dbcc.maxallMaximum number of cached connections for any data source
5 (8*)
visokio.dbcc.maxperMaximum number of cached connections for each data source
3 (5*)
visokio.dbcc.maxageMaximum age of cached connections (in milliseconds) - e.g. 5 minutes is 5x60x1000 = 300000
60000 (300000*)
visokio.dbcc.debugTrue/False - If true, database connection caching status and activity is printed to the console - useful for debugging server configuration false

* Use zero for these options to disable caching - connections will be created and discarded immediately before and after use. The numbers in brackets are the defaults used when the Omniscope process is in headless / silent mode.

 

These options can be configured by editing installconfig.properties in the installation folder (typically C:\Program Files\Visokio Omniscope) and adding/changing the ADDITIONAL_JVM_ARGS property. For example, the following turns on debug output and a 2 second expiry:

ADDITIONAL_JVM_ARGS=-Dvisokio.dbcc.debug=true -Dvisokio.dbcc.maxage=2000

 

If you are running Omniscope Server / Scheduler as a service, you instead need to edit "C:\Program Files\Visokio Omniscope\service\wrapper.conf", by adding lines such as:

wrapper.java.additional.1=-Dvisokio.dbcc.debug=true
wrapper.java.additional.2=-Dvisokio.dbcc.maxage=2000

Restart the service after making changes. Warning: at present this "wrapper.conf" file is overwritten on re-installation of Omniscope. Look in "wrapper.log" for debug output when running as a service.