TechNote

ColdFusion MX 7.x: Preventing client variables from purging every millisecond

Issue

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In order to control the frequency of client variable purging, some administrators may set the Client Variable Purge Interval to 0 hours 0 minutes, believing this will disable the client purge scheduler. However, this causes ColdFusion MX 7 to immediately begin purging client variables approximately every millisecond. The additional scheduler load could consume the server and possibly begin queuing client requests.

Reason

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The Client Purge Interval is actually the period of time the scheduler waits between purges. Setting a value of 0 hours and 0 minutes effectively creates 0 second wait time, thus causing the scheduler to continually purge client variables.

Solution

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The proper way to lessen the amount of client variable purges is to create a high purge interval. For example, to have ColdFusion MX 7 purge client variables once weekly, set the hour value to 168. If you can reach the ColdFusion MX 7 Administrator's Client Variables page, set the hour value high and click "Apply". The change takes effect immediately. However, if you cannot reach the Administrator, stop ColdFusion MX 7 and follow these steps:

1. Edit cf_root/lib/neo-clientstore.xml for Server configuration; or cf_web_root/WEB-INF/cfusion/lib/neo-clientstore.xml for Multiserver and J2EE configurations.
2. Find the PURGE_INTERVAL variable:
   
   <var name='PURGE_INTERVAL'>
3. Set the string value to the desired time length using the format hour:minutes:
   
   For example, <var name='PURGE_INTERVAL'><string>168:0</string></var>
4. Save the file.
5. Restart ColdFusion MX 7.

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