[FRS-457] Potential performance issues using Event Snapshots


Introduction


In certain cases, the Event Snapshot can have a performance impact on an environment - especially when running in ColdFusion where the pages are being constantly recompiled.  When Event Snapshots have been enabled, this causes the JVM to activate a special mode, allowing it to capture detailed variable scope information. Although generally no performance impact will be felt with this mode, it can cause some operations to become slow.   

If you enable Event Snapshot, it is recommended that you also enable the "Save Classes" feature on ColdFusion servers to avoid recompilation. The "Save Classes" feature can be found in the ColdFusion admin console under Server Settings > Caching.
Enabling the Event Snapshot feature is known to heavily affect the compilation time of large files on ColdFusion and operations which throw a lot of exceptions (like javacc-based parsers). 

Enabling Support for Event Snapshots


Event Snapshot (Exception) Support can be switched on by configuring the following system property in the JVM arguments file:

 -Dfr.jvmti.enable.exceptions=true

 You can modify your JVM arguments file by following the steps below:

  1. Navigate to the following directory;
    1. ColdFusion9:
      1. {ColdFusion_Home}/runtime/bin

        ## ColdFusion 10/11/2016/2018:
        ### {ColdFusion_Home}

        /cfusion/bin

  2. Locate and open the jvm.config file with a text editor of your preference.
  3. Add the system property at the end of the line after "# Arguments to VM". Please make sure that all the Java Arguments are on the same line.
  4. Save the changes made.

Issue Details

Type: Technote
Issue Number: FRS-457
Components:
Environment:
Resolution:
Last Updated: Just now
Affects Version:
Fixed Version: new
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