IBM Support

How to Enable Garbage Collection (GC) Logging on the Cognos Analytics Server

How To


There may be times where Garbage Collection logging is required to diagnose a specific problem with Cognos Analytics. This document outlines the steps required to enable Garbage Collection logging for the bundled WebSphere Liberty Application Server using default IBM Java.


1. Navigate to the <ca install>\bin64\ directory on the Cognos Analytics Server
2. Find and backup the bootstrap_wlp_<os>.xml file
3. Open and edit the bootstrap_wlp_<os>.xml file with a text editor
4. Search for the following line:
5.  Insert a new below the one above this line to add a new parameter to the existing list of parameters, by pasting the following:
    <param condName="${java_vendor}" condValue="IBM">"-Xverbosegclog:${install_path}/logs/verbosegc_%Y%m%d.%H%M%S.%pid.log,1,5000"</param>
example bootstrap entry
6. Restart the Cognos Analytics Service to enable the GC logging.

The Garbage Collection log file will be written to the <ca install>\logs\ directory as verbosegc_TIMESTAMP_PID.log
This will capture 10 logs files with 5000 garbage collection entries and  it should produce a log specific to each PID when the process restarts.

Document Location


[{"Type":"SW","Line of Business":{"code":"LOB10","label":"Data and AI"},"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSTSF6","label":"IBM Cognos Analytics"},"ARM Category":[{"code":"a8m50000000Cl3zAAC","label":"Administration"}],"ARM Case Number":"TS005463164","Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"11.0.0;and future releases"}]

Document Information

Modified date:
20 April 2021