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Pentaho Documentation

OLAP Log Output

The Pentaho Server and the standalone Mondrian engine both use log4j to record information about generated OLAP-generated SQL queries. It may be useful to examine this log output if you are having trouble with configuration or performance-tuning.

Analysis SQL Output Logging

Follow the directions below to turn on logging for SQL generation in the Pentaho Server or Mondrian engine. If you are aware of other log4j classes that will assist you in configuration troubleshooting or performance-tuning, you can add them during this process.

  1. Stop the Pentaho Server or standalone Mondrian engine.
  2. Edit the log4j.xml file in the /WEB-INF/classes/ directory inside of the deployed pentaho.war or Mondrian engine.
    Note: In some Mondrian implementations, this file is log4j.properties. Substitute this filename accordingly if you do not see a log4j.xml file.
  3. Add the following line anywhere inside of the </log4j:configuration> node (but not inside of other constituent node tags):
    log4j.logger.mondrian.sql=DEBUG
  4. Save and close the file.
  5. Start the Pentaho Server or Mondrian engine.

A significant amount of Analysis SQL query debugging information will now be available in your application server's logs. Some data about the segment cache plugin will also appear, but there are some other steps to take beyond this if you want log data specific to the segment cache. Refer to Enabling Segment Cache Logging for more information

Enabling Segment Cache Logging

The Pentaho Server allows you to view Analysis engine segment cache logs by opening the log window from within Analyzer.

If you are using Analyzer with a standalone Mondrian engine, cache log information is available through log4j. Edit your log4j configuration as explained in Analysis SQL Output Logging, and set the value of com.pentaho.analysis.segmentcache to DEBUG. The table below lists other log4j categories that can help you diagnose configuration and performance problems.

Class name Cache system
com.pentaho.​analysis.segmentcache.​impl.infinispan Outputs information related to the Infinispan implementation of the segment cache.
com.pentaho.​analysis.segmentcache.​impl.memcached Outputs information related to the Memcached implementation of the segment cache.
com.pentaho.​analysis.segmentcache.​impl.pentaho Outputs information related to the Pentaho BI Platform Delegating Cache implementation.

View Log Output in Analyzer

Create a new Pentaho Analyzer report and drag a measure or a dimension in the report. Once your report is displaying numbers, click on the top link, identified as "More actions and options", and choose “Administration / Log” item. If there is no such link available within Pentaho Analyzer, it is because you have not used an administrator account to login to Pentaho User Console. You must log out and log back in using an administrator account credentials.

If your plugin was successfully configured, you should see log information relating to the segment cache. If there was an error in your configuration, all exception messages will be displayed here as well.