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Maximo -- Saving an adhoc report (QBR) causes performance problems.

Technical Blog Post


Abstract

Maximo -- Saving an adhoc report (QBR) causes performance problems.

Body

Maximo environments using BIRT reporting engine as part of the reporting solution could experience this performance problem.  Maximo adhoc reports (QBR reports) can be saved for future use.  This saving instructs the Maximo reporting engine to refresh the report library cache on the application server (JVM).  The report library cache is cached on all application server for improving the performance.  The report library cache which is a sub-cache of Maximo presentation cache causes the Maximo presentation cache to reload along with the report library cache.  The Maximo application server while reloading the presentation cache blocks all access to the presentation cache.  This causes applications to freeze for the duration of the presentation cache reload.

In an environment with very low number of application server and a fast database, this reload on a JVM could take about a minute or less and during this time users may see some freeze or no response on the screen.  Once the JVM has reloaded the application cache, it returns to normal performance response.  In an environment with large number of JVM's such as 30 or higher, this reloading is cascaded to all JVM's and all JVM's start loading the presentation cache.  This results in large amount of data being fetched from the database side and slows the reloading process.  Due to the large number of application servers trying to reload, the reload process could take several minutes and during this time users will see their application freeze.  This situation can give the end users a feeling that Maximo is not responding and hence try to open new sessions to get a good connection.  These new connections start putting more load on the database while waiting for the application server to reload the cache.  This situation can cause an environment to become very slow until all application servers finish the reload process and the system returns to normal response.

This problem was experienced by some Maximo customers and the issue required Maximo code changes to separate the report library cache from the application presentation cache.  These changes are in APARs IV70541 and  IV73471. These APARs are also included in Maximo 7.5.0.9 fixpack and Maximo 7.6.0.2. ( to be released as of this blog writing).  With these APAR fixes, report library cache has been separated from presentation cache and the application does not freeze while adhoc reports are being saved.  The report execution may appear to be a bit slow for the first time while the report library cache is reloaded, but the system should not freeze as before.

A workaround until the fixes are in place is to disable the save check box on the adhoc (QBR) save dialog.  Users can still create adhoc (QBR) reports and run, but will not be able to save the reports for future use until the save button is re-enabled.

 

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UID

ibm11132227