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Live - solving the jasper report out of memory and high cpu usage problems

I still can not find the solution. So I summary all the things and tell my boss about it. If any one knows the solution, please let me know.

1.       The JVM became Out of memory when creating big consumption report
2.       Those JRTemplateElement-instances is still there occupied even if I logged out the system

        1. There is a large number of JRTemplateElement-instances cached in the memory
2.    The clearobjects() method in ReportThread class has not been triggered when logging out

Action I tried:
     About the Virtualizer:
1.    Replacing the JRSwapFileVirtualizer with JRFileVirtualizer
2.    Not use any FileVirtualizer for cache the report in the hard disk
Result: The japserreport still creating the a large number of JRTemplateElement-instances in the memory
    About the work around below,
     I tried: item 3(in below work around list) – result: it helps to reduce  the size of the JRTemplateElement Object
               Item 4,5 – result : it helps a lot to reduce the number of  JRTemplateElement Object, and mitigate the symptom a lot

Solution: not found so far, this bug has been report since 2008
Work around(as per our discussion):
1.    Add new options AMR_Interval(KVA,KVAH or  all features) in the web UI and limit the time period depends on option user select(e.g. for kVA,kVAH – within 3 Months, for the all features within 1 month)

2.    Limit the time period depends on the number of meters(e.g. for 1000 meters , only one month something)

3.    Removing the fancy features for the report field(e.g. not border lines) - to reduce the size of JRTemplateElement instances

4.    Removing the headers(just for exporting correct headers in CSV file) – to reduce the number of JRTemplateElement instances – will introduce csv non-header problem)

5.    Don’t create JRTemplateElement when the content is blank - to reduce the number of JRTemplateElement instances – will introduce csv  in-correct format problem)

6.    Set  net.sf.jasperreports.governor.max.pages) to stop the report execution when the report becomes greater than this value– will prevent system from running out of memory

7.    Only display the data after the meter has been registered(e.g. meter A has been registered on Dec 27,2010, when use select Nov 27 ,2010 as the start date, we only display data from Dec 27
) – to reduce the number of JRTemplateElement instances 

Increase the max memory for the JVM(now it’s 512M) – to keep more JRTemplateElement instances in the memory

Improve the garage collection (ReportThread.class)  for the objects– reduce the JRTemplateElement instances if they are not in use

The solution for above item 4 and 5:
Use the new csv export features from jasper report v4.0.0 (net.sf.jasperreports.export.csv.write.header,,net.sf.jasperreports.export.csv.column.names)
Comments: the new feature works and make the codes simpler


  1. Related Technologies:
    java -Xmx option is used to set the maximum heap space available to a Java program


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