Optimizing Memory in Large Reports

[2005 IR Help]

By: Edward Dale - scompt

Optimizing Memory in Large Reports

2004-06-15 08:16

We're having OutOfMemoryErrors occurring in our reports pretty regularly as they get larger. Instead of bumping up our heap settings every time we hit the boundary, we're exploring a way to reduce the memory rquirement.

 

The initial idea came from http://sourceforge.net/forum/message.php?msg_id=2468828. We're thinking of writing a class that implements the List interface that serializes its elements to the disk and only keeps a fixed number in memory. This would just be a drop-in replacement. This would potentially decrease the memory footprint, which is what is killing us now. The downside is increased disk activity and cpu load.

 

Does anybody have any comments as to why this would or would not work? Is there a reason it's not done already in Jasper?

 

Thanks, Ed

 

 

 

 

By: Chuck Deal - cdeal

RE: Optimizing Memory in Large Reports

2004-06-17 08:58

I believe the biggest obstacle in this type of activity is the variable calculations. For example, in order to display "Page N of M" you would need to finish filling the report to get the value of M.

 

I think this is why there is no support for this yet. I imagine that a filling post processor could be written that when filling of all of the "pages" has completed the post-processor could go back over each filled "page" and run the variable calculations.

 

 

 

 

By: Edward Dale - scompt

RE: Optimizing Memory in Large Reports

2004-06-18 02:51

The List would still have references to all the pages in it, so it would still be able to keep track of variables for the 'page n of m'. It would just serialize the individual pages when it hit a certain limit and unserialize them out when requested.