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From Jeremias Maerki <dev.jerem...@greenmail.ch>
Subject Re: Why is FOP MUCH slower the first time than all other runs?
Date Fri, 06 Feb 2004 21:06:59 GMT
No, it's not in FOP. George is on the right track and Robert is not that
far away IMO.

FOP is a relatively big package and with a number of dependecies. Lots
of classes take a lot of time to load. After loading they need to be
initialized and then the JIT (Just in time Compiler) clicks in and compiles
some of the often used Java byte code to native code on the fly. This is
commonly called virtual machine warm-up. Once it's warmed up it gets
real fast.

The caching comment from Robert if rephrased points to another possible
speed difference between the first and the second run. FOP caches images.
So if you use the same images in many documents FOP can reuse the
already loaded images. Loading images takes quite some time.

Every program will need some time to ramp up in the beginning, be it
written in Java or any other language. In Java this may be a bit more
distinctive due to class loading and VM warm-up.

So, I don't think there is a way to fix this. It's pretty common
knowledge that you have to let the VM warm up before performance
benchmarks (as an example) can be done (at least on the Java platform).

This fact can be a problem for people using the FOP command-line very
often as they have to endure the VM warm-up every time.

On 06.02.2004 21:21:12 Robert Paris wrote:
> I don't think it's the tomcat issue, it takes a long time the first time 
> even when I call it from a java class (if the class creates a pdf then 
> creates another one before exiting, the second one is much faster). It's got 
> to be in the FOP. Is there a way to fix this?


Jeremias Maerki


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