Hello.
It is hard to tell where the memory problems are without looking at
the actual used memory. I normally use jmap to dump memory info and
then jhat on a different computer to analyze the dump.
jmap -dump:live,file=filename pid
jhat -J-Xmx10G filename
Depending on your heap size, jhat may need a lot of memory and cpu.
That is why I normally copy the file to a separate non-production
server.
If your memory are filled with cayenne DataRows, then you should look
at the size of the datarow cache. Both DataRows and CayenneDataObject
use Maps that need quite a lot of memory, so you should not have too
many.
Regards,
- Tore.
On Aug 13, 2009, at 6:22 PM, Joe Baldwin wrote:
Background:
I have been attempting to do as much performance tuning as I can
given the visibility of the middleware I am using, but am running
into severe "out of memory" errors with Tomcat on my production
server. My current theory is that I may have missed something
concerning how to properly maintain my Cayenne data objects.
Configuration:
1. I am using the most recent version of Cayenne.
2. This is primarily a web app, using JSP, Tomcat, Cayenne and MySQL
3. Tested both on OSX and Linux
4. Essentially, it is a webstore with a lot of products
- small amount of UPDATES
- very large amount of searches resulting in result sets that will
average between 50-500 products for read-only
- occasional large result sets of a few thousand products for read-
only
5. The design is a simple 3-tier.
After a few hours to a few days of what appears to be very light
usage, Tomcat reports "out of memory" errors. Since the vast
majority of the tasks performed by the app are funneled through
Cayenne, I am assuming that is where I am making the mistake.
Question:
What is the best way to manage the data objects in this
configuration? (i.e. caching, releasing memory, etc)
Note:
I was researching the Java Library ArrayList (which I believe is the
work-horse for the Cayenne result sets), and there are many
recommendations concerning custom clearing of the list and releasing
memory. Is this possibly where I am may have missed something?
Thanks,
Joe
