Basically, if there is a memory constraint, we want more Daily Project
objects and less sensor data objects to stay in memory, because our
layered hierarchy is: analysis -> DailyProjectObjects -> SensorData.
If DailyProjectObject hold references to SensorData through its field
variables (in our case, mostly some map structures other than
WeakHashMap) and never release those references (i.e. set those
variables to null), then the referenced SensorData will never be GCed
unless the DailyProjectObject itself is GCed first. But our goal is to
sacrifice cached SensorData first in case we need memory, and have as
many DailyProjectObject as possible to stay in memory. This also leads
to another goal: reduce the footprint of DailyProjectObject themselves.
Netbeans profiler is great to profile is netbean project. No problem
encountered. But when I try to profile an external installation of
tomcat, the "take snapshot" button often get disabled for reasons
unknown to me, and I encountered several instances of null pointer
exception.
Cheers,
Cedric
Aaron Akihisa Kagawa wrote:
Hey Guys,
I just noticed this issue: http://hackydev.ics.hawaii.edu:8080/browse/HACK-595 . According to Cedric DailyProjectCoverage was holding references to Coverage objects. I was hoping that Cedric could explain the situation a little more, because I did bring up that point way back in 2004 in http://www.mail-archive.com/[email protected]/msg00349.html . I just want to understand what the issue was and how it was fixed.
Furthermore, is this a problem with a lof the other DailyProjectData implementations? I've been thinking for a long while that we need another abstraction that gathers the necessary data that the DailyProjectData implementations use to process. Thereby eliminating the many different implementations and problems such as this.
The other thing noted in the HACK-595 is "3. Profiler tool evaluation: Netbeans
profiler sucks.". Again, I was hoping to know a little more about why it sucks...
Cedric could you explain a little further. I was under the impression that the netbeans
profiler was pretty good.
thanks, aaron
