Profile petascope regarding RAM usage

[Dimitar Misev]

It seems like petascope/tomcat is using quite some memory after many WCS requests. We should check for memory leaks and the like by e.g. monitoring with top and the NetBeans profiler during a session of 1000 queries sent to petascope. These queries could come from the wcs/wcps tests in the systemtest.

[Piero Campalani]

I'd put in this ticket the profiling of performances too.

[Dimitar Misev]

I profiled a simple query

for c in (eobstest)
return avg(c)

The first run loses a lot of time on CRS parsing and checking, but second time caching already fixes that as it seems.

Attached the results.

[Dimitar Misev]

first query after tomcat restart

[Dimitar Misev]

second query repeated after tomcat restart

[Piero Campalani]

Good that the caches work fine, but still the RasQL execution represents a 60% of the overall response time: ideally I'd say it should be around 80%.

[Dimitar Misev]

I think it's still reasonable, note that the rasql will take significantly more on more complex queries. It's not so critical to optimize it to death. But it would be good to check on the memory usage.

[Piero Campalani]

Looking at the absolute times anyway, we're in the ms scale. On a tougher query the RasQL time increases while Petascope overhead should be fixed.

[Piero Campalani]

Heap profile for 10 consecutive WCS systemtest runs.

[Piero Campalani]

Heap profile for 5 consecutive WCPS systemtest runs.

[Piero Campalani]

I made a preliminary general profiling of the heap usage of Petascope by running WCPS and WCS tests several times (5x and 10x respectively).

Looking at the telemetry plots, I generally see a stable behavior, WCS queries eating a little more memory as expected (~150 MB versus ~120MB for WCPS).

Comments/ideas?

Let me know if I should proceed with more detailed (objects/snapshots) profiling.

[Dimitar Misev]

Would be good to profile the GetCapabilities issue to see where the time is mostly spent.

Not sure if you've tested for memory leaks specifically?

[Piero Campalani]

Yes, the ​surviving generations' count is stable throughout the run, so there does not seem to be any leak.

Good idea: I'll profile the GetCapabilities (for #735 too).

[Piero Campalani]

Regarding the issue of the GetCapabilities performance, refer to #735 and ​m-list for discussions.