[Treebase-devel] treebase file download issues

[Mattison W. <mat...@ne...>]

Sorry for the repeat message to some folks, but I wanted to send this
to the whole list.

Occasionally the tomcat process on the production or development site
will go through the roof for cpu usage and stop responding until
killed and restarted.  I have searched through the error logs, but
haven't found anything obvious to me.  I am starting to suspect that
trying to download certain studies in nexml format precipitates the
problem.  If several of these nexml files in a row start to pile up,
memory usage by the JVM keeps increasing and the server stops
responding.

You can see this yourself if you try to download the nexml file from
http://treebase-dev.nescent.org/treebase-web/search/study/summary.html?id=12742

The nexus file for that study downloads almost immediately.

You can see in the screenshot one that I left running for over 10
minutes.  It maybe if I left these running long enough they would
complete, but in practice these requests can overwhelm the server if
they are not serial (like in my test).

Other "problem" study ids between 12800 and 11753
12201 killed after 10 minutes (killed nexus download after 10
minutes,but database was busy rather than java/tomcat)
12156 killed after 10 minutes (5 seconds for nexus)
12064 = 5 minutes (3 seconds for nexus)
12032 = 4 minutes (1 second for nexus)
11872 = 10 minutes (52 seconds for nexus)
11811 killed after 10 minutes (35 seconds for nexus)

Note that I turned Apache caching off for these tests and will leave
it off for anyone else to test.

Could timeouts for uploading and downloading files be implemented so
too many concurrent downloads don't disable the site?

Maybe some studies are too large to be converted to nexml in a
workable amount of time?

Is treebase written in such a way that we could deploy many tomcat
instances pointed to a common database so that if one client requested
many downloads, it would only tie up one tomcat instance while the
other 7 would keep serving requests happily?

--
Mattison