[mapguide-users] AIMS crashing with King Oracle FDO layers and multiple users

[Jackie Ng]

Part of the problem here is obviously the lack of a small, localizable data
set that we can use to consistently reproduce the problem to be able to
determine if it is:

 * An issue with the feature data that the KingOracle FDO provider or
MapGuide is failing to properly process/sanitize.
 * A threading issue with the KingOracle FDO provider.

Try using a tool like gatling (http://gatling.io) and write/record a "user
[selects feature -OR- hovers for tooltips] on oracle layer" scenario and
then see how easy it is to crash with the same error as you crank up the
repetitiveness and concurrent users when replaying that particular scenario.

Then if you can get this scenario to consistently crash, capture as much
data on the requests that cause the crash (the crashing request will most
likely return a http status code of 559, so you could programmatically save
the request parameters of any request whose response is 559).

Then with this data, you can try to look for patterns in the offending
requests (ie. Does it consistently crash on a particular input geographic
polygon, or a particular combination of QUERYMAPFEATURES parameter values?)

At this point, there should hopefully be enough data points to be able to
determine if this is a problem in how the KingOracle FDO provider is reading
the feature data or a thread safety issue in the KingOracle FDO provider,
and be able to take further action from there.

- Jackie



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