extatom10.hex sometimes fails

[credl]

The testcase extatom10.hex sometimes fails because one atom from the reference result is missing in the delivered answer set. The problem was only observed in debug mode and only on the KBS benchmark server lion node 1. In release mode and on other computers or other lion nodes it works.

The wrong result is very likely due to some memory issue rather than an algorithmic problem, maybe in combination with some specific library version or setup on lion node 1. However, I still document that the problem disappears if "replacements->addPredicate(reg->getAuxiliaryConstantSymbol('r', predicateID));" in method "setRegistry" in file "PluginInterface.cpp" (line 637 in commit aceb0ce) is disabled. In case the problem gets worse or it turns out that it is an algorithmic problem, this is a good starting point for debugging.