Fabian wrote:

Update of /cvsroot/monetdb/MonetDB5/src/optimizer In directory sfp-cvsdas-1.v30.ch3.sourceforge.com:/tmp/cvs-serv10474

Modified Files: opt_mapreduce.mx Log Message: One of the optimisers 'inline,remap,evaluate,costModel,coercions,emptySet,aliases' replaces a nil statement in such a way that it ends up as argument 'nil' witout type, causing execution to fail. Push barrier up, such that we don't get undefined var errors because the reduce phase was performed in the dataflow block too.

You can freeze the type of variables using setVarUDFtype. As a line of defense, at the end of an optimizer all non-UDFtypes are thrown away and a fresh type resolve step is taken.