When starting Rex using the Mondrian default demo data (FoodMart), it complains about LucidDB. Since FoodMart comes with Mondrian, and many people will try Rex on Mondrian first, it should at least recognise the FoodMart.xml schema.
DEBUG [main] (S.java:46) - Error(getCatalogList):rex.exceptions.RexXMLADiscoverException:
faultstring = XMLA Discover unparse results error
desc = The Mondrian XML: In element 'Schema': In element 'Cube': In element 'Dimension': In element 'Hierarchy': In element 'Level': In element 'NameExpression': In element 'SQL': Value 'luciddb' of attribute 'dialect' has illegal value 'luciddb'. Legal values: {generic, access, db2, derby, firebird, hsqldb, mssql, mysql, oracle, postgres, sybase}
DEBUG [main] (S.java:46) - Error(getCatalogList):rex.exceptions.RexXMLADiscoverException:
faultstring = XMLA Discover unparse results error
desc = The Mondrian XML: socket creation error