ExprWalkerInfo ctx = (ExprWalkerInfo) procCtx;
String alias = null;
exprNodeGenericFuncDesc expr = (exprNodeGenericFuncDesc) nd;
UDFType note = expr.getGenericUDFClass().getAnnotation(UDFType.class);
if(note != null && !note.deterministic()) {
// this GenericUDF can't be pushed down
ctx.setIsCandidate(expr, false);
ctx.setDeterministic(false);
return false;
}