Our Change Data Type is a smart feature. It will attempt to change the data type or cast the columns in an intuitive way. For instance, if you want to change the data type of string (ABC) column to a numeric (123) column you do not have to worry about any exception conditions. Xcalar manages this using Integrity Constraint Violations (ICVs). For instance, if you encounter a String like "NA" and attempt to convert it to an Integer, Xcalar will generate an FNF (Field Not Found).
You can then compare the fields that field and do a Profile to see what percentage of your data is valid. You can generate scores or even use the Map exists() function to compute how many rows in your column have FNF. When you try to Sort a column with FNF, the FNF rows will be excluded. This allows for an intuitive user experience where we do not attempt to Sort invalid rows.