Hi, I've noticed an odd behavior with the 'hive.io.file.readcolumn.names' conf property.
Imagine a simple table "mytable" with two fields: "text" and "number". - If you run the query "SELECT * FROM mytable", then the "hive.io.file.readcolumn.names" has the value: "text,number". Makes sense so far. - If you run the query "SELECT text FROM mytable", then the "hive.io.file.readcolumn.names" has the value: "text". Still makes sense. However, if you add a predicate (WHERE clause), then the behavior of that property seems strange to me: - If you run the query "SELECT * FROM mytable WHERE number = 999", then the "hive.io.file.readcolumn.names" has the value: "text". The "number" column is missing from the property. - If you run the query "SELECT number FROM mytable WHERE number = 999", then the "hive.io.file.readcolumn.names" has the value: "" (empty string). The "number" column is still missing from the property. In other terms, it looks like if a column is part of a predicate, then it is omitted from the "hive.io.file.readcolumn.names" property. Do you know why that is? I'm writing a custom StorageHandler and so I would need to know exactly what columns the user is requesting. Is there a way to consistently retrieve all the requested columns either from the configuration or from within the InputFormat class, even when there is a WHERE clause? Thanks, Julien
