Checking compatibility of column changes
A default configuration change can cause applications that change column types to fail.
In HDP 2.x
hive.metastore.disallow.incompatible.col.type.changes is false by
default to allow changes to incompatible column types. For example, you can change a STRING
column to a column of an incompatible type, such as MAP<STRING, STRING>. No error occurs.
hive.metastore.disallow.incompatible.col.type.changes is true by default.
Hive prevents changes to incompatible column types. Compatible column type changes, such as INT,
STRING, BIGINT, are not blocked.
Change applications to disallow incompatible column type changes to prevent possible data corruption.