Changing incompatible column types
A default configuration change can cause applications that change column types to fail.
Before Upgrade to CDP
In HDP 2.x and CDH 5.x
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
After Upgrade to CDP
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. Check ALTER TABLE statements and change those that would fail due to incompatible column types.