Hadoop – Why hive doesn’t allow create external table with CTAS

Hive has a relational database on the master node it uses to keep track of state. For instance, when you CREATE TABLE FOO(foo string) LOCATION 'hdfs://tmp/';, this table schema is stored in the database.

If you have a partitioned table, the partitions are stored in the database(this allows hive to use lists of partitions without going to the file-system and finding them, etc). These sorts of things are the 'metadata'.

When you drop an internal table, it drops the data, and it also drops the metadata.

When you drop an external table, it only drops the meta data. That means hive is ignorant of that data now. It does not touch the data itself.

Hive will not create the partitions for you this way.
Just create a table partitioned by the desired partition key, then execute insert overwrite table from the external table to the new partitioned table (setting hive.exec.dynamic.partition=true and hive.exec.dynamic.partition.mode=nonstrict).

If you must keep the table partitioned externally you have to manually create the directories (1 directory per partition the name should be PARTION_KEY=VALUE) then use the MSCK REPAIR TABLE table_name; command