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• • The list of dependent partitions are materialized and stored in the metastore, and use that for querying.
    A query like 'select .. from Tdependent where ds = 1' gets transformed to 'select .. from (select * from T where ((ds = 1 and hr = 1) or (ds = 1 and hr = 2) .... or (ds=1 and hr=24))'
    Can put a lot of load on the query layer.

= Final Proposal =
Instead of enhancing external tables to solve a convoluted usecase, create a new type of tables - dependent tables. The reason for the existence of external tables is to point to some existing data.

== Dependent Tables ==
Create a table which explicitly depends on another table. Consider the following scenario for the first use case mentioned:
<code>

create table T (key string, value string) partitioned by (ds string, hr string);
</code>