On Fri, May 25, 2012 at 12:03 PM, Jan Dolinár <dolik....@gmail.com> wrote:
>
> -- see what happens when you try to perform multi-group-by query on one of
> the partitions
> EXPLAIN EXTENDED
> FROM partition_test
> LATERAL VIEW explode(col1) tmp AS exp_col1
> INSERT OVERWRITE DIRECTORY '/test/1'
> SELECT exp_col1
> WHERE (part_col=2)
> INSERT OVERWRITE DIRECTORY '/test/2'
> SELECT exp_col1
> WHERE (part_col=2);
> -- result: it wants to scan all partitions :-(
>
Since nobody else did, let me answer myself... In the end I found out that
the correct partition pruning can be achieved using subquery. Continuing
the example from my last post, the query would be:
FROM (
SELECT * FROM partition_test
LATERAL VIEW explode(col1) tmp AS exp_col1
WHERE part_col=2
) t
INSERT OVERWRITE DIRECTORY '/test/1'
SELECT exp_col1
INSERT OVERWRITE DIRECTORY '/test/2'
SELECT exp_col1;
I still think the pruning should work correctly no matter how the query is
written, but for now I'm happy with this solution.
J. Dolinar
