Matthew Jacobs 8a55982105 Add OFFSET to skip rows returned with a LIMIT ...

Adds support for skipping a number of rows with an ORDER BY clause and a LIMIT. Hive
does not support OFFSET so creating a view with an OFFSET will not work in Hive.

For example, "SELECT * FROM T1 ORDER BY ID LIMIT 20 OFFSET 5" will do the sorting, skip
5 rows, then return the next 20. OFFSET requires an ORDER BY clause.

Note this is not very efficient as we must actually keep (limit+offset) rows in memory
in the topn-node, and all child sort nodes must as well. Users should be careful when
using this feature.

Change-Id: I4d7021c278296e7bdbfa0e6f2699cd6f23eef59d
Reviewed-on: http://gerrit.ent.cloudera.com:8080/900
Tested-by: jenkins
Reviewed-by: Matthew Jacobs <mj@cloudera.com>
Tested-by: Matthew Jacobs <mj@cloudera.com>

2014-01-08 10:54:02 -08:00

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