[IMPALA-1433] Min/max analytic fns should support windows that can be rewritten to be unbounded preceding

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: Impala 2.1
• Fix Version/s: Impala 2.1

Environment

commit c9b65ee52689ab33a06124388b1cf679f9756982
Author: Skye Wanderman-Milne <[e-mail]>
Date: Wed Oct 22 17:28:35 2014 -0700

    GetNext() should always set eos.

• Assignee: Matthew Jacobs
• Reporter: casey
• Created: 30/Oct/14 00:19
• Updated: 06/Nov/14 06:07
• Resolved: 06/Nov/14 06:07

Description

We currently don't support executing min/max over sliding windows (i.e. start is not unbounded), but we should support them if we can re-write the window to be unbounded preceding (i.e. because the end is unbounded we can flip the window and sort).

E.g.

Query: select MAX(bigint_col) OVER (ORDER BY int_col ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING) FROM alltypes t1
ERROR: AnalysisException: 'max(bigint_col)' is only supported with an UNBOUNDED PRECEDING start bound.

This query should be re-written to be "... order by int_col desc rows between unbounded preceding and current row" and then we can execute it.