[TAJO-1275] Optimizer pushs down non-equi filter as theta join qualifier

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 0.10.0
• Assignee: Keuntae Park
• Reporter: Keuntae Park
• Created: 02/Jan/15 03:40
• Updated: 05/Jan/15 01:34
• Resolved: 05/Jan/15 01:34

Description

Plan rewriter pushes down filters to leaf node as possible and changes filter condition to join qualifier if possible.

Even though Tajo does not support theta-join completely, however,
it pushes down non-equi compare and makes it as join qualifier sometimes.

For example,

select * from (select a.r_name as a_name, b.c_name as c_name from region a, customer b) xx where a_name < c_name

is rewritten as

select a.r_name as a_name, b.c_name as c_name from region a join customer b on a.r_name < b.c_name

And

select * from region a join customer b on a.r_regionkey = b.c_custkey where a.r_name < c.c_name

is rewritten as

select * from region a join customer b on a.r_regionkey = b.c_custkey and a.r_name < c.c_name

Until TAJO-742 is resolved (that means theta join is supported),
I think it should not be allowed to rewrite non-equi filter condition as join qualifier.