[TAJO-619] SELECT count(1) after joins on text keys causes wrong plans

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 0.8.0, 0.9.0
• Component/s: Planner/Optimizer
• Assignee: Hyunsik Choi
• Reporter: Hyunsik Choi
• Created: 21/Feb/14 16:59
• Updated: 24/Feb/14 11:51
• Resolved: 24/Feb/14 11:33

Description

select count(1) from table1 join table2 on table1.name = table2.name;

When there are constant values in select list and equi-join keys are text columns, it causes some errors due to schema mismatch.

Its cause of this bug is as follows:

• the number 1 results in a generated column name '?literal'.
• This name is used in both table1 and table2. Output schemas of table1 and table2 include ?literal
• The input schema of join has only three columns because ?literal is duplicated name.

So, its essential bug may be one of following:

• The constant value is evaluated twice. In other words, literal? occurs in both table1 and table2.
• Schema class does not allow the same column name.