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From "Hyunsik Choi (JIRA)" <j...@apache.org>
Subject [jira] [Created] (TAJO-186) Improve column resolve method
Date Tue, 17 Sep 2013 02:05:52 GMT
Hyunsik Choi created TAJO-186:
---------------------------------

             Summary: Improve column resolve method
                 Key: TAJO-186
                 URL: https://issues.apache.org/jira/browse/TAJO-186
             Project: Tajo
          Issue Type: Bug
          Components: planner/optimizer
            Reporter: Hyunsik Choi
            Assignee: Hyunsik Choi
             Fix For: 0.2-incubating


The current column resolving method (LogicalPlanner::createFieldEval) usually finds columns
from relations in the current query block. If not found, it tries to find columns from other
query blocks.

However, this way cannot resolve some cases. Please take a look at the below example:

{noformat}
select col1 as rank from table1 order by rank
{noformat}

In the above case, the column 'rank' cannot be found in any relation. So, in this case, we
currently use LogicalPlan::findColumnFromChildNode method to resolve columns from a child
node.

But, this way cannot resolve a column 'total' in the below cases:

{noformat}
select ..., sum(col1) as total ... having total > 1
{noformat}

Resolving columns should also consider the current node's output schema.

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