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Posted to dev@tajo.apache.org by "Jihoon Son (JIRA)" <ji...@apache.org> on 2013/09/21 02:54:52 UTC
[jira] [Commented] (TAJO-186) Improve column resolving method
[ https://issues.apache.org/jira/browse/TAJO-186?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13773644#comment-13773644 ]
Jihoon Son commented on TAJO-186:
---------------------------------
This patch looks good, but I have a suggestions.
In TableDesc, how about remove 'public' for consistency?
> Improve column resolving 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
>
> Attachments: TAJO-186.patch
>
>
> 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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