[jira] Commented: (HADOOP-4084) Add explain plan capabilities to Hive QL

["Namit Jain (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HADOOP-4084?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12631466#action_12631466 ] 

Namit Jain commented on HADOOP-4084:
------------------------------------


Overall, looks good - just some minor comments.

LoadSemanticAnalyzer: line 32/33 - nitpick: remove commented import 
ExplainSemanticAnalyzer (line 47): not needed 
explain.java: no apache license header on top of file 
DDLWork.java: why display name only for create table ? why not for other DDLs 
MapRedTask: (line 91) remove explain() 
MoveTask: remove explain()




> Add explain plan capabilities to Hive QL
> ----------------------------------------
>
>                 Key: HADOOP-4084
>                 URL: https://issues.apache.org/jira/browse/HADOOP-4084
>             Project: Hadoop Core
>          Issue Type: New Feature
>          Components: contrib/hive
>            Reporter: Ashish Thusoo
>            Assignee: Ashish Thusoo
>         Attachments: patch-4084
>
>
> Adding explain plan for queries in hive.
> The current proposal is to support something like:
> EXPLAIN [EXTENDED]
> SELECT ....
> This will output the following:
> Abstract Syntax Tree:
> Number of Stages:
> Dependencies between Stages:
> Plan for each stage:
> If EXTENDED keyword is used then much more information will be emitted where as without that keyword only logical information will be emitted.
> e.g. In case of a group by query 
> EXPLAIN
> SELECT T.c1, count(1) FROM T GROUP BY T.c1;
> The explain plan itself has two stages
> Stage1 and Stage2
> Stage1 will have the plan for generating the partial aggregates
> and Stage2 will have the plan for generating the complete aggregates.
> I also plan to convert the parse and semantic analysis tests so that they use this for finding differences in the plan instead of the programmatic plan dumps that we are using today (tests/queries/positive).

-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.