hive-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Amareshwari Sriramadasu (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-3952) merge map-job followed by map-reduce job
Date Wed, 27 Feb 2013 11:21:14 GMT

    [ https://issues.apache.org/jira/browse/HIVE-3952?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13588233#comment-13588233
] 

Amareshwari Sriramadasu commented on HIVE-3952:
-----------------------------------------------

Tried out the patch, when we run query like the following :

INSERT OVERWRITE DIRECTORY "/dir"
Select ....

It fails with exception :

{noformat}
java.lang.ClassCastException: org.apache.hadoop.hive.ql.exec.MoveTask cannot be cast to org.apache.hadoop.hive.ql.exec.MapRedTask
	at org.apache.hadoop.hive.ql.optimizer.physical.CommonJoinResolver$CommonJoinTaskDispatcher.mayBeMergeMapJoinTaskWithMapReduceTask(CommonJoinResolver.java:291)
	at org.apache.hadoop.hive.ql.optimizer.physical.CommonJoinResolver$CommonJoinTaskDispatcher.processCurrentTask(CommonJoinResolver.java:535)
	at org.apache.hadoop.hive.ql.optimizer.physical.CommonJoinResolver$CommonJoinTaskDispatcher.dispatch(CommonJoinResolver.java:701)
	at org.apache.hadoop.hive.ql.lib.TaskGraphWalker.dispatch(TaskGraphWalker.java:111)
	at org.apache.hadoop.hive.ql.lib.TaskGraphWalker.walk(TaskGraphWalker.java:194)
	at org.apache.hadoop.hive.ql.lib.TaskGraphWalker.startWalking(TaskGraphWalker.java:139)
	at org.apache.hadoop.hive.ql.optimizer.physical.CommonJoinResolver.resolve(CommonJoinResolver.java:113)
	at org.apache.hadoop.hive.ql.optimizer.physical.PhysicalOptimizer.optimize(PhysicalOptimizer.java:79)
	at org.apache.hadoop.hive.ql.parse.SemanticAnalyzer.genMapRedTasks(SemanticAnalyzer.java:8138)
	at org.apache.hadoop.hive.ql.parse.SemanticAnalyzer.analyzeInternal(SemanticAnalyzer.java:8470)
	at org.apache.hadoop.hive.ql.parse.BaseSemanticAnalyzer.analyze(BaseSemanticAnalyzer.java:259)
	at org.apache.hadoop.hive.ql.Driver.compile(Driver.java:431)
	at org.apache.hadoop.hive.ql.Driver.compile(Driver.java:335)
	at org.apache.hadoop.hive.ql.Driver.run(Driver.java:898)
	at org.apache.hadoop.hive.cli.CliDriver.processLocalCmd(CliDriver.java:259)
	at org.apache.hadoop.hive.cli.CliDriver.processCmd(CliDriver.java:216)
	at org.apache.hadoop.hive.cli.CliDriver.processLine(CliDriver.java:413)
	at org.apache.hadoop.hive.cli.CliDriver.run(CliDriver.java:756)
	at org.apache.hadoop.hive.cli.CliDriver.main(CliDriver.java:614)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at org.apache.hadoop.util.RunJar.main(RunJar.java:197)
{noformat}


                
> merge map-job followed by map-reduce job
> ----------------------------------------
>
>                 Key: HIVE-3952
>                 URL: https://issues.apache.org/jira/browse/HIVE-3952
>             Project: Hive
>          Issue Type: Improvement
>          Components: Query Processor
>            Reporter: Namit Jain
>            Assignee: Vinod Kumar Vavilapalli
>         Attachments: HIVE-3952-20130226.txt
>
>
> Consider the query like:
> select count(*) FROM
>         ( select idOne, idTwo, value FROM
>               bigTable                                       
>               JOIN                                                                
>               smallTableOne on (bigTable.idOne = smallTableOne.idOne)               
                                   
>           ) firstjoin                                                             
>             JOIN                                                                  
>             smallTableTwo on (firstjoin.idTwo = smallTableTwo.idTwo);
> where smallTableOne and smallTableTwo are smaller than hive.auto.convert.join.noconditionaltask.size
and
> hive.auto.convert.join.noconditionaltask is set to true.
> The joins are collapsed into mapjoins, and it leads to a map-only job
> (for the map-joins) followed by a map-reduce job (for the group by).
> Ideally, the map-only job should be merged with the following map-reduce job.

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira

Mime
View raw message