[
https://issues.apache.org/jira/browse/HIVE-11502?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14696920#comment-14696920
]
Yongzhi Chen commented on HIVE-11502:
-------------------------------------
The TestDummy failure is not related:
It failed because of FileNotFoundException:
[exec] + javac -cp
/home/hiveptest/54.147.251.176-hiveptest-2/maven/org/apache/hive/hive-exec/2.0.0-SNAPSHOT/hive-exec-2.0.0-SNAPSHOT.jar
/tmp/UDFExampleAdd.java -d /tmp
[exec] + jar -cf /tmp/udfexampleadd-1.0.jar -C /tmp UDFExampleAdd.class
[exec] java.io.FileNotFoundException: /tmp/UDFExampleAdd.class (No such
file or directory)
[exec] at java.io.FileInputStream.open(Native Method)
[exec] at java.io.FileInputStream.<init>(FileInputStream.java:146)
[exec] at sun.tools.jar.Main.copy(Main.java:791)
[exec] at sun.tools.jar.Main.addFile(Main.java:740)
[exec] at sun.tools.jar.Main.create(Main.java:491)
[exec] at sun.tools.jar.Main.run(Main.java:201)
[exec] at sun.tools.jar.Main.main(Main.java:1177)
> Map side aggregation is extremely slow
> --------------------------------------
>
> Key: HIVE-11502
> URL: https://issues.apache.org/jira/browse/HIVE-11502
> Project: Hive
> Issue Type: Bug
> Components: Logical Optimizer, Physical Optimizer
> Affects Versions: 1.2.0
> Reporter: Yongzhi Chen
> Assignee: Yongzhi Chen
> Attachments: HIVE-11502.1.patch, HIVE-11502.2.patch
>
>
> For the query as following:
> {noformat}
> create table tbl2 as
> select col1, max(col2) as col2
> from tbl1 group by col1;
> {noformat}
> If the column for group by has many different values (for example 400000) and
> it is in type double, the map side aggregation is very slow. I ran the query
> which took more than 3 hours , after 3 hours, I have to kill the query.
> The same query can finish in 7 seconds, if I turn off map side aggregation by:
> {noformat}
> set hive.map.aggr = false;
> {noformat}
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
