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https://issues.apache.org/jira/browse/HIVE-7669?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Szehon Ho updated HIVE-7669:
----------------------------
Release Note:
Background: HIVE-1402 added parallelism (multiple reducers) to an order-by
query, enabled by "hive.optimize.sampling.orderby". As order-by requires total
order, partitioning data among reducers uses a range-partition, and thus
sampling is needed to give us the values for the ranges of each reducer (eg,
1-100, 100-200, etc).
HIVE-7669 fixes the algorithm to generate a better range-partition split when
the sample data lacks enough unique values.
was:
Background: HIVE-1402 added parallelism (multiple reducers) to an order-by
query, enabled by "hive.optimize.sampling.orderby". As order-by requires total
order, partitioning data among reducers uses a range-partition, and thus
sampling is needed to give us the values for the ranges of each reducer (eg,
1-100, 100-200, etc).
HIVE-7669 fixes the algorithm to generate a better range-partition split when
the sample data lacks enough unique values, and throws exception if the
calculated number of reducers falls below a certain threshold.
> parallel order by clause on a string column fails with IOException: Split
> points are out of order
> -------------------------------------------------------------------------------------------------
>
> Key: HIVE-7669
> URL: https://issues.apache.org/jira/browse/HIVE-7669
> Project: Hive
> Issue Type: Bug
> Components: HiveServer2, Query Processor, SQL
> Affects Versions: 0.12.0
> Environment: Hive 0.12.0-cdh5.0.0
> OS: Redhat linux
> Reporter: Vishal Kamath
> Assignee: Navis
> Labels: TODOC14, orderby
> Fix For: 0.14.0
>
> Attachments: HIVE-7669.1.patch.txt, HIVE-7669.2.patch.txt,
> HIVE-7669.3.patch.txt, HIVE-7669.4.patch.txt
>
>
> The source table has 600 Million rows and it has a String column
> "l_shipinstruct" which has 4 unique values. (Ie. these 4 values are repeated
> across the 600 million rows)
> We are sorting it based on this string column "l_shipinstruct" as shown in
> the below HiveQL with the following parameters.
> {code:sql}
> set hive.optimize.sampling.orderby=true;
> set hive.optimize.sampling.orderby.number=10000000;
> set hive.optimize.sampling.orderby.percent=0.1f;
> insert overwrite table lineitem_temp_report
> select
> l_orderkey, l_partkey, l_suppkey, l_linenumber, l_quantity,
> l_extendedprice, l_discount, l_tax, l_returnflag, l_linestatus, l_shipdate,
> l_commitdate, l_receiptdate, l_shipinstruct, l_shipmode, l_comment
> from
> lineitem
> order by l_shipinstruct;
> {code}
> Stack Trace
> Diagnostic Messages for this Task:
> {noformat}
> Error: java.lang.RuntimeException: Error in configuring object
> at
> org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:109)
> at
> org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:75)
> at
> org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:133)
> at
> org.apache.hadoop.mapred.MapTask$OldOutputCollector.<init>(MapTask.java:569)
> at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:430)
> at org.apache.hadoop.mapred.MapTask.run(MapTask.java:342)
> at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:168)
> at java.security.AccessController.doPrivileged(Native Method)
> at javax.security.auth.Subject.doAs(Subject.java:415)
> at
> org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1548)
> at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:163)
> Caused by: java.lang.reflect.InvocationTargetException
> at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> at
> sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
> at
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
> at java.lang.reflect.Method.invoke(Method.java:601)
> at
> org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:106)
> ... 10 more
> Caused by: java.lang.IllegalArgumentException: Can't read partitions file
> at
> org.apache.hadoop.mapreduce.lib.partition.TotalOrderPartitioner.setConf(TotalOrderPartitioner.java:116)
> at
> org.apache.hadoop.mapred.lib.TotalOrderPartitioner.configure(TotalOrderPartitioner.java:42)
> at
> org.apache.hadoop.hive.ql.exec.HiveTotalOrderPartitioner.configure(HiveTotalOrderPartitioner.java:37)
> ... 15 more
> Caused by: java.io.IOException: Split points are out of order
> at
> org.apache.hadoop.mapreduce.lib.partition.TotalOrderPartitioner.setConf(TotalOrderPartitioner.java:96)
> ... 17 more
> {noformat}
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