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From "Jacky Li (JIRA)" <j...@apache.org>
Subject [jira] [Resolved] (CARBONDATA-1076) Join Issue caused by dictionary and shuffle exchange
Date Wed, 24 May 2017 08:21:04 GMT

     [ https://issues.apache.org/jira/browse/CARBONDATA-1076?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Jacky Li resolved CARBONDATA-1076.
----------------------------------
       Resolution: Fixed
    Fix Version/s: 1.2.0

> Join Issue caused by dictionary and shuffle exchange
> ----------------------------------------------------
>
>                 Key: CARBONDATA-1076
>                 URL: https://issues.apache.org/jira/browse/CARBONDATA-1076
>             Project: CarbonData
>          Issue Type: Bug
>          Components: core
>    Affects Versions: 0.1.1-incubating, 1.1.0
>         Environment: Carbon + spark 2.1
>            Reporter: chenerlu
>            Assignee: Ravindra Pesala
>             Fix For: 1.2.0
>
>          Time Spent: 40m
>  Remaining Estimate: 0h
>
> We can reproduce this issue as following steps:
> Step1: create a carbon table
>  
> carbon.sql("CREATE TABLE IF NOT EXISTS carbon_table (col1 int, col2 int, col3 int) STORED
by 'carbondata' TBLPROPERTIES('DICTIONARY_INCLUDE'='col1,col2,col3','TABLE_BLOCKSIZE'='4')")
>  
> Step2: load data
> carbon.sql("LOAD DATA LOCAL INPATH '/opt/carbon_table' INTO TABLE carbon_table")
> data in file carbon_table as follows:
> col1,col2,col3
> 1,2,3
> 4,5,6
> 7,8,9
>  
> Step3: do the query
> carbon.sql("SELECT c1.col1,c2.col1,c2.col3 FROM (SELECT col1,col2 FROM carbon_table GROUP
BY col1,col2) c1 FULL JOIN (SELECT col1,count(col2) as col3 FROM carbon_table GROUP BY col1)
c2 ON c1.col1 = c2.col1").show()
> [expected] Hive table and parquet table get same result as below and it should be correct.
> |col1|col1|col3|
> |   1|   1|   1|
> |   4|   4|   1|
> |   7|   7|   1|
> [acutally] carbon will get null because wrong match.
> |col1|col1|col3|
> |   1|null|null|
> |null|   4|   1|
> |   4|null|null|
> |null|   7|   1|
> |   7|null|null|
> |null|   1|   1|
> Root cause analysis:
>  
> It is because this query has two subquery, and one subquey do the decode after exchange
and the other subquery do the decode before exchange, and this may lead to wrong match when
execute full join.
>  
> My idea: Can we move decode before exchange ? Because I am not very familiar with Carbon
query, so any idea about this ?
> Plan as follows:
>  
> == Physical Plan ==
> SortMergeJoin [col1#3445], [col1#3460], FullOuter
> :- Sort [col1#3445 ASC NULLS FIRST], false, 0
> :  +- Exchange hashpartitioning(col1#3445, 200)
> :     +- CarbonDictionaryDecoder [CarbonDecoderRelation(Map(col1#3445 -> col1#3445,
col2#3446 -> col2#3446, col3#3447 -> col3#3447),CarbonDatasourceHadoopRelation [ Database
name :tempdev, Table name :carbon_table, Schema :Some(StructType(StructField(col1,IntegerType,true),
StructField(col2,IntegerType,true), StructField(col3,IntegerType,true))) ]), CarbonDecoderRelation(Map(col1#3460
-> col1#3460, col2#3461 -> col2#3461, col3#3462 -> col3#3462),CarbonDatasourceHadoopRelation
[ Database name :tempdev, Table name :carbon_table, Schema :Some(StructType(StructField(col1,IntegerType,true),
StructField(col2,IntegerType,true), StructField(col3,IntegerType,true))) ])], IncludeProfile(ArrayBuffer(col1#3445)),
CarbonAliasDecoderRelation(), org.apache.spark.sql.CarbonSession@69e87cbe
> :        +- HashAggregate(keys=[col1#3445, col2#3446], functions=[], output=[col1#3445])
> :           +- Exchange hashpartitioning(col1#3445, col2#3446, 200)
> :              +- HashAggregate(keys=[col1#3445, col2#3446], functions=[], output=[col1#3445,
col2#3446])
> :                 +- Scan CarbonDatasourceHadoopRelation [ Database name :tempdev, Table
name :carbon_table, Schema :Some(StructType(StructField(col1,IntegerType,true), StructField(col2,IntegerType,true),
StructField(col3,IntegerType,true))) ] tempdev.carbon_table[col1#3445,col2#3446] 
> +- Sort [col1#3460 ASC NULLS FIRST], false, 0
>    +- CarbonDictionaryDecoder [CarbonDecoderRelation(Map(col1#3445 -> col1#3445, col2#3446
-> col2#3446, col3#3447 -> col3#3447),CarbonDatasourceHadoopRelation [ Database name
:tempdev, Table name :carbon_table, Schema :Some(StructType(StructField(col1,IntegerType,true),
StructField(col2,IntegerType,true), StructField(col3,IntegerType,true))) ]), CarbonDecoderRelation(Map(col1#3460
-> col1#3460, col2#3461 -> col2#3461, col3#3462 -> col3#3462),CarbonDatasourceHadoopRelation
[ Database name :tempdev, Table name :carbon_table, Schema :Some(StructType(StructField(col1,IntegerType,true),
StructField(col2,IntegerType,true), StructField(col3,IntegerType,true))) ])], IncludeProfile(ArrayBuffer(col1#3460)),
CarbonAliasDecoderRelation(), org.apache.spark.sql.CarbonSession@69e87cbe
>       +- HashAggregate(keys=[col1#3460], functions=[count(col2#3461)], output=[col1#3460,
col3#3436L])
>          +- Exchange hashpartitioning(col1#3460, 200)
>             +- HashAggregate(keys=[col1#3460], functions=[partial_count(col2#3461)],
output=[col1#3460, count#3472L])
>                +- CarbonDictionaryDecoder [CarbonDecoderRelation(Map(col1#3445 ->
col1#3445, col2#3446 -> col2#3446, col3#3447 -> col3#3447),CarbonDatasourceHadoopRelation
[ Database name :tempdev, Table name :carbon_table, Schema :Some(StructType(StructField(col1,IntegerType,true),
StructField(col2,IntegerType,true), StructField(col3,IntegerType,true))) ]), CarbonDecoderRelation(Map(col1#3460
-> col1#3460, col2#3461 -> col2#3461, col3#3462 -> col3#3462),CarbonDatasourceHadoopRelation
[ Database name :tempdev, Table name :carbon_table, Schema :Some(StructType(StructField(col1,IntegerType,true),
StructField(col2,IntegerType,true), StructField(col3,IntegerType,true))) ])], IncludeProfile(ArrayBuffer(col2#3461)),
CarbonAliasDecoderRelation(), org.apache.spark.sql.CarbonSession@69e87cbe
>                   +- Scan CarbonDatasourceHadoopRelation [ Database name :tempdev, Table
name :carbon_table, Schema :Some(StructType(StructField(col1,IntegerType,true), StructField(col2,IntegerType,true),
StructField(col3,IntegerType,true))) ] tempdev.carbon_table[col1#3460,col2#3461]]



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