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https://issues.apache.org/jira/browse/DRILL-5480?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jinfeng Ni reassigned DRILL-5480:
---------------------------------

    Assignee: Jinfeng Ni

> Empty batch returning from HBase may cause SchemChangeException or incorrect 
> query result
> -----------------------------------------------------------------------------------------
>
>                 Key: DRILL-5480
>                 URL: https://issues.apache.org/jira/browse/DRILL-5480
>             Project: Apache Drill
>          Issue Type: Bug
>            Reporter: Jinfeng Ni
>            Assignee: Jinfeng Ni
>
> The following repo was provided by [~haozhu].
> 1. Create a Hbase table with 4 regions
> {code}
> create 'myhbase', 'cf1','cf2', {SPLITS => ['a', 'b', 'c']}
> put 'myhbase','a','cf1:col1','somedata'
> put 'myhbase','b','cf1:col2','somedata'
> put 'myhbase','c','cf2:col1','somedata'
> {code}
> One region has cf1.col1.  One region has column family 'cf1', but does not 
> have 'col1' under 'cf1'. One region has only column family 'cf2'. And last 
> region is complete empty.
> 2. Prepare a csv file.
> {code}
> select * from dfs.tmp.`joinhbase.csv`;
> +-------------------+
> |      columns      |
> +-------------------+
> | ["1","somedata"]  |
> | ["2","somedata"]  |
> | ["3","somedata"]  |
> {code}
> Now run the following query on drill 1.11.0-SNAPSHOT:
> {code}
> select cast(H.row_key as varchar(10)) as keyCol, CONVERT_FROM(H.cf1.col1, 
> 'UTF8') as col1
> from 
> hbase.myhbase H JOIN dfs.tmp.`joinhbase.csv` C
> ON CONVERT_FROM(H.cf1.col1, 'UTF8')= C.columns[1]
> ;
> {code}
> The correct query result show be:
> {code}
> +---------+-----------+
> | keyCol  |   col1    |
> +---------+-----------+
> | a       | somedata  |
> | a       | somedata  |
> | a       | somedata  |
> +---------+-----------+
> {code}
> Turn off broadcast join, then we will see SchemaChangeException, or incorrect 
> result randomly. By 'randomly', it means in the same session, the same query 
> would hit SchemaChangeException in one run, while gets incorrect result in a 
> second run. 
> {code}
> alter session set `planner.enable_broadcast_join`=false;
> {code}
> {code}
> select cast(H.row_key as varchar(10)) as keyCol, CONVERT_FROM(H.cf1.col1, 
> 'UTF8') as col1
> . . . . . . . . . . . . . . . . . .> from
> . . . . . . . . . . . . . . . . . .> hbase.myhbase H JOIN 
> dfs.tmp.`joinhbase.csv` C
> . . . . . . . . . . . . . . . . . .> ON CONVERT_FROM(H.cf1.col1, 'UTF8')= 
> C.columns[1]
> . . . . . . . . . . . . . . . . . .> ;
> Error: SYSTEM ERROR: SchemaChangeException: Hash join does not support schema 
> changes
> {code}
> {code}
> +---------+-------+
> | keyCol  | col1  |
> +---------+-------+
> +---------+-------+
> No rows selected (0.302 seconds)
> {code}



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