[jira] [Created] (DRILL-5480) Empty batch returning from HBase may cause SchemChangeException or incorrect query result

[Jinfeng Ni (JIRA)]

Jinfeng Ni created DRILL-5480:
---------------------------------

             Summary: 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


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.

{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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