[jira] [Commented] (HIVE-3179) HBase Handler doesn't handle NULLs properly

["Lars Francke (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HIVE-3179?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13572282#comment-13572282 ] 

Lars Francke commented on HIVE-3179:
------------------------------------

As far as I can tell this is still an issue. Would anyone mind doing a review on this one?
                
> HBase Handler doesn't handle NULLs properly
> -------------------------------------------
>
>                 Key: HIVE-3179
>                 URL: https://issues.apache.org/jira/browse/HIVE-3179
>             Project: Hive
>          Issue Type: Bug
>          Components: HBase Handler
>    Affects Versions: 0.9.0
>            Reporter: Lars Francke
>            Priority: Critical
>         Attachments: HIVE-3179.1.patch
>
>
> We found a quite severe issue in the HBase Handler which actually means that Hive potentially returns incorrect data if a column has NULL values in HBase (which means the cell doesn't even exist)
> In HBase Shell:
> {noformat}
> create 'hive_hbase_test', 'test'
> put 'hive_hbase_test', '1', 'test:c1', 'c1-1'
> put 'hive_hbase_test', '1', 'test:c2', 'c2-1'
> put 'hive_hbase_test', '1', 'test:c3', 'c3-1'
> put 'hive_hbase_test', '2', 'test:c1', 'c1-2'
> {noformat}
> In Hive:
> {noformat}
> DROP TABLE IF EXISTS hive_hbase_test;
> CREATE EXTERNAL TABLE hive_hbase_test (
>   id int,
>   c1 string,
>   c2 string,
>   c3 string
> )
> STORED BY 'org.apache.hadoop.hive.hbase.HBaseStorageHandler'
> WITH SERDEPROPERTIES ("hbase.columns.mapping" =
> ":key#s,test:c1#s,test:c2#s,test:c3#s")
> TBLPROPERTIES("hbase.table.name" = "hive_hbase_test");
> hive> select * from hive_hbase_test;
> OK
> 1	c1-1	c2-1	c3-1
> 2	c1-2	NULL	NULL
> hive> select c1 from hive_hbase_test;
> c1-1
> c1-2
> hive> select c1, c2 from hive_hbase_test;
> c1-1	c2-1
> c1-2	NULL
> {noformat}
> So far everything is correct but now:
> {noformat}
> hive> select c1, c2, c2 from hive_hbase_test;
> c1-1	c2-1	c2-1
> c1-2	NULL	c2-1
> {noformat}
> Selecting c2 twice works the first time but the second time we
> actually get the value from the previous row.
> {noformat}
> hive> select c1, c3, c2, c2, c3, c3, c1 from hive_hbase_test;
> c1-1	c3-1	c2-1	c2-1	c3-1	c3-1	c1-1
> c1-2	NULL	NULL	c2-1	c3-1	c3-1	c1-2
> {noformat}
> We've narrowed this down to an early initialization of {{fieldsInited\[fieldID] = true}} in {{LazyHBaseRow#uncheckedGetField}} and we'll try to provide a patch which surely needs review.

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