Chiran Ravani created HIVE-23873:
------------------------------------
Summary: Querying Hive JDBCStorageHandler table fails with NPE
Key: HIVE-23873
URL: https://issues.apache.org/jira/browse/HIVE-23873
Project: Hive
Issue Type: Bug
Components: HiveServer2, JDBC
Affects Versions: 3.1.2, 3.1.1, 3.1.0
Reporter: Chiran Ravani
Scenario is Hive table having same schema as table in Oracle, however when we
query the table with data it fails with NPE, below is the trace.
{code}
Caused by: java.io.IOException: java.lang.NullPointerException
at
org.apache.hadoop.hive.ql.exec.FetchOperator.getNextRow(FetchOperator.java:617)
~[hive-exec-3.1.0.3.1.5.0-152.jar:3.1.0.3.1.5.0-152]
at
org.apache.hadoop.hive.ql.exec.FetchOperator.pushRow(FetchOperator.java:524)
~[hive-exec-3.1.0.3.1.5.0-152.jar:3.1.0.3.1.5.0-152]
at org.apache.hadoop.hive.ql.exec.FetchTask.fetch(FetchTask.java:146)
~[hive-exec-3.1.0.3.1.5.0-152.jar:3.1.0.3.1.5.0-152]
at org.apache.hadoop.hive.ql.Driver.getResults(Driver.java:2739)
~[hive-exec-3.1.0.3.1.5.0-152.jar:3.1.0.3.1.5.0-152]
at
org.apache.hadoop.hive.ql.reexec.ReExecDriver.getResults(ReExecDriver.java:229)
~[hive-exec-3.1.0.3.1.5.0-152.jar:3.1.0.3.1.5.0-152]
at
org.apache.hive.service.cli.operation.SQLOperation.getNextRowSet(SQLOperation.java:473)
~[hive-service-3.1.0.3.1.5.0-152.jar:3.1.0.3.1.5.0-152]
... 34 more
Caused by: java.lang.NullPointerException
at
org.apache.hive.storage.jdbc.JdbcSerDe.deserialize(JdbcSerDe.java:164)
~[hive-jdbc-handler-3.1.0.3.1.5.0-152.jar:3.1.0.3.1.5.0-152]
at
org.apache.hadoop.hive.ql.exec.FetchOperator.getNextRow(FetchOperator.java:598)
~[hive-exec-3.1.0.3.1.5.0-152.jar:3.1.0.3.1.5.0-152]
at
org.apache.hadoop.hive.ql.exec.FetchOperator.pushRow(FetchOperator.java:524)
~[hive-exec-3.1.0.3.1.5.0-152.jar:3.1.0.3.1.5.0-152]
at org.apache.hadoop.hive.ql.exec.FetchTask.fetch(FetchTask.java:146)
~[hive-exec-3.1.0.3.1.5.0-152.jar:3.1.0.3.1.5.0-152]
at org.apache.hadoop.hive.ql.Driver.getResults(Driver.java:2739)
~[hive-exec-3.1.0.3.1.5.0-152.jar:3.1.0.3.1.5.0-152]
at
org.apache.hadoop.hive.ql.reexec.ReExecDriver.getResults(ReExecDriver.java:229)
~[hive-exec-3.1.0.3.1.5.0-152.jar:3.1.0.3.1.5.0-152]
at
org.apache.hive.service.cli.operation.SQLOperation.getNextRowSet(SQLOperation.java:473)
~[hive-service-3.1.0.3.1.5.0-152.jar:3.1.0.3.1.5.0-152]
... 34 more
{code}
Problem appears when column names in Oracle are in Upper case and since in
Hive, table and column names are forced to store in lowercase during creation.
User runs into NPE error while fetching data.
While deserializing data, input consists of column names in lower case which
fails to get the value
https://github.com/apache/hive/blob/rel/release-3.1.2/jdbc-handler/src/main/java/org/apache/hive/storage/jdbc/JdbcSerDe.java#L136
{code}
rowVal = ((ObjectWritable)value).get();
{code}
Log Snio:
=============
{code}
2020-07-17T16:49:09,598 INFO [04ed42ec-91d2-4662-aee7-37e840a06036
HiveServer2-Handler-Pool: Thread-104]: dao.GenericJdbcDatabaseAccessor (:()) -
Query to execute is [select * from TESTHIVEJDBCSTORAGE]
2020-07-17T16:49:10,642 INFO [04ed42ec-91d2-4662-aee7-37e840a06036
HiveServer2-Handler-Pool: Thread-104]: jdbc.JdbcSerDe (:()) - *** ColumnKey = ID
2020-07-17T16:49:10,642 INFO [04ed42ec-91d2-4662-aee7-37e840a06036
HiveServer2-Handler-Pool: Thread-104]: jdbc.JdbcSerDe (:()) - *** Blob value =
{fname=OW[class=class java.lang.String,value=Name1], id=OW[class=class
java.lang.Integer,value=1]}
{code}
Simple Reproducer for this case.
=============
1. Create table in Oracle
{code}
create table TESTHIVEJDBCSTORAGE(ID INT, FNAME VARCHAR(20));
{code}
2. Insert dummy data.
{code}
Insert into TESTHIVEJDBCSTORAGE values (1, 'Name1');
{code}
3. Create JDBCStorageHandler table in Hive.
{code}
CREATE EXTERNAL TABLE default.TESTHIVEJDBCSTORAGE_HIVE_TBL (ID INT, FNAME
VARCHAR(20))
STORED BY 'org.apache.hive.storage.jdbc.JdbcStorageHandler'
TBLPROPERTIES (
"hive.sql.database.type" = "ORACLE",
"hive.sql.jdbc.driver" = "oracle.jdbc.OracleDriver",
"hive.sql.jdbc.url" = "jdbc:oracle:thin:@10.96.95.99:49161/XE",
"hive.sql.dbcp.username" = "chiran",
"hive.sql.dbcp.password" = "hadoop",
"hive.sql.table" = "TESTHIVEJDBCSTORAGE",
"hive.sql.dbcp.maxActive" = "1"
);
{code}
4. Query Hive table, fails with NPE.
{code}
> select * from default.TESTHIVEJDBCSTORAGE_HIVE_TBL;
INFO : Compiling
command(queryId=hive_20200717164857_cd6f5020-4a69-4a2d-9e63-9db99d0121bc):
select * from default.TESTHIVEJDBCSTORAGE_HIVE_TBL
INFO : Semantic Analysis Completed (retrial = false)
INFO : Returning Hive schema:
Schema(fieldSchemas:[FieldSchema(name:testhivejdbcstorage_hive_tbl.id,
type:int, comment:null), FieldSchema(name:testhivejdbcstorage_hive_tbl.fname,
type:varchar(20), comment:null)], properties:null)
INFO : Completed compiling
command(queryId=hive_20200717164857_cd6f5020-4a69-4a2d-9e63-9db99d0121bc); Time
taken: 9.914 seconds
INFO : Executing
command(queryId=hive_20200717164857_cd6f5020-4a69-4a2d-9e63-9db99d0121bc):
select * from default.TESTHIVEJDBCSTORAGE_HIVE_TBL
INFO : Completed executing
command(queryId=hive_20200717164857_cd6f5020-4a69-4a2d-9e63-9db99d0121bc); Time
taken: 0.019 seconds
INFO : OK
Error: java.io.IOException: java.lang.NullPointerException (state=,code=0)
{code}
Assuming that there are no repercussions, can we convert the column names to
lowercase fetched from Database/Query pointing to table in JDBCStorageHandler?
Attaching the patch for the case.
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