[HIVE-23873] Querying Hive JDBCStorageHandler table fails with NPE when CBO is off

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 3.1.0, 3.1.1, 3.1.2
• Fix Version/s: 4.0.0-alpha-1
• Component/s: HiveServer2, JDBC
• Labels: pull-request-available
• Assignee: Chiran Ravani
• Reporter: Chiran Ravani
• Created: 17/Jul/20 17:06
• Updated: 27/Feb/24 22:24
• Resolved: 03/Aug/20 14:41

Description

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.

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

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

rowVal = ((ObjectWritable)value).get();

Log Snio:
=============

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]}

Simple Reproducer for this case.
=============
1. Create table in Oracle

create table TESTHIVEJDBCSTORAGE(ID INT, FNAME VARCHAR(20));

2. Insert dummy data.

Insert into TESTHIVEJDBCSTORAGE values (1, 'Name1');

3. Create JDBCStorageHandler table in Hive.

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:@orachehostname/XE", 
"hive.sql.dbcp.username" = "chiran", 
"hive.sql.dbcp.password" = "supersecurepassword", 
"hive.sql.table" = "TESTHIVEJDBCSTORAGE", 
"hive.sql.dbcp.maxActive" = "1" 
);

4. Query Hive table, fails with NPE.

> 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)

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.

Issue Links

• links to: GitHub Pull Request #1328
• links to: GitHub Pull Request #1328