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https://issues.apache.org/jira/browse/HIVE-23873?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17160110#comment-17160110
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Syed Shameerur Rahman commented on HIVE-23873:
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[~chiran54321] Do you see the same issue with hive master branch?
> 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: 3.1.0, 3.1.1, 3.1.2
> Reporter: Chiran Ravani
> Assignee: Chiran Ravani
> Priority: Critical
> Attachments: HIVE-23873.01.patch
>
>
> 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:@orachehostname/XE",
> "hive.sql.dbcp.username" = "chiran",
> "hive.sql.dbcp.password" = "supersecurepassword",
> "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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