[IMPALA-3219] Concurrency problems using prepared statements on JDBC driver

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: Impala 2.3.0
• Fix Version/s: Impala 2.3.0
• Component/s: Clients
• Labels: concurrency jdbc preparedstatements
• Environment: Impala JDBC41 driver 2.5.28 and 2.5.30
• Assignee: Unassigned
• Reporter: Jacobo Sánchez López
• Created: 21/Mar/16 16:12
• Updated: 25/Jul/16 14:31
• Resolved: 25/Jul/16 14:31

Description

Executing selects using JDBC41 driver in a concurrent environment throws exceptions on accessing the result set. Enviroment must match the following:

1. Concurrency
2. Use of prepared statements even without parameters (does not happen with statements)
3. Queries having a very different schema (in column types and number of columns)

Debugging i have found that when i receive an error there is a S41ForwardResultSet having a m_resultSetMetadata (S41ResultSetMetadata) with the columns of one query and m_parentStatement(S41PreparedStatement) with a m_preparedSql from other query

Exceptions obtained from the driver are like the following:

java.sql.SQLException: [Simba][JDBC](10340) Invalid column index: 9.
	at com.cloudera.exceptions.ExceptionConverter.toSQLException(Unknown Source)
	at com.cloudera.jdbc.common.SForwardResultSet.checkIfValidColumnNumber(Unknown Source)
	at com.cloudera.jdbc.common.SForwardResultSet.getData(Unknown Source)
	at com.cloudera.jdbc.common.SForwardResultSet.getObject(Unknown Source)

 [Simba][JDBC](10140) Error converting value to long.
	at com.cloudera.exceptions.ExceptionConverter.toSQLException(Unknown Source)
	at com.cloudera.utilities.conversion.TypeConverter.toLong(Unknown Source)
	at com.cloudera.utilities.conversion.TypeConverter.toObject(Unknown Source)
	at com.cloudera.jdbc.common.SForwardResultSet.getObject(Unknown Source)

java.sql.SQLException: [JDBC Driver]1
	at com.cloudera.hivecommon.api.HS2Client.getData(Unknown Source)
	at com.cloudera.hivecommon.dataengine.HiveJDBCResultSet.getData(Unknown Source)
	at com.cloudera.jdbc.common.SForwardResultSet.getData(Unknown Source)
	at com.cloudera.jdbc.common.SForwardResultSet.getObject(Unknown Source)

Original use case is a client using connection pool but i managed to reproduce the problem using the Java class attached (Main.java). This class needs to be updated with connection parameters and at least two threads with queries having a very different schema (different data types and column number)