[FLINK-30371] JdbcOutputFormat is at risk of database connection leaks

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 1.16.0, 1.16.1, jdbc-3.0.0
• Fix Version/s: jdbc-3.3.0
• Component/s: Connectors / JDBC
• Labels: pull-request-available stale-assigned
• Assignee: Echo Lee
• Reporter: Echo Lee
• Created: 12/Dec/22 09:02
• Updated: 1 week ago 14:03

Description

When writing to the target table fails for some reason, for example, the target table does not exist.

The internal call sequence of JdbcOutputFormat is:
JdbcOutputFormat#flush(throws IOException) --> JdbcOutputFormat#close --> JdbcOutputFormat#flush(throws RuntimeException).

Will not call the close method of the database connection, when the restart strategy is fixeddelay, maxNumberRestartAttempts is Integer.MAX, this will cause the number of database connections to continue to rise and reach the limit.

 

2022-12-07 10:49:32,050 ERROR org.apache.flink.connector.jdbc.internal.JdbcBatchingOutputFormat [] - JDBC executeBatch error, retry times = 3
java.sql.BatchUpdateException: ORA-00942: table or view does not exist

Caused by: java.sql.SQLException: Listener refused the connection with the following error:
ORA-12519, TNS:no appropriate service handler found 

Issue Links

• links to: GitHub Pull Request #5
• links to: GitHub Pull Request #75