[FLINK-19435] Deadlock when loading different driver classes concurrently using Class.forName

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.10.2
• Fix Version/s: 1.12.1, 1.13.0
• Component/s: Connectors / JDBC
• Labels: pull-request-available
• Assignee: Kezhu Wang
• Reporter: xiaodao
• Created: 27/Sep/20 12:25
• Updated: 13/Jan/21 12:28
• Resolved: 22/Dec/20 02:55

Description

when we sink data to multi jdbc outputformat , 

protected void establishConnection() throws SQLException, ClassNotFoundException {
 Class.forName(drivername);
 if (username == null) {
 connection = DriverManager.getConnection(dbURL);
 } else {
 connection = DriverManager.getConnection(dbURL, username, password);
 }
}

may cause jdbc driver deadlock. it need to change to synchronized function.

Issue Links

• links to: GitHub Pull Request #14361