[ARROW-10441] [FlightRPC][Java] FlightClients from FlightGrpcUtils#createFlightClient shutdown gRPC channel when closed

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 2.0.0
• Fix Version/s: 3.0.0
• Component/s: FlightRPC, Java
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/26419
• Assignee: Kyle Porter
• Reporter: Kyle Porter
• Created: 30/Oct/20 22:19
• Updated: 11/Jan/23 08:13
• Resolved: 04/Nov/20 22:55

Description

It seems there may be a mistake in the Java FlightClient where it's possible to create multiple FlightClients from a single ManagedChannel.

 

See https://github.com/apache/arrow/blob/master/java/flight/flight-grpc/src/main/java/org/apache/arrow/flight/FlightGrpcUtils.java#L55 which lets you specify the channel. However, if you do create multiple FlightClients from a single channel, then calling close() (https://github.com/apache/arrow/blob/master/java/flight/flight-core/src/main/java/org/apache/arrow/flight/FlightClient.java#L503) on a single FlightClient will close the channel for all of the FlightClients that share that channel, which seems incorrect.

 

It's possible that the FlightGrpcUtils was intended only for testing purposes and this should never happen in practice. A few possible options would be to:

• This behaviour is intended, no action.
• Track if a channel is used by multiple clients and only close on the last client to close.
• Disallow creation of a FlightClient with a specified ManagedChannel.

Issue Links

• links to: GitHub Pull Request #8581