WebSockets: Clients may unexpectedly disconnect

Detail name	Value
Changelog Number	9443
Type	Bug
Status	Resolved
Affected Versions	EXASOL 6.0.0, Exasol 6.1.0, Exasol 6.2.0
Fix Versions	Exasol 7.0.0, Exasol 6.1.9, Exasol 6.2.5
Resolution Date	2020-01-29

Background

The WebSocket protocol operates asynchronously and the server may send 'pong control frames' to the client in regular intervals.

Problem

During query execution, Exasol may not send pong control frames to the client as heartbeat/feedback messages. This may cause the client to disconnect from Exasol if a timeout value has been set for the connection.

Fix

This issue has been fixed such that Exasol will now send Pong frames to the client as expected to avoid connection timeout issues.