Hanging query or logserver due to race conditions in communication layer

Detail name	Value
Changelog Number	13768
Type	Bug
Status	Resolved
Affected Versions	Exasol 7.0.0, Exasol 7.1.0
Fix Versions	Exasol 8.0.0, Exasol 7.0.17, Exasol 7.1.7
Resolution Date	2022-03-15

Description

A race condition in the communication layer may cause a session to hang or the logserver to stop updating statistics. In the case of the logserver, it may use a lot of memory causing queries to fail with "System out of memory".

Workaround

Abort the affected statement and rerun it.
Restart the database if logserver stopped updating statistics or if queries fail with "System out of memory" errors. There will be a gap in statistics and auditing.

Fix

Communication layer is more robust against those race conditions.