’Thanks to Jens von Bulow’
Most QueueMetrics tables use a storage engine called myISAM - this was the default storage engine, and works well on tables that are written infrequently and read often. If you run a clustered call-center with multiple partitions and many rows being inserted per second, you may see database response times degrade. In this case, moving the storage engine to InnoDB, a storage engine that is way better for contended tables, may make a difference.