HeatWave Release Notes
Before MySQL 9.0.0, HeatWave MySQL uses a query cost threshold to choose the execution engine for the query.
As of MySQL 9.0.0, HeatWave MySQL uses dynamic query offload to choose the optimal execution engine for queries based on query and execution engine characteristics, which achieves improved performance.
Dynamic query offload analyses the query characteristics and execution engine static and dynamic characteristics to choose the best engine for the query, given the current system state. This includes the following:
Secondary engine change propagation.
Secondary engine query queue.
The presence of indexes on the primary engine.
Dynamic query offload introduces a minimal overhead for fast queries. The overhead for more complex queries is also minimal, compared to the time required for query optimisation and subsequent execution.