MySQL HeatWave compresses data as it is loaded, which permits MySQL HeatWave nodes to store more data. More data per node reduces costs by minimizing the size of the MySQL HeatWave Cluster required to store the data.

While data compression results in a smaller MySQL HeatWave Cluster, decompression operations that occur as data is accessed affect performance to a small degree. Specifically, decompression operations have a minor effect on query runtimes, on the rate at which queries are offloaded to MySQL HeatWave during change propagation, and on recovery time from Object Storage.

If data storage size is not a concern, disable data compression by setting the rapid_compression session variable to OFF before loading data:

mysql> SET SESSION rapid_compression=OFF;

As of MySQL version 8.3.0, the default option is AUTO which automatically chooses the best compression algorithm for each column. Prior to that only ON and OFF were supported.