FAQ - What happens to existing records when compression is switched off?
Compression is a feature that is unlocked via a feature key. What happens to exisrting compressed records if the compression feature is removed from the license and the server restarted with a new feature file.
Records on the disk that were compressed when the feature was being used will remain compressed. When these records are re-written they will be written uncompressed. As an update is a read of the record followed by a subsequent re-write into a fresh block, an update will also cause the data to be re-written uncompressed.
Refer to the Configure Compression documentation for further details.
COMPRESSION REMOVE WRITE DATA COMPRESSED