Suppose that both block-level compression and temperature-based block-level compression are enabled for your site.
If an unpopulated table using manual compression is loaded, the data blocks are stored with block-level compression. However, if an unpopulated table set for automatic compression is loaded, and the default threshold for temperature-based block-level compression is COLD, its data blocks are not compressed because for an automatic table, the compression implied by the specified temperature and the related DBS Control parameters overrides the specific BLOCKCOMPRESSION clause.
SET QUERY_BAND = 'BLOCKCOMPRESSION=YES; TVSTEMPERATURE=VERYHOT;' FOR SESSION;