Support for switch between cache compression and no compression

[mengmengy]

Hi,

Currently, if I enable query frontend query results cache with cache compression not enabled, and later on I wanted to enable cache compression. It will throw error when cortex try to decode the uncompressed cache values. It throws errors the same way if you first set cache compression and later on you decide not to compress the cache values. I'm curious is there a plan to make this cache compress and uncompressing smarter? For example, append some flag to the cache key, if there is a flag, decompress it, otherwise not.