I'd add that when you look into the DB and process by columns I do not doubt that frequently you will be able to come up with a compression scheme that beats ge

I'd add that when you look into the DB and process by columns I do not doubt that frequently you will be able to come up with a compression scheme that beats generic compression of an SQL dump. But at what cost? Data is only successfully compressed when it can be reliably restored. This is not the case when I invent a new compression format that is super efficient but also hard to reverse engineer and only exists on a single or a few machines on the planet. things like gzip are bound to be around for some time, my homebrew format not so much. A compression scheme that is not widely reconstructable is a fancy way to hit the delete button for that piece of data, only with more costs involved.