Yes, we have customers using CrateDB as part of their proprietary product.
Also the SSPL is so vague, that we probably would not only have to release CrateDB itself - which we already do, but also everything we use for the services we provide. Also we could never make any kind of deals with OEMs, etc.
> This begs the question: isn't "a restrictive OSS licence" not less "fully open source" than a more permissive licence like GPL, MIT or BSD?
We gonna change CrateDB fully to Apache License v2 ;) I would say that counts as a "more permissive" license.
> Is that really only because of some enterprises not liking GPL?
There are various reasons for the change. A big part is definitely also the spirit of many our contributors. We built CrateDB on open source software and also want to make the software available as open source. It also was planned for quite some time to be more open.
> If your business model cannot survive when a critical upstream piece of your infrastructure moves to GPL, you probably have a bad business model to begin with.
To be clear CrateDB started out as OSS and we decide to stay OSS. Elasticsearch used the Apache License and so did CrateDB. All in the spirit of OSS. Elastic are however now the ones how decided, that their business model isn't viable anymore.
> It sounds like they are making up excuses for not wanting to fully Open Source their code
We do want to make it fully open source! Everything that was under a more restrictive License is going to be offered under Apache License.
Also the SSPL is so vague, that we probably would not only have to release CrateDB itself - which we already do, but also everything we use for the services we provide. Also we could never make any kind of deals with OEMs, etc.