Does excision count towards the 1 billion datom limit?

My team has found some use cases with Datomic where we’d like to store temporary data and delete it at some later point. For example: deleted old user sessions, queuing jobs for a worker process etc.

I know that retracting such data still leaves it in the system. If I excise the data instead, should I be concerned about it creating garbage that can’t be collected? How does excision impact the db/id allocation?