Before the deeper evaluation we simply made a table of pros and cons of all the different databases. Below are what we considered the pros and cons of CouchDB for our use case.
Pros:
* Projection feature
address “weird” Ansible data format requirements.
allow for a more compact and logical structure to be presented to the api.
* Built in support for compaction
* Built-in versioning
Cons:
* couchdb versioning may not align with our notion of versioning
* Requires a lot of space
* Views instead of arbitrary queries
* Performance not so predictable. (see how reads trigger version logic) (Colleague has had experience with this problem)
Edit: I found some other notes ...
CouchDB appears to be a strong candidate. I am worried about the space requirements/consumptions. CouchDB uses views of data rather than queries.
Database comparison by feature matrix:
http://i.imgur.com/6bdIvwE.png
