1. Drupal and MongoDB
or the road to APIs

2. Drupal 7

3. What went well? Entity-field storage: node, comment, user...
Session (frequent writes)
Watchdog (capped collection)
Cache

4. What worked out so-so?
Blocks. Unmaintainable solution.

5. Where were things stored?
List of modules: system table
Date formats:
date_format_type
date_formats
date_format_locale tables
Text formats:
filter
filter_format tables
Arbitrary contrib
arbitrary table

6. How were things handled?
Field widgets, formatters:
Some info hook
settings stored in an arbitrary table
handled by arbitrary callbacks
Cache, query:
variable_get defines include file
variable_get defines settings

7. Consequences
Even with a SQL abstraction driver, full MongoDB is practically impossible.
Pluggability is totally arbitrary

9. Drupal 8
There can be only one

10. Where are things stored?
List of modules: CMI
Date formats: CMI
Text formats: CMI
Arbitrary contrib: CMI or bust

11. How are things handled?
Defined in a dependency injection container: easy and uniform to change
Annotated classes: every kind of plugin has the same metadata definition
Again, settings in CMI

13. So how will MongoDB fit? Inject via the DIC
Sweep up the remaining little via a DB driver, but this is limited.

14. MongoDB distribution Necessary to be able to install without MySQL
Ability to change things early and keep them changed

15. Existing drivers? Session: might become Symfony, then needs new driver
Watchdog: this might change to Monolog or PSR-3.
Entity storage: hopefully base entity storage also (I will work on this)

16. New drivers
File usage
Flood

17. CMI "driver" CMI canonical is YAML file Plus caching
We have a cache driver
For speed on queries, do not serialize on cache_config (other bins might have objects/arrays so serialize needed)