- base Expiring class
- ensures expiring values (OAuthCode, OAuthAccessToken, APIToken) are not returned from `find`
- all expire appropriately via purge_expired
query on Server objects instead of User objects
avoids lots of ORM work on startup since there are typically a small number of running servers
relative to the total number of users
this also means that the users dict is not fully populated. Is that okay? I hope so.
In current versions of MySQL and MariaDB `innodb_file_format`
and `innodb_large_prefix` have been removed. This allows them to not
exist and makes sure the format for the rows are `Dynamic` (default
for current versions).
TEXT is wrong on Oracle, LargeBinary is wrong everywhere else.
Text seems to be the high-level type that maps to the right thing both places.
This results in no change on supported implementations, as Text == TEXT there.
define some pending/ready helpers as static constants on orm.Spawner
allows treating orm.Spawner the same as Spawner wrappers,
as long as `.active` etc. checks are performed first
from the sqlalchemy docs
checks if a connection is valid via `SELECT 1` prior to using it.
Since we have long-running connections, this helps us survive database restarts, disconnects, etc.
in order to use sqlalchemy's expire_on_commit=False optimization,
we need to make sure that objects are kept up to date.
This means we cannot rely on ForeignKey ondelete/onupdate behavior,
we must use sqlalchemy's local relationship cascades
The main key here is that we must use relationships to set foreign-key relations,
e.g. APIToken.user = user instead of APIToken.user_id = user.id.
It also means that we cannot use passive_deletes,
which allows sqlalchemy to defer to the database's more efficient ON DELETE behavior.
This makes deletions more expensive in particular,
but should improve db performance overall.
- set ONDELETE='set null' on spawner->server relation (fixes error when deleting servers that stopped)
- set `spawner.server = None`, which is not triggered when deleting orm_spawner.server
