Turns out this caused a *different* problem. It would work for the first
delete batch in `BulkSqlDelete`, but subsequent `DELETE` queries would
then get their `statement_timeout`s reset to the global setting. The
issue was that `BulkSqlDelete` uses methods that don't respect nested
transactions, and we were already resetting the value of the setting to
its previous value anyway, so there was really no reason to run it
inside a transaction.
The only failure mode I know of here is that the `ensure` block breaks
because `connection` is severed. In that case, the value is reset anyway
when the connection pool replaces the connection so the failure does not
propagate.
* Allow Emails::RemoveOldEmailsWorker to run longer
We set the SQL statement timeout based on the STATEMENT_TIMEOUT
environment variable (defaulting to 2.5 seconds in production), but not
all SQL queries are created equal. Since some may take longer out of
necessity, this PR introduces a `Model.with_statement_timeout` method
that allows you to change the SQL statement timeout only for a given
block.
* EmailMessage doesn't inherit ApplicationRecord
It inherits from `Ahoy::Message`, which inherits directly from
`ActiveRecord::Base`.
[3] pry(main)> EmailMessage.ancestors
=> [EmailMessage(id: integer, clicked_at: datetime, content: text, feedback_message_id: integer, mailer: string, sent_at: datetime, subject: text, to: text, token: string, user_id: integer, user_type: string, utm_campaign: string, utm_content: string, utm_medium: string, utm_source: string, utm_term: string),
EmailMessage::GeneratedAssociationMethods,
EmailMessage::GeneratedAttributeMethods,
Ahoy::Message(id: integer, clicked_at: datetime, content: text, feedback_message_id: integer, mailer: string, sent_at: datetime, subject: text, to: text, token: string, user_id: integer, user_type: string, utm_campaign: string, utm_content: string, utm_medium: string, utm_source: string, utm_term: string),
Kaminari::ConfigurationMethods,
Kaminari::ActiveRecordModelExtension,
Ahoy::Message::GeneratedAssociationMethods,
Ahoy::Message::GeneratedAttributeMethods,
Bullet::SaveWithBulletSupport,
ActiveRecord::Base,
...
* Use milliseconds to match STATEMENT_TIMEOUT units
