Previously, Jobs::EnqueueDigestEmails would enqueue a digest job for every user, even if there are no topics to send. The digest job would exit, no email would send, and last_emailed_at would not change. 30 minutes later, Jobs::EnqueueDigestEmails would run again and re-enqueue jobs for the same users.
120fa8ad introduced a temporary mitigation for this issue, by randomly selecting a subset of those users each time.
This commit adds a new `digest_attempted_at` column to the `user_stats` table. This column is updated every time a digest job completes for a user. Using this, we can avoid scheduling digest jobs for the same user every 30 minutes. This also removes the random user selection in 120fa8ad, and instead prioritizes users who had digests attempted the longest time ago.
To avoid blocking the sidekiq queue a limit of 10,000 digests per 30 minutes
is introduced.
This acts as a safety measure that makes sure we don't keep pouring oil on
a fire.
On multisites it is recommended to set the number way lower so sites do not
dominate the backlog. A reasonable default for multisites may be 100-500.
This can be controlled with the environment var
DISCOURSE_MAX_DIGESTS_ENQUEUED_PER_30_MINS_PER_SITE
It might happen that some User records have no associated primary emails.
In which case we don't ever want to send them a digest.
Also added a new "user_email_no_email" skipped email log to ensure these cases
are properly handled and surfaced.
Zeitwerk simplifies working with dependencies in dev and makes it easier reloading class chains.
We no longer need to use Rails "require_dependency" anywhere and instead can just use standard
Ruby patterns to require files.
This is a far reaching change and we expect some followups here.
This reduces chances of errors where consumers of strings mutate inputs
and reduces memory usage of the app.
Test suite passes now, but there may be some stuff left, so we will run
a few sites on a branch prior to merging
As it stands we load up user records quite frequently on the topic pages,
this in turn pulls all the columns for the users being selected, just to
discard them after they are loaded
New structure keeps all options in a discrete table, this is better organised
and allows us to easily add more column without worrying about bloating the
user table
There were actually 2 bugs:
1/ Calling '.try(:key)' on a hash doesn't work. So EmailLogs were never associated to a user.
2/ Turns out that we update the 'user.last_emailed_at' whenever we create an EmailLog (in the 'after_create' callback).
So we need to always create an EmailLog (whenever the email is sent or skipped).
David Taylor
Sam
Régis Hanol
Dan Ungureanu
Krzysztof Kotlarek
Guo Xiang Tan
Guo Xiang Tan
Robin Ward
Neil Lalonde
Arpit Jalan