previously we checked notifications table, and if the results were
zero, checked the notification history table to see if there's data
in there. When we know that data isn't in notifications, we're still
checking. These queries take half a second per service, and we're
doing at least ten for each of the five thousand services we have in
notify. Most of these services have no data in either table for any
given day, and we can reduce the amount of queries we do by only
checking one table.
Check the data retention for a service, and then if the date is older
than the retention, get from history table.
NOTE: This requires that the delete tasks haven't run yet for the day!
If your retention is three days, this will look in the Notification
table for data from three days ago - expecting that shortly after the
task finishes, we'll delete that data.
This PR updates those queries to look in either Notification or NotificationHistory. Since the data does not exist in both tables at the same time we can do with and not worry about the data retention.
The query will iterate over each service, then each notification type and query the data if no results then try the history table.
the create_nightly_notification_status task runs at 00:30am UK time,
however this means that in summer datetime.today() will return the
wrong date as the server (which runs on UTC) will run the task at
23:30 (populating the wrong row in the table).
fix this to use nice tz aware functions
The previous query was including all notifications regardless of notification_status. I don't think that's right, it shouldn't include things like technical-failure or validation-failed. Thoughts?
I also need to remove the query that's no longer being used.
Currently, admin app requests service statistics (with notification
counts grouped by status) and template statistics (with counts by
template) in order to display the service dashboard.
Service statistics are gathered from FactNotificationStatus table
(counts for the last 7 days) combined with Notification (counts for
today).
Template statistics are currently gathered from redis cache, which
contains a separate counter per template per day. It's hard for us
to maintain consistency between redis and DB counts. Currently it
doesn't update the count for cancelled letters, counter resets in
the middle of the day might produce a wrong result for the rest of
the week and cleared redis cache can't be repopulated for services
with low data retention periods).
Since FactNotificationStatus already contains separate counts for
each template_id we can use the existing logic with some additional
filters to get separate counts for each template and status combination,
which would allow us to populate the service dashboard page from one
query response.
a query for notifications was filtering on FtNotificationStatus - we
aren't joining to that table in the query, so sqlalchemy added a cross
join between ft_notification_status (3.7k rows) and Notifications (3.9m
rows), resulting in a 1.3 trillion row materialised table. This query
took 17 hours and pending.
Also, remove orders from querys other than the outer one, since we're
grouping anyway.
The query follows the same pattern as the other queries, getting the statistics from the fact_notification_status table for dates older than today and union that with today.
Tests required.
we previously always read from NotificationHistory to get the
notification status stats for a job. Now, if the job is more than three
days old read from ft_notification_status table, otherwise read from
the notifications table (to keep live updates).
Bumped notifications-utils to 3.7.0. Version 3.7.0 includes the
`convert_utc_to_bst` and `convert_bst_to_utc` functions and the
`LETTER_PROCESSING_DEADLINE` constant, so these have been removed from
this repo and anywhere using these has now been updated to get these
from `notifications-utils`.
Also bumped pytest by a patch version to bring in a bug fix.
it now uses the ft_notification_status table - nice and quick. if you
ask for the current tax year it'll top up the data with numbers from
the notification table.
the data is in exactly the same shape as the old endpoint - no changes
to the admin app are necessary
