insert/update, and then delete notifications in hourly batches. This
means that if the task gets interrupted part-way through, we'll have at
least something to show for it. Previously we would insert and update
into the history table but might not delete from the notification table
properly.
Keeping the offsets and limits for confidence around reliability and
queries timing out.
Keeping the join to notification_history to ensure we don't delete
anything prematurely while our DB is in a bit of a weird state with lots
of these tasks failing over the last week.
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