A dead letter queue that reached zero

A dead letter queue that had held between forty and eight thousand messages since 2019, empty for the first time.

what got it there, over eighteen months:

  an owner per queue, named in the configuration
  a daily message to the owner if the queue is
    non-empty
  a weekly report that fails if anything is older
    than seven days
  a documented replay command

and the last hundred, cleared in March: all of them
from one consumer with no backoff, retrying a poison
message 40 times a minute in 2021.

An empty dead letter queue is not the goal and it is a signal — a queue that is never empty is a queue nobody reads, and a queue that reaches zero is one where every failure has been classified. The staleness check is what does the work; the daily message was ignored for the first four months.