Signs it is time to revisit queues and message brokers

Teams tend to reach for this after something has already gone wrong. A few signals that queues and message brokers is due some attention.

Most systems fail at the seams rather than inside any one component. It is the sort of thing that looks like polish right up until it costs you an enquiry.

The signals

• Nobody can say when it was last reviewed
• The answer depends on who you ask
• Queues absorb spikes that would otherwise take a system down
• Every queue needs a dead letter destination and someone watching it

The practical version

Ordering guarantees are weaker than most teams assume. The cost of getting this wrong is rarely visible on the day it happens. The practical test is whether someone new to the project could tell, in a minute, that it had been handled.

In practice

Architecture is the set of decisions that are expensive to reverse, which is the only reason they deserve the name. Three things worth confirming about queues and message brokers before you move on:

• Someone can say what the current setup is without going to look
• Ordering guarantees are weaker than most teams assume — and you know whether that is true here
• There is a way to tell whether the last change to this helped

Worth checking on your own setup before it becomes someone else's problem to fix.