[doc_manhat]

Got up to the TL;DR paragraph. This was a major red flag given the initial presentation of the discovery of a bottleneck:

''' When a NOTIFY query is issued during a transaction, it acquires a global lock on the entire database (ref) during the commit phase of the transaction, effectively serializing all commits. '''

Am I missing something - this seems like something the original authors of the system should have done due diligence on before implementing a write heavy work load.

[kccqzy]

I think it's just difficult to predict how heavy is heavy enough to make this a problem. FWIW I had worked at a startup with a much more primitive data storage system where serialized commits were actually totally fine. The startup never outgrew that bottleneck.

[Someone]

If “doing due diligence” involves reading the source code of a database server to verify a design, I doubt many people writing such systems do due diligence.

The documentation doesn’t mention any caveats in this direction, and they had 3 periods of downtime in 4 days, so I don’t think it’s a given that testing would have hit this problem.

[whatevaa]

You don't know how heavy it will be in new systems. As another commenter mentioned, you might never reach that point. Simplier is always better.