[fullstop]

Not really, new connections will block as it's pausing. But you won't be able to shut down Postgres until those long queries complete. Perhaps I was not super clear, but what I'm trying to say is that PAUSE is not instantaneous.

[fierro]

yeah what I'm saying is that you can only pause as fast as your slowest currently initiated query. So if you have a diverse set of query patterns, you could be waiting for a really small percentage of small queries to wrap up.

[fullstop]

I understand now. Yes, this is true and should be taken into consideration during upgrades.

Most of our queries are fast, and the longer ones hit a read-only secondary instance. Cleanup jobs, though, can take hours to complete.