Re: Listen / Notify rewrite

On 11/12/09 8:30 AM, Tom Lane wrote:
> So while a payload string for NOTIFY has been on the to-do list since
> forever, I have to think that Greg's got a good point questioning
> whether it is actually a good idea.

Sure, people will abuse it as a queue. But people abuse arrays when
they should be using child tables, use composite types to make data
non-atomic, and use dblink when they really should be using schema.
Does the potential for misuse mean that we should drop the features? No.

Payloads are also quite useful even in a lossy environment, where you
understand that LISTEN is not a queue. For example, I'd like to be
using LISTEN/NOTIFY for cache invalidation for some applications; if it
misses a few, or double-counts them, it's not an issue. However, I'd
like to be able to send message like players_updated|45321 where 45321
is the ID of the player updated.

--Josh Berkus