Обсуждение: Listen/Notify in 9.0
Hi As I understand the changes to the notification system in 9.0, apart from being able to carry a payload, it will guarantee the order of delivery, and also it will keep the notification and notify any listener, even if the listener didn't register at the time of notification. Is this correct? What happens if the listener process dies, for how long time will it take up ressources? What happens if the listener process never picks up the notification, same question? What happens if the same process makes the same LISTEN request again. Will it take up more ressources? -- Med venlig hilsen Kaare Rasmussen, Jasonic Jasonic Telefon: +45 3816 2582 Nordre Fasanvej 12 2000 Frederiksberg Email: kaare@jasonic.dk
Kaare Rasmussen <kaare@jasonic.dk> writes: > As I understand the changes to the notification system in 9.0, apart from > being able to carry a payload, it will guarantee the order of delivery, and > also it will keep the notification and notify any listener, even if the > listener didn't register at the time of notification. Is this correct? Well, order of delivery depends on commit order, so there's only a pretty weak guarantee there, although I guess it is stronger than before. As for the other thing, listeners are *not* guaranteed to get any notices that were committed before they commit their LISTEN. They are guaranteed to get ones that were committed afterwards, but that's the same as before. regards, tom lane