gcm how many devices can receive a push message at

问题:

I have about 1500 registration ID, i tried to send 1 push notification. But it didn't. Is it GCM does not allow sending to more than 1000 registration ID per message ?

回答1:

That's correct. A single request to GCM can contain up to 1000 Registration IDs. You'll have to split your 1500 IDs into two separate requests.

回答2:

Quoting from Google Docs:

GCM is support for up to 1,000 recipients for a single message. This capability makes it much easier to send out important messages to your entire user base. For instance, let's say you had a message that needed to be sent to 1,000,000 of your users, and your server could handle sending out about 500 messages per second. If you send each message with only a single recipient, it would take 1,000,000/500 = 2,000 seconds, or around half an hour. However, attaching 1,000 recipients to each message, the total time required to send a message out to 1,000,000 recipients becomes (1,000,000/1,000) / 500 = 2 seconds. This is not only useful, but important for timely data, such as natural disaster alerts or sports scores, where a 30 minute interval might render the information useless.

Taking advantage of this functionality is easy. If you're using the GCM helper library for Java, simply provide a List collection of registration IDs to the send or sendNoRetry method, instead of a single registration ID.