This article applies to the BlackBerry® Mobile Data System (BlackBerry MDS) Connection Service.
When performing either a RIM push or a PAP push, you have the option of assigning a push ID. If the push ID is not unique, the push will fail and the BlackBerry MDS Connection Service will return an error. However, BlackBerry MDS Connection Service does not retain the push IDs indefinitely, so it is possible to re-use the same ID. A push ID can be any alphanumeric string.
If BlackBerry MDS is configured to store push messages in the database, then BlackBerry MDS identifies the ID as long as it is still in the database (i.e., it has not been purged). The maximum age of a record is configurable.
If BlackBerry MDS is not configured to store push messages in the database, then BlackBerry MDS can identify the ID as long as it is still in its cache. The default cache size is 10000. The cache is also cleared when the BlackBerry MDS Connection Service is restarted.
When performing a RIM push, the push ID is set using the “X-RIM-Push-ID” header. When using a PAP push, it is set using the “<push-message push-id="mypushID45">” parameter.