Chapter 22. Paging
HornetQ transparently supports huge queues containing millions of messages while the server is running with limited memory.
In such a situation it is not possible to store all of the queues in memory at one time, so HornetQ transparently pages messages in and out of memory as they are needed. This allows massive queues with a low memory footprint.
HornetQ will start paging messages to disk when the size of all messages in memory for an address exceeds a configured maximum size.
By default, HornetQ does not page messages; this must be explicitly configured to activate it.
22.1. Page Files
Messages are stored per address on the file system. Each address has an individual folder where messages are stored in multiple files (page files). Each file will contain messages up to a max configured size (
page-size-bytes). When reading page-files all messages on the page-file are read, routed, and the file is deleted as soon as the messages are recovered.
