Persistence

PPS maintains its objects in memory while it's running. It will, as required:

save its objects to persistent storage, either on demand while it's running, or at shutdown
restore its objects on startup, either immediately, or on first access (deferred loading)

Note:

PPS may be used to create objects that are rarely (or never) published or subscribed to, but that require persistence.
“Shutdown” means the orderly exit of the PPS server process. An orderly exit can be triggered by SIGTERM, SIGINT, or SIGQUIT. Since other signals (such as SIGKILL, SIGSEGV, and SIGABRT) don't result in an orderly exit, they don't constitute a “shutdown” for the purposes of persistence.