RE: Poll response data

[Rick H Wesson <wessorh@ar.com>]

Sheer,

On Wed, 27 Jun 2001, Sheer El-Showk wrote:


> To give a concrete example, I might use a cron job running every two hours
> to scan my registry database for queable records and then make entries in
> another database used by the queue server.  Even if my process finds no
> records in the registry database that need to be queued, it will still
> mark my queue database (in a header or special purpose record) every two
> hours to indicate that the queue represents the state of the registry up
> until this point in time (the time the last cron job was run).  Since this
> timestamp is then passed on to registrars with each poll request they
> know how recently the queue was synchronized with the canonical data
> source (the registry database) -- a useful piece of information in my
> opinion.  This presumes queue updates will be a batched process rather
> then some event-driven (pushed) system such as refreshing the queue in
> real-time as events occur at the registry.   Even in the later case
> however, it will be useful to know that the queue represents the state
> of the registry in real time.

From a client perspective, I'm sending a poll request to keep my
connections alive and don't care when the last time the queue was updated.

From an API perspective I register listeners that will be "called back" if
a queue has messages. If while I am keping a connection alive I learn of
messages I handle them, or tell something else it needs to handle them.

If you are keeping many sessions alive then you'll get tons of
notification that there are things inqueue that need somethings attention.
Having the last date the queue was updated, even if no updates were
applied, is uninteresting for me.

-rick