Re: Message Queuing

["Mary" <mary@xxxxxxxxxxxxxxx>]

Glenn,

Firstly, you _are_ aware of the existing xAP message logger, aren't you?
www.ascentium.co.uk/xap

Secondly, in xAPHomeVision, we ran across this problem because of the way
that
we map X10 devices onto xAP devices within BSC. (The X10 schema is rather
more
lightweight - the BSC encoding of X10 has to cope with some odd things
introduced by the way that HomeSeer represents virtual X10 devices.)

There, we introduced a message queue, with a "throttle" setting,
on the send
side to prevent xAP storms. It seemed more sensible to throttle xAP
_senders_
than to assume that any receiver could handle big runs.

Regards,

Mark and Mary

----- Original Message -----
From: "Sullivan, Glenn" <gsullivan@xxxxxxx>
To: <xAP_developer@xxxxxxx>
Sent: Monday, June 27, 2005 12:55 PM
Subject: [xAP_developer] Message Queuing


> In preparation for my next xAPplication, a one-wire connector service,
I
> needed a way to capture the data for use later on (i.e., producing a
> graph of temperature over time).  I didn't see the point in create a
> different database for each new application, and being a Microsoft
DBA,
> so I decided that a xAP MSDE Logger service was the next step.
>
> My first pass seemed to work OK, but when a "xAP Storm"
situation came
> up, where there was a steady stream of messages (xAP TV startup, with
> all 76 channels selected for reporting), it started dropping them.
>
> I think I figured out that, since it was taking a few milliseconds to
> log the last message into the database, my listener object stopped
> seeing messages for that amount of time.
>
> Since this was supposed to be a reliable database application, that
> wasn't going to fly...
>
> So, I wrapped the xAP Framework.Net listener object into a component
> that just listens and queues message, it it's own, non-blocking
thread.
> Then the main service app can read the queue at it's leisure.
>
> I'm just wondering how other people handle situations like this?  I
> figure it would affect any listening application that takes any time
at
> all to process the messages it is listening for.  Is there a feature
of
> xAPFramework.net that I'm not seeing that handles this?
>
> Glenn Sullivan, MCSE+I  MCDBA
> David Clark Company Inc.
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
>
>
>