Re: [xmlblaster] When does a topic get marked dead?

[David Kerry <xml at navahonetworks.com>]

Hi Michele,

Right now, we're using PubSub, all clients are connected before a publish
(losing the odd message is ok in our environment) and we are setting the
isVolatile() on all messages as well.

Shouldn't setting the volatile flag (as we're already doing) cause the
topics to get destroyed right away?

Limiting the number of topics isn't an option at this moment, but 
we'll probably start moving in that general direction going forward.

-- 
David Kerry

On Tue, Jun 08, 2004 at 05:25:38PM +0200, Michele Laghi wrote:
> hallo David,
> 
> As I see it you have several possibilities to solve your problem:
> first of all you should consider structuring your system in such a way 
> to get a limited amount of topics. Topic creation is timeconsuming and 
> should be kept to a minimum.
> 
> An alternative to the described approach would be to limit the lifetime 
> of the topics by reducing the destroyDelay of the topic or the lifetime 
> of the message. Read more about it in the following requirement:
> 
> http://www.xmlBlaster.org/xmlBlaster/doc/requirements/engine.message.lifecycle.html
> 
> If you are using a PtP pattern or a PubSub where all subscribers are 
> connected before any publishing then you could also consider using the 
> volatile flag in the publish qos.
> 
> As you see you have several options. Personally I would focus in trying 
> to limit the amount of topics.
> 
> 
> Saluti
> Michele
> 
> 
> David Kerry wrote:
> >Hello,
> >
> >We used to run xmlblaster v0.8 for quite some time, but have now
> >moved to v0.9.
> >
> >Everything is running fine, but we have a problem where xmlblaster
> >keeps running out of memory.
> >
> >We're using ram based storage for now (which we also used in the
> >v0.8 version).  This shouldn't be a problem as our traffic is
> >fairly low and all messages are volatile.
> >
> >The problem seems to be that a new topic gets created for every
> >message (when we publish we give a blank oid and let the server
> >fill it in).  The server then gets all plugged up with hundreds
> >or thousands of topics with no messages in them.
> >
> >We also see this behaviour when we use a database (Oracle) and
> >use it for all the topic/message storage.  The database tables
> >just keep getting bigger and bigger and never seem to shrink.
> >This causes a problem when we restart xmlblaster too because it goes
> >and loads in all the old entries from the database which can take
> >a long time (10-15 minutes).
> >
> >So I guess the question is - how can I force xmlblaster to check
> >for dead topics more often and clean them out?
> >
> 
> 
> -- 
> Michele Laghi
> mailto:laghi at swissinfo.org
> tel. +46 8 7492952 / mob. +46 70 4103964
> http://eclettic.tripod.com
> http://www.xmlBlaster.org