[Helma-user] Request based Priority Queues

[Bernhard Froehlich]

Hi List.

Has anyone of you guys ever played with Request based Priority Queues [1]
using Helma? Common cases where you need that are mostly to reduce latency
for some Sessions (admins, ...) or URIs (webservices, ajax ...) under high
load.

There are various places where connections are pooled when using Apache
and mod_jk so an absolutely correct solution might need to modify mod_jk,
jetty and helma but i really want to avoid hacking all of them.


* AFAIK mod_jk only has the functionality to route specific URIs to
different workers but that seems a bit hackish to me because you would
need an mostly idle worker to get good results.

* On the Jetty side it would be possible to write an Filter [2] that
respects that priority but i am not sure how much that would help because
it heavily depends on the ratio of the mod_jk and jetty poolsize and seems
to need Jetty 7.0 which is experimental at this time.

In Helma the only thing that is left to do is to include the priority
somewhere in the cookies to help the Filter making the right decision.


Maybe someone with a better knowledge of the architecture could shed some
light on a good solution.

Kind regards,
Bernhard Fröhlich

[1]
http://weblogs.java.net/blog/jfarcand/archive/2007/06/improving_ajax_1.html
[2]
http://svn.codehaus.org/jetty/jetty/trunk/modules/extra/jetty-servlet/src/main/java/org/mortbay/servlet/QoSFilter.java