-
Can EDA SOA eventing systems be fast
A lot of traditional eventing systems use C++ and are dubious about whether the Lego block style SOA can provide sufficient performance.
Again it boils down to design
WCF C# can process over 22000 small messeges per second on an average 2 year old quad server. http://msdn.microsoft.com/en-us/library/bb310550.aspx#wcfperform_topic4.
This is more than sufficient for most applications especially as with eventing systems you can add servers relatively simply , the algorithms which manage the propogation of subscriptions and the path are far more important . ( Distributed Event-Based Systems (Muhl , Fiege and Pietzuch) is a good book which covers the theory here...
-
EDAM -What is EDAM trying to do.
Just been working on EDAM ( my event driven architecture product) and wanted to note down and restate the long term goal (in addition to being a great eventing system).
The goal of EDAM is for people to be able to quickly add programs to the enterprise and to provide a fast event driven service to make this happen . Note i avoided the term framework as i want this to be usable with no dll linked though we will provide one later to make it even easier.
Remember when we used UNIX commands such as
cat file* | tr...
-
Eventing with and without Topics
While WS-Eventing has no support for Topics ( see last post) it is almost essential for efficient processing of messages if you have a large amount of subscriptions.
Consider the case of 10,000 Subscriptions for 10,000 Notification you are looking at 10^8 expensive xPath comparisons which will bring many servers down to its knees.
With EDA we can easily solve this problem ( compare to an overloaded DB) .
Lets say we have a Topicless share pricing feed something like
<Trades>
<Trade>
<Symbol>BHP</Symbol>
<Price>38.12</Price>
<Volume>10000</Volume>
<Exchange>ASX</Exchange>
</Trade>
</Trades>
Now WS-Eventing has a really nice feature in that subscriptions can force notifications to contain a header this header can...