Thursday, 22 July 2010

Microsoft AppFabric (former Velocity code name)

I visited yesterday a "Introduction to AppFabric caching" session in Microsoft offices in Raanana. The session was held by AppFabric team developer - Shani Pozin. In this post I'd like to summarize the session for those who missed it and as a reminder for myself.

What is AppFabric Caching?

1. A successor of Velocity - a distributed cache service
2. A part of AppFabric - Microsoft vision of application server
3. A competitor to Memcached, NCache and others

What does it do?

It provides an abstract level of clustered distributed caching for serializable objects. Cached data is stored in different physical machines in order to enable High Availability. Each value is stored in two machines (if configured) Primary and Secondary. If Primary fails, then Secondary becomes Primary and another machine becomes Secondary. If Secondary fails, another machine is chosen to be secondary.

What are additional things it knows to do?

1. There is support for locking objects they are retrieved from cache. It is provided by GetAndLock and PutAndUnlock methods. It is important to mention, that if object is locked by one thread the other one will receive an exception and will not be blocked.
2. There is support for versioning cached objects. If a thread is trying to Put an older version of cached object, it will experience an exception, saying that it has to get the most updated version from cache.

What it does not do?

1. It does not persist cached data, which is different than Velocity worked. There were several options for data persistency: SQL Server, XML file, MDF file.
3. It does not provide Read-through and Write-behind features. It is promised, that they will be supported in future releases

If/when the presentation will be available on the web, I'll put a link here.

1 comment:

macaulifrachal said...

This web site is free for you to can} use however we might receive commission from the companies we characteristic on this site. Having selected your chosen on line casino, enter the site and spend a couple of minutes getting to grips with where issues are and what is on provide. Provide a sound e-mail handle and password, specify your nation of 1xbet residence, and set the desired forex in your account. E-wallets don’t reveal any private or banking knowledge when processing transactions – as an alternative, all of it's encrypted. Because of that, your deposits and withdrawals can’t be seized or blocked by third parties, and charges are predictable. Before signing up to as} a on line casino South Korea residents can access, you need to be aware of|to concentrate on|to pay attention to} a number of} key elements in your safety and peace of mind.