How can I use caching to improve performance?

My scenario is : WebApp -> WCF Service -> EDMX -> Oracle DB

When I want to bind grid I fetch records from Oracle DB using EDMX i.e LINQ Query. But, this degrades performance as multiple layers take place between WebApp & Oracle DB. Can I use caching mechan开发者_JAVA技巧ism to improve the performance? But as far as I know cache is shared across the whole application. So, if I update cache other user might receive wrong information. Can we use caching per user? Or is there any other way to improve performance of the application?

Yes, you can definitely use caching techniques to improve performance. Generally speaking, caching is “application wide” (or it should be) and the same data is available to all users. But this really depends on your scenario and implementation. I don't see how adding the extra caching layer will degrade performance, it's a sound architecture and well worth the extra complexity.

ASP.NET Caching has a concept of "cache dependencies" which is a method to notify the caching mechanism that the underlying source has changed, and the cached data should be flushed and reloaded on the next request. ASP.NET has a built-in cache dependency for SQL Server, and a quick Google search revealed there’s probably also something you can use with Oracle.

As Jakob mentioned, application-wide caching is a great way to improve performance. Generally user context-agnostic data (eg reference data) can be cached at the application level.

You can also cache user context data by storing data in the user's session when they login. Then the data can be cached for the duration of that users session (HttpContext.Session) Session data can be configured to be stored in the web application process memory, in a state server (a special WCF service) or in a SQL Server database, depending on the architecture and infrastructure.