Interview Questions Part 7 - ASP.NET , Session , Caching

Interview Questions Part 7 - ASP.NET , Session , Caching

Question 1 :
How to make SQLServer session mode work ?

Answer 1 :
Please do below steps to make SQLServer session mode to work properly :

1. To use SQLServer mode, you must first be sure the ASP.NET session state database is installed on SQL Server. You can install the ASP.NET session state database using the Aspnet_regsql.exe tool.

2. To configure an ASP.NET application to use SQLServer mode, do the following in the application's Web.config file:

•Set the mode attribute of the sessionState element to SQLServer.
•Set the sqlConnectionString attribute to a connection string for your SQL Server database.

Question 2 :
What is SQL Server session mode in ASP.NET ?

Answer 2 :
SQLServer mode stores session state in a SQL Server database. This ensures that session state is preserved if the Web application is restarted and also makes session state available to multiple Web servers in a Web farm.

Question 3 :
How to make State server session mode work ?

Answer 3 :
Please do the below to make State Server session mode work :

1. To use StateServer mode, you must first be sure the ASP.NET state service is running on the server used for the session store. The ASP.NET state service is installed as a service when ASP.NET and the .NET Framework are installed. The ASP.Net state service is installed at the following location:
systemroot\Microsoft.NET\Framework\versionNumber\aspnet_state.exe

2. To configure an ASP.NET application to use StateServer mode, in the application's Web.config file do the following:
•Set the mode attribute of the sessionState element to StateServer.
•Set the stateConnectionString attribute to tcpip=serverName:42424.

3. To use StateServer mode in a Web farm, you must have the same encryption keys specified in the machineKey element of your Web configuration for all applications that are part of the Web farm.

What is StateServer Session mode in ASP.NETIn StateServer mode, session is stored on seperate computer . It stores session state in a separate process called the ASP.NET state service. This ensures that session state is preserved if the Web application is restarted and also makes session state available to multiple Web servers in a Web farm. This does not support Session_End event in global.asax

Question 4 :
What are different modes of storing ASP.NET Sessions ?

Answer 4 :

The different modes ASP.NET sessions are :

1. InProc
2. StateServer
3. SqlServer

Question 5 :
How to make Output Cache maintain seperate cahce entries for each browser ?

Answer 5 :
This is done using below directive :
VaryByCustom="browser"
<%@ OutputCache Duration="60" VaryByParam="None" VaryByCustom="browser" %>

Question 6 :
What are different types of caching ?

Answer 6 :
Types of caching are :

1. Page Output Caching
2. Page Fragment Caching
3. Data Caching

Question 7 :
Specify various options for Location attribute in OutputCache directive ?

Answer 7 :
If locaction attribute is specified, must be one of: Any, Client, Downstream, None, Server or ServerAndClient.

Question 8 :
Explain VaryByParam attribute in Output Cache ?

Answer 8 :
VaryByParam attribute is a required attribute in OutputCache directive. The names of the variables in the Request, which should result in, separate cache entries. "none" can be used to specify no variation. "*" can be used to create new cache entries for every different set of variables. Separate variables with ";".

Question 9 :
What is Cache Callback ?

Answer 9 :
Cache Callback provides an ability where by some actions can be performed when that item is removed from cache
CacheItemRemovedCallback example

System.Web.Caching.CacheItemRemovedCallback callback = new System.Web.Caching.CacheItemRemovedCallback (OnRemove);
Cache.Insert("key",myFile,null,
System.Web.Caching.Cache.NoAbsoluteExpiration,
TimeSpan.Zero,
System.Web.Caching.CacheItemPriority.Default, callback);
. . .

public static void OnRemove(string key,
object cacheItem,
System.Web.Caching.CacheItemRemovedReason reason)
{
AppendLog("The cached value with key '" + key +
"' was removed from the cache. Reason: " +
reason.ToString());
}

Question 10:
What are different types of cache dependencies ?

Answer 10:
Different type cache dependencies are :
File dependency
Time Based Expiration
Key dependency