Browser sends multiple request 5 to 10 request in a second withoutuser action.

[Hiten]

Our application is created in C#, ASP.Net 2.0, SQL 2005; the session
is managed in SQL server with ASPState. We often file below exception

Error Details :

Exception of type 'System.Web.HttpException' was thrown.

Source : System.Web

Stack Information : at System.Web.HttpAsyncResult.End() at
System.Web.SessionState.SessionStateModule.EndAcquireState(IAsyncResult
ar) at
System.Web.HttpApplication.AsyncEventExecutionStep.OnAsyncEventCompletion(IAsyncResult
ar)

Inner Exception : System.Web.HttpException: Unable to connect to SQL
Server session database. ---> System.InvalidOperationException:
Timeout expired. The timeout period elapsed prior to obtaining a
connection from the pool. This may have occurred because all pooled
connections were in use and max pool size was reached. at
System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection
owningConnection) at
System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection
outerConnection, DbConnectionFactory connectionFactory) at
System.Data.SqlClient.SqlConnection.Open() at
System.Web.SessionState.SqlSessionStateStore.SqlStateConnection..ctor(SqlPartitionInfo
sqlPartitionInfo) --- End of inner exception stack trace --- at
System.Web.SessionState.SqlSessionStateStore.ThrowSqlConnectionException(SqlConnection
conn, Exception e) at
System.Web.SessionState.SqlSessionStateStore.SqlStateConnection..ctor(SqlPartitionInfo
sqlPartitionInfo) at
System.Web.SessionState.SqlSessionStateStore.GetConnection(String id,
Boolean& usePooling) at
System.Web.SessionState.SqlSessionStateStore.DoGet(HttpContext
context, String id, Boolean getExclusive, Boolean& locked, TimeSpan&
lockAge, Object& lockId, SessionStateActions& actionFlags) at
System.Web.SessionState.SqlSessionStateStore.GetItemExclusive(HttpContext
context, String id, Boolean& locked, TimeSpan& lockAge, Object&
lockId, SessionStateActions& actionFlags) at
System.Web.SessionState.SessionStateModule.GetSessionStateItem() at
System.Web.SessionState.SessionStateModule.PollLockedSessionCallback(Object
state)

Target Site : System.Object End()


The wondering thing here is these exceptions are just flooding in from
the cleint while they request the application via browser and time it
go on and on for 30 minutes, please do any one has any clue or faced
such issue in past, we were looking at the solution but not able to
find any.

Thanks in advance.
H Patel

 

[Jon Skeet [C# MVP]]

The wondering thing here is these exceptions are just flooding in from
the cleint while they request the application via browser and time it
go on and on for 30 minutes, please do any one has any clue or faced
such issue in past, we were looking at the solution but not able to
find any.

I guess the obvious question is: what was your database doing at the
time? Did you perhaps have connections that you hadn't closed properly
elsewhere in your code?

Jon

 

[Hiten]

I guess the obvious question is: what was your database doing at the
time? Did you perhaps have connections that you hadn't closed properly
elsewhere in your code?

Jon

Hi Jon,

we did check that but there is no such case we found, the thig here is
when e see the IIS web log, we find that there is n number od requsts
are comming in from client, and frequency is very high in a second say
20 request in one second.
and after some time when server cant handle such flooding request this
error occurs "Exception of type 'System.Web.HttpException' was
thrown."

Thats clear that requests are coming in from client side and thats the
reason of this error, the wondering thing is the concurrency is not
more than 5 thousand users, and the intresting part is flodding
request will come from only one session of the user which is not at
possible by human to send that mych requets to the server 20-30 in a
second for arround 30 minutes .....So the question is how browser will
do like this? because every time it is not comming from one user it is
comming from diffrent users, diffrent location and diffrent browsers
[IE,FF,Safari etc]

Please could you suggest what could be the possiblity from client
side?

Thanks