Consistently receiving "timeout period elapsed" from session state provider (Entity Framework) with SQL Azure

5
votes

Consistently i am receiving an error from the session state module in ASP.NET 4.5 Windows Azure Web Role which points to a SQL Azure database. The session state module is using the dbcontext. The exception incl. stacktrace is:

System.Data.EntityException: The underlying provider failed on Open. ---> System.Data.SqlClient.SqlException: Connection Timeout Expired.  The timeout period elapsed while attempting to consume the pre-login handshake acknowledgement.  This could be because the pre-login handshake failed or the server was unable to respond back in time.  The duration spent while attempting to connect to this server was - [Pre-Login] initialization=2; handshake=14993;  ---> System.ComponentModel.Win32Exception: The wait operation timed out
--- End of inner exception stack trace ---
at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)
at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose)
at System.Data.SqlClient.TdsParserStateObject.ReadSniError(TdsParserStateObject stateObj, UInt32 error)
at System.Data.SqlClient.TdsParserStateObject.ReadSniSyncOverAsync()
at System.Data.SqlClient.TdsParserStateObject.TryReadNetworkPacket()
at System.Data.SqlClient.TdsParser.ConsumePreLoginHandshake(Boolean encrypt, Boolean trustServerCert, Boolean integratedSecurity, Boolean& marsCapable)
at System.Data.SqlClient.TdsParser.Connect(ServerInfo serverInfo, SqlInternalConnectionTds connHandler, Boolean ignoreSniOpenTimeout, Int64 timerExpire, Boolean encrypt, Boolean trustServerCert, Boolean integratedSecurity, Boolean withFailover)
at System.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(ServerInfo serverInfo, String newPassword, SecureString newSecurePassword, Boolean ignoreSniOpenTimeout, TimeoutTimer timeout, Boolean withFailover)
at System.Data.SqlClient.SqlInternalConnectionTds.LoginNoFailover(ServerInfo serverInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString connectionOptions, SqlCredential credential, TimeoutTimer timeout)
at System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(TimeoutTimer timeout, SqlConnectionString connectionOptions, SqlCredential credential, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance)
at System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, SqlCredential credential, Object providerInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString userConnectionOptions)
at System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection, DbConnectionOptions userOptions)
at System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnectionPool pool, DbConnectionOptions options, DbConnectionPoolKey poolKey, DbConnectionOptions userOptions)
at System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnectionOptions userOptions)
at System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnectionOptions userOptions)
at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptions userOptions, DbConnectionInternal& connection)
at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal& connection)
at System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection owningConnection, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal& connection)
at System.Data.ProviderBase.DbConnectionClosed.TryOpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions)
at System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource`1 retry)
at System.Data.SqlClient.SqlConnection.Open()
at System.Data.EntityClient.EntityConnection.OpenStoreConnectionIf(Boolean openCondition, DbConnection storeConnectionToOpen, DbConnection originalConnection, String exceptionCode, String attemptedOperation, Boolean& closeStoreConnectionOnFailure)
--- End of inner exception stack trace ---
at System.Data.EntityClient.EntityConnection.OpenStoreConnectionIf(Boolean openCondition, DbConnection storeConnectionToOpen, DbConnection originalConnection, String exceptionCode, String attemptedOperation, Boolean& closeStoreConnectionOnFailure)
at System.Data.EntityClient.EntityConnection.Open()
at System.Data.Objects.ObjectContext.EnsureConnection()
at System.Data.Objects.ObjectQuery`1.GetResults(Nullable`1 forMergeOption)
at System.Data.Objects.ObjectQuery`1.System.Collections.Generic.IEnumerable<T>.GetEnumerator()
at System.Linq.Enumerable.SingleOrDefault[TSource](IEnumerable`1 source)
at System.Linq.Queryable.SingleOrDefault[TSource](IQueryable`1 source)
at System.Data.Entity.Internal.Linq.InternalSet`1.FindInStore(WrappedEntityKey key, String keyValuesParamName)
at System.Data.Entity.Internal.Linq.InternalSet`1.Find(Object[] keyValues)
at System.Web.Providers.DefaultSessionStateProvider.<>c__DisplayClass14.<SetAndReleaseItemExclusive>b__13()
at Microsoft.Practices.TransientFaultHandling.RetryPolicy.<>c__DisplayClass1.<ExecuteAction>b__0()
at Microsoft.Practices.TransientFaultHandling.RetryPolicy.ExecuteAction[TResult](Func`1 func)
at System.Web.SessionState.SessionStateModule.OnReleaseState(Object source, EventArgs eventArgs)
at System.Web.HttpApplication.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

Can you help me with this problem, please?

1
sql-serverazuretimeoutazure-sql-database
Did you ever find an answer to this? I seem to bet getting these as well but only occasionally. – dreza
Perhaps a retry-delay algorithm like: stackoverflow.com/questions/17215377/… – user3811037

1 Answers

0
votes

SQL Azure provides limited resources since each database lives in shared servers, it means if another client is running long queries in the same server that your are working, your application performance will decrease.

In my experience along two years working with SQL Azure, you need implement some retry-logic in your DAL in order your application avoid crashes with this kind of errors. Also, each database are limited up to 180 simultaneous connections, and another limitations (as size, administration, etc). Each connection after 180 will be rejected. You must carefully protect your application against DoS attacks!

There is no option (or configuration) available for standar users (as you or me) of SQL Azure to mitigate this limitations (even in Enterprise databases). In my company as DBA Team, we had open several tickets with Microsoft Ops team about a lot of issues related with high transactional loads, and the recommendations received from them talked about partitioning of data along several databases, indexing, retry policy and delayed retry policy (for connects / logins and queries) - setted at 5 retries; and for large SELECTs / INSERTs / UPDATEs / DELETEs segment the records in groups of 1000 up to 10,000 according to lenght of record.

After several years, we have migrated our data to IaaS (SQL Server hosted as vM on the Azure Cloud).

My recommendation for you, is be careful before choose SQL Azure, think about advantages and disadvantages!

Luck !!