I’ve some SQL Server db connection from an App Service in Azure (with dedicated vnet) that at some point (moment X) start to become weird and stops every following connection for 1 hour or so.
Here’s the complete Exception I got for every new connection I start after the moment X:
{
"ClassName": "System.Data.Entity.Core.EntityException",
"Message": "The underlying provider failed on Open.",
"Data": null,
"InnerException": {
"Errors": [{
"Source": ".Net SqlClient Data Provider",
"Number": 5,
"State": 0,
"Class": 20,
"Server": "",
"Message": "A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server)",
"Procedure": null,
"LineNumber": 0
}
],
"ClientConnectionId": "00000000-0000-0000-0000-000000000000",
"ClassName": "System.Data.SqlClient.SqlException",
"Message": "A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server)",
"Data": {
"HelpLink.ProdName": "Microsoft SQL Server",
"HelpLink.EvtSrc": "MSSQLServer",
"HelpLink.EvtID": "5",
"HelpLink.BaseHelpUrl": "http://go.microsoft.com/fwlink",
"HelpLink.LinkId": "20476"
},
"InnerException": {
"NativeErrorCode": 5,
"ClassName": "System.ComponentModel.Win32Exception",
"Message": "Access is denied",
"Data": null,
"InnerException": null,
"HelpURL": null,
"StackTraceString": null,
"RemoteStackTraceString": null,
"RemoteStackIndex": 0,
"ExceptionMethod": null,
"HResult": -2147467259,
"Source": null,
"WatsonBuckets": null
},
"HelpURL": null,
"StackTraceString": " at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptions userOptions, DbConnectionInternal& connection)rn at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal& connection)rn at System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection owningConnection, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal oldConnection, DbConnectionInternal& connection)rn at System.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions)rn at System.Data.ProviderBase.DbConnectionClosed.TryOpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions)rn at System.Data.SqlClient.SqlConnection.TryOpenInner(TaskCompletionSource`1 retry)rn at System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource`1 retry)rn at System.Data.SqlClient.SqlConnection.Open()rn at System.Data.Entity.Infrastructure.Interception.DbConnectionDispatcher.<>c.<Open>b__13_0(DbConnection t, DbConnectionInterceptionContext c)rn at System.Data.Entity.Infrastructure.Interception.InternalDispatcher`1.Dispatch[TTarget,TInterceptionContext](TTarget target, Action`2 operation, TInterceptionContext interceptionContext, Action`3 executing, Action`3 executed)rn at System.Data.Entity.Infrastructure.Interception.DbConnectionDispatcher.Open(DbConnection connection, DbInterceptionContext interceptionContext)rn at System.Data.Entity.Core.EntityClient.EntityConnection.<Open>b__55_0()rn at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.<>c__DisplayClass2_0.<Execute>b__0()rn at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute[TResult](Func`1 operation)rn at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute(Action operation)rn at System.Data.Entity.Core.EntityClient.EntityConnection.Open()",
"RemoteStackTraceString": null,
"RemoteStackIndex": 0,
"ExceptionMethod": "8nTryGetConnectionnSystem.Data, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089nSystem.Data.ProviderBase.DbConnectionPoolnBoolean TryGetConnection(System.Data.Common.DbConnection, UInt32, Boolean, Boolean, System.Data.Common.DbConnectionOptions, System.Data.ProviderBase.DbConnectionInternal ByRef)",
"HResult": -2146232060,
"Source": ".Net SqlClient Data Provider",
"WatsonBuckets": null
},
"HelpURL": null,
"StackTraceString": " at System.Data.Entity.Core.EntityClient.EntityConnection.Open()rn at System.Data.Entity.Core.Objects.ObjectContext.EnsureConnection(Boolean shouldMonitorTransactions)rn at System.Data.Entity.Core.Objects.ObjectContext.ExecuteInTransaction[T](Func`1 func, IDbExecutionStrategy executionStrategy, Boolean startLocalTransaction, Boolean releaseConnectionOnSuccess)rn at System.Data.Entity.Core.Objects.ObjectQuery`1.<>c__DisplayClass41_0.<GetResults>b__0()rn at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute[TResult](Func`1 operation)rn at System.Data.Entity.Core.Objects.ObjectQuery`1.GetResults(Nullable`1 forMergeOption)rn at System.Data.Entity.Core.Objects.ObjectQuery`1.<System.Collections.Generic.IEnumerable<T>.GetEnumerator>b__31_0()rn at System.Data.Entity.Internal.LazyEnumerator`1.MoveNext()rn at System.Linq.Enumerable.FirstOrDefault[TSource](IEnumerable`1 source)rn at System.Data.Entity.Core.Objects.ELinq.ObjectQueryProvider.<>c__14`1.<GetElementFunction>b__14_1(IEnumerable`1 sequence)rn at System.Data.Entity.Core.Objects.ELinq.ObjectQueryProvider.ExecuteSingle[TResult](IEnumerable`1 query, Expression queryRoot)rn at System.Data.Entity.Core.Objects.ELinq.ObjectQueryProvider.System.Linq.IQueryProvider.Execute[TResult](Expression expression)rn at System.Data.Entity.Internal.Linq.DbQueryProvider.Execute[TResult](Expression expression)rn at System.Linq.Queryable.FirstOrDefault[TSource](IQueryable`1 source)rn at PRJAPI.Helpers.MyHelper.LoadData(String dataNumber) in C:\Users\source\repos\Project\MySolution\PRJ\PRJAPI\Helpers\MyHelper.cs:line 398",
"RemoteStackTraceString": null,
"RemoteStackIndex": 0,
"ExceptionMethod": "8nOpennEntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089nSystem.Data.Entity.Core.EntityClient.EntityConnectionnVoid Open()",
"HResult": -2146233087,
"Source": "EntityFramework",
"WatsonBuckets": null
}
For what I see (but maybe its a false positive) the firewall between the app and sql server, sometime it drop a single TCP package in return from SQL Server; not sure if this is relevant or not.
The fact is: I can accept one connection to be broken (I could set a polly and a retry), but it blocks the following connection for such an hour, this make no sense at all?
Also: during this “downtime”, I can access to remote DB using the same credentials (or the same App from another Server), so that “Access Denied” its very strange.
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