Invalid operation. The connection is closed - sql-server

Question

We're using EntityFramework in a project that just went live. According to our logs, several users are suffering from "Invalid operation. The connection is closed", it happends about 50 times per day.
Exception looks like:
An error occurred while executing the command definition. See the inner exception for details. at System.Data.EntityClient.EntityCommandDefinition.ExecuteStoreCommands(EntityCommand entityCommand, CommandBehavior behavior)
at System.Data.Objects.Internal.ObjectQueryExecutionPlan.Execute[TResultType](ObjectContext context, ObjectParameterCollection parameterValues)
at System.Data.Objects.ObjectQuery`1.GetResults(Nullable`1 forMergeOption)
at System.Data.Objects.ObjectQuery`1.System.Collections.Generic.IEnumerable<T>.GetEnumerator()
at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
at xxxx.SelectResultToPeople(IEnumerable`1 result)
at xxxx.GetResult()
at DynamicModule.ns.Wrapped_IPeopleGetter_a853d13914444ca6ab0e016e035520c5.<People_DelegateImplementation>__0(IMethodInvocation inputs, GetNextInterceptionBehaviorDelegate getNext)
Invalid operation. The connection is closed. at System.Data.SqlClient.TdsParserStateObject.ReadSniSyncOverAsync()
at System.Data.SqlClient.TdsParserStateObject.TryReadNetworkPacket()
at System.Data.SqlClient.TdsParserStateObject.TryPrepareBuffer()
at System.Data.SqlClient.TdsParserStateObject.TryReadByte(Byte& value)
at System.Data.SqlClient.TdsParserStateObject.TryPeekByte(Byte& value)
at System.Data.SqlClient.SqlDataReader.TrySetMetaData(_SqlMetaDataSet metaData, Boolean moreInfo)
at System.Data.SqlClient.TdsParser.TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj, Boolean& dataReady)
at System.Data.SqlClient.SqlDataReader.TryCloseInternal(Boolean closeReader)
at System.Data.SqlClient.SqlDataReader.Close()
at System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString)
at System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async, Int32 timeout, Task& task, Boolean asyncWrite)
at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, TaskCompletionSource`1 completion, Int32 timeout, Task& task, Boolean asyncWrite)
at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method)
at System.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior behavior, String method)
at System.Data.SqlClient.SqlCommand.ExecuteDbDataReader(CommandBehavior behavior)
at System.Data.Common.DbCommand.ExecuteReader(CommandBehavior behavior)
at System.Data.EntityClient.EntityCommandDefinition.ExecuteStoreCommands(EntityCommand entityCommand, CommandBehavior behavior)
This exception is thrown on very specific pages, so it's not randomly distributed across the application. One of these pages makes a simple query to the database through Entity framework using a table function. The table function is named "GetPeopleNames" and our ObjectContext class is the one named "SiteEntities".
public class PeopleGetter : IPeopleGetter
{
public List<object> GetResult()
{
using (var siteEntities = new SiteEntities())
{
IQueryable<someResultEntity> result =
siteEntities.GetPeopleNames()
.SortBy("Name", "asc")
.Skip(20*query.CurrentPagingPosition)
.Take(20);
List<People> people = SelectResultToPeople(result)
return people;
}
}
private List<People> SelectResultToPeople(IQueryable<someResultEntity> result)
{
return result
.ToList()
.Select(x => new People { })
.ToList();
}
}
I can't see why it should have something to do with our fault, but i'd better mention that PeopleGetter class is resolved and created by Unity IoC container. The PeopleGetter is registered with a 'PerRquest' LifeTimeManager like this:
public class PerCallContextLifeTimeManager : HierarchicalLifetimeManager
{
private readonly string _key = string.Format("PerCallContextOrRequestLifeTimeManager_{0}", Guid.NewGuid());
public override object GetValue()
{
if (HttpContext.Current != null)
return GetFromHttpContext();
else
return base.GetValue();
}
private object GetFromHttpContext()
{
return HttpContext.Current.Items[_key];
}
public override void SetValue(object newValue)
{
if (HttpContext.Current != null)
SetInHttpContext(newValue);
else
base.SetValue(newValue);
}
private void SetInHttpContext(object newValue)
{
HttpContext.Current.Items.Add(_key, newValue);
}
public override void RemoveValue()
{
}
}
Any ideas why we're getting closed connections?
Thanks for you help!