We have an ASP.NET app where every so often an error will take place then any query by the app to the appts table results in errors like this.

Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding. 9/18/2008 12:30:48 PMSystem.Data.SqlClient.SqlException: Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding. at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection) at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection) at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj) at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj) at System.Data.SqlClient.SqlDataReader.ReadInternal(Boolean setTimeout) at System.Data.SqlClient.SqlDataReader.Read() at SD.LLBLGen.Pro.ORMSupportClasses.DaoBase.ExecuteMultiRowRetrievalQuery(IRetrievalQuery queryToExecute, ITransaction containingTransaction, IEntityCollection collectionToFill, Boolean allowDuplicates, IEntityFields fieldsUsedForQuery, IFieldPersistenceInfo[] fieldPersistenceInfos) at SD.LLBLGen.Pro.ORMSupportClasses.DaoBase.PerformGetMultiAction(ITransaction containingTransaction, IEntityCollection collectionToFill, Int64 maxNumberOfItemsToReturn, ISortExpression sortClauses, IPredicate selectFilter, IRelationCollection relations, IPrefetchPath prefetchPathToUse, ExcludeIncludeFieldsList excludedIncludedFields, Int32 pageNumber, Int32 pageSize) at SD.LLBLGen.Pro.ORMSupportClasses.DaoBase.GetMulti(ITransaction containingTransaction, IEntityCollection collectionToFill, Int64 maxNumberOfItemsToReturn, ISortExpression sortClauses, IEntityFactory entityFactoryToUse, IPredicate selectFilter, IRelationCollection relations, IPrefetchPath prefetchPathToUse, ExcludeIncludeFieldsList excludedIncludedFields, Int32 pageNumber, Int32 pageSize) at SD.LLBLGen.Pro.ORMSupportClasses.EntityCollectionBase1.GetMulti(IPredicate selectFilter, Int64 maxNumberOfItemsToReturn, ISortExpression sortClauses, IRelationCollection relations, IPrefetchPath prefetchPathToUse, ExcludeIncludeFieldsList excludedIncludedFields, Int32 pageNumber, Int32 pageSize) at SD.LLBLGen.Pro.ORMSupportClasses.EntityCollectionBase1.GetMulti(IPredicate selectFilter, IRelationCollection relations) at EntityClasses.ApptTerpEntity.PastAppts() at Scheduler.EmailApptTimecards() at Scheduler.StartScheduler()

and

An exception was caught during the execution of a retrieval query: Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding.. Check InnerException, QueryExecuted and Parameters of this exception to examine the cause of this exception. 9/9/2008 11:05:36 AMSD.LLBLGen.Pro.ORMSupportClasses.ORMQueryExecutionException: An exception was caught during the execution of a retrieval query: Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding.. Check InnerException, QueryExecuted and Parameters of this exception to examine the cause of this exception. ---> System.Data.SqlClient.SqlException: Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding. at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection) at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection) at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj) at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj) at System.Data.SqlClient.SqlDataReader.ConsumeMetaData() at System.Data.SqlClient.SqlDataReader.get_MetaData() 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) at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, DbAsyncResult result) 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.System.Data.IDbCommand.ExecuteReader(CommandBehavior behavior) at SD.LLBLGen.Pro.ORMSupportClasses.RetrievalQuery.Execute(CommandBehavior behavior) --- End of inner exception stack trace --- at SD.LLBLGen.Pro.ORMSupportClasses.RetrievalQuery.Execute(CommandBehavior behavior) at SD.LLBLGen.Pro.ORMSupportClasses.DaoBase.ExecuteMultiRowRetrievalQuery(IRetrievalQuery queryToExecute, ITransaction containingTransaction, IEntityCollection collectionToFill, Boolean allowDuplicates, IEntityFields fieldsUsedForQuery, IFieldPersistenceInfo[] fieldPersistenceInfos) at SD.LLBLGen.Pro.ORMSupportClasses.DaoBase.PerformGetMultiAction(ITransaction containingTransaction, IEntityCollection collectionToFill, Int64 maxNumberOfItemsToReturn, ISortExpression sortClauses, IPredicate selectFilter, IRelationCollection relations, IPrefetchPath prefetchPathToUse, ExcludeIncludeFieldsList excludedIncludedFields, Int32 pageNumber, Int32 pageSize) at SD.LLBLGen.Pro.ORMSupportClasses.DaoBase.GetMulti(ITransaction containingTransaction, IEntityCollection collectionToFill, Int64 maxNumberOfItemsToReturn, ISortExpression sortClauses, IEntityFactory entityFactoryToUse, IPredicate selectFilter, IRelationCollection relations, IPrefetchPath prefetchPathToUse, ExcludeIncludeFieldsList excludedIncludedFields, Int32 pageNumber, Int32 pageSize) at SD.LLBLGen.Pro.ORMSupportClasses.EntityCollectionBase1.GetMulti(IPredicate selectFilter, Int64 maxNumberOfItemsToReturn, ISortExpression sortClauses, IRelationCollection relations, IPrefetchPath prefetchPathToUse, ExcludeIncludeFieldsList excludedIncludedFields, Int32 pageNumber, Int32 pageSize) at SD.LLBLGen.Pro.ORMSupportClasses.EntityCollectionBase1.GetMulti(IPredicate selectFilter, IRelationCollection relations) at EntityClasses.ApptTerpEntity.PastAppts() at Scheduler.EmailApptTimecards() at Scheduler.StartScheduler()

Direct SQL to the appt table also can't complete the select.

These issues persist until the SQL Server process is manually restarted (or the locks listed in sp_lock are manually killed).

We've had a hard time tracking down the exact root of this problem. We've done our best so that fetches are done before saves, however this still crops up from time to time.
We have think it could be related to the fact that a separate chron-job type thread accesses the same tables as the ASP.NET webapp does.

Although it would be nice to fix what's causing the deadlock (appears to be just a row in the table), the biggest concern is that the SQL server needs to be reset and that for whatever reason the deadlock isn't released whenever this conflict starts.

Seems like using the NOLOCK modifier might work, but we'd like to try and at least come up with a solution so that the table doesn't stay permanently locked.

Any ideas how to: 1. Track down what's exactly causing the lock 2. Prevent locks from being permanent and requiring SQL restart?

Also, we're on 2.5.7.906. Should we upgrade?

Please check the suggestions in this thread: http://www.llblgen.com/TinyForum/Messages.aspx?ThreadID=11367