无法建立随机SQL连接问题

Question

Our code is simple

using (var context = dbNewsEntities.CreateContext())
{
            CheckClient(clientId, context);

            var articles = context.GetArticlesForRSS(clientId, 0, ArchiveStartDays, false);
}

Randomly we get sql connection issues. I used windbg to check the SqlConnection, and indeed there are 100 (the default) connections in the pool.

However, when I use the method described here to check those connections, they are all closed. (as the _innerConnection object is System.Data.ProviderBase.DbConnectionClosedNeverOpened, not some methods that we were doing).

What going to happen when there are 100 closed connections in the pool? I assume c# code will just pick one other than create one. Am I right?

Many Thanks

Answer 1

Sorry, now I realised that our code is not as simple as I put there.

Turned out that there was some code hidden in another function, which wasn't closed properly. If helps anyone, you can use:

SELECT 
  DBID, 
  DB_NAME(dbid) as DBName, 
  COUNT(dbid) as NumberOfConnections,
  loginame as LoginName
FROM
    sys.sysprocesses
WHERE 
  dbid > 0 
GROUP BY 
   dbid, loginame

To see how how many connections in database, if your live system's exception is not properly catched, Then in windbg, you can use

.foreach (ex {!dumpheap -type System.Data.EntityException -short}){.echo "********************************";!pe ${ex} }

This will print you the exceptions and stack traces you need.