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Access to database server blocks
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tj62 View Drop Down
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Joined: 21-May-2009
Location: Iceland
Posts: 81 		Post Options Post Options   Quote tj62 Quote  Post ReplyReply Direct Link To This Post Topic: Access to database server blocks
    Posted: 24-Mar-2011 at 5:17am
Hi,
We are using DevForce 6.0.9 and INformix Dynamic Server 11.7. 
First of all when version 6.0.7 came we where forced to do this to get it working:

TransactionSettings.Default = new TransactionSettings (System.Transactions.IsolationLevel.ReadCommitted, new TimeSpan(0, 1, 0), false);

If we set the last parameter to true all queries timed out. However the above workaround seemd to work untill we upgraded our database server from version 11.5 to 11.7. After that we get very misterious errors in between:

After running our Silverlight app. a few times (arbitrary) all queries start to hang  "for ever". The only way to get it running again is to restart the Informix database engine. It is not enough to restart the Visual Studio Development web server. However as this is true we do not see anything wrong with the databas server. Other applictions can logon via ODBC or native Informix to the databas server and we can query the database, update, insert just as usulay. It is only the Silvelight application that seems to somehow be totally blocked to enter. Investigating Informix sessions, log files etc. does not reveal anything abnormal.

Any idea what might be causing this?

Regards
  TJ
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tj62 View Drop Down
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Joined: 21-May-2009
Location: Iceland
Posts: 81 		Post Options Post Options   Quote tj62 Quote  Post ReplyReply Direct Link To This Post Posted: 24-Mar-2011 at 5:25am
One important thing I forgot. When this happens and I try to login the next time (without restarting the database server). This is the InnerException:
"The underlying provider failed on Open."

We are using IBM Data Provider beta, that has revealed to be rock stable until this problem started.
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DenisK View Drop Down
IdeaBlade
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Joined: 25-Aug-2010
Posts: 715 		Post Options Post Options   Quote DenisK Quote  Post ReplyReply Direct Link To This Post Posted: 24-Mar-2011 at 8:00pm
Hi tj62;

This sounds like something is holding on to the connection pool. Have you tried resetting them by calling System.Data.SqlClient.SqlConnection.ClearAllPools() ?
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tj62 View Drop Down
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Joined: 21-May-2009
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Posts: 81 		Post Options Post Options   Quote tj62 Quote  Post ReplyReply Direct Link To This Post Posted: 25-Mar-2011 at 8:43am
From the Microsoft documentation:
The System.Data.SqlClient namespace is the.NET Framework Data Provider for SQL Server.
So this is available for SQL Server only.
Even though we had such functionalety for the IBM data provider (it might exist, I don't know) then it would not help as, the connection is hung even if I restart Visual Studio and restart it again. The only way to get it running again is to restart the whole database server.
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DenisK View Drop Down
IdeaBlade
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Joined: 25-Aug-2010
Posts: 715 		Post Options Post Options   Quote DenisK Quote  Post ReplyReply Direct Link To This Post Posted: 25-Mar-2011 at 11:00am
Yes, I apologize. I meant to say the Informix equivalent of clearing the connection pool. As of this moment, that is the best advice I can give.

DevForce does no direct database access. Everything is through the Entity Framework. We open and close the connection to the Entity Framework with each query and save request. There have been no reports of this problem with other databases.

I suspect that the problem is between the Entity Framework provider and the database. Have you tried posting the questions to the Informix guys?
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