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connection.close vs. connection.disposeI understand that the dispose method releases umnanaged resources, but I am
trying to understand what those resources are when it comes to a database connection. If my connection is closed, then what unmanaged resources does the connection object still have? There is no hard and fast rule that the Dispose method must release
unmanaged resources. All dispose means is IDisposable is implemented, and then it is upto the implementer what he wishes to do there. For all you know he could allocate even more resources in dispose :) (Bad implementation of course). Re: SqlConnection.Dispose - in addition to closing the connection, it also clears stateful nature of the SqlConnection instance, like connection string etc.Beneath this layer, in SqlConnection atleast, there is a connection pooling mechanism, which eventually holds actual physical database connections. Again, they aren't really unmanaged resources, but non .NET resources nonetheless. Lest I cause any confusion SqlClient has TDS parsing built into .NET code, so technically in this scenario - there wasn't any unmanaged resource. So in short, Dispose does not **have** to release unmanaged resources - and by convention it does cleanup. Thats exactly what SqlConnection.Dispse does - "clean up clean up everybody do your share" :-) - Sahil Malik [MVP] ADO.NET 2.0 book - http://codebetter.com/blogs/sahil.malik/archive/2005/05/13/63199.aspx __________________________________________________________ Show quote "Scott M." <s-mar@nospam.nospam> wrote in message news:u44cxcaPGHA.2176@TK2MSFTNGP10.phx.gbl... >I understand that the dispose method releases umnanaged resources, but I am >trying to understand what those resources are when it comes to a database >connection. If my connection is closed, then what unmanaged resources does >the connection object still have? > Thanks Sahil. I do understand the concept of IDisposable when it comes to
custom classes, but my question is strictly about the ADO.NET Connection class(es). I'm trying to understand from your message exactly what it is about a connection that would need to be released by using Dispose though. Are you saying that calling Dispose on a connection would remove it from the connection pool? And, what exactly do you mean by "the stateful nature of a connection string"? How can a connection string be stateful? As I pondered earlier, if I close my connection, how could the .NET connection object still use any DB resources? Thanks. Show quote "Sahil Malik [MVP C#]" <contactmethrumyblog@nospam.com> wrote in message news:O%23qZGpaPGHA.3272@tk2msftngp13.phx.gbl... > There is no hard and fast rule that the Dispose method must release > unmanaged resources. All dispose means is IDisposable is implemented, and > then it is upto the implementer what he wishes to do there. For all you > know he could allocate even more resources in dispose :) (Bad > implementation of course). > > Re: SqlConnection.Dispose - in addition to closing the connection, it also > clears stateful nature of the SqlConnection instance, like connection > string etc.Beneath this layer, in SqlConnection atleast, there is a > connection pooling mechanism, which eventually holds actual physical > database connections. Again, they aren't really unmanaged resources, but > non .NET resources nonetheless. Lest I cause any confusion SqlClient has > TDS parsing built into .NET code, so technically in this scenario - there > wasn't any unmanaged resource. > > So in short, Dispose does not **have** to release unmanaged resources - > and by convention it does cleanup. Thats exactly what SqlConnection.Dispse > does - "clean up clean up everybody do your share" :-) > > - Sahil Malik [MVP] > ADO.NET 2.0 book - > http://codebetter.com/blogs/sahil.malik/archive/2005/05/13/63199.aspx > __________________________________________________________ > > > > > "Scott M." <s-mar@nospam.nospam> wrote in message > news:u44cxcaPGHA.2176@TK2MSFTNGP10.phx.gbl... >>I understand that the dispose method releases umnanaged resources, but I >>am trying to understand what those resources are when it comes to a >>database connection. If my connection is closed, then what unmanaged >>resources does the connection object still have? >> > > Calling Dispose or Close marks the underlying physical connection as "Not in
use" - but doesn't really close it. A "Not in use" connection that isn't yet physically closed is thus available for pooling. Therefore - calling dispose would return a connection to the pool. Re: the stateful nature - the stateful nature is of the SqlConnection object. A "closed" SqlConnection can be reopened, but if you dispose it, you can't reopen it again. - Sahil Malik [MVP] ADO.NET 2.0 book - http://codebetter.com/blogs/sahil.malik/archive/2005/05/13/63199.aspx __________________________________________________________ Show quote "Scott M." <s-mar@nospam.nospam> wrote in message news:%23faRf$lPGHA.2300@TK2MSFTNGP15.phx.gbl... > Thanks Sahil. I do understand the concept of IDisposable when it comes to > custom classes, but my question is strictly about the ADO.NET Connection > class(es). > > I'm trying to understand from your message exactly what it is about a > connection that would need to be released by using Dispose though. Are > you saying that calling Dispose on a connection would remove it from the > connection pool? And, what exactly do you mean by "the stateful nature of > a connection string"? How can a connection string be stateful? As I > pondered earlier, if I close my connection, how could the .NET connection > object still use any DB resources? > > Thanks. > > "Sahil Malik [MVP C#]" <contactmethrumyblog@nospam.com> wrote in message > news:O%23qZGpaPGHA.3272@tk2msftngp13.phx.gbl... >> There is no hard and fast rule that the Dispose method must release >> unmanaged resources. All dispose means is IDisposable is implemented, and >> then it is upto the implementer what he wishes to do there. For all you >> know he could allocate even more resources in dispose :) (Bad >> implementation of course). >> >> Re: SqlConnection.Dispose - in addition to closing the connection, it >> also clears stateful nature of the SqlConnection instance, like >> connection string etc.Beneath this layer, in SqlConnection atleast, there >> is a connection pooling mechanism, which eventually holds actual physical >> database connections. Again, they aren't really unmanaged resources, but >> non .NET resources nonetheless. Lest I cause any confusion SqlClient has >> TDS parsing built into .NET code, so technically in this scenario - there >> wasn't any unmanaged resource. >> >> So in short, Dispose does not **have** to release unmanaged resources - >> and by convention it does cleanup. Thats exactly what >> SqlConnection.Dispse does - "clean up clean up everybody do your share" >> :-) >> >> - Sahil Malik [MVP] >> ADO.NET 2.0 book - >> http://codebetter.com/blogs/sahil.malik/archive/2005/05/13/63199.aspx >> __________________________________________________________ >> >> >> >> >> "Scott M." <s-mar@nospam.nospam> wrote in message >> news:u44cxcaPGHA.2176@TK2MSFTNGP10.phx.gbl... >>>I understand that the dispose method releases umnanaged resources, but I >>>am trying to understand what those resources are when it comes to a >>>database connection. If my connection is closed, then what unmanaged >>>resources does the connection object still have? >>> >> >> > > "Sahil Malik [MVP C#]" <contactmethrumyblog@nospam.com> wrote in message Then why bother calling Dispose on a connection object if it doesn't do any news:u4BUmgrPGHA.3432@TK2MSFTNGP12.phx.gbl... > Calling Dispose or Close marks the underlying physical connection as "Not > in use" - but doesn't really close it. A "Not in use" connection that > isn't yet physically closed is thus available for pooling. > > Therefore - calling dispose would return a connection to the pool. more to free up any more resources than Close does? > Isn't this true of all the connection objects as well?> Re: the stateful nature - the stateful nature is of the SqlConnection > object. A "closed" SqlConnection can be reopened, but if you dispose it, > you can't reopen it again. Thanks, Scott > Then why bother calling Dispose on a connection object if it doesn't do Call either Close or Dispose. Dispose will close an open connection for you, > any more to free up any more resources than Close does? or simply leave a closed conn as is. So as long as you've called Close, not calling Dispose is not a huge big deal. > Isn't this true of all the connection objects as well? MOSTLY :) The exact implementation depends on the .NET data provider though. So I can't say 100% confidently that nobody will ever break this rule. - Sahil Malik [MVP] ADO.NET 2.0 book - http://codebetter.com/blogs/sahil.malik/archive/2005/05/13/63199.aspx __________________________________________________________ Show quote "Scott M." <s-mar@nospam.nospam> wrote in message news:%23YAk$xxPGHA.2012@TK2MSFTNGP14.phx.gbl... > > "Sahil Malik [MVP C#]" <contactmethrumyblog@nospam.com> wrote in message > news:u4BUmgrPGHA.3432@TK2MSFTNGP12.phx.gbl... >> Calling Dispose or Close marks the underlying physical connection as "Not >> in use" - but doesn't really close it. A "Not in use" connection that >> isn't yet physically closed is thus available for pooling. >> >> Therefore - calling dispose would return a connection to the pool. > > Then why bother calling Dispose on a connection object if it doesn't do > any more to free up any more resources than Close does? > >> >> Re: the stateful nature - the stateful nature is of the SqlConnection >> object. A "closed" SqlConnection can be reopened, but if you dispose it, >> you can't reopen it again. > > Isn't this true of all the connection objects as well? > > Thanks, > > Scott > > > > Scott,
Pablo Castro writes this in my opinion the most simple in this newsgroup. http://groups.google.com/group/microsoft.public.dotnet.framework.adonet/msg/515919344c3c556a See as well his follow up message. Cor Show quote "Scott M." <s-mar@nospam.nospam> schreef in bericht news:%23faRf$lPGHA.2300@TK2MSFTNGP15.phx.gbl... > Thanks Sahil. I do understand the concept of IDisposable when it comes to > custom classes, but my question is strictly about the ADO.NET Connection > class(es). > > I'm trying to understand from your message exactly what it is about a > connection that would need to be released by using Dispose though. Are > you saying that calling Dispose on a connection would remove it from the > connection pool? And, what exactly do you mean by "the stateful nature of > a connection string"? How can a connection string be stateful? As I > pondered earlier, if I close my connection, how could the .NET connection > object still use any DB resources? > > Thanks. > > "Sahil Malik [MVP C#]" <contactmethrumyblog@nospam.com> wrote in message > news:O%23qZGpaPGHA.3272@tk2msftngp13.phx.gbl... >> There is no hard and fast rule that the Dispose method must release >> unmanaged resources. All dispose means is IDisposable is implemented, and >> then it is upto the implementer what he wishes to do there. For all you >> know he could allocate even more resources in dispose :) (Bad >> implementation of course). >> >> Re: SqlConnection.Dispose - in addition to closing the connection, it >> also clears stateful nature of the SqlConnection instance, like >> connection string etc.Beneath this layer, in SqlConnection atleast, there >> is a connection pooling mechanism, which eventually holds actual physical >> database connections. Again, they aren't really unmanaged resources, but >> non .NET resources nonetheless. Lest I cause any confusion SqlClient has >> TDS parsing built into .NET code, so technically in this scenario - there >> wasn't any unmanaged resource. >> >> So in short, Dispose does not **have** to release unmanaged resources - >> and by convention it does cleanup. Thats exactly what >> SqlConnection.Dispse does - "clean up clean up everybody do your share" >> :-) >> >> - Sahil Malik [MVP] >> ADO.NET 2.0 book - >> http://codebetter.com/blogs/sahil.malik/archive/2005/05/13/63199.aspx >> __________________________________________________________ >> >> >> >> >> "Scott M." <s-mar@nospam.nospam> wrote in message >> news:u44cxcaPGHA.2176@TK2MSFTNGP10.phx.gbl... >>>I understand that the dispose method releases umnanaged resources, but I >>>am trying to understand what those resources are when it comes to a >>>database connection. If my connection is closed, then what unmanaged >>>resources does the connection object still have? >>> >> >> > >  |
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