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Suppress finalize in dataset constructor???Does any body know or have a clue why the constructor of DataSet needs
GC.SuppressFinalize(this) call -- Regards, Alvin Bruney [Shameless Author Plug] The Microsoft Office Web Components Black Book with .NET available at www.lulu.com/owc _________________________ Hi Alvin,
That's because DataSet is derived from MarshalByValueComponent and this class implements Finalize method (which does nothing - it calls dispose, but its derived classes my need it). Since DataSet doesn't need a finalizer because it doesn't hold any unmanaged resources it doesn't need a finalization (which would occur since it implements finalizer) it simply calls SuppressFinalize and so it is taken off the finalization queue. -- Show quoteMiha Markic [MVP C#] - RightHand .NET consulting & development www.rthand.com SLODUG - Slovene Developer Users Group www.codezone-si.info "Alvin Bruney [ASP.NET MVP]" <www.lulu.com/owc> wrote in message news:ewFRrYnMFHA.1268@TK2MSFTNGP14.phx.gbl... > Does any body know or have a clue why the constructor of DataSet needs > GC.SuppressFinalize(this) call > > -- > Regards, > Alvin Bruney > [Shameless Author Plug] > The Microsoft Office Web Components Black Book with .NET > available at www.lulu.com/owc > _________________________ > > > Alvin,
This is really a question for the folks who architected the dataset but here are my thoughts - You *should* *must* dispose DataSets. Why? Because if you don't Dispose the dataset, then when the Garbage Collector runs and the DataSet is unreachable, instead of freeing the memory the DataSet is using the Collector will add the DataSet to the FReachable queue and promote it to a higher generation. And a dataset might occupy considerable memory. So why supress a finalizer? Because it doesn't do anything in Datasets. (Or anything that inherits from MarshalByValueComponent). Finalize in that class simply calls dispose(false) --- completely useless, so might as well supress it. Why such an implementation? Because Disposing a dataset, should not dispose underlying datatables (hey someone else might be using them). This logic is controlled inside the dispose(true) stuff. So what happens when you forget to call Dispose on a dataset? Well I guess it sticks around in memory until the GC gets to it. Given that it is a complex object, the entire object tree must be clean - and that might take a while, so go ahead and dispose datasets/datatables/data*.* whenever ur done using them. - Sahil Malik http://codebetter.com/blogs/sahil.malik/ Show quote "Alvin Bruney [ASP.NET MVP]" <www.lulu.com/owc> wrote in message news:ewFRrYnMFHA.1268@TK2MSFTNGP14.phx.gbl... > Does any body know or have a clue why the constructor of DataSet needs > GC.SuppressFinalize(this) call > > -- > Regards, > Alvin Bruney > [Shameless Author Plug] > The Microsoft Office Web Components Black Book with .NET > available at www.lulu.com/owc > _________________________ > > > Sahil,
I don't think you are right here. Dispose is primarly meant to free unmanaged resources and doesn't do much on managed resources. It normally doesn't matter whether you call or don't call Dispose on a instance that doesn't use unamanged resources - from the GC point of view. However, since DataSet implementes (or better inherits) IDisposable and you never know of future changes it is better to call it. But for now, one really doesn't need to call Dispose on DataSet (note that you actually should call it since it might act differently in a future upgrade). -- Show quoteMiha Markic [MVP C#] - RightHand .NET consulting & development www.rthand.com SLODUG - Slovene Developer Users Group www.codezone-si.info "Sahil Malik" <contactmethrumyblog@nospam.com> wrote in message news:u0TO843MFHA.1096@tk2msftngp13.phx.gbl... > Alvin, > > This is really a question for the folks who architected the dataset but > here are my thoughts - > > You *should* *must* dispose DataSets. Why? Because if you don't Dispose > the dataset, then when the Garbage Collector runs and the DataSet is > unreachable, instead of freeing the memory the DataSet is using the > Collector will add the DataSet to the FReachable queue and promote it to a > higher generation. And a dataset might occupy considerable memory. > > So why supress a finalizer? > Because it doesn't do anything in Datasets. (Or anything that inherits > from MarshalByValueComponent). Finalize in that class simply calls > dispose(false) --- completely useless, so might as well supress it. > > Why such an implementation? > Because Disposing a dataset, should not dispose underlying datatables (hey > someone else might be using them). This logic is controlled inside the > dispose(true) stuff. > > So what happens when you forget to call Dispose on a dataset? > Well I guess it sticks around in memory until the GC gets to it. Given > that it is a complex object, the entire object tree must be clean - and > that might take a while, so go ahead and dispose > datasets/datatables/data*.* whenever ur done using them. > > - Sahil Malik > http://codebetter.com/blogs/sahil.malik/ > > > > > "Alvin Bruney [ASP.NET MVP]" <www.lulu.com/owc> wrote in message > news:ewFRrYnMFHA.1268@TK2MSFTNGP14.phx.gbl... >> Does any body know or have a clue why the constructor of DataSet needs >> GC.SuppressFinalize(this) call >> >> -- >> Regards, >> Alvin Bruney >> [Shameless Author Plug] >> The Microsoft Office Web Components Black Book with .NET >> available at www.lulu.com/owc >> _________________________ >> >> >> > > Miha,
I don't think you are right here, When this would be true in a program language from Microsoft than they would be a very unstable vendor. That is not my expirience. > (note that you actually should call it since it might act differently in a This I have as well readed in some text from some blogs, newsgroup messages > future upgrade). > ect. I nowhere saw this text in an official way, while that should than have been in fat letters from the first day VB2002 was released on MSDN on the first page of the documentation and even protected by the IDE's. A program tool maker cannot change the outcomming from that tool, or he should deliver as Microsoft did with VB6 a migration tool with that. About the rest we agree of course. :-) Cor
Show quote
"Cor Ligthert" <notmyfirstn***@planet.nl> wrote in message Cor,news:eY8Ozl5MFHA.432@TK2MSFTNGP10.phx.gbl... > Miha, > > I don't think you are right here, > > When this would be true in a program language from Microsoft than they > would be a very unstable vendor. That is not my expirience. > >> (note that you actually should call it since it might act differently in >> a future upgrade). >> > > This I have as well readed in some text from some blogs, newsgroup > messages ect. > > I nowhere saw this text in an official way, while that should than have > been in fat letters from the first day VB2002 was released on MSDN on the > first page of the documentation and even protected by the IDE's. > > A program tool maker cannot change the outcomming from that tool, or he > should deliver as Microsoft did with VB6 a migration tool with that. MS recommendes to call Dispose when class implements it. Simple as that. Nowhere is stated that you don't need to call Dispose on DataSet. -- Miha Markic [MVP C#] - RightHand .NET consulting & development www.rthand.com SLODUG - Slovene Developer Users Group www.codezone-si.info Miha,
> MS recommendes to call Dispose when class implements it. Simple as that. What are in my opinion always messages from individuals, so show me one > Nowhere is stated that you don't need to call Dispose on DataSet. > where that is said in a non free way with statements as, "it does not hurt much to call it". Most statements does not hurt much to call. However referering now a time the always told statement when I tell that boxing does not hurt much. "When you do it 10000000 times in a loop it will cost time". What you tells would mean that you should every time use Dispose when you use one of the classes on the bellow page and even the classes which derives from those. http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlrfsystemcomponentmodelcomponentclasshierarchy.asp Therefore every time for a label, textbox, checkbox or whatever. What would than mean that your program would almost only exist from dispose statement. The implementation from IDisposable should do that. (This when dispose is not overloaded (as connection) or for reasons to get hugh amounts of memory/resources as bitmaps/pens free) a little bit earlier free. Just my thought, Cor "Cor Ligthert" <notmyfirstn***@planet.nl> wrote in message Yes. However, disposing is a required action while boxing/unboxing can be news:OgmF0BDNFHA.576@TK2MSFTNGP15.phx.gbl... > Miha, > >> MS recommendes to call Dispose when class implements it. Simple as that. >> Nowhere is stated that you don't need to call Dispose on DataSet. >> > What are in my opinion always messages from individuals, so show me one > where that is said in a non free way with statements as, "it does not hurt > much to call it". Most statements does not hurt much to call. However > referering now a time the always told statement when I tell that boxing > does not hurt much. "When you do it 10000000 times in a loop it will cost > time". avoided. > Sure.> What you tells would mean that you should every time use Dispose when you > use one of the classes on the bellow page and even the classes which > derives from those. > Sure.> http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlrfsystemcomponentmodelcomponentclasshierarchy.asp > > Therefore every time for a label, textbox, checkbox or whatever. > I really don't think you create and destroy IDisposable classes all the > What would than mean that your program would almost only exist from > dispose statement. time, do you? No. So, for example, what exactly do you think is going on in Form.Dispose method, more precisely, in components.Dispose() line? > Can you clarify this statement - it is not entirely clear to me.> The implementation from IDisposable should do that. (This when dispose is > not overloaded (as connection) or for reasons to get hugh amounts of > memory/resources as bitmaps/pens free) a little bit earlier free. -- Miha Markic [MVP C#] - RightHand .NET consulting & development www.rthand.com SLODUG - Slovene Developer Users Group www.codezone-si.info Miha,
> See the link therefore I showed it, almost every Net class derives from >> >> http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlrfsystemcomponentmodelcomponentclasshierarchy.asp >> >> What would than mean that your program would almost only exist from >> dispose statement. > > I really don't think you create and destroy IDisposable classes all the > time, do you? component and that means that every class you create from that has a dispose method. Which accoording to that crazy statement it does not hurts should be disposed. (That kind of statements in documentation stops me direct with reading. It shows for me that the author for not sure about what he is writing) > That is exactly what I mean and therefore there is in my opinion no need to > No. > So, for example, what exactly do you think is going on in Form.Dispose > method, more precisely, in components.Dispose() line? > call it yourself or there should be a time aspect. >> That is what I mean with what you told me about the form dispose method, >> The implementation from IDisposable should do that. (This when dispose >> is not overloaded (as connection) or for reasons to get hugh amounts of >> memory/resources as bitmaps/pens free) a little bit earlier free. > > Can you clarify this statement - it is not entirely clear to me. > which should be in every Idisposable class however is that in every RAD usable class. When it was not, than every RAD created programs would be garbage. You see not in any RAD created program an individual dispose line. Cor Miha,
What prevents me from releasing managed resources in dispose() ? And really what is managed .. is a SqlConnection object managed? - Sahil Malik http://codebetter.com/blogs/sahil.malik/ Show quote "Miha Markic [MVP C#]" <miha at rthand com> wrote in message news:Ol81HE4MFHA.580@TK2MSFTNGP15.phx.gbl... > Sahil, > > I don't think you are right here. > Dispose is primarly meant to free unmanaged resources and doesn't do much > on managed resources. > It normally doesn't matter whether you call or don't call Dispose on a > instance that doesn't use unamanged resources - from the GC point of view. > However, since DataSet implementes (or better inherits) IDisposable and > you never know of future changes it is better to call it. > But for now, one really doesn't need to call Dispose on DataSet (note that > you actually should call it since it might act differently in a future > upgrade). > > -- > Miha Markic [MVP C#] - RightHand .NET consulting & development > www.rthand.com > SLODUG - Slovene Developer Users Group www.codezone-si.info > > "Sahil Malik" <contactmethrumyblog@nospam.com> wrote in message > news:u0TO843MFHA.1096@tk2msftngp13.phx.gbl... >> Alvin, >> >> This is really a question for the folks who architected the dataset but >> here are my thoughts - >> >> You *should* *must* dispose DataSets. Why? Because if you don't Dispose >> the dataset, then when the Garbage Collector runs and the DataSet is >> unreachable, instead of freeing the memory the DataSet is using the >> Collector will add the DataSet to the FReachable queue and promote it to >> a higher generation. And a dataset might occupy considerable memory. >> >> So why supress a finalizer? >> Because it doesn't do anything in Datasets. (Or anything that inherits >> from MarshalByValueComponent). Finalize in that class simply calls >> dispose(false) --- completely useless, so might as well supress it. >> >> Why such an implementation? >> Because Disposing a dataset, should not dispose underlying datatables >> (hey someone else might be using them). This logic is controlled inside >> the dispose(true) stuff. >> >> So what happens when you forget to call Dispose on a dataset? >> Well I guess it sticks around in memory until the GC gets to it. Given >> that it is a complex object, the entire object tree must be clean - and >> that might take a while, so go ahead and dispose >> datasets/datatables/data*.* whenever ur done using them. >> >> - Sahil Malik >> http://codebetter.com/blogs/sahil.malik/ >> >> >> >> >> "Alvin Bruney [ASP.NET MVP]" <www.lulu.com/owc> wrote in message >> news:ewFRrYnMFHA.1268@TK2MSFTNGP14.phx.gbl... >>> Does any body know or have a clue why the constructor of DataSet needs >>> GC.SuppressFinalize(this) call >>> >>> -- >>> Regards, >>> Alvin Bruney >>> [Shameless Author Plug] >>> The Microsoft Office Web Components Black Book with .NET >>> available at www.lulu.com/owc >>> _________________________ >>> >>> >>> >> >> > > Hi Sahil,
"Sahil Malik" <contactmethrumyblog@nospam.com> wrote in message Nothing actually. But why would they (you mean references held by dataset?) news:eGyWO85MFHA.2384@tk2msftngp13.phx.gbl... > Miha, > > What prevents me from releasing managed resources in dispose() ? be released (you mean setting references to null/nothing?) in Dispose? It is enough if you set variable with reference to dataset to null/nothing and everything will go away - no sooner or later then if you explicitly release them (any reference that dataset holds) in dispose. > And really what is managed .. is a SqlConnection object managed? Yes, it is managed but it holds unmanaged resources thus should it be treated as an unmanaged resource in this context. -- Show quoteMiha Markic [MVP C#] - RightHand .NET consulting & development www.rthand.com SLODUG - Slovene Developer Users Group www.codezone-si.info > > - Sahil Malik > http://codebetter.com/blogs/sahil.malik/ > > > "Miha Markic [MVP C#]" <miha at rthand com> wrote in message > news:Ol81HE4MFHA.580@TK2MSFTNGP15.phx.gbl... >> Sahil, >> >> I don't think you are right here. >> Dispose is primarly meant to free unmanaged resources and doesn't do much >> on managed resources. >> It normally doesn't matter whether you call or don't call Dispose on a >> instance that doesn't use unamanged resources - from the GC point of >> view. >> However, since DataSet implementes (or better inherits) IDisposable and >> you never know of future changes it is better to call it. >> But for now, one really doesn't need to call Dispose on DataSet (note >> that you actually should call it since it might act differently in a >> future upgrade). >> >> -- >> Miha Markic [MVP C#] - RightHand .NET consulting & development >> www.rthand.com >> SLODUG - Slovene Developer Users Group www.codezone-si.info >> >> "Sahil Malik" <contactmethrumyblog@nospam.com> wrote in message >> news:u0TO843MFHA.1096@tk2msftngp13.phx.gbl... >>> Alvin, >>> >>> This is really a question for the folks who architected the dataset but >>> here are my thoughts - >>> >>> You *should* *must* dispose DataSets. Why? Because if you don't Dispose >>> the dataset, then when the Garbage Collector runs and the DataSet is >>> unreachable, instead of freeing the memory the DataSet is using the >>> Collector will add the DataSet to the FReachable queue and promote it to >>> a higher generation. And a dataset might occupy considerable memory. >>> >>> So why supress a finalizer? >>> Because it doesn't do anything in Datasets. (Or anything that inherits >>> from MarshalByValueComponent). Finalize in that class simply calls >>> dispose(false) --- completely useless, so might as well supress it. >>> >>> Why such an implementation? >>> Because Disposing a dataset, should not dispose underlying datatables >>> (hey someone else might be using them). This logic is controlled inside >>> the dispose(true) stuff. >>> >>> So what happens when you forget to call Dispose on a dataset? >>> Well I guess it sticks around in memory until the GC gets to it. Given >>> that it is a complex object, the entire object tree must be clean - and >>> that might take a while, so go ahead and dispose >>> datasets/datatables/data*.* whenever ur done using them. >>> >>> - Sahil Malik >>> http://codebetter.com/blogs/sahil.malik/ >>> >>> >>> >>> >>> "Alvin Bruney [ASP.NET MVP]" <www.lulu.com/owc> wrote in message >>> news:ewFRrYnMFHA.1268@TK2MSFTNGP14.phx.gbl... >>>> Does any body know or have a clue why the constructor of DataSet needs >>>> GC.SuppressFinalize(this) call >>>> >>>> -- >>>> Regards, >>>> Alvin Bruney >>>> [Shameless Author Plug] >>>> The Microsoft Office Web Components Black Book with .NET >>>> available at www.lulu.com/owc >>>> _________________________ >>>> >>>> >>>> >>> >>> >> >> > > You are right .. even managed resources can be set to "Nothing". Truly this
isn't much better than their falling out of scope - with one exception. By calling Dispose, they will be collected, by falling out of scope, they will be promoted by a generation by GC before being collected. So even on managed resources, setting stuff = nothing/null has some advantage, and thus should be done in Dispose for large objects - such as a dataset (Even though dataset.dispose won't call dispose in datatable .. hmm !!). I could be wrong, but these are just my feelings. Either way, hopefully someone else will express their views on the topic. - Sahil Malik http://codebetter.com/blogs/sahil.malik/ Show quote "Miha Markic [MVP C#]" <miha at rthand com> wrote in message news:ef%23GQB6MFHA.576@TK2MSFTNGP15.phx.gbl... > Hi Sahil, > > "Sahil Malik" <contactmethrumyblog@nospam.com> wrote in message > news:eGyWO85MFHA.2384@tk2msftngp13.phx.gbl... >> Miha, >> >> What prevents me from releasing managed resources in dispose() ? > > Nothing actually. But why would they (you mean references held by > dataset?) be released (you mean setting references to null/nothing?) in > Dispose? > It is enough if you set variable with reference to dataset to null/nothing > and everything will go away - no sooner or later then if you explicitly > release them (any reference that dataset holds) in dispose. > >> And really what is managed .. is a SqlConnection object managed? > > Yes, it is managed but it holds unmanaged resources thus should it be > treated as an unmanaged resource in this context. > > -- > Miha Markic [MVP C#] - RightHand .NET consulting & development > www.rthand.com > SLODUG - Slovene Developer Users Group www.codezone-si.info > >> >> - Sahil Malik >> http://codebetter.com/blogs/sahil.malik/ >> >> >> "Miha Markic [MVP C#]" <miha at rthand com> wrote in message >> news:Ol81HE4MFHA.580@TK2MSFTNGP15.phx.gbl... >>> Sahil, >>> >>> I don't think you are right here. >>> Dispose is primarly meant to free unmanaged resources and doesn't do >>> much on managed resources. >>> It normally doesn't matter whether you call or don't call Dispose on a >>> instance that doesn't use unamanged resources - from the GC point of >>> view. >>> However, since DataSet implementes (or better inherits) IDisposable and >>> you never know of future changes it is better to call it. >>> But for now, one really doesn't need to call Dispose on DataSet (note >>> that you actually should call it since it might act differently in a >>> future upgrade). >>> >>> -- >>> Miha Markic [MVP C#] - RightHand .NET consulting & development >>> www.rthand.com >>> SLODUG - Slovene Developer Users Group www.codezone-si.info >>> >>> "Sahil Malik" <contactmethrumyblog@nospam.com> wrote in message >>> news:u0TO843MFHA.1096@tk2msftngp13.phx.gbl... >>>> Alvin, >>>> >>>> This is really a question for the folks who architected the dataset but >>>> here are my thoughts - >>>> >>>> You *should* *must* dispose DataSets. Why? Because if you don't Dispose >>>> the dataset, then when the Garbage Collector runs and the DataSet is >>>> unreachable, instead of freeing the memory the DataSet is using the >>>> Collector will add the DataSet to the FReachable queue and promote it >>>> to a higher generation. And a dataset might occupy considerable memory. >>>> >>>> So why supress a finalizer? >>>> Because it doesn't do anything in Datasets. (Or anything that inherits >>>> from MarshalByValueComponent). Finalize in that class simply calls >>>> dispose(false) --- completely useless, so might as well supress it. >>>> >>>> Why such an implementation? >>>> Because Disposing a dataset, should not dispose underlying datatables >>>> (hey someone else might be using them). This logic is controlled inside >>>> the dispose(true) stuff. >>>> >>>> So what happens when you forget to call Dispose on a dataset? >>>> Well I guess it sticks around in memory until the GC gets to it. Given >>>> that it is a complex object, the entire object tree must be clean - and >>>> that might take a while, so go ahead and dispose >>>> datasets/datatables/data*.* whenever ur done using them. >>>> >>>> - Sahil Malik >>>> http://codebetter.com/blogs/sahil.malik/ >>>> >>>> >>>> >>>> >>>> "Alvin Bruney [ASP.NET MVP]" <www.lulu.com/owc> wrote in message >>>> news:ewFRrYnMFHA.1268@TK2MSFTNGP14.phx.gbl... >>>>> Does any body know or have a clue why the constructor of DataSet needs >>>>> GC.SuppressFinalize(this) call >>>>> >>>>> -- >>>>> Regards, >>>>> Alvin Bruney >>>>> [Shameless Author Plug] >>>>> The Microsoft Office Web Components Black Book with .NET >>>>> available at www.lulu.com/owc >>>>> _________________________ >>>>> >>>>> >>>>> >>>> >>>> >>> >>> >> >> > > "Sahil Malik" <contactmethrumyblog@nospam.com> wrote in message No, no. Dispose won't do a thing to managed resources. At best it might set news:%23PPWPK6MFHA.2252@TK2MSFTNGP15.phx.gbl... > You are right .. even managed resources can be set to "Nothing". Truly > this isn't much better than their falling out of scope - with one > exception. By calling Dispose, they will be collected, by falling out of > scope, they will be promoted by a generation by GC before being collected. to nothing references it holds - nothing else. You can't control collection of managed resources (you can force garbage collecton that will collect all collectable resources though). When there are no *live* references on the instance it is marked for collection - it doesn't matter whether this happens through dispose or by falling out of scope. > Ok, let's have an example here. You have a dataset with several tables and > So even on managed resources, setting stuff = nothing/null has some > advantage, and thus should be done in Dispose for large objects - such as > a dataset (Even though dataset.dispose won't call dispose in datatable .. > hmm !!). you hold a reference to the dataset but not to any instance dataset holds. When you release the reference to dataset there will be no more live references to dataset nor to instances dataset holds. Thus all object graph will be marked as collectable and will be collected when GC runs. It wouldn't make a difference if DataSet.Dispose releases references to DataTables it holds.. -- Show quoteMiha Markic [MVP C#] - RightHand .NET consulting & development www.rthand.com SLODUG - Slovene Developer Users Group www.codezone-si.info > > I could be wrong, but these are just my feelings. Either way, hopefully > someone else will express their views on the topic. > > - Sahil Malik > http://codebetter.com/blogs/sahil.malik/ > > > > "Miha Markic [MVP C#]" <miha at rthand com> wrote in message > news:ef%23GQB6MFHA.576@TK2MSFTNGP15.phx.gbl... >> Hi Sahil, >> >> "Sahil Malik" <contactmethrumyblog@nospam.com> wrote in message >> news:eGyWO85MFHA.2384@tk2msftngp13.phx.gbl... >>> Miha, >>> >>> What prevents me from releasing managed resources in dispose() ? >> >> Nothing actually. But why would they (you mean references held by >> dataset?) be released (you mean setting references to null/nothing?) in >> Dispose? >> It is enough if you set variable with reference to dataset to >> null/nothing and everything will go away - no sooner or later then if you >> explicitly release them (any reference that dataset holds) in dispose. >> >>> And really what is managed .. is a SqlConnection object managed? >> >> Yes, it is managed but it holds unmanaged resources thus should it be >> treated as an unmanaged resource in this context. >> >> -- >> Miha Markic [MVP C#] - RightHand .NET consulting & development >> www.rthand.com >> SLODUG - Slovene Developer Users Group www.codezone-si.info >> >>> >>> - Sahil Malik >>> http://codebetter.com/blogs/sahil.malik/ >>> >>> >>> "Miha Markic [MVP C#]" <miha at rthand com> wrote in message >>> news:Ol81HE4MFHA.580@TK2MSFTNGP15.phx.gbl... >>>> Sahil, >>>> >>>> I don't think you are right here. >>>> Dispose is primarly meant to free unmanaged resources and doesn't do >>>> much on managed resources. >>>> It normally doesn't matter whether you call or don't call Dispose on a >>>> instance that doesn't use unamanged resources - from the GC point of >>>> view. >>>> However, since DataSet implementes (or better inherits) IDisposable and >>>> you never know of future changes it is better to call it. >>>> But for now, one really doesn't need to call Dispose on DataSet (note >>>> that you actually should call it since it might act differently in a >>>> future upgrade). >>>> >>>> -- >>>> Miha Markic [MVP C#] - RightHand .NET consulting & development >>>> www.rthand.com >>>> SLODUG - Slovene Developer Users Group www.codezone-si.info >>>> >>>> "Sahil Malik" <contactmethrumyblog@nospam.com> wrote in message >>>> news:u0TO843MFHA.1096@tk2msftngp13.phx.gbl... >>>>> Alvin, >>>>> >>>>> This is really a question for the folks who architected the dataset >>>>> but here are my thoughts - >>>>> >>>>> You *should* *must* dispose DataSets. Why? Because if you don't >>>>> Dispose the dataset, then when the Garbage Collector runs and the >>>>> DataSet is unreachable, instead of freeing the memory the DataSet is >>>>> using the Collector will add the DataSet to the FReachable queue and >>>>> promote it to a higher generation. And a dataset might occupy >>>>> considerable memory. >>>>> >>>>> So why supress a finalizer? >>>>> Because it doesn't do anything in Datasets. (Or anything that inherits >>>>> from MarshalByValueComponent). Finalize in that class simply calls >>>>> dispose(false) --- completely useless, so might as well supress it. >>>>> >>>>> Why such an implementation? >>>>> Because Disposing a dataset, should not dispose underlying datatables >>>>> (hey someone else might be using them). This logic is controlled >>>>> inside the dispose(true) stuff. >>>>> >>>>> So what happens when you forget to call Dispose on a dataset? >>>>> Well I guess it sticks around in memory until the GC gets to it. Given >>>>> that it is a complex object, the entire object tree must be clean - >>>>> and that might take a while, so go ahead and dispose >>>>> datasets/datatables/data*.* whenever ur done using them. >>>>> >>>>> - Sahil Malik >>>>> http://codebetter.com/blogs/sahil.malik/ >>>>> >>>>> >>>>> >>>>> >>>>> "Alvin Bruney [ASP.NET MVP]" <www.lulu.com/owc> wrote in message >>>>> news:ewFRrYnMFHA.1268@TK2MSFTNGP14.phx.gbl... >>>>>> Does any body know or have a clue why the constructor of DataSet >>>>>> needs GC.SuppressFinalize(this) call >>>>>> >>>>>> -- >>>>>> Regards, >>>>>> Alvin Bruney >>>>>> [Shameless Author Plug] >>>>>> The Microsoft Office Web Components Black Book with .NET >>>>>> available at www.lulu.com/owc >>>>>> _________________________ >>>>>> >>>>>> >>>>>> >>>>> >>>>> >>>> >>>> >>> >>> >> >> > > Miha, if I were to write a class, and if I put managed resource cleanup in
Dispose, wouldn't that clean up managed resources if someone called a dispose on my class? Anyway, it is impossible for us to clearly determine what exactly does Dataset.dispose really do .. (cause we can't see the source code), so I guess this is a softie question. But one thing I would still insist on is "If you see a dispose, call it !!". And datasets do have dispose. But I do have a question here I'd your views on. "If a dataset falls out of scope, what will eventually get called on it, "Finalize" or "Dispose" ? " - Sahil Malik http://codebetter.com/blogs/sahil.malik/ Show quote "Miha Markic [MVP C#]" <miha at rthand com> wrote in message news:OEFfVP6MFHA.3228@TK2MSFTNGP12.phx.gbl... > > "Sahil Malik" <contactmethrumyblog@nospam.com> wrote in message > news:%23PPWPK6MFHA.2252@TK2MSFTNGP15.phx.gbl... > > You are right .. even managed resources can be set to "Nothing". Truly > > this isn't much better than their falling out of scope - with one > > exception. By calling Dispose, they will be collected, by falling out of > > scope, they will be promoted by a generation by GC before being collected. > > No, no. Dispose won't do a thing to managed resources. At best it might set > to nothing references it holds - nothing else. > You can't control collection of managed resources (you can force garbage > collecton that will collect all collectable resources though). > When there are no *live* references on the instance it is marked for > collection - it doesn't matter whether this happens through dispose or by > falling out of scope. > > > > So even on managed resources, setting stuff = nothing/null has some > > advantage, and thus should be done in Dispose for large objects - such as > > a dataset (Even though dataset.dispose won't call dispose in datatable ... > > hmm !!). > > Ok, let's have an example here. You have a dataset with several tables and > you hold a reference to the dataset but not to any instance dataset holds. > When you release the reference to dataset there will be no more live > references to dataset nor to instances dataset holds. Thus all object graph > will be marked as collectable and will be collected when GC runs. > It wouldn't make a difference if DataSet.Dispose releases references to > DataTables it holds.. > > -- > Miha Markic [MVP C#] - RightHand .NET consulting & development > www.rthand.com > SLODUG - Slovene Developer Users Group www.codezone-si.info > > > > I could be wrong, but these are just my feelings. Either way, hopefully > > someone else will express their views on the topic. > > > > - Sahil Malik > > http://codebetter.com/blogs/sahil.malik/ > > > > > > > > "Miha Markic [MVP C#]" <miha at rthand com> wrote in message > > news:ef%23GQB6MFHA.576@TK2MSFTNGP15.phx.gbl... > >> Hi Sahil, > >> > >> "Sahil Malik" <contactmethrumyblog@nospam.com> wrote in message > >> news:eGyWO85MFHA.2384@tk2msftngp13.phx.gbl... > >>> Miha, > >>> > >>> What prevents me from releasing managed resources in dispose() ? > >> > >> Nothing actually. But why would they (you mean references held by > >> dataset?) be released (you mean setting references to null/nothing?) in > >> Dispose? > >> It is enough if you set variable with reference to dataset to > >> null/nothing and everything will go away - no sooner or later then if you > >> explicitly release them (any reference that dataset holds) in dispose. > >> > >>> And really what is managed .. is a SqlConnection object managed? > >> > >> Yes, it is managed but it holds unmanaged resources thus should it be > >> treated as an unmanaged resource in this context. > >> > >> -- > >> Miha Markic [MVP C#] - RightHand .NET consulting & development > >> www.rthand.com > >> SLODUG - Slovene Developer Users Group www.codezone-si.info > >> > >>> > >>> - Sahil Malik > >>> http://codebetter.com/blogs/sahil.malik/ > >>> > >>> > >>> "Miha Markic [MVP C#]" <miha at rthand com> wrote in message > >>> news:Ol81HE4MFHA.580@TK2MSFTNGP15.phx.gbl... > >>>> Sahil, > >>>> > >>>> I don't think you are right here. > >>>> Dispose is primarly meant to free unmanaged resources and doesn't do > >>>> much on managed resources. > >>>> It normally doesn't matter whether you call or don't call Dispose on a > >>>> instance that doesn't use unamanged resources - from the GC point of > >>>> view. > >>>> However, since DataSet implementes (or better inherits) IDisposable and > >>>> you never know of future changes it is better to call it. > >>>> But for now, one really doesn't need to call Dispose on DataSet (note > >>>> that you actually should call it since it might act differently in a > >>>> future upgrade). > >>>> > >>>> -- > >>>> Miha Markic [MVP C#] - RightHand .NET consulting & development > >>>> www.rthand.com > >>>> SLODUG - Slovene Developer Users Group www.codezone-si.info > >>>> > >>>> "Sahil Malik" <contactmethrumyblog@nospam.com> wrote in message > >>>> news:u0TO843MFHA.1096@tk2msftngp13.phx.gbl... > >>>>> Alvin, > >>>>> > >>>>> This is really a question for the folks who architected the dataset > >>>>> but here are my thoughts - > >>>>> > >>>>> You *should* *must* dispose DataSets. Why? Because if you don't > >>>>> Dispose the dataset, then when the Garbage Collector runs and the > >>>>> DataSet is unreachable, instead of freeing the memory the DataSet is > >>>>> using the Collector will add the DataSet to the FReachable queue and > >>>>> promote it to a higher generation. And a dataset might occupy > >>>>> considerable memory. > >>>>> > >>>>> So why supress a finalizer? > >>>>> Because it doesn't do anything in Datasets. (Or anything that inherits > >>>>> from MarshalByValueComponent). Finalize in that class simply calls > >>>>> dispose(false) --- completely useless, so might as well supress it. > >>>>> > >>>>> Why such an implementation? > >>>>> Because Disposing a dataset, should not dispose underlying datatables > >>>>> (hey someone else might be using them). This logic is controlled > >>>>> inside the dispose(true) stuff. > >>>>> > >>>>> So what happens when you forget to call Dispose on a dataset? > >>>>> Well I guess it sticks around in memory until the GC gets to it. Given > >>>>> that it is a complex object, the entire object tree must be clean - > >>>>> and that might take a while, so go ahead and dispose > >>>>> datasets/datatables/data*.* whenever ur done using them. > >>>>> > >>>>> - Sahil Malik > >>>>> http://codebetter.com/blogs/sahil.malik/ > >>>>> > >>>>> > >>>>> > >>>>> > >>>>> "Alvin Bruney [ASP.NET MVP]" <www.lulu.com/owc> wrote in message > >>>>> news:ewFRrYnMFHA.1268@TK2MSFTNGP14.phx.gbl... > >>>>>> Does any body know or have a clue why the constructor of DataSet > >>>>>> needs GC.SuppressFinalize(this) call > >>>>>> > >>>>>> -- > >>>>>> Regards, > >>>>>> Alvin Bruney > >>>>>> [Shameless Author Plug] > >>>>>> The Microsoft Office Web Components Black Book with .NET > >>>>>> available at www.lulu.com/owc > >>>>>> _________________________ > >>>>>> > >>>>>> > >>>>>> > >>>>> > >>>>> > >>>> > >>>> > >>> > >>> > >> > >> > > > > > > Sahil and Miha,
There appears to be some confusion about Dispose. Hopefully I can clear it up a bit. -Dispose is primarily used to released unmanaged resources, although there is nothing wrong with releasing managed resources inside Dispose as well (Dataset is a good example of this). -If a class implements IDisposable, you *should* call Dispose as soon as you no longer need the object. >"If a dataset falls out of scope, what will eventually get called on it, "Finalize" or "Dispose" ? "Neither. Since DataSet's finalizer is suppressed, it's finalizer will not be called. Dispose must be called by user code. >You are right .. even managed resources can be set to "Nothing". Truly Setting instance fields to null (or Nothing) is valuable if the fields are this >isn't much better than their falling out of scope - with one exception. By large, and you plan on keeping the class instance alive. >calling Dispose, they will be collected, by falling out of scope, they No, Dispose does not make object be collected any sooner. Dispose is *just will >be promoted by a generation by GC before being collected. a method*, there's nothing special about it with respect to the GC. It's the code that's inside Dispose that releases resources. See also: http://blogs.msdn.com/clyon/archive/2004/09/21/232445.aspx http://blogs.msdn.com/clyon/archive/2004/09/23/233464.aspx Hope that helps! -Chris Hi Chris,
""Chris Lyon [MSFT]"" <cl***@online.microsoft.com> wrote in message news:W1thp%237MFHA.964@TK2MSFTNGXA03.phx.gbl... What exactly do you mean by releasing managed resources?> Sahil and Miha, > > There appears to be some confusion about Dispose. Hopefully I can clear > it > up a bit. > > -Dispose is primarily used to released unmanaged resources, although there > is nothing wrong with releasing managed resources inside Dispose as well > (Dataset is a good example of this). DataSet actually doesn't implement Dispose it just inherits it. > -If a class implements IDisposable, you *should* call Dispose as soon as True.> you no longer need the object. >>"If a dataset falls out of scope, what will eventually get called on it, Yup.> "Finalize" or "Dispose" ? " > > Neither. Since DataSet's finalizer is suppressed, it's finalizer will not > be called. Dispose must be called by user code. -- Miha Markic [MVP C#] - RightHand .NET consulting & development www.rthand.com SLODUG - Slovene Developer Users Group www.codezone-si.info Hi Miha
| > -Dispose is primarily used to released unmanaged resources, although Calling DataSet.Dispose will realease any resources used by there | > is nothing wrong with releasing managed resources inside Dispose as well | > (Dataset is a good example of this). | | What exactly do you mean by releasing managed resources? | DataSet actually doesn't implement Dispose it just inherits it. MarshalByValueComponent. Since the entire inheritence tree implements IDisposable, it usually means there are resources (managed or unmanaged) to release. These are rules of thumb. Of course there may be classes than implement Dispose when they don't really need resources released, but personally, I would call Dispose unless I had a good reason not to. Hope that helps -Chris ""Chris Lyon [MSFT]"" <cl***@online.microsoft.com> wrote in message
Show quote news:RTlhEwINFHA.1016@TK2MSFTNGXA03.phx.gbl... Just to make it clear. You really can't release managed resources. OTOH you > Hi Miha > > > | > -Dispose is primarily used to released unmanaged resources, although > there > | > is nothing wrong with releasing managed resources inside Dispose as > well > | > (Dataset is a good example of this). > | > | What exactly do you mean by releasing managed resources? > | DataSet actually doesn't implement Dispose it just inherits it. > > > Calling DataSet.Dispose will realease any resources used by > MarshalByValueComponent. Since the entire inheritence tree implements > IDisposable, it usually means there are resources (managed or unmanaged) > to > release. can release unmanaged ones. At best, you can null references to managed instances... For example, calling Form.Dispose will call Dispose of each contained component and in turn each component will delegate the call down the tree - ath the end all unmaanged resources should be free. > These are rules of thumb. Of course there may be classes than implement Sure, no doubt about that.> Dispose when they don't really need resources released, but personally, I > would call Dispose unless I had a good reason not to. -- Miha Markic [MVP C#] - RightHand .NET consulting & development www.rthand.com SLODUG - Slovene Developer Users Group www.codezone-si.info Thanks Chris, this clarifies a lot. Would you agree with this -
"There is a GC.SuppressFinalize on a dataset constructor because, finalize in a dataset doesn't really do anything." I agree, call Dispose first, ask questions later !!! - Sahil Malik http://codebetter.com/blogs/sahil.malik/ ""Chris Lyon [MSFT]"" <cl***@online.microsoft.com> wrote in message Show quote news:W1thp#7MFHA.964@TK2MSFTNGXA03.phx.gbl... > Sahil and Miha, > > There appears to be some confusion about Dispose. Hopefully I can clear it > up a bit. > > -Dispose is primarily used to released unmanaged resources, although there > is nothing wrong with releasing managed resources inside Dispose as well > (Dataset is a good example of this). > -If a class implements IDisposable, you *should* call Dispose as soon as > you no longer need the object. > > >"If a dataset falls out of scope, what will eventually get called on it, > "Finalize" or "Dispose" ? " > > Neither. Since DataSet's finalizer is suppressed, it's finalizer will not > be called. Dispose must be called by user code. > > >You are right .. even managed resources can be set to "Nothing". Truly > this > >isn't much better than their falling out of scope - with one exception. By > > Setting instance fields to null (or Nothing) is valuable if the fields are > large, and you plan on keeping the class instance alive. > > >calling Dispose, they will be collected, by falling out of scope, they > will > >be promoted by a generation by GC before being collected. > > No, Dispose does not make object be collected any sooner. Dispose is *just > a method*, there's nothing special about it with respect to the GC. It's > the code that's inside Dispose that releases resources. > > See also: > http://blogs.msdn.com/clyon/archive/2004/09/21/232445.aspx > http://blogs.msdn.com/clyon/archive/2004/09/23/233464.aspx > > Hope that helps! > -Chris > "Sahil Malik" <contactmethrumyblog@nospam.com> wrote in message Sure.news:umCFQ68MFHA.244@TK2MSFTNGP12.phx.gbl... > Thanks Chris, this clarifies a lot. Would you agree with this - > > "There is a GC.SuppressFinalize on a dataset constructor because, finalize > in a dataset doesn't really do anything." -- Miha Markic [MVP C#] - RightHand .NET consulting & development www.rthand.com SLODUG - Slovene Developer Users Group www.codezone-si.info Yes, I agree.
-Chris -------------------- Show quote | "Sahil Malik" <contactmethrumyblog@nospam.com> wrote in message | news:umCFQ68MFHA.244@TK2MSFTNGP12.phx.gbl... | > Thanks Chris, this clarifies a lot. Would you agree with this - | > | > "There is a GC.SuppressFinalize on a dataset constructor because, finalize | > in a dataset doesn't really do anything." | | Sure. | | -- | Miha Markic [MVP C#] - RightHand .NET consulting & development | www.rthand.com | SLODUG - Slovene Developer Users Group www.codezone-si.info | | | Chris,
> -If a class implements IDisposable, you *should* call Dispose as soon as This means for every label or whatever?> you no longer need the object. Amost every class implements IDisposable. I had always thought, that that was disposing using the components (and have to insert in this the unmanaged resources when those are used). \\\ Protected override void Dispose( bool disposing ) { if( disposing ) { if (components != null) { components.Dispose(); } } base.Dispose( disposing ); } /// Maybe can you clearify this for me? Cor Cor,
What do you think components.Dispose does? It loops through all components it has and it disposes them plus few minor things. -- Show quoteMiha Markic [MVP C#] - RightHand .NET consulting & development www.rthand.com SLODUG - Slovene Developer Users Group www.codezone-si.info "Cor Ligthert" <notmyfirstn***@planet.nl> wrote in message news:%235KUlGDNFHA.1396@TK2MSFTNGP10.phx.gbl... > Chris, > >> -If a class implements IDisposable, you *should* call Dispose as soon as >> you no longer need the object. > > This means for every label or whatever? > > Amost every class implements IDisposable. I had always thought, that that > was disposing using the components (and have to insert in this the > unmanaged resources when those are used). > \\\ > Protected override void Dispose( bool disposing ) > { > if( disposing ) > { > if (components != null) > { > components.Dispose(); > } > } > base.Dispose( disposing ); > } > /// > > Maybe can you clearify this for me? > > Cor > > Miha,
> Exactly and therefore there is in my opinion to need to call them > What do you think components.Dispose does? > It loops through all components it has and it disposes them plus few minor > things. > individually although that they have a dispose method. Now you are writting what I try to tell all the time in this thread. :-) CorThat's a good point Cor.
Let me rephrase then... If an object implements IDisposable, then you should ensure Dispose gets called, whether that means calling Dispose explicitly on that instance, or calling Dispose on a parent class which, in turn, will dispose its children. Hope that clears things up. -Chris -------------------- Show quote | | Miha, | | > | > What do you think components.Dispose does? | > It loops through all components it has and it disposes them plus few minor | > things. | > | Exactly and therefore there is in my opinion to need to call them | individually although that they have a dispose method. Now you are writting | what I try to tell all the time in this thread. | | :-) | | Cor | | |  |
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