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Application performance decrease after deleting rowsHi, thank you for your help.
My VB.Net application contains a document that the user can refresh at any time. The refresh works fine and needs to loop through few datatables (hundreds of rows). This works fine until I delete some rows in two tables. Just after the delete if I do the refresh there is a huge memory allocated and the time needed to perform the refresh increase, the memory and time continue to increase on each refresh until I save and force garbage collector, after the GC the memory return to its normal size. I cheked using analysis tool and the rows that allocated huge memory are 'select' commands and I have no idea how to solve this problem (the only choice I have is to save and force GC). My dataset contains only about 20 datatables and few hundreds of rows. I guess there is a problem with the select after the delete it seems allocating huge memory. Thanks Nadir,
Every time there are a lot of messages about the taskmanager showing a hugh amount of memory. Be aware that the taskmanager is not correct giving memory, while on the other hand there is no need to be afraid as there is still enough memory. If you really want to investigate this for whatever reason, than use other tools. If you search the newsgroup dotnet general for that you find tons of messages about this. Cor Show quoteHide quote "NAdir" <NA***@discussions.microsoft.com> schreef in bericht news:C42CCAF3-08A0-42B5-AE70-CF32271DCDB1@microsoft.com... > Hi, thank you for your help. > My VB.Net application contains a document that the user can refresh at any > time. > The refresh works fine and needs to loop through few datatables (hundreds > of > rows). This works fine until I delete some rows in two tables. Just after > the > delete if I do the refresh there is a huge memory allocated and the time > needed to perform the refresh increase, the memory and time continue to > increase on each refresh until I save and force garbage collector, after > the > GC the memory return to its normal size. I cheked using analysis tool and > the > rows that allocated huge memory are 'select' commands and I have no idea > how > to solve this problem (the only choice I have is to save and force GC). My > dataset contains only about 20 datatables and few hundreds of rows. I > guess > there is a problem with the select after the delete it seems allocating > huge > memory. > Thanks On Nov 14, 5:53 am, "Cor Ligthert [MVP]" <notmyfirstn***@planet.nl> Cor, explain why you think task manager does not correctly reportwrote: > Nadir, > > Every time there are a lot of messages about the taskmanager showing a hugh > amount of memory. > > Be aware that the taskmanager is not correct giving memory, while on the > other hand there is no need to be afraid as there is still enough memory. > > If you really want to investigate this for whatever reason, than use other > tools. If you search the newsgroup dotnet general for that you find tons of > messages about this. memory usage. If you compare it to perfmon you'll see that it does. Perhaps the problem is that you do not know how to interpret the information displayed. or the question asked ...
the OP asked for possible solutions as to why the delete causes lags and increased memory usage when using a refresh ... not does the task manager report accurately ... and as far as I know ... the task managers works just fine for this!. Show quoteHide quote "Hugh Janus" <my-junk-acco***@hotmail.com> wrote in message news:1163494676.883968.266690@k70g2000cwa.googlegroups.com... > On Nov 14, 5:53 am, "Cor Ligthert [MVP]" <notmyfirstn***@planet.nl> > wrote: >> Nadir, >> >> Every time there are a lot of messages about the taskmanager showing a >> hugh >> amount of memory. >> >> Be aware that the taskmanager is not correct giving memory, while on the >> other hand there is no need to be afraid as there is still enough memory. >> >> If you really want to investigate this for whatever reason, than use >> other >> tools. If you search the newsgroup dotnet general for that you find tons >> of >> messages about this. > > Cor, explain why you think task manager does not correctly report > memory usage. If you compare it to perfmon you'll see that it does. > Perhaps the problem is that you do not know how to interpret the > information displayed. > There is a huge memory allocated after deleting rows and executing select
command, this is not normal because not only memory increase in subsequent refreshs but also the execution time increase. I checked with dev partner studio and found that I need to save my document (including the data set) then execute a GC.collect, this will bring the memory to its normal size. Executing CG.collect without prior save does not free memory. I suspect something with ADO .NET commands (what happens after executing delete rows then select). Show quoteHide quote "jeff" wrote: > or the question asked ... > > the OP asked for possible solutions as to why the delete causes lags and > increased memory usage when using a refresh ... not does the task manager > report accurately ... and as far as I know ... the task managers works just > fine for this!. > > > "Hugh Janus" <my-junk-acco***@hotmail.com> wrote in message > news:1163494676.883968.266690@k70g2000cwa.googlegroups.com... > > On Nov 14, 5:53 am, "Cor Ligthert [MVP]" <notmyfirstn***@planet.nl> > > wrote: > >> Nadir, > >> > >> Every time there are a lot of messages about the taskmanager showing a > >> hugh > >> amount of memory. > >> > >> Be aware that the taskmanager is not correct giving memory, while on the > >> other hand there is no need to be afraid as there is still enough memory. > >> > >> If you really want to investigate this for whatever reason, than use > >> other > >> tools. If you search the newsgroup dotnet general for that you find tons > >> of > >> messages about this. > > > > Cor, explain why you think task manager does not correctly report > > memory usage. If you compare it to perfmon you'll see that it does. > > Perhaps the problem is that you do not know how to interpret the > > information displayed. > > > > > You didn't mention which version of the framework you are
using. Check this article to see if it applies to you: FIX: The DataTable.Select method leaks memory from the index when you set some specific filter properties http://support.microsoft.com/kb/814470 Please post your code so that we can see what you are doing. Also, be aware that a datatable.select creates indexes as needed on the fly, and in .NET 2.0 it discards them after the call completes. If it needs to create indexes each time this will lead to slower performance and increased memory pressure. You may want to experiment with using a dataview instead. Thanks. -TP NAdir wrote: Show quoteHide quote > There is a huge memory allocated after deleting rows and executing > select command, this is not normal because not only memory increase > in subsequent refreshs but also the execution time increase. I > checked with dev partner studio and found that I need to save my > document (including the data set) then execute a GC.collect, this > will bring the memory to its normal size. Executing CG.collect > without prior save does not free memory. I suspect something with ADO > .NET commands (what happens after executing delete rows then select). > A pity Jeff, that it is a very known issue.
http://groups-beta.google.com/group/microsoft.public.dotnet.general/search?group=microsoft.public.dotnet.general&q=taskmanager&qt_g=Search+this+group Cor Show quoteHide quote "jeff" <jhersey at allnorth dottt com> schreef in bericht news:O4lpDBACHHA.4740@TK2MSFTNGP03.phx.gbl... > or the question asked ... > > the OP asked for possible solutions as to why the delete causes lags and > increased memory usage when using a refresh ... not does the task manager > report accurately ... and as far as I know ... the task managers works > just fine for this!. > > > "Hugh Janus" <my-junk-acco***@hotmail.com> wrote in message > news:1163494676.883968.266690@k70g2000cwa.googlegroups.com... >> On Nov 14, 5:53 am, "Cor Ligthert [MVP]" <notmyfirstn***@planet.nl> >> wrote: >>> Nadir, >>> >>> Every time there are a lot of messages about the taskmanager showing a >>> hugh >>> amount of memory. >>> >>> Be aware that the taskmanager is not correct giving memory, while on the >>> other hand there is no need to be afraid as there is still enough >>> memory. >>> >>> If you really want to investigate this for whatever reason, than use >>> other >>> tools. If you search the newsgroup dotnet general for that you find tons >>> of >>> messages about this. >> >> Cor, explain why you think task manager does not correctly report >> memory usage. If you compare it to perfmon you'll see that it does. >> Perhaps the problem is that you do not know how to interpret the >> information displayed. >> > > Many of the past posts regarding the task manager can
be misleading. People could get the false impression that task manager is "defective" or that the numbers it shows are "meaningless". It seems to me that things in the group have degraded to: 1. Person asks question regarding leak or possible high memory use/performance problem 2. Knee-jerk response of "Are you looking at Task Manager--forget that, it is wrong anyway. Besides, today's machines have tons of RAM, who cares?" This is not a good approach, because high memory use and/or leaks can cause performance problems and errors, even on machines with relatively large amounts of RAM. It is important to remember that an app may be used under terminal services, in which case sloppy memory/resource use issues are multiplied. Task manager displays a number of performance counters in an easy to use format. It displays the correct values of these performance counters, just as it did *long* before the first .NET application existed. What it doesn't show, and never has shown, is the amount of memory sharing that is occuring, how much of allocated memory has recently been touched by the process, the minimum working set that each process requires to perform well, how much of allocated memory is resident, etc. Task manager can be very helpful in detecting substantial memory leaks in .NET apps. For example, it is easy to create a winforms app with a leak and then use taskman to view an ever-increasing amount of private bytes (VM Size) allocated. It is not helpful for very small leaks, for example, 4 bytes every once in a while. I would strongly recommend that you and anyone else who would like to understand memory management under windows read chapter 7 of Windows Internals, by Mark Russinovich & David Solomon: http://www.amazon.com/Microsoft-Windows-Internals-Fourth-Pro-Developer/dp/0735619174/ -TP Cor Ligthert [MVP] wrote: Show quoteHide quote > A pity Jeff, that it is a very known issue. > > http://groups-beta.google.com/group/microsoft.public.dotnet.general/search?group=microsoft.public.dotnet.general&q=taskmanager&qt_g=Search+this+group > > Cor Thank you TP,
I could not publish my code because it is long and I use the select is multiple subroutines. Your suggestion about the problem with SELECT index maybe the right problem. I was thinking about a problem with the SELECT OR DELETE COMMANDS. I will experiement and publish the code. As I described in previous post: using devPartner software, the test shown a problem with the select after deleting datatable rows, the memory increase about 20 Mb and time of executing next selects increases, only after executing accpet changes on the dataset and GC.collect the memory and time become normal. Thanks again this was a big issue for my application performance. Show quoteHide quote "TP" wrote: > Many of the past posts regarding the task manager can > be misleading. People could get the false impression > that task manager is "defective" or that the numbers it > shows are "meaningless". > > It seems to me that things in the group have degraded to: > > 1. Person asks question regarding leak or possible > high memory use/performance problem > > 2. Knee-jerk response of "Are you looking at Task > Manager--forget that, it is wrong anyway. Besides, > today's machines have tons of RAM, who cares?" > > This is not a good approach, because high memory > use and/or leaks can cause performance problems and > errors, even on machines with relatively large amounts > of RAM. It is important to remember that an app > may be used under terminal services, in which case > sloppy memory/resource use issues are multiplied. > > Task manager displays a number of performance > counters in an easy to use format. It displays the correct > values of these performance counters, just as it did *long* > before the first .NET application existed. > > What it doesn't show, and never has shown, is the amount > of memory sharing that is occuring, how much of allocated > memory has recently been touched by the process, the > minimum working set that each process requires to perform > well, how much of allocated memory is resident, etc. > > Task manager can be very helpful in detecting substantial > memory leaks in .NET apps. For example, it is easy to > create a winforms app with a leak and then use taskman to > view an ever-increasing amount of private bytes (VM Size) > allocated. It is not helpful for very small leaks, for example, > 4 bytes every once in a while. > > I would strongly recommend that you and anyone else who > would like to understand memory management under windows > read chapter 7 of Windows Internals, by Mark Russinovich & > David Solomon: > > http://www.amazon.com/Microsoft-Windows-Internals-Fourth-Pro-Developer/dp/0735619174/ > > -TP > > Cor Ligthert [MVP] wrote: > > A pity Jeff, that it is a very known issue. > > > > http://groups-beta.google.com/group/microsoft.public.dotnet.general/search?group=microsoft.public.dotnet.general&q=taskmanager&qt_g=Search+this+group > > > > Cor > > 
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