Re: Optimizing for speed

From: W.G. Ryan eMVP (WilliamRyan_at_gmail.com)
Date: 10/04/04 

Date: Mon, 4 Oct 2004 09:50:36 -0400

What loop are you referencing? Are you using a DataReader and adding
everything through it in the while dataReader.Read()? Otherwise if you have
a DataTable, I'd just bind directly to it , or to a DataView and just
manimpulate the RowFilter without changing the bindings. 

-- 
W.G. Ryan, MVP
www.tibasolutions.com | www.devbuzz.com | www.knowdotnet.com
"Carlos Fernandez" <CarlosFernandez@discussions.microsoft.com> wrote in
message news:8E800305-CE97-4D20-8541-D98218498EAA@microsoft.com...
> Ryan,
>
> Thanks for your quick reply. I'm going to read through your links
carefully,
> but in the mean time, this is the typical situation in the application:
> Simple query (such as SELECT ID, CODE, STOCK FROM PRODUCTS) which returns
> 1100 records or so. The grid (which has room for like 10-11 rows) displays
ID
> and CODE, while I use STOCK to display a msgbox if the user clicks on a
> sold-out product.
>
> The query itself is fast, it's actually the loop that reads all the
records
> and takes the time. I'd like to inmediately display records and allow user
> interaction. My idea is to fetch the minimum number of records, display
them,
> and load the rest as the user moves through the grid with the scrollbar
but
> maybe there's another way.
>
> Thanks.
>
> "W.G. Ryan eMVP" wrote:
>
> > Carlos:
> >
> > There's a lot of 'ifs' here that could be affecting things.  The first
thing
> > I'd consider is how much data am I loading in the grid vs. what the user
> > needs.  If you're pulling out 1000 records but the user really only uses
10
> > most of the time, then query size would definitely be something to look
at.
> > Another thing is how many trips to the db are you making?  You have
chioce 1
> > of basically grabbing all the data and then storing the dataset as
static
> > property for instance which will front load processing time but save
time
> > over the long haul.  In general, the as you need it approach is my
leaning.
> >
> > As far as grids, you can't bind them to datareaders but if I just needed
a
> > value or two, I'd definitely look to using one where possible.  Indexes
are
> > another thing.  If you're really trying to squeeze out everythign that
you
> > can get, set the BeginLoadData method of any given datatable before you
> > start loading the data
> >
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlrfsystemdatadatatableclasstopic.asp
> > and then call EndLoadData
> >
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlrfsystemdatadatatableclasstopic.asp
> > ..I'd also shut of the EnforceConstraints property of the dataset if you
have
> > them
> >
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlrfSystemDataDataSetClassTopic.asp -
> > but don't leave them off of course, just set it back when you're done
with
> > the load.  Lots less events will get fired if you do this - but I can't
> > promise a huge performance increase because I don't know where the
> > bottleneck is on your app.  In some instances the diffferences are
stunning,
> > in others where this isn't the bottleneck the differences aren't worth
> > mentioning.
> >
> > Those are the first thigns that come to mind, but if you could elaborate
on
> > what you mean by " put
> >  them in rows and display the grid " that may provide some insight into
> > where the bottleneck is.  At least the nice part of CE is that you don't
> > have to worry about network congestion being the bottleneck ;-)
> > "Carlos Fernandez" <CarlosFernandez@discussions.microsoft.com> wrote in
> > message news:115783D8-1360-4CB3-91CE-A96A65EB9E05@microsoft.com...
> > > Due to time constraint, my last project (first one in VB.NET for us, I
> > might
> > > add) was done 'quickly' rather that right, meaning that it is 'good
> > enough'
> > > for the client but not the kind of project one feels proud of after
> > delivery.
> > >
> > > I happen to have some spare time on my hands which I plan to spend
> > > optimizing the whole thing just to improve myself.
> > >
> > > One of the things I know we didn't do right, simple as it is, is the
> > display
> > > of SQL.CE based data on grids. We just execute a query, grab all
records,
> > put
> > > them in rows and display the grid - slow as hell as you can easily
guess.
> > >
> > > Given you have the data in one or several tables, what is the fastest
way
> > to
> > > display it on a grid? Fastest as in 'fastest availabity to the user',
so
> > > retrieving records as needed by user interaction is fine. This is
actually
> > my
> > > first idea.
> > >
> > > Also, suppose you need one of the fields from the query not for
display
> > but
> > > for something else (i.e. you can't just feed the results to the
datagrid,
> > > even if it's possible to do so, which I'm not sure).
> > >
> > > All suggestions welcome, I have the time to try them all.
> > >
> >
> >
> >

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