Re: Enhancing ADO Performance

From: Arnie Mauer (someone_at_microsoft.com)
Date: 06/24/04 

Date: Thu, 24 Jun 2004 10:23:51 -0400

"Dave" <dave@powerworld.com> wrote in message
news:40d9cd1a$1@newsgroups.borland.com...
> We are currently exploring the retrieval of data for our software from
> database sources by composing some small test applications (D7 Pro). We
> currently have applications constructed to retrieve data from ODBC
> tables using the native BDE connection and using the ADO connection. We
> worked with both because of the installation issues when using the BDE
> approach, such as the bundled BDE dll and potential registry access for
> BDE purposes during the application installation. It seems that ADO
> would avoid many of these BDE installation issues, but also seems to be
> somewhat slower in its data retrieval than the BDE application we've
> written to retrieve the same data from the same source.
>
> Does anybody have any suggestions on how to improve the performance of the
> ADO connection?
>
> Thanks
> Dave Savageau

We went through the same thing when porting from the BDE to ADO.

You can do a lot to tune up an ADO dataset or query via the properties. You
have to understand these. Check the help. For example, if looking up a lot
of data and hooking to a DB grid, use a server-side cursor (CursorLocation).
Only enough data will be brought over to the client to satisfy the grid. A
cient side cursor will read the entire result set over to the client.

If you're not hooked to a DB aware control and just have to read and process
the data (and a lot of it), set CursorType to ctOpenForwardOnly. ctKeyset
is required for hooking to a grid and is much slower because the grid has to
move forward AND backward in the result set.

If you're reading quite a bit of data, set the BlockReadSize property to
100-400. This improves performance quite a bit.

Also, as Del said, avoid the TADOTable like the plague.

HTH,

- Arnie

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