Continuing the W2k thread ... I am just now offering some experience on the
issue since we put up our application, newly converted to 6.5++ Windows,
and operating on W2k server with W2k Terminal services and Metaframe, not
to mention RF-based scanners and two RF-based thin clients last
weekend. We now have a week's operation under our belt and some
observations can be made.
Generally performance is great. I have noted those who stated here that
connecting a second user to a database when the database resides on W2k
server will cause the response to degrade remarkably. Ours has not.
However, we had one condition that was problematic and the solution was simple.
The RF thin client runs a shipping module on a fork lift. It communicates
via TCP/IP over a Spectrum 24 RF network connected to our ethernet back to
the terminal server. The RF thin client runs a Metaframe client using the
ICA protocol.
The application running on this thin client had incredibly bad response
times. It was to the point of being unusable. We could run the app on a
desktop machine with a local database and the response was as
expected. Desktop to server was degraded, but not as badly as the RF
device. The solution to the response time problem was to examine the WHERE
clauses of SQL commands and discover that the conditions were not enclosed
in parenthesis. Putting parenthesis around the conditions, as many
(notably Bill Downall) have noted, forces R:Base to use indexes. Example:
SELECT .... WHERE blcode = .vblcode *(this is bad)
versus
SELECT .... WHERE (blcode = .vblcode) *(this is good)
This simple change made some response times drop from 9 - 13 seconds to
nearly instantaneous. For whatever reason, R:Base was deciding to not use
the indexes on these queries when the parens were absent.
The natural corollary to this is that you need to properly index your database.
I would encourage anyone noticing such degradation to check their code and
indexes and see if the above suggestion doesn't improve response times.
Emmitt Dove
Manager, DairyPak Business Systems
Blue Ridge Paper Products, Inc.
40 Lindeman Drive
Trumbull, CT 06611
(203) 673-2231
[EMAIL PROTECTED]
[EMAIL PROTECTED]
