Re: odbc. reliable, a performance hit?

["John Taylor" <john.taylor@xxxxxxxxxxxxxxx>]

Steve,

 

I dropped ODBC in favour of OLE-DB some time ago, but they both use the same host servers on the 400, so results should be comparable.

 

Reliability has been very good at the 400 side, with mixed results on the PC's. If at all possible, spec the PC's for W2K & 128MB ram for best results. The W2K machines don't give me any trouble. It's the Win9x & NT boxes that tend to act up occasionally.

 

You didn't mention what size 720 you have (CPW) and how loaded it is, but your projected volume seems light so you'll probably be ok. In my experience, the 400 is not exactly a screamer with a client/server workload, so you'll want to pay attention to your techniques.

 

1) Use stored procedures as much as possible - especially considering your WAN layout.  

2) Prepared statements are best.

3) Instead of polling the print request file, consider the use of a data queue instead.

4) Don't open/close connections with each request.

 

HTH,

 

John Taylor

Canada

 

----- Original Message -----

From: Steve Richter

To: MIDRANGE-L@midrange.com

Sent: Friday, May 18, 2001 08:41

Subject: odbc. reliable, a performance hit?

Here is the question: How trouble free a connection and how as400 cpu efficient is odbc in a CA windows to As400 setting? In the appl in question,  there will be frequent polling of an as400 database ( once a minute ) from each of 7 remote win95 pc's, each in a diff branch location.

 

The comm topology is a central as400 model 720 (V4R4) and 7 remote offices ( branches ). Each branch has an avg of 10 CA win 5250 users. Each remote branch has a 64kb line and cisco router that connects to the comm cloud. The central 720 has a T1 connection to the cloud.

 

The odbc appl is a proposed win95 pc based imaging system. The odbc tranported data will be a print request file on the as400 that will be polled every minute by each branch located imaging station pc. A 2nd use of odbc will be a data rcd ( 100 bytes ) sent to the as400 when an image is scanned. About 400 images will be scanned each day.

 

Our comm lines can and will be upgraded, so the increase in comm traffic is not a concern.

 

Our first concern is that odbc will not ramp up very well.

 

Does odbc start and stop a new job on the as400 for each odbc request?

 

Any estimate on how much cpu is needed for each odbc rqs, rltv to say a custom written tcp/ip socket pgm? The current proposal will call for 7 x 60 = 420 odbc transactions per hour.

 

The 2nd concern is the reliability of odbc.

 

Do odbc jobs on the as400 hang from time to time, requiring as400 operator intervention?

 

Will the image system pc lock up from time to time because of odbc, especially when there are comm hits on the branch 64kb connection to the cloud?

 

Thanks a lot,

Steve Richter