Re: Application server approach to Informix 4GL -Reply

In article <4p7qeg$1at@cssun.mathcs.emory.edu>, Peter Tashkoff <TASHKOP@kiwi.co.nz> writes >>>> <Spetc@aol.com> 6/June/1996 10:49pm >>> >Is there any advantage to running all 4GL programs >on one server, while the >(Online 5.x or 7.x) database is on another? > >Does it give better performance? > > I would have thought that the 4Gl programs would be doing little processing as they just display the data to the screen and leave most of the data access to the engine. Whilst the user is viewing the screen the 4GL program is idle so I would have thought there would be litte difference. If the 4Gl program does a lot of processing I would guess that it fetches a lot fo data so the overhead of sending the data across the network would on average outway any performance gains. Of course if the network is very fast or the program does a lot of processing on not a lot of data then you may get a performance increase. Across a network the following data path occurs:- 1. Informix engine sends data to network driver 2. Network driver gets the CPU and sends data out to device driver for network card 3. Device driver gets data and send out across network. 4. 4GL machine netowkr card gets data. 5. Device driver for netowrk card gets data and passes it up to the network. driver. 6. Network driver sends data to 4Gl program, 5. 4Gl program gets CPU. 6. 4GL program processes data. Step 4 means that if something else has the CPU when the data arrives over the netowrk there is a dealy before the 4GL program "wakes up" and gets the data. ALso a heavy load on EITHER machine causes slowdown in the processing of data. Each machine only running either the 4Gl programs or the database engine there is a good chance that neither machine will be decicated to the Informix/the 4Gl programs. I'd almost always go for the single decicated machine approach. Cheers, -- David Williams