Re: Comparason between SE and On-Line DSA and/or OWS

"V.K.A. Aarts" <development@casavhv.nl> wrote: :We are an application software company for a local market using Informix SE :for some years now. Our customers want to upgrade to On-Line (on Unix) and :OWS (on NT) :Like the majority of us, we do not want to re-engineer our 4gl and NewEra :applications much, but we are aware of behavior changes between SE and the :other engines. : :QU: Has anyone made a comparison matrix between the above mentioned engines :(in a readable format) on subjects like: : :4GL code to be changed We run exactly the same 4GL source code on SE 5.x, SE 7.x, OnLine DSA and OWS 7.x on SCO Unix. For the one customer we still have on SE 5.x we maintain an old version of the 4GL compiler that we use solely for compiling code for this customer. The key issue with 4GL is that you need to use different compilers for 5.x (SE or Online) and 7.x of the engines. Although you could theoretically use the relay module and use the old compilers (4.x) for the 7.x engines as well you do not want to do that. The performance penalty is too large. There are some significant differences between the 4.x and 6.x versions for 4GL that makes it difficult to use both on the same source. Particularly if you use free on prepared statements and cursors as you should. If you haven't allready you should make all your customers upgrade to 7.x engines and you will have little problems with the different engines. There are some nasty locking differences between SE and OnLine that can hit you. If you lock a table in exclusive mode in SE no other user can read from it. Not so in Online. This is more or less well documented in the manuals. Basically I would write a set of test programs to see how locking and transactions in general worked in the different versions you want to use. :Performance issues We have used SE on a 2 GB database with about 10 users runing OLTP as well as large update jobs on an old 50MHz 486 with reasonable performance. Online would hardly run on that machine. When we upgraded that to a 90MHz Pentium some years ago we did some tests that showed SE to be faster than Online on a few large selects. That was however before we knew too much about tuning of Online. Overall Online (7.10) was on the order of 2 times faster than SE 5.x at the time. Later we have not found any significant performance gains from SE 7.x appart from a much better optimiser which have solved some significant problems for us, although at the cost of having to do a lot of update statistics commands beyond what the manual says is necessary (we had to do update statistics high on non indexed columns). Online in later versions have however gained in performance in some areas. :Tuning aspects Online is initially harder to tune. However it sounds like you have a fairly stable database (not much change from one customer to the next) with size within the same order of magnitude, and not particularly large (4 GB is small for Online). We have found that in such an environement you can learn relatively easy what you have to do and repeat that at every installation. It now isn't much more work to install Online at a site than SE and it will run for a long time with very little if any DBA type work. The only problem is that if something does crash it's much harder to get OnLine up and runing again than SE. We have however hardly had any crash. So far I have never had to use a backup tape for anything but testing at any customer site or on our own development site. Our databases have even survived when someone turned off the power on the machine while users used it. :Scalability With Online this isn't much of an issue until you pass at least 10 GB or perhaps more or have very many users (may be it starts to kick in at 50 or more, I don't realy know as I haven't tested too much). With SE you will hit problems much earlier than with Online although I have heard of multi GB databases on SE with 50 users. The key however is what these users do. With a lot of large update jobs Online is much faster. If all users do hardly anything but simple indexed queries and some small updates and inserts SE can do a lot. You should however be aware that SE isn't a prioritized product for Informix. All new developments goes into Online. :Multi-Tier solutions Both SE and Online can be used effetively for this. There is no real difference in their capabilities in this area appart from the performance and scalability issues. :I went through the www.iiug.org info and Tech.Notes from Informix but they :do not clarify were to watch out for. : :Our customer database sizes are aprox. 1 GB up to 4 GB and are in the OLTP :environment using client/server applications in a Windows 95 environment.. : :Thanks : :e-mail : development@casavhv.nl :homepage (in Dutch, sorry....) casavhv@casavhv.nl Found it at http://www.casavhv.nl As you do GIS and drawings/photo systems you would have a significant advantage from using Online. You could store drawings and photos in BLOBS in the database and make them more easily accessible in your applications. For GIS you might also want to look into the I-DS (Online's new name) Universal Data Option (new name for Informix Universal Server) with the GIS datablade from MapInfo (www.mapinfo.com I think). Lot's of nifty features that might prove usefull. The Universal Data Option now is "only" US$ 300 extra per user on top of I-DS so your customers might accept it (it used to be US$ 1000). I don't know if you can get it at this price on top of the I-DS Workgroup Edition or if you are required to start with the plain I-DS server which is something like 4 times as expensive per user. Ask your Informix representative. (Someone might be able to clarify this here in c.d.i. as well???) :Vincent Aarts e-mail : vaarts@club.tip.nl Nils.Myklebust@idg.no NM Data AS, P.O.Box 9090 Gronland, N-0133 Oslo, Norway My opinions are those of my company The Informix FAQ is at http://www.iiug.org