Search390.com Expert Question of the Week July 16, 2001 ===================================== SPONSORED BY: Postmaster Direct ===================================== GET THE INFO YOU WANT TODAY! What do YOU want in your e-mailbox? How about FREE info and offers about computers, networking, wireless devices, finance and lots more? Visit http://search390.techtarget.com/postmasterDirect/, choose the topics that interest you, and you'll get the e-mail you want. ===================================== Welcome to Search390's Expert Question of the Week newsletter. Remember, no question is too simple for Ask the Experts! If you have a 390-related question, send it to [EMAIL PROTECTED] Selected questions will be answered by our experts. This week's question was answered by Tom Moulder, search390's Database Management Expert. THIS WEEK'S QUESTION: Q: Is it always true that for very high volume data IMS gives better performance than DB2? What are the situations when we can think of moving from IMS to DB2 without degrading performance? Is housekeeping of a DB2 database (including CPU and storage cost) higher than that of an IMS database? A: You have asked this particular question from the aspect of performance and I want to honor that perspective, but I also want to put out the disclaimer that this is not the only perspective that people use in deciding what database to use for an application. The total cost of an application is important as well as the availability of an application. In both of these areas IBM has provided solid support for both of its flagship databases. So my first comment would be that anyone who has a very high volume or very high availability application should look to running that application on IMS or DB2 on the new zSeries computer from IBM. The only exception I would make to this general rule is if the application is very highly CPU intensive. If I were an IMS bigot, I could point to several large installations that are sustaining very high transaction rates using IMS, primarily Fast Path. One shop I know of attains processes 145 million transactions a day (24 hour period) which translates to a little less than 1700 transactions per second on a daily basis. They are always online, but the traffic is obviously not smooth over the 24 hour period, so transaction rates of well over 2000 per second for short periods of time are a reality. If I were a DB2 bigot, I could point to several large installations that have vast amounts of data in DB2 and process user requests in a timely manner. I know of one DB2 shop that has bursts of processing at 2500 transactions per second. I know of one large installation that uses batched data from other systems to update DB2 data bases that are used for reporting. They process 10 - 15 million updates a day and the updates we're talking about are not trivial updates. Now what I don't have is the hardware profile that sustains these transaction rates. In all of these I do know that the customers are using IBM mainframes coupled together in a sysplex with n way data sharing. My belief is, though I can't back this up with the facts at the current time, that the IMS systems sustain the rates they do with less resources in terms of CPU cycles and memory usage. However, there are many other factors, the primary one is the people cost of maintaining an application. Perhaps the reason you might consider a change from IMS to DB2 is the retiring IMS talent. DB2 programming talent is more available these days. Perhaps if I knew more about your system and application I could make more specific recommendations. But this should give you a general idea of what can be done with high volume IMS and DB2 applications today. ---------------------------- If you have a question for Tom, submit it here http://search390.techtarget.com/ateQuestion/0,289624,sid10_tax286336,00.html What are your thoughts on DB2 vs IMS? Agree with Tom Moulder, or have a completely different outlook on the above question? Share your thoughts on this week's expert Q&A with the rest of us in the Sound Off Discussion Forum. Speak your mind--we love hearing from you! To post your feedback now, go to: http://search390.discussions.techtarget.com/WebX?50@@.ee83ff9. While you're there, see if you can answer this question for search390 user"VSEESA"-- "Can anyone inform me of the future of VSE/ESA, all the print I read is for MVS,VM,LINUX. =========================== SHOW US THE MONEY! =========================== Ok, we meant to say show us the tip! Send us that great tip you have stored in that cranium of yours! 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