Path: utzoo!attcan!uunet!cs.utexas.edu!milano!cadillac!joy!speyer From: speyer@joy.cad.mcc.com (Bruce Speyer) Newsgroups: comp.databases Subject: Re: Extended RDB vs OODB Message-ID: <2177@cadillac.CAD.MCC.COM> Date: 10 Aug 89 22:26:20 GMT References: <3560052@wdl1.UUCP> <411@odi.ODI.COM> <458@cimshop.UUCP> Sender: news@cadillac.CAD.MCC.COM Reply-To: speyer%cad@MCC.COM (Bruce Speyer) Organization: MCC CAD Program, Austin, TX Lines: 34 In article <458@cimshop.UUCP> davidm@cimshop.UUCP (David Masterson) writes: >>On the other hand, many CAD/CAM and CASE developers have bypassed >>relational DBMSs due to performance problems. >> >Could you elaborate on the performance problems in this case? I mean is it >inherit in what the CAD/CAM or CASE developers are doing that leads to >performance problems with relational databases or is it just they chose the >wrong (aka. slow) relational database system? Perhaps there are things that >OODBMSs can be optimized to do better than a relational database system, but I >still think that a relational database can provide a strong foundation for an >object-oriented database. I'd like to hear why that can't be true. > >David Masterson >uunet!cimshop!davidm If an application must cross its process boundary in order to communicate with the database system it probably is at least two orders of magnitude too slow. That is why all of the C++ based OODBMS efforts are using the application memory heap for the cache. CAE applications (I don't know about CASE) are highly iterative and work around directed graphs. The cost of navigating or accessing attributes must be as few instructions as possible. I don't know of a relational system which can or could support this type of activity. The C++ based OODBMS systems are being developed to meet this criteria. Bruce Speyer / MCC CAD Program WORK: [512] 338-3668 3500 W. Balcones Center Dr., Austin, TX. 78759 ARPA: speyer@mcc.com Bruce Speyer / MCC CAD Program WORK: [512] 338-3668 3500 W. Balcones Center Dr., Austin, TX. 78759 ARPA: speyer@mcc.com