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Show 2 of 1lw nwti v<tt ioJJS of t hi s t hesis is to ex plore the funct iona li ty provided by various J>OSs for an existing Computer Aided Ccometric Des ign (C.AG D) sys tem, .A lpba_l [4], a s pline-based geometric modeler wr itten at the University of Utah. One of the ,2;11id ing facto rs in th is exploration will be performance . .Apa rt from perform ance, Lhc functionali ty p rovided by a POS is also importan t . However, many kinds of fun ct iona lities can be added in an appli cation on top of a POS, bu t poor pPrforma JJ<'<-' gPrwrally cannot bP improved at the app li cation level [7]. To m ea.s un~ Ll 1e performan ce of OODBMSs, tbere a lready exis ts the Cattell benchmark [18]. It con cent rates on areas wbere t he b igbest perforn1;:wce is required ('. g. , inserting obj ects, looking up obj ects, and fo ll owing connections between objects. It also assumes an "interactive" model for CAD appli cation s. l\lfod eling engi nef'ring OODBMS requ irements in a. generic way is very di fficu lt, since every <~pplicat i on has somewhat different requirements. For instan ce, f\ lpha_l proceeds in a "batcb" fas bion, i.e., all the data is loaded at t he start of the session and dumped ctL t he end of t be des ign sess ion . T hus, tbe resul ts from a generic benchmark may JJoL he S11ffi cienL. Tbe best eva.lmttion for a specific a,pp li cation can on ly Lw given l>y i mplf~ nwntin g t he appli cation itself' for different persistent object stores. The rest of t he thesis is organi zed as follows. Chapter 2 provides a general l>ackgrouud for various OODBMSs and POSs. Most current OODBMSs and POSs are co ve n~ d in tbis chapter. Chapter :3 Pxplains tbe exist ing .A lpha_l system. Chapter 4 describes tl1e modificat ions required to .Al pha_l storage management for Lh is st udy and t he various interfaces that have been developed for different POSs. C' IJ <tpLer ,l de;;tls with Llw res JJ! Ls obtain ed for vario11S t es ts and an a na lys is of t hese results. Finally, chapter 6 summarizes thi s work and di scusses fu t ure directions for fur t her research. The appendix contains statisti cs of some typical Alpha_l models. |
