Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!wuarchive!mit-eddie!uw-beaver!zephyr.ens.tek.com!tektronix!sequent!dafuller From: dafuller@sequent.UUCP (David Fuller) Newsgroups: comp.databases Subject: Re: Any TUXEDO users here? Message-ID: <51386@sequent.UUCP> Date: 24 Jan 91 02:33:14 GMT References: <1991Jan11.164445.22320@oracle.com> <2374@edat.UUCP> <51164@sequent.UUCP> Reply-To: dafuller@sequent.UUCP (David Fuller) Distribution: comp.databases Organization: Sequent Computer Systems, Inc Lines: 35 >2-phase commit does not necessarily equate to "high availability" >to me, 2-phase commit has more to do with logical and geographic >distribution of data than additional reliability. (2 phase commit is >conventionally the ability of a distributed system to permit unilateral >abort of all concerned parties in the first phase and abort by only >the comitter in the second phase. See papers by Gray, et al for >details.) I guess I should edit myself here. The availability of 2 phase commit fosters 3 phase commit, whereas multiple commiters (with one dedicated master) handling more than one location for valid data. In essence, if the master cannot respond to the commit, its subordinates can arbitrate mastery and commit. This means that the DBMS will be OK if the master's gone down and the remaining interested parties will become more interested and organize them- selves to ensure the DBMS is available. But this requires advanced diagnosis of why the original commit failed. As we know, asking "why" tends to prove dicey for computers. The easiest failures to detect tend to be those least likely to occur... >-- >Dave Fuller >Sequent Computer Systems Think of this as the hyper-signature. >(708) 318-0050 (humans) It means all things to all people. >dafuller@sequent.com -- Dave Fuller Sequent Computer Systems Think of this as the hyper-signature. (708) 318-0050 (humans) It means all things to all people. dafuller@sequent.com