From: Jon Strayer Subject: Re: Informix vs. Sybase vs. Oracle vs. (gasp) MS SQL Server Date: 1999/01/01 Message-ID: <368D5BB0.4F2972A2@acm.org>#1/1 Content-Transfer-Encoding: 7bit References: <3351f3b1.8299223@gate.idg.no> <5ith88$14g@mew.corp.sgi.com> <3357D8D8.35C5@informix.com> <5jiij9$3bi@mew.corp.sgi.com> <34757DA2.31228676@informix.com> <34799917.5002172@surge.sfs.com> <347A8F21.825910FA@echonyc.com> <347B239E.CF0485C6@strengur.is> <347BCB78.1025@agd.nsw.gov.au> <347C3888.739683DD@NOSPAM.King.of.MyDomain.NOSPAM.Segel.com> <347D3DF3.54DE@agd.nsw.gov.au> <34849ab2.420767000@elf.bri.hp.com> <3482AEE8.7538BEB2@NOSPAM.King.of.MyDomain.NOSPAM.Segel.com> <3482E5A7.30EDA94@NOSPAM.King.of.MyDomain.NOSPAM.Segel.com> <34838DAD.7845@agd.nsw.gov.au> X-Accept-Language: en Content-Type: text/plain; charset=us-ascii Organization: IQuest Internet, Inc. Mime-Version: 1.0 Newsgroups: comp.databases.informix,comp.databases.sybase,comp.databases.oracle Anthony Mandic wrote: > > David Williams wrote: > > > Imagine 1 page with 2 rows one it. > > > > 1. Page level locking > > > > User A updates row 1 > > At the same time user B updates row 2. User B has to wait for > > User B to commit. > > You're forgetting latency. There's no way that you'd ever > get immediate concurrency as in your second scenario below. How about a multi-processor system with a multi-threaded db server? > > Lock granularity is still a problem. Why do UNIX kernels lock > > individual files and data structures rather than having one large > > kernel lock? Try reading > > Hey but they don't lock rows of text in a file do they? There is no such thing as a row of text in a UNIX file. They are nothing by streams of bytes.