Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84 SMI; site sun.uucp Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxt!houxm!ihnp4!ucbvax!decvax!decwrl!sun!rmarti From: rmarti@sun.uucp (Bob Marti) Newsgroups: net.database Subject: Re: IBM DB2 lacks record locking Message-ID: <2953@sun.uucp> Date: Thu, 31-Oct-85 16:25:52 EST Article-I.D.: sun.2953 Posted: Thu Oct 31 16:25:52 1985 Date-Received: Sun, 3-Nov-85 06:30:02 EST Distribution: net Organization: Sun Microsystems, Inc. Lines: 22 > >From Datamation, October 15 issue, page 13: > > "... Notably absent so far from [DB2] has been an effective record-level > locking feature that is critically important for performing simultaneous > updates to a single database." > > And we thought that only Unix DBMS's had problems with record locking :-) According to Chris Date's book "A Guide to DB2", DB2 does implicit record- level locking inside transactions. It turns out, however, that depending on some "lockable unit" system parameter, locking a record implies one of the following: - locking of the page where the record is physically stored - locking of the tablespace (a set of tables defined by the DBA) to which the record belongs The parameter can be set to PAGE, TABLESPACE, or ANY. In the latter case, DB2 decides for itself what it thinks is best for a given access plan. If you want to know more about locking in DB2 see chapter 11 in Date's DB2 book. --Bob Marti {decvax, ucbvax, seismo}!sun!rmarti