Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!samsung!emory!stiatl!dmn From: dmn@stiatl.UUCP (Michael Nowacki) Newsgroups: comp.databases Subject: Re: Lock problem on Ingres, Please help. Keywords: Ingres Message-ID: <9072@stiatl.UUCP> Date: 20 Feb 90 21:36:50 GMT References: <673@modulex.dk> <1671@aurora.AthabascaU.CA> Reply-To: dmn@stiatl.UUCP (Michael Nowacki) Organization: Sales Technologies Inc., "The Prototype IS the Product..." Lines: 41 In article <1671@aurora.AthabascaU.CA> ron@augeas.AthabascaU.CA (Ron Haukenfrers) writes: >bni@modulex.dk (Bent Nielsen) writes: > > >>1) Is it correct that if I have a record length of 128 bytes >> and uses SELECT .... FOR UPDATE on one record then 4 records, >> one whole page (512 bytes on UNIX), will be locked? > >>2) I am familiar with Oracle SQL*Forms and Forms is using >> SELECT .... FOR UPDATE, when a user start to change a >> retrieved record and only this record will be locked. >> How can I implement this in Ingres if 1) is correct? > >Ingres has the concept of a page (2k). When it performs a lock, it locks >the whole page. i am interested in this issue, too. note that the lock request made by the user is, naturally, in terms of data. locking is provided in terms of disk space. at a recent ingres training class, i was told that when defining the original locking mechanism for ingres, a poll of then-current users was taken and few wanted to spend the system resources necessary for record level locking, so they implemented page-at-a-time locking. clearly, this is unacceptable for on-line applications with many users. i am planning to create an SIR about this, proposing the option of record level locking be implemented in ingres. note that this is not as large a request as it would have been in v5, because as of v6, all ports of ingres use ingres' implementaion of a lock manager; vms does not use vms's anymore. i mention it here because Ingres Corp (tm) does not appear to be pro-active in addressing this, so if users want it, they will have to ask for it. so, next time you're on the phone to customer support... -- Michael Nowacki gatech!stiatl!dmn Sales Technologies, Inc |\ /| 3399 Peachtree Rd, NE | \/ | Atlanta, GA (404) 841-4000 _|ike |_