i guess my question wasnt clear. What Im getting at is do other databases have wait interfaces? Is there architecture such that Physical I/Os are a serious concern. Far more than other bottlenecks. Or is this book just garbage... > > From: Daniel Fink <[EMAIL PROTECTED]> > Date: 2003/10/02 Thu PM 01:09:36 EDT > To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]> > Subject: Re: Physical I/O and databases other than oracle > > This is not an issue of answering the question, but pointing out that the question > is not correct. > > Why do databases exist (aside to make Larry money)? To 'permanently' store data. As > this storage must survive a system failure, we choose to place the data on a > non-volatile medium (disk, paper, stone tablets). In order to save and retrieve this > data, we need to perform some sort of physical action (write/read). Let's take the > telephone system as an example. If we need to look up a phone number, we open the > phone book and do a search for the right entry. This can be rather time consuming, > especially if we don't know the person's last name or business name. Let's assume we > do know the last name, we can get to the proper entry > fairly quickly, but it still takes some time. Once we have retrieved the information > into our memory, we can dial the phone fairly quickly. In this case, the bottleneck > is indeed physical i/o. Of course, if we get a busy signal, we can access our memory > to redial, completely bypassing the phone book. However, if we are using an old > rotary dial phone and we have to make a long distance call, it may take longer to > dial the phone than look up the number. > > The real question should be "What is the primary bottleneck in presenting data to > the user?" In my recent projects, I have found that the database is rarely the > bottleneck. I have seen bad code, cpu-starvation, spooling to RAID-5 devices, > cartesian products. > > Did I mention that I once got an A on an essay test because I argued that the > question asked was itself invalid? > > Dan > > Mladen Gogala wrote: > > > On Thu, 2003-10-02 at 11:44, Garry Gillies wrote: > > > > Im reading an academic book on databases and it states that Physical I/O > > > > > Eh? > > > What IS the primary bottleneck in tuning Oracle? > > > > Cache hit ratio. You tune the buffer cache hit ratio (BCHR) and your job > > is done. Database with 99.9% BCHR must be OK. > > > > Note: > > This message is for the named person's use only. It may contain confidential, > > proprietary or legally privileged information. No confidentiality or privilege is > > waived or lost by any mistransmission. If you receive this message in error, > > please immediately delete it and all copies of it from your system, destroy any > > hard copies of it and notify the sender. You must not, directly or indirectly, > > use, disclose, distribute, print, or copy any part of this message if you are not > > the intended recipient. Wang Trading LLC and any of its subsidiaries each reserve > > the right to monitor all e-mail communications through its networks. > > Any views expressed in this message are those of the individual sender, except > > where the message states otherwise and the sender is authorized to state them to > > be the views of any such entity. > > > > -- > > Please see the official ORACLE-L FAQ: http://www.orafaq.net > > -- > > Author: Mladen Gogala > > INET: [EMAIL PROTECTED] > > > > Fat City Network Services -- 858-538-5051 http://www.fatcity.com > > San Diego, California -- Mailing list and web hosting services > > --------------------------------------------------------------------- > > To REMOVE yourself from this mailing list, send an E-Mail message > > to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in > > the message BODY, include a line containing: UNSUB ORACLE-L > > (or the name of mailing list you want to be removed from). You may > > also send the HELP command for other information (like subscribing). > >
-- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: <[EMAIL PROTECTED] INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
