Oracle FAQ Your Portal to the Oracle Knowledge Grid
HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US
 

Home -> Community -> Mailing Lists -> Oracle-L -> RE: RE: LGWR's Writing Habits

RE: RE: LGWR's Writing Habits

From: Kimberly Smith <kimberly.smith_at_gmd.fujitsu.com>
Date: Thu, 14 Dec 2000 10:42:51 -0800
Message-Id: <10710.124598@fatcity.com>


Also, there are a few who do monitor the ODTUG lists and they actually respond fully stating they are Oracle personnel.

-----Original Message-----
From: Rachel Carmichael [mailto:carmichr_at_hotmail.com] Sent: Thursday, December 14, 2000 8:46 AM To: Multiple recipients of list ORACLE-L Subject: Re:RE: LGWR's Writing Habits

Dick,

There ARE people from Oracle on this list.... (they are not using their Oracle email addresses for obvious reasons)... and Steve said he had gotten an email from an Oracle employee with access to the source code. So we do have people here who can explain what Oracle is doing.. maybe not the rationale, but at least they can confirm that things are happening the way they do because they are coded to do so.

Rachel

>From: dgoulet_at_vicr.com
>To: "Rachel Carmichael" <carmichr_at_hotmail.com>, Multiple recipients
>of list ORACLE-L <ORACLE-L_at_fatcity.com>
>Subject: Re:RE: LGWR's Writing Habits
>Date: Thu, 14 Dec 2000 11:04:20 -0500
>
>I would also say that for this forum to have access to any of the source
>code
>would be rather futile. I mean, what are you going to do with it? You
>sure as
>heck can't incorporate any change you want into the DB kernel. What would
>be
>really great is to have someone at Oracle on this list who at least could
>explain the rational behind some of these "weird" behaviors that the kernel
>exhibits from time to time. Or at least let us know they don't understand
>as
>well.
>
>Dick Goulet
>
>____________________Reply Separator____________________
>Subject: RE: LGWR's Writing Habits
>Author: "Rachel Carmichael" <carmichr_at_hotmail.com>
>Date: 12/14/2000 7:36 AM
>
>Releasing the source code is grounds for immediate dismissal from Oracle
>and
>might in fact be grounds for legal action....
>
>I don't think anyone wants to take that risk, and I certainly don't want to
>be the cause of such actions by asking someone to do it.
>
>And Gaja didn't say he had access to the code, he said he had a friend who
>had access, so yes, he had to speculate before checking with his friend.
>
>
> >From: "Khedr, Waleed" <Waleed.Khedr_at_FMR.COM>
> >Reply-To: ORACLE-L_at_fatcity.com
> >To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
> >Subject: RE: LGWR's Writing Habits
> >Date: Wed, 13 Dec 2000 12:56:18 -0800
> >
> >
> >I do not understand if you have access to the source code then why do you
> >have to speculate about LGWR behavior?
> >
> >Also it could be a good idea to ask your friend in Oracle to post some of
> >the source code here in this list so that we can answer many of the
> >questions we have.
> >
> >
> >-----Original Message-----
> >Sent: Wednesday, December 13, 2000 12:45 PM
> >To: Multiple recipients of list ORACLE-L
> >
> >
> >Hello everyone,
> >
> >A couple of days ago I had posted a response to someone's query
> >about copy latches and in that discussion I had mentioned that
> >the 1/3 full event of the redo log buffer will really not 'kick
> >in' unless log_buffer is set to at least 1Mb. I must confess
> >that the number here is actually 3Mb and not 1Mb as posted
> >before. I apologize for that typo.
> >
> >However, the fact remains that from Oracle8, LGWR will not be
> >posted by the 1/3rd full event of the redo log buffer, unless
> >there are at least 1 Mb worth of redo entries in the log_buffer.
> >In my previous posting, I said that for this to occur the
> >log_buffer should be sized at least 1 Mb, but that number is
> >actually even higher - 3 Mb.
> >
> >And the rationale behind that stems from the events on which
> >LGWR writes to disk. They are as follows:
> >
> >1) Every 3 secs (independent of DBWR, yes this has been proven
> >to be true by testing and looking up the source code).
> >2) On a Commit.
> >3) When DBWR posts LGWR to write. (This is to make sure that the
> >redo entires are written before 'dirty' blocks are written to
> >disk).
> >4) On checkpoints.
> >5) When the log_buffer is 1/3rd full, but subject to the
> >following formula MAX(1 Mb., log_buffer/3), i.e., at least 1 Mb
> >of redo entries need to be there, for the 1/3 event to occur.
> >
> >Now let's think about this for a minute. Realistically the need
> >for the 1/3rd full event is not that critical, as events 1-4
> >will take care of getting the redo entries down to disk. And
> >this in no way will cause more 'log buffer space' waits than
> >what the system is already experiencing.
> >
> >To make doubly sure that I was not 'under the influence', I
> >called a very good friend of mine at Oracle, and had him check
> >the source code for 8.0.5, and he corroborated my claim. We are
> >doing some further digging, to determine whether 'all' or 'one'
> >of the redo copy latches are used to protect the buffer, while
> >'flushing' the entire contents of the log_buffer. There are 2
> >references to this (one mentioning 1 copy latch and the other
> >mentioning all copy latches) and we will get to the bottom of
> >that and I will then post our findings.
> >
> >End of technical stuff;
> >
> >********************************************************
> >Begin non-technical stuff;
> >
> >When I originally posted that the 1/3rd full event has changed
> >in functionality in Oracle8, it was termed as a 'ludicrous
> >suggestion'. Now, that comment may have gone 'just a bit too
> >far' to my personal comfort, as it was directed against me
> >'point blank'. I just could not hit the 'delete key' on that
> >one.
> >
> >In light of all the 'country of origin' and 'ethnic background'
> >stuff that has gone through our list in the past couple of days,
> >I humbly urge all of us to exercise some caution in our
> >communications. This is an forum where we cannot guage the
> >poster's feelings, hence we need to make sure that we are
> >sensitive to the reader's feelings.
> >
> >While it is absolutely OK to question the contents of a posting,
> >please do it in a manner that is 'amicable'. After all, we are
> >human beings first, aside of our ethnic, cultural, religious and
> >political backgrounds. Let's try to respect thatm core fact.
> >
> >When I met Jared approx. 3 years ago at an IOUG-A conference, we
> >talked about creating an Oracle listserv to 'share relevant and
> >accurate information'. I don't think Jared or any one of us,
> >would want this to become 'electronic battleground' for food
> >fights or to be a forum to 'force and assert one's technical or
> >personal ego'.
> >
> >This list today has a few thousand individuals from all corners
> >of the world, and all of us contribute to the best of our
> >abilities. Let's continue the great technical content exchange
> >that we have had and let's do that with 'respect for the
> >reader'. Thanks for your patience, tolerance and technical
> >prowess.
> >
> >End non-technical stuff;
> >
> >********************************************************
> >
> >Seasons Greetings,
> >
> >Gaja
> >
> >
> >=====
> >Gaja Krishna Vaidyanatha
> >Director, Storage Management Products, Quest Software Inc.
> >Office : (972)-304-1170, E-mail : gaja_at_quest.com
> >
> >Author:Oracle Performance Tuning 101 by Osborne McGraw-Hill
> >"Opinions and views expressed are my own and not of Quest"
> >
> >__________________________________________________
> >Do You Yahoo!?
> >Yahoo! Shopping - Thousands of Stores. Millions of Products.
> >http://shopping.yahoo.com/
> >--
> >Please see the official ORACLE-L FAQ: http://www.orafaq.com
> >--
> >Author: Gaja Krishna Vaidyanatha
> > INET: gajav_at_yahoo.com
> >
> >Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
> >San Diego, California -- Public Internet access / Mailing Lists
> >--------------------------------------------------------------------
> >To REMOVE yourself from this mailing list, send an E-Mail message
> >to: ListGuru_at_fatcity.com (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.com
> >--
> >Author: Khedr, Waleed
> > INET: Waleed.Khedr_at_FMR.COM
> >
> >Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
> >San Diego, California -- Public Internet access / Mailing Lists
> >--------------------------------------------------------------------
> >To REMOVE yourself from this mailing list, send an E-Mail message
> >to: ListGuru_at_fatcity.com (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).
>
>___________________________________________________________________________



>_____
>Get more from the Web. FREE MSN Explorer download :
>http://explorer.msn.com
>
>--
>Please see the official ORACLE-L FAQ: http://www.orafaq.com
>--
>Author: Rachel Carmichael
> INET: carmichr_at_hotmail.com
>
>Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
>San Diego, California -- Public Internet access / Mailing Lists
>--------------------------------------------------------------------
>To REMOVE yourself from this mailing list, send an E-Mail message
>to: ListGuru_at_fatcity.com (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).



Get more from the Web. FREE MSN Explorer download : http://explorer.msn.com
-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.com
-- 
Author: Rachel Carmichael
  INET: carmichr_at_hotmail.com

Fat City Network Services    -- (858) 538-5051  FAX: (858) 538-5051
San Diego, California        -- Public Internet access / Mailing Lists
--------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
Received on Thu Dec 14 2000 - 12:42:51 CST

Original text of this message

HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US