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Re: Fav. Urban Legend...Mem vs Disk

From: Alan Davey <adavey_at_competitrack.com>
Date: Wed, 20 Mar 2002 08:13:33 -0800
Message-ID: <F001.0042E909.20020320081333@fatcity.com>


On 3/20/02, Mark Leith <mark_at_cool-tools.co.uk> wrote:
>Ahh, but how can you be sure that "42" does not also *cause* all of
>life's
>problems? ;)

Because, as Homer Simpson said, "Ahhh booze. The cause of and the solution to all of life's problems." ;^)

-- 

Alan Davey
adavey_at_competitrack.com


On 3/20/02, Mark Leith <mark_at_cool-tools.co.uk> wrote:

>Ahh, but how can you be sure that "42" does not also *cause* all of
>life's
>problems? ;)
>
>Does this also mean that the "preferred" number of disks, tablespaces,
>and
>extents should also be 42? ;>
>
>-----Original Message-----
>Krishna Vaidyanatha
>Sent: 20 March 2002 14:03
>To: Multiple recipients of list ORACLE-L
>
>
>My dear friend Mogens,
>
>I am so glad we share the same kind of "bedtime
>reading" in our own parts of the world. I totally
>agree with you, every cache hit ratio and performance
>metric within Oracle needs to be 42, for us to be in a
>sublime and happy state...;-). After all "42" does
>solve all of life's problems!!
>
>Cheers,
>
>Gaja
>
>--- Mogens Nxrgaard <mln_at_miracleas.dk> wrote:
>> I always thought 42 was a good number. Perhaps I was
>> wrong.
>>
>> Bjxrn Engsig wrote:
>>
>> >Cary Milsap from hotsos has much data to confirm an
>> approximate 1:100 ratio
>> >between LIO time and PIO time.
>> >
>> >Can we therefore conclude, that the buffer cache
>> hit ratio should be 99%? :-)
>> >
>> >Rgds, Bjxrn.
>> >On Wednesday 20 March 2002 10:48, Connor McDonald
>> wrote:
>> >
>> >>Some rudimentary testing on a laptop here (500Mhz,
>> >>512M RAM, typical single disk)
>> >>
>> >>a) visiting a single block via 4,000,000 logical
>> IO's
>> >>got me approx 35000 gets/sec
>> >>
>> >>b) repeated full table scans similar system got me
>> >>approx 350 phys reads/sec
>> >>
>> >>After this extensive, thorough and exhaustive
>> >>exercise, I can definitely say that memory access
>> >>versus disk access (as it pertains to Oracle) is
>> 100
>> >>times faster on this machine in single user mode
>> >>
>> >>I think we can generalise this to be the rule for
>> all
>> >>servers under all conditions :-)
>> >>
>> >>Connor
>> >>
>> >> --- "Freeman, Robert " <Robert_Freeman_at_csx.com>
>> >>wrote: > I've heard the disk vs. memory arguments
>> >>before, but
>> >>
>> >>>never have seen
>> >>>quantifiable data either way... if anyone has
>> any,
>> >>>I'd love to see it.
>> >>>
>> >>>RF
>> >>>
>> >>>Robert G. Freeman - Oracle8i OCP
>> >>>Oracle DBA Technical Lead
>> >>>CSX Midtier Database Administration
>> >>>
>> >>>The Cigarette Smoking Man: Anyone who can appease
>> a
>> >>>man's conscience can
>> >>>take his freedom away from him.
>> >>>
>> >>>
>> >>>
>> >>>-----Original Message-----
>> >>>Sent: Monday, March 18, 2002 5:54 PM
>> >>>To: Multiple recipients of list ORACLE-L
>> >>>
>> >>>
>> >>>Robert - So THAT is the title of your next book.
>> I'm
>> >>>primed to buy it
>> >>>already.
>> >>>I just recalled a legend, maybe. "Disk is 10,000
>> >>>times slower than memory,
>> >>>so memory access times are infinitesimal compared
>> to
>> >>>disk access". Cary
>> >>>Millsap covers this in his Hotsos Clinic. He has
>> run
>> >>>tests that prove "ain't
>> >>>so". The point is that you can't just use ratios
>> to
>> >>>tune Oracle, but need to
>> >>>look at wait times.
>> >>>Dennis Williams
>> >>>DBA
>> >>>Lifetouch, Inc.
>> >>>dwilliams_at_lifetouch.com
>> >>>
>> >>>
>> >>>-----Original Message-----
>> >>>Sent: Monday, March 18, 2002 1:04 PM
>> >>>To: Multiple recipients of list ORACLE-L
>> >>>
>> >>>
>> >>>So, does the CoO (Church of Oracle) have an
>> >>>infallibility doctrine then???
>> >>>
>> >>>... From the Book of Oracle, chapter 5 ...
>> >>>
>> >>>...and the DBA did look upon his database, and he
>> >>>saw it was good.
>> >>>His tablespace datafiles being distributed tither
>> >>>and fro, spread amongst
>> >>>the
>> >>>platters of his disks. And he did complete that
>> >>>which was called
>> >>>documentation,
>> >>>and then he rested from his labors, and drank
>> >>>Mountain Dew Code Red...
>> >>>
>> >>>:-)
>> >>>
>> >>>Robert G. Freeman - Oracle8i OCP
>> >>>Oracle DBA Technical Lead
>> >>>CSX Midtier Database Administration
>> >>>
>> >>>The Cigarette Smoking Man: Anyone who can appease
>> a
>> >>>man's conscience can
>> >>>take his freedom away from him.
>
><stuff deleted>
>
>
>=====
>Gaja Krishna Vaidyanatha
>Director, Storage Management Products,
>Quest Software, Inc.
>Co-author - Oracle Performance Tuning 101
>http://www.osborne.com/database_erp/0072131454/0072131454.shtml
>
>__________________________________________________
>Do You Yahoo!?
>Yahoo! Sports - live college hoops coverage
>http://sports.yahoo.com/
>--
>Please see the official ORACLE-L FAQ: http://www.orafaq.com
>--
>Author: Gaja Krishna Vaidyanatha
> INET: oraperfman_at_yahoo.com
>
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>Author: Mark Leith
> INET: mark_at_cool-tools.co.uk
>
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-- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Alan Davey INET: adavey_at_competitrack.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).
Received on Wed Mar 20 2002 - 10:13:33 CST

Original text of this message

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