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Home -> Community -> Mailing Lists -> Oracle-L -> Re: OT: Exploding the Mythns
Mike,
The presentation was called Exploding the Myths... but we were tricky, rather than include only things that were wrong (that would make it too easy for the audience), we also included things that were right.
So we had "sounds right but is wrong" "sounds wrong but is right" "sounds okay but is 'well, maybe'" statements in it
It started as an all-day seminar at ECO. We wanted to start discussions and tangents. We did.
So, setting timed_statistics=true was a sounds wrong but is right
having lots of extents is not a problem is a sounds okay but is a well, maybe
the reason for that one is, "it depends" (don't you love clear concise answers?). You need (as Paul pointed out) to define "lots" and you need to know your database and how it is being used. In general, for a table that is only being inserted into and is not being deleted from/updated on an ad hoc basis (say a table that logs page hits), then lots of extents can be a high number and isn't bad.
But if you have a table that is in flux, with large volumes of data being deleted, then lots of extents can be bad (example: table with 60,000 extents. truncate table. finished 16 hours later)
I was told in the Data Server Internals class I took that in general, Oracle can handle up to 1000 extents very well, and that going over 4096 could have repercussions. Please note this was for 8i
Rachel
>From: MHately_at_etech-uk.com
>Reply-To: ORACLE-L_at_fatcity.com
>To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
>Subject: Re: OT: Exploding the Mythns
>Date: Thu, 28 Jun 2001 03:36:56 -0800
>
>
>
>I think I've missed a bit of this thread so apologies in advance.
>I always set timed_statistics-true and I don't worry unduly about lots of
>extents.
>I'm aware of problems with both approaches (bugs etc.) but as general
>principles
>I'm happy with them and they've never caused a problem.
>
>What's to repent about?
>
>Regards,
>Mike
>
>
>
>
>> >
-- 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).Received on Thu Jun 28 2001 - 09:30:09 CDT
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