Jack, I've got no experience with out-of-line CLOB segments, so I don't know if that changes how the drop would work.
As for the maximum number of extents, that's what I was told. Not that it was necessarily "don't ever do that", just something to think about. Rachel --- [EMAIL PROTECTED] wrote: > Rachel, > > At a recent past job, under 8.1.6 on Win2k we had tables with > out-of-line > CLOB segments of 30,000 extents (1MB each). Every month we dropped > one to > make room for another (6 months of CLOB documents online). It always > just > took a few seconds for the drop. These were in DMTs. > > Later we switched servers and I changed to LMTs of 100MB Uniform > Extents > for the CLOB segments. Going from 30,000 to 300 extents for those > hulks > made no noticeable difference in query or interMedia indexing > performance, > nor did it noticeably change the time it took to drop the tables. > > Here at AISD, our student information database (SASI, for those in > Education who know this 3rd party app) has over 47,000 tables and > 70,000 > indexes (typical abysmal design for a 3rd party app, eh?), many of > them > empty or with very few rows. A few months ago I rebuilt it under > 8.1.7.4.6 > (Win2k - it was previously at 8.1.7.0.0) with LMTs of 8KB Uniform > Extents > to save space. Surprisingly, only 40 or so segments have over 1000 > extents. One, a consolidated Student table, has a little over 10,000 > extents. We've noticed no problem at all with performance, etc. > > I've not been concerned about extent counts for several years now, > and I've > seen nothing convincing that I should be. Maybe I've just not hit > the > situation where it matters. That is not to say that extents don't > matter, > but it's only if they obey the stupid directives of uninformed > duhvelopers, > such as those of our 3rd party Financials system, where they used > PctIncrease of 50. Like children and dogs, there are no bad extents, > just > bad designers. ;-) > > Jack C. Applewhite > Database Administrator > Austin Independent School District > Austin, Texas > 512.414.9715 (wk) > 512.935.5929 (pager) > [EMAIL PROTECTED] > > > > > > Rachel Carmichael > > <[EMAIL PROTECTED] To: Multiple > recipients of list ORACLE-L > o.com> > <[EMAIL PROTECTED]> > Sent by: cc: > > [EMAIL PROTECTED] Subject: Re: > Autoallocate vs Uniform extent performance > > > > > 04/04/2003 07:01 > > AM > > Please respond to > > ORACLE-L > > > > > > > > > > rumor hath it (as I've never actually had an object hit that high a > number) that when you exceed 4K extents it's time to resize. This > came > from one of the instructors in Oracle University, one who is > well-known > to actually have more than a clue. He said this at the Data Internals > class, before 9i was released. > > I have not seen his test results but.... I do know that tests done > with > DMTs have shown that large numbers of extents (I believe Kevin Loney > tested with 60K extents, and I vaguely remember a conversation with > Cary where he said he had also tested large numbers) are a problem > during operations that empty a lot of extents (think large deletes) > because of thrashing on FET$ and UET$. Since an LMT doesn't access > those tables by design, I would think that that problem goes away. > -- > Author: Rachel Carmichael > INET: [EMAIL PROTECTED] > > > > > -- > Please see the official ORACLE-L FAQ: http://www.orafaq.net > -- > Author: > 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). > __________________________________________________ Do you Yahoo!? Yahoo! Tax Center - File online, calculators, forms, and more http://tax.yahoo.com -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Rachel Carmichael 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).
