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Home -> Community -> Mailing Lists -> Oracle-L -> Re:OT: Misinformation Ranting
Jared,
What version of the database does this book refer to? I do remember back in Version 6 and early 7 that having all of your data for a table and/or index all in the first extent was a performance benefit. Regrettably that idea had been proved false more than once after 7.2 hit the street. I notice a performance improvement if tables/indexes are in more than one extent. But if she's talking about migrated and/or chained rows that's another matter & one that I'm chasing as I type.
Looks like you've got a classic case of someone with enough information to be dangerous.
Dick Goulet
____________________Reply Separator____________________Subject: OT: Misinformation Ranting
<RANT>
I've just spent 30 minutes with our SAP administrator trying to convince her that we really don't need to reorganize the tables in our production SAP database.
Due to some misinformation in an Oracle Press book, 'Oracle Unleashed' I think, she is equating number of extents with fragmentation.
The text she referred me to is in fact discussing 'migrated rows' though that term is never used. She has become convinced that if the extents allocated for tables are not all in contigous space, some very nasty fragmentation will occur.
I tried taking it down to disk and explaining that an OLTP system with hundreds of users won't really see much benefit from this, but she wasn't really ready for that. :)
Her concern is that there are 29000 extents in an index tablespace. This might have something to do with there being 3400 indexes in said tablespace.
Total 'wasted' ( honeycomb ) space in this 250 gig DB is < 20 meg. Not much to gain there.
The text of the book states that you should expect a '10 to 20 percent performance increase' by reorganizing the tables/indexes. No data to back it up of course.
This is on a database that performs very well most of the time, outside of a couple of custom reports that run too long. No complaints from users about slowness.
Arrghhh!
I just had to vent to the list, cuz there's no one here that understands.
<\RANT>
Jared
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INET: Jared.Still_at_radisys.com
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