Index Internals – Rebuilding The Truth December 11, 2007Posted by Richard Foote in Index Coalesce, Index Height, Index Internals, Index Rebuild, Index Shrink, Index statistics, Oracle Indexes, Oracle Myths, Oracle Opinion, Richard's Musings.
The issue of when to rebuild indexes crops up again and again and again. Unfortunately, so do the same incorrect, myth-filled uninspired responses which considering how important and “key” (no pun intended) indexes are to database design and performance generally, is very puzzling indeed.
In the coming days I’ll post why I believe these index related myths simply refuse to go away …
This presentation was originally written several years ago but is still as relevant today as it’s always been.
Recently updated version: Index Internals – Rebuilding The Truth
Invisible Indexes December 11, 2007Posted by Richard Foote in 11g, Index Access Path, Invisible Indexes, Oracle Cost Based Optimizer, Oracle Indexes, Performance Tuning.
New in 11g are “Invisible Indexes”, which are basically indexes that exist and are maintained by Oracle but are “invisible” to the CBO. Specific sessions can be set to see these invisible indexes as necessary.
Potentially useful if one has a problematic (and very large) index causing performance issues that you want to make invisible until the specific issue is addressed without the expensive of having to drop and latter recreate the index. Also useful if you want to introduce a new index but want it to be invisible until it’s been given a workout first in a specific “test” session.
Here’s a bit of a demo: Invisible Indexes
Richard Foote’s Oracle Blog Has Arrived !! December 11, 2007Posted by Richard Foote in Oracle Blog, Richard's Musings, Uncategorized.
Finally decided it might be worth giving this blogging lark a go.
Occasionally, as I come across interesting Oracle Database related issues, I’ll post my thoughts and opinions and who knows what else and perhaps, just maybe, others may find it interesting or useful as well.
However, will try and focus on the specific topic of Oracle Indexes as it’s such a huge and important area in any Oracle database design. It’s also an area in which there is much confusion, more than it’s far share of myths and popular misconceptions and one in which DBAs, Developers, Database Designers and the like all have a key role to play.
Let the fun begin …