Branimir
Beware of simple ratios.
The logic is seductive. It seems likely that an easy way to find
unnecessary indexes is to look at a ratio such as you describe. And it
shouldn't pose much load on a system to do a quick report on ratio. But what
would it mean in practice? Just go around dropping indexes on tables that
exceed their quota?
I haven't used the index monitoring feature, and a cautious DBA always
makes a small test before widespread deployment, but from what I've been
told, the monitoring feature is pretty low overhead.
Dennis Williams
DBA
Lifetouch, Inc.
[EMAIL PROTECTED]
-----Original Message-----
Sent: Wednesday, January 21, 2004 9:39 AM
To: Multiple recipients of list ORACLE-L
Wondering if there is a "rule of thumb", quick'n fast but good enough
to be used as an indicator, litmus paper so to speak, of overly indexed
table(s)...
Can, better yet - should, sheer size comparison of index versus table
segments be used as a reliable pointer to problematic table indexing?
If it can, what could be considered as average "healthy ratio" above
which would be prudent to have a closer look and investigate?
Related to the above dilemma, how "expensive" is to monitor index usage,
say if script is run against all few hundred indexes on app tables,
would the additional load noticeably affect application performance or
is it better/safer or may be required to monitor not more than just a
few "most suspected" indexes at a time?
Thoughts, pointers, opinions - appreciated.
Branimir
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