I vote for Cary Millsap's book. Truly excellent, one of the few books worth reading about performance tuning: in essence the book speaks about how to apply standard methodology used in systems modeling/tuning (eg resource profiles, emphasys on response time/wait time etc) to Oracle. Easier said than done, of course - the book closes the link.

Anyway IMHO to be proficient in Performance Tuning you have to be a *real* expert in the system you want to tune (difficult to make a car run faster if you're not a clever mechanical engineer). You must have tons of experience, and you must be an expert and effective developer/dba: the recipe for success in Performance Tuning is the same recipe you would use for success in development/administration, and the books to read are the same (and i've put a subliminal hint to some titles above :-) )

hth
Alberto

and also 5 Stars for Oracle 101 Performance Tuning by Gaja, for getting u think in the right direction. ( A Toned Down version of Cary Milsaps book)

Cheers
Ganesh R

For overall knowledge of Oracle (essential for any
performance tuning)

Tom's
Expert one on one Oracle

For some more advanced stuff as a continuation of
the above book:

Tom's Effective Oracle by Design

Cary's Optimizing Oracle Performance
is an excellent book that gives you solid insights
into performance tuning philosophy and in depth analysis
of sql tracing.

Oracle documentation
Concepts
Performance Tuning Guide

Could you refer something on data modelling or designing ?


Thanks,