On 1 Feb 2005 14:36:08 -0800, iamoracledba_at_gmail.com wrote:
>Thanks for your prompt reply.
>
>on 2, I still need to use that index. Anyway I can hint it to use
>index range scan?
>
>on 3, So what does VALIDATE STRUCTURE on a table do?
>
>on 4, how do I tell if clustering factor of the index is bad? If I
>decide it is bad, should I just rebuild the index? In my system that 1
>query had only read 2035 out of 116542 Blocks in almost an hour and
>half! and it is using half of cpu.
>
>Thanks a million!
- The INDEX hint will use the normal access methods. However it is a
*hint*. As you are deliberately vague about the actual statement, it's
explain plan etc, and you obviously didn't run explain plan with event
10053 set, it is impossible to tell why Oracle choose the index_ffs
method
- I hardly use it, you will need to very that in the docs
- If the clustering factor approximates the number of records it is
good (recalling from memory), it is approximates the number of blocks
it is bad.
You would need to rebuild the table and make sure the records are
loaded in the correct order. Obviously, if your table is a heap table,
you would need to repeat this periodically.
--
Sybrand Bakker, Senior Oracle DBA
Received on Tue Feb 01 2005 - 23:34:19 CST
