Re: Hints and statistics

From: Philip Chee <philip_at_aleytys.pc.my>
Date: Sat, 05 Feb 2000 14:37:20 GMT
Message-ID: <949761440.5089snx@aleytys.pc.my>

In article <389c058d.1021804_at_news.demon.nl> postbus_at_sybrandb.demon.nl writes:

>The way Oracle works is:
>with statistics:
>Oracle will use the cost based optimizer
>
>with statistics and hints
>Oracle will use the cost based optimizer and ocassionally ignore the
>hint
>
>without statistics and without hints:
>Oracle will use the rule based optimizer (where the way you write your
>query will influence the plan)
>
>without statistics and with hints:
>Oracle will use the cost based optimizer and try to determine
>statistics on the fly.

How does the optimizer_undo_changes parameter in the initSID.ora file affect the above?

Philip

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 Philip Chee: Tasek Corporation Berhad, P.O.Box 254, 30908 Ipoh, MALAYSIA   e-mail: philip_at_aleytys.pc.my Voice:+60-5-545-1011 Fax:+60-5-547-3932    Guard us from the she-wolf and the wolf, and guard us from the thief,

                  oh Night, and so be good for us to pass.

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 þ 20247.96 þ Nine times out of ten the statisticians are wrong. Received on Sat Feb 05 2000 - 08:37:20 CST