Once again thanx a lot Tanel for spending your precious time to make me understand.
Regards, Jp. 28-07-2003 22:59:25, "Tanel Poder" <[EMAIL PROTECTED]> wrote: >The point is, that index access is cheap in reality, but CBO thinks it's >very expensive and chooses next best executin plan in it's opinion, but this >opinion is actually wrong, because unset optimizer_ parameters for example. >One more thing, your test query returned no rows, it could be that with >index access Oracle didn't even have to visit any table blocks because no >relevant keys found in index. But when you'll have keys matching your query >conditions in future, index access might get slower as well (here's where >clustering_factor comes into play). >Without analyzing, the index cost in reality is still low, and with >super-optimistic default statistics CBO luckily picks that path. > >No, according plan in your orignal post, index range scan was used. >Btw, I submitted a simple research about CBO table/index access costs to >comp.databases.oracle.server yesterday under subject "2 Oracel doubts", you >might want to read that one as well to get more understanding on your issue. > >Tanel. -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Prem Khanna J INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
