Thanks all the responses.
It's the syntax error like Naveen said. Oracle didn't detect the error, it just simply ignore the hints if the syntax is wrong. Thanks again, Chuan -----Original Message----- Sent: Friday, 30 August 2002 5:33 PM To: Multiple recipients of list ORACLE-L If you specify a hint Oracle is forced to use the index. Your hint's syntax is wrong. USE - /*+ INDEX(test index_a) */ **** Don't use the comma ******* between the table name and the index name Naveen -----Original Message----- Sent: Friday, August 30, 2002 12:33 PM To: Multiple recipients of list ORACLE-L Hi, All, On a million row table, test, there is primary key on column a. when I run select /*+ index (test,indx_a) */ a, b, c, from test, according to Oracle, I should get the following explain plan. TABLE ACCESS BY INDEX ROWID test 1 INDEX UNIQUE SCAN PK_test 1 But I acctucally got : TABLE ACCESS FULL test 1 The database optimizer mode is choose, and I gathered the statistics on table and index using dbms_utitlity and analyze. In the session level, I also set optimizer_mode=first_rows to push optimizer to choose the index. According to Oracle Doc "use hints to force the optimizer to use the optimal execution plan.", to my understanding, the explain plan under such a situation, should be the first one. Does Oracle follow the hint? or to waht extents, it follows? Appreciated if someone guides me to the right direction. Chuan, -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Naveen Nahata INET: [EMAIL PROTECTED] Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- 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).
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