No, because if Oracle wasn't choosing an index, it would be a db file scattered read. In other words, a full scan. I meant an index, f.e, with bad cardinality or the values you need have a bad distribution.
Regards. --- Anjo Kolk <[EMAIL PROTECTED]> wrote: > That is the 1st problem that I mentioned (too many > I/Os because Oracle > doesn't use an index for example). > > Anjo. > > Christian Trassens wrote: > > > Or Oracle is choosing an awful index. Check the > > execution plan. > > > > Regards. > > --- Robertson Lee - lerobe <[EMAIL PROTECTED]> > > wrote: > > > Not my solution, just something I was meaning to > > > try. > > > > > > -----Original Message----- > > > Sent: 25 February 2002 11:18 > > > To: Multiple recipients of list ORACLE-L > > > > > > > > > > > > Performance problems with db file sequential > read > > > can happen for two > > > reasons: > > > 1) you are doing too many I/O > > > 2) each I/O is too slow (now there can many > reaons > > > why I/O is slow). > > > > > > So your solution of going with the INDEX_FFS > hint is > > > too reduce the number > > > of > > > I/O. Well what if the problem is that the I/O is > too > > > slow ? > > > > > > Anjo Kolk > > > > > > http://www.oraperf.com > > > > > > > > > Robertson Lee - lerobe wrote: > > > > > > > All, > > > > > > > > Oracle 8.0.5.0.0 Tru64 4.0f > > > > > > > > We are having a performance issue with one of > our > > > applications and it > > > looks > > > > like it is pointing to the db file sequential > > > reads event. I have been > > > doing > > > > some digging around and a recommendation in a > book > > > I have has suggested a > > > > possible way to alleviate this is to use the > > > INDEX_FFS hint in the query. > > > > Anyone used this before ??. or indeed any > other > > > recommendations where I > > > > should be looking. > > > > > > > > Regards > > > > > > > > Lee > > > > > > > > The information contained in this > communication is > > > > confidential, is intended only for the use of > the > > > recipient > > > > named above, and may be legally privileged. If > the > > > reader > > > > of this message is not the intended recipient, > you > > > are > > > > hereby notified that any dissemination, > > > distribution or > > > > copying of this communication is strictly > > > prohibited. > > > > If you have received this communication in > error, > > > please > > > > re-send this communication to the sender and > > > delete the > > > > original message or any copy of it from your > > > computer > > > > system. > > > > -- > > > > Please see the official ORACLE-L FAQ: > > > http://www.orafaq.com > > > > -- > > > > Author: Robertson Lee - lerobe > > > > 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). > > > > > > > > > -- > > > Please see the official ORACLE-L FAQ: > > > http://www.orafaq.com > > > -- > > > Author: Anjo Kolk > > > 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). > > > -- > > > Please see the official ORACLE-L FAQ: > > > http://www.orafaq.com > > > -- > > > Author: Robertson Lee - lerobe > > > 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). > > > > ===== > > Ing. Christian Trassens > > Senior DBA & Unix Administrator > > Phone: 0034-699240979 > > 0034-649824704 > > > > __________________________________________________ > > Do You Yahoo!? > > Yahoo! Sports - Coverage of the 2002 Olympic Games > > http://sports.yahoo.com > > -- > > Please see the official ORACLE-L FAQ: > http://www.orafaq.com > > -- > > Author: Christian Trassens > > 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). > > > -- > Please see the official ORACLE-L FAQ: > http://www.orafaq.com > -- > Author: Anjo Kolk > 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). ===== Ing. Christian Trassens Senior DBA & Unix Administrator Phone: 0034-699240979 0034-649824704 __________________________________________________ Do You Yahoo!? Yahoo! Sports - Coverage of the 2002 Olympic Games http://sports.yahoo.com -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Christian Trassens 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).
