Hello Gaja I could not find x$dual. Did select on all_objects got zip. Oracle 8.1.6.3.4 on NT.
Yechiel Adar Mehish ----- Original Message ----- To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]> Sent: Sunday, April 21, 2002 8:28 PM > Hi Yechiel, > > Any full-table-scan in Oracle 8i (or below) consumes 4 > LIOs to the segment header. This number has reduced to > 2 in 9i. Given that the 1 row that you are going after > is in 1 data block, there is 1 LIO for the data block > itself, given you a total of 5 LIOs. You can verify > this by setting 10046 for the session and looking at > the trace output. > > The workaround is to reference x$dual in your > application. Alternatively, you can create a view on > x$dual, create a synonym for it and then go from > there. You will incur some I/O for the first access of > the query (with the synonym), but subsequent accesses > will incur 0 LIOs against x$dual. > > Cheers, > > Gaja > --- Yechiel Adar <[EMAIL PROTECTED]> wrote: > > I did two statspack snapshots, one hour and forty > > minutes apart. > > Then I generated a report and loaded it into > > oraperf.com. > > In the report I saw that the two SQL statements that > > where executed the most > > times where: > > > > Select xxxx.currval from dual; > > > > Select xxxx.nextval from dual;. > > > > Each one was executed about 90,000 times with 5 > > buffer gets per execution. > > The net result was about 950,000 buffer get for > > nextval and currval. > > > > My question is: > > Why should there be about 5 buffer gets per > > execution? > > > > Yechiel Adar > > Mehish > > -- > > Please see the official ORACLE-L FAQ: > > http://www.orafaq.com > > -- > > Author: Yechiel Adar > > 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). > > > ===== > Gaja Krishna Vaidyanatha > Director, Storage Management Products, > Quest Software, Inc. > Co-author - Oracle Performance Tuning 101 > http://www.osborne.com/database_erp/0072131454/0072131454.shtml > > __________________________________________________ > Do You Yahoo!? > Yahoo! Games - play chess, backgammon, pool and more > http://games.yahoo.com/ > -- > Please see the official ORACLE-L FAQ: http://www.orafaq.com > -- > Author: Gaja Krishna Vaidyanatha > 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: Yechiel Adar 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).
