Well you may be right, but rman is using x$dual. X$dual has been there since 8.1.5 (?).
Anjo. Yechiel Adar wrote: > Redefine the view to work on dual and pay the price !!! > Checked it on oracle 8.1.6 and 9.0.1. > I will take the risk that maybe in some future date this will not work > if it can save a lot of resources now. > > Yechiel Adar > Mehish > > ----- Original Message ----- > To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]> > Sent: Tuesday, April 23, 2002 3:13 PM > > > what would you do if Oracle removed this x$dual or made it multiple row > > table in future upgrades? > > > > -----Original Message----- > > To: Multiple recipients of list ORACLE-L > > Sent: 4/23/02 4:08 AM > > > > Hello Gaja > > > > Thanks for the detailed info. > > I created a view and did grant to public. > > I did 10 selects and they did only 2 buffers get. > > BTW - describe on x$dual does not work but select * works. > > > > Yechiel Adar > > Mehish > > > > ----- Original Message ----- > > To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]> > > Sent: Monday, April 22, 2002 8:15 PM > > > > > > > Hello Yechiel, > > > > > > X$DUAL is an Oracle-internal table "in the SGA" and > > > will not be shown in an ALL_OBJECTS listing. > > > Obviously, you need to be SYS to see this. You can do > > > a describe as SYS and you will see it. Which is the > > > reason why I recommended creating a view and a public > > > synonym on the view, so that the application may > > > reference it without any issues. > > > > > > Cheers, > > > > > > Gaja > > > > > > --- Yechiel Adar <[EMAIL PROTECTED]> wrote: > > > > Hello Gaja > > > > > > > > I could not find x$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). > > > > > > > > > ===== > > > 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). > > -- > > Please see the official ORACLE-L FAQ: http://www.orafaq.com > > -- > > Author: Khedr, Waleed > > 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). -- 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).
