Hi Dan and list, Here is the output from a test after setting 10046 at level 12. Please tell me whether this is really 0 or not accounted for. If it is not accounted for, then I stand corrected.
Thanks, Gaja ----Trace file output starts here---- *** 2002-04-22 16:04:14.090 *** SESSION ID:(11.752) 2002-04-22 16:04:14.060 ===================== PARSING IN CURSOR #1 len=70 dep=0 uid=0 oct=42 lid=0 tim=5655178 hv=347037164 ad='51d70a0' alter session set events '10046 trace name context forever, level 12' END OF STMT EXEC #1:c=2,e=4,p=0,cr=0,cu=0,mis=0,r=0,dep=0,og=4,tim=5655179 WAIT #1: nam='SQL*Net message to client' ela= 0 p1=1111838976 p2=1 p3=0 *** 2002-04-22 16:04:25.617 WAIT #1: nam='SQL*Net message from client' ela= 1152 p1=1111838976 p2=1 p3=0 ===================== PARSING IN CURSOR #1 len=21 dep=0 uid=0 oct=3 lid=0 tim=5656331 hv=2119980703 ad='51d5564' select * from x$dual END OF STMT PARSE #1:c=0,e=0,p=0,cr=0,cu=0,mis=1,r=0,dep=0,og=4,tim=5656331 BINDS #1: EXEC #1:c=0,e=0,p=0,cr=0,cu=0,mis=0,r=0,dep=0,og=4,tim=5656332 WAIT #1: nam='SQL*Net message to client' ela= 0 p1=1111838976 p2=1 p3=0 FETCH #1:c=0,e=0,p=0,cr=0,cu=0,mis=0,r=1,dep=0,og=4,tim=5656332 WAIT #1: nam='SQL*Net message from client' ela= 2 p1=1111838976 p2=1 p3=0 FETCH #1:c=0,e=0,p=0,cr=0,cu=0,mis=0,r=0,dep=0,og=4,tim=5656334 WAIT #1: nam='SQL*Net message to client' ela= 0 p1=1111838976 p2=1 p3=0 WAIT #1: nam='SQL*Net message from client' ela= 815 p1=1111838976 p2=1 p3=0 STAT #1 id=1 cnt=1 pid=0 pos=0 obj=0 op='FIXED TABLE FULL X$DUAL ' ===================== ----Trace file output ends here---- --- Danisment Gazi Unal <[EMAIL PROTECTED]> wrote: > Hello Gaja, > > am I missing something ? > > is it 0 logical IO indeed ? or it's not accounted > for X$ tables ? > > regards... > > > > Gaja Krishna Vaidyanatha wrote: > > > 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). > > -- > Danisment Gazi Unal > http://www.ubTools.com > > > -- > Please see the official ORACLE-L FAQ: > http://www.orafaq.com > -- > Author: Danisment Gazi Unal > 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).
