Wu, Is there some other SQL or job running when you got your 'Bad running'？Or the hardware, esp. disks were busy with backup? On Nov 10, 2007 3:12 PM, qihua wu <staywithpin@xxxxxxxxx> wrote: > Hi, we have a batch job(run throught SQLPLUS) which runs every day. For the > same sql with the same execution plan, but the time spent on CPU is largely > different. One is 781 seconds and another one is 2193 seconds. As buffer > gets eat CPU, so I also compared the number of buffer gets and found the > number of buffer gets are very close. SQL parsing also eats CPU, but the sql > run millions of times inside a procedure, so it should be only parsed once, > and one time of parse shouldn't use much CPU. What else can eat so much CPU? > > > > > Elapsed Time (s) > > CPU Time (s) > > Executions > > Buffer Gets > > SQL Text > > > Good running > > 829 > > 781 > > 1,587,382 > > 96,640,879 > > UPDATE PM_ELIGIBILITY_TEMP ELI... > > > Bad running > > 2,978 > > 2,193 > > 1,587,382 > > 96,642,211 > > UPDATE PM_ELIGIBILITY_TEMP ELI... > > . > > -- Yao Yongping Learning Oracle, UNIX/Linux... Love Reading, Classical Music, Philosophy, Economics etc. Blog: http://spaces.msn.com/yaoyp/ -- http://www.freelists.org/webpage/oracle-l