Mohammed, See pages 161–164 of the same book. It boils down to the fact that the c statistic comes from a less granular clock than the e statistic. Cary Millsap Method R Corporation http://method-r.com http://carymillsap.blogspot.com http://twitter.com/cary_millsap On Wed, Oct 28, 2009 at 3:32 PM, mkb <mkb125@xxxxxxxxx> wrote: > I traced a very simple SQL statement (10046 level 12). Something like: > > select id from issues > > which returned 195 rows. > > Here's a snippet from my trace file and on the PARSE line I get the > following: > > PARSING IN CURSOR #5 len=40 dep=0 uid=49 oct=3 lid=49 tim=1227288824370256 > hv=1876028296 ad='777f6f40' > select id from issues > END OF STMT > > PARSE > #5:c=11998,e=11427,p=0,cr=0,cu=0,mis=1,r=0,dep=0,og=1,tim=1227288824370250 > > BINDS #5: > EXEC #5:c=0,e=82,p=0,cr=0,cu=0,mis=0,r=0,dep=0,og=1,tim=1227288824370419 > > > My understanding was that the e ~ c + SUM ela (Optimizing Oracle > Performance, Ch 5 p87, Millsap). So why is my e value less than my c value? > Should it not be greater than or equal to my c value? > > Database is 64-bit 10gR2 EE on RHAS 4u7. > > Thanks > > -- > mohammed > > > > > -- > //www.freelists.org/webpage/oracle-l > > >