Steve: I am seeing it other way around. PIO is getting reduced with increased estimate size. Below detail from a production statspack report. We recycle the DB during weekend.. Jay Buffer Pool Advisory for DB: WDSP Instance: WDSP End Snap: 4040 -> Only rows with estimated physical reads >0 are displayed -> ordered by Block Size, Buffers For Estimate Size for Size Buffers for Est Physical Estimated P Estimate (M) Factr Estimate Read Factor Physical Reads --- ------------ ----- ---------------- ------------- ------------------ D 32 .1 3,970 33.20 1,601,419,883 D 64 .2 7,940 23.86 1,150,897,477 D 96 .3 11,910 15.87 765,448,716 D 128 .4 15,880 1.61 77,887,469 D 160 .5 19,850 1.33 63,917,781 D 192 .5 23,820 1.20 58,065,691 D 224 .6 27,790 1.13 54,488,453 D 256 .7 31,760 1.08 52,177,905 D 288 .8 35,730 1.05 50,519,436 D 320 .9 39,700 1.02 49,257,170 D 352 1.0 43,670 1.00 48,240,061 D 384 1.1 47,640 0.98 47,376,752 D 416 1.2 51,610 0.97 46,571,856 D 448 1.3 55,580 0.95 45,897,062 D 480 1.4 59,550 0.94 45,287,072 D 512 1.5 63,520 0.93 44,733,134 D 544 1.5 67,490 0.92 44,206,534 D 576 1.6 71,460 0.91 43,725,760 D 608 1.7 75,430 0.90 43,284,321 D 640 1.8 79,400 0.89 42,853,995 ------------------------------------------------------------- On 3/28/06, Stephen Anderson <st.anderson@xxxxxxxxx> wrote: > > Can anyone let me know why the advisory is saying i can so drastically > reduce my PIO's by reducing my db_cache_size? I have looked around the web > and have never seen an explanation for this. I also looked on metalink to > see if it was a know bug. > > This was from a lvl 5 statspack 15 minute snap on 9.2.0.3 on Sun Solaris. > The instance has been up for over 8 months. The results are the same no > matter when I snap. > > Buffer Pool Advisory for DB: MERLIN Instance: MERLIN End Snap: 15 > -> Only rows with estimated physical reads >0 are displayed > -> ordered by Block Size, Buffers For Estimate > > Size for Size Buffers for Est Physical Estimated > P Estimate (M) Factr Estimate Read Factor Physical Reads > --- ------------ ----- ---------------- ------------- ------------------ > D 16 .3 1,985 0.06 54,232,173 > D 32 .5 3,970 0.03 28,255,991 > D 48 .8 5,955 0.01 7,094,145 > D 64 1.0 7,940 1.00 937,436,311 > D 80 1.3 9,925 0.99 924,356,448 > D 96 1.5 11,910 0.97 912,150,561 > ... > D 272 4.3 33,745 0.85 792,237,723 > D 288 4.5 35,730 0.84 783,014,854 > D 304 4.8 37,715 0.82 769,676,998 > D 320 5.0 39,700 0.79 738,539,663 > ------------------------------------------------------------- > > Regards, > Steve Anderson >