一下就是根据建议调整的buffer Pool Advisory
刚开始Buffer Hit %:94.7该值较低；
| P | Size for Est (M) | Size Factor | Buffers (thousands) | Est Phys Read Factor | Estimated Phys Reads (thousands) | Est Phys Read Time | Est %DBtime for Rds |
|---|---|---|---|---|---|---|---|
| D | 512 | 0.10 | 63 | 7.08 | 261,770,174 | 1 | 220595653.00 |
| D | 1,024 | 0.19 | 126 | 4.65 | 172,044,819 | 1 | 139923021.00 |
| D | 1,536 | 0.29 | 189 | 3.61 | 133,379,440 | 1 | 105158752.00 |
| D | 2,048 | 0.38 | 252 | 3.00 | 111,051,960 | 1 | 85083978.00 |
| D | 2,560 | 0.48 | 316 | 2.47 | 91,484,743 | 1 | 67490981.00 |
| D | 3,072 | 0.57 | 379 | 2.01 | 74,320,150 | 1 | 52058187.00 |
| D | 3,584 | 0.67 | 442 | 1.66 | 61,438,100 | 1 | 40475858.00 |
| D | 4,096 | 0.77 | 505 | 1.38 | 51,142,841 | 1 | 31219320.00 |
| D | 4,608 | 0.86 | 568 | 1.19 | 43,824,758 | 1 | 24639590.00 |
| D | 5,120 | 0.96 | 631 | 1.04 | 38,372,303 | 1 | 19737259.00 |
| D | 5,344 | 1.00 | 659 | 1.00 | 36,976,340 | 1 | 18482139.00 |
| D | 5,632 | 1.05 | 694 | 0.95 | 35,115,291 | 1 | 16808858.00 |
| D | 6,144 | 1.15 | 757 | 0.88 | 32,415,165 | 1 | 14381157.00 |
| D | 6,656 | 1.25 | 820 | 0.82 | 30,150,375 | 1 | 12344873.00 |
| D | 7,168 | 1.34 | 883 | 0.76 | 28,188,753 | 1 | 10581165.00 |
| D | 7,680 | 1.44 | 947 | 0.72 | 26,437,222 | 1 | 9006352.00 |
| D | 8,192 | 1.53 | 1,010 | 0.67 | 24,880,019 | 1 | 7606261.00 |
| D | 8,704 | 1.63 | 1,073 | 0.64 | 23,525,555 | 1 | 6388455.00 |
| D | 9,216 | 1.72 | 1,136 | 0.60 | 22,329,845 | 1 | 5313386.00 |
| D | 9,728 | 1.82 | 1,199 | 0.58 | 21,263,138 | 1 | 4354302.00 |
| D | 10,240 | 1.92 | 1,262 | 0.55 | 20,278,629 | 1 | 3469124.00 |
按照这个建议把Buffer Pool 设置成9700M,以下是设置完运行10天后的awr报告：
Buffer Hit %:97.51有所提高；
| P | Size for Est (M) | Size Factor | Buffers (thousands) | Est Phys Read Factor | Estimated Phys Reads (thousands) | Est Phys Read Time | Est %DBtime for Rds |
|---|---|---|---|---|---|---|---|
| D | 928 | 0.10 | 114 | 4.69 | 6,988,717 | 1 | 9252202.00 |
| D | 1,856 | 0.20 | 229 | 3.78 | 5,624,509 | 1 | 7239861.00 |
| D | 2,784 | 0.30 | 343 | 3.55 | 5,281,706 | 1 | 6734193.00 |
| D | 3,712 | 0.40 | 458 | 2.59 | 3,861,516 | 1 | 4639273.00 |
| D | 4,640 | 0.49 | 572 | 2.29 | 3,410,587 | 1 | 3974109.00 |
| D | 5,568 | 0.59 | 686 | 2.02 | 3,009,302 | 1 | 3382174.00 |
| D | 6,496 | 0.69 | 801 | 1.50 | 2,230,332 | 1 | 2233117.00 |
| D | 7,424 | 0.79 | 915 | 1.26 | 1,878,483 | 1 | 1714105.00 |
| D | 8,352 | 0.89 | 1,029 | 1.12 | 1,663,844 | 1 | 1397492.00 |
| D | 9,280 | 0.99 | 1,144 | 1.01 | 1,502,853 | 1 | 1160014.00 |
| D | 9,376 | 1.00 | 1,156 | 1.00 | 1,488,586 | 1 | 1138970.00 |
| D | 10,208 | 1.09 | 1,258 | 0.92 | 1,375,348 | 1 | 971932.00 |
| D | 11,136 | 1.19 | 1,373 | 0.86 | 1,277,099 | 1 | 827004.00 |
| D | 12,064 | 1.29 | 1,487 | 0.80 | 1,190,838 | 1 | 699761.00 |
| D | 12,992 | 1.39 | 1,601 | 0.75 | 1,109,328 | 1 | 579526.00 |
| D | 13,920 | 1.48 | 1,716 | 0.70 | 1,039,882 | 1 | 477087.00 |
| D | 14,848 | 1.58 | 1,830 | 0.65 | 974,874 | 1 | 381194.00 |
| D | 15,776 | 1.68 | 1,944 | 0.61 | 911,365 | 1 | 287511.00 |
| D | 16,704 | 1.78 | 2,059 | 0.58 | 865,815 | 1 | 220322.00 |
| D | 17,632 | 1.88 | 2,173 | 0.56 | 831,085 | 1 | 169090.00 |
| D | 18,560 | 1.98 | 2,288 | 0.53 | 794,147 | 1 | 114604.0 |
总结：Buffer Pool Advisory表只是oracle按照相应的曲线来计算逻辑读和物理读；
但是实际的数据库运行，逻辑读和物理读跟这个相差很多；
内存的调优也是一个长期的过程，都是在不断的调试中找出符合系统的参数；