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6#
发表于 2012-12-26 14:53:48
monkeybron 发表于 2012-12-26 13:43
另外:数据库是专有模式数据库pga 是自动管理的
在awr 中TOP5也没可能到明显的LC cache 的问题,更多的是并 ...
Snap Id | Snap Time | Sessions | Cursors/Session | Begin Snap: | 22217 | 26-Dec-12 08:00:09 | 1184 | 8.2 | End Snap: | 22218 | 26-Dec-12 09:00:15 | 1203 | 9.2 | Elapsed: | | 60.11 (mins) | | | DB Time: | | 607.80 (mins) | | |
Per Second | Per Transaction | Redo size: | 56,659.15 | 5,108.76 | Logical reads: | 199,930.54 | 18,027.03 | Block changes: | 269.30 | 24.28 | Physical reads: | 15,478.91 | 1,395.68 | Physical writes: | 44.26 | 3.99 | User calls: | 3,317.67 | 299.14 | Parses: | 726.77 | 65.53 | Hard parses: | 241.02 | 21.73 | Sorts: | 10,561.42 | 952.29 | Logons: | 0.06 | 0.01 | Executes: | 2,063.78 | 186.08 | Transactions: | 11.09 | |
这个快照负载不低啊, 尤其指定注意的是 每秒硬解析241次, 耗费1488s的DB TIME
hard parse elapsed time 1,488.85
cursor_space_for_time TRUE 这个参数非推荐
PGA Target Est (MB) | Size Factr | W/A MB Processed | Estd Extra W/A MB Read/ Written to Disk | Estd PGA Cache Hit % | Estd PGA Overalloc Count | 786 | 0.13 | 12,322,504.25 | 1,735,245.76 | 88.00 | 33,754 | 1,572 | 0.25 | 12,322,504.25 | 1,712,451.58 | 88.00 | 32,530 | 3,144 | 0.50 | 12,322,504.25 | 1,377,710.46 | 90.00 | 24,355 | 4,715 | 0.75 | 12,322,504.25 | 1,018,126.48 | 92.00 | 18,104 | 6,287 | 1.00 | 12,322,504.25 | 211,253.94 | 98.00 | 6,819 | 7,544 | 1.20 | 12,322,504.25 | 148,607.50 | 99.00 | 0 | 8,802 | 1.40 | 12,322,504.25 | 139,732.13 | 99.00 | 0 | 10,059 | 1.60 | 12,322,504.25 | 139,732.13 | 99.00 | 0 | 11,317 | 1.80 | 12,322,504.25 | 139,732.13 | 99.00 | 0 | 12,574 | 2.00 | 12,322,504.25 | 139,732.13 | 99.00 | 0 | 18,861 | 3.00 | 12,322,504.25 | 139,732.13 | 99.00 | 0 | 25,148 | 4.00 | 12,322,504.25 | 139,732.13 | 99.00 | 0 | 37,722 | 6.00 | 12,322,504.25 | 139,732.13 | 99.00 | 0 | 50,296 | 8.00 | 12,322,504.25 | 139,732.13 | 99.00 | 0 |
从PGA Memory Advisory看 目前pga_aggregate_target=6g时 仍存在PGA overalloc,考虑增大pga_aggregate_target 到8g左右
1. 考虑优化解析减少hard parse,可以有效减少 PGA的使用
2、 考虑上面提到的参数
3、 考虑增大pga_aggregate_target 减少PGA overalloc |
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