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再实验mysql中批量查询使用in还是n+1?

阅读更多
延续上次的实验,http://willko.iteye.com/blog/407964

200m记录,innodb

先从小量查询开始实验,只考虑随机情况,毕竟生产环境比较少出现顺序.

20个值的情况
|        3 | 0.23469200 | SELECT * FROM Member WHERE MemberID IN (1072317,944960,232144,1221849,1718824,1971030,1634860,219179,1733544,618875,1033368,914264,1657167,687934,2164378,1675400,816727,1072638,56834,798724)                                                                                                               | 
|        4 | 0.00271600 | SELECT * FROM Member WHERE MemberID = 1072317 UNION SELECT * FROM Member WHERE MemberID = 944960 UNION SELECT * FROM Member WHERE MemberID = 232144 UNION SELECT * FROM Member WHERE MemberID = 1221849 UNION SELECT * FROM Member WHERE MemberID = 1718824 UNION SELECT * FROM Member WHERE MemberID = 1971 |


50个值的情况
|        3 | 0.23469200 | SELECT * FROM Member WHERE MemberID IN (1072317,944960,232144,1221849,1718824,1971030,1634860,219179,1733544,618875,1033368,914264,1657167,687934,2164378,1675400,816727,1072638,56834,798724)                                                                                                               | 
|        4 | 0.00271600 | SELECT * FROM Member WHERE MemberID = 1072317 UNION SELECT * FROM Member WHERE MemberID = 944960 UNION SELECT * FROM Member WHERE MemberID = 232144 UNION SELECT * FROM Member WHERE MemberID = 1221849 UNION SELECT * FROM Member WHERE MemberID = 1718824 UNION SELECT * FROM Member WHERE MemberID = 1971 |


500个值的情况
|       11 | 4.89638400 | SELECT * FROM Member WHERE MemberID IN (1940366,1592700,1400564,745603,439521,1782230,1627418,1968030,1173113,1406275,1157786,382329,1252380,2202431,2142859,714044,1178282,1463622,1069076,955140,2071311,647081,619895,154986,1068419,1900229,1792226,1796517,1568490,687304,2059599,912862,1797395,168722 | 
|       12 | 0.07686600 | SELECT * FROM Member WHERE MemberID = 1940366 UNION SELECT * FROM Member WHERE MemberID = 1592700 UNION SELECT * FROM Member WHERE MemberID = 1400564 UNION SELECT * FROM Member WHERE MemberID = 745603 UNION SELECT * FROM Member WHERE MemberID = 439521 UNION SELECT * FROM Member WHERE MemberID = 1782 | 


在一张只有100k记录的表上实验
|       18 |  0.12457700 | SELECT * FROM Product WHERE ProductID IN (11089,108843,80895,6486,91179,109813,97611,49713,90237,56495,114315,773,119650,55401,8965,61268,60379,13692,114931,71883)                                                                                                                                          | 
|       19 |  0.00348100 | SELECT * FROM Product WHERE ProductID = 11089 UNION SELECT * FROM Product WHERE ProductID = 108843 UNION SELECT * FROM Product WHERE ProductID = 80895 UNION SELECT * FROM Product WHERE ProductID = 6486 UNION SELECT * FROM Product WHERE ProductID = 91179 UNION SELECT * FROM Product WHERE ProductID =  | 
|       20 |  0.35769600 | SELECT * FROM Product WHERE ProductID IN (52447,28980,59590,80193,98487,22829,78756,70810,86308,60046,81279,67714,99244,89245,69998,48611,81038,17256,45283,119693,108364,97453,47837,81514,457,26157,115691,13263,102098,101610,38318,32815,101610,45720,31842,90977,53938,86167,6973,3819,22670,81914,8805 | 
|       21 |  0.00640500 | SELECT * FROM Product WHERE ProductID = 52447 UNION SELECT * FROM Product WHERE ProductID = 28980 UNION SELECT * FROM Product WHERE ProductID = 59590 UNION SELECT * FROM Product WHERE ProductID = 80193 UNION SELECT * FROM Product WHERE ProductID = 98487 UNION SELECT * FROM Product WHERE ProductID =  | 


注意,即使使用union,query cache还是按照整条sql来算的。

看到这样的结果,我想大家都有结论了,使用n+1比用in快n倍,估计上次实验有问题,,我们来看看他们的执行过程

这是in的情况
+--------------------------------+----------+----------+------------+--------------+---------------+
| Status                         | Duration | CPU_user | CPU_system | Block_ops_in | Block_ops_out |
+--------------------------------+----------+----------+------------+--------------+---------------+
| starting                       | 0.000014 | 0.000000 |   0.000000 |            0 |             0 | 
| checking query cache for query | 0.000048 | 0.000000 |   0.000000 |            0 |             0 | 
| Opening tables                 | 0.000011 | 0.000000 |   0.000000 |            0 |             0 | 
| System lock                    | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| Table lock                     | 0.000019 | 0.000000 |   0.000000 |            0 |             0 | 
| init                           | 0.000039 | 0.000000 |   0.000000 |            0 |             0 | 
| optimizing                     | 0.000007 | 0.000000 |   0.000000 |            0 |             0 | 
| statistics                     | 0.000047 | 0.000000 |   0.000000 |            0 |             0 | 
| preparing                      | 0.000009 | 0.000000 |   0.000000 |            0 |             0 | 
| executing                      | 0.000002 | 0.000000 |   0.000000 |            0 |             0 | 
| Sending data                   | 0.234442 | 0.002000 |   0.001000 |            0 |             0 | 
| end                            | 0.000007 | 0.000000 |   0.000000 |            0 |             0 | 
| query end                      | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| freeing items                  | 0.000031 | 0.000000 |   0.000000 |            0 |             0 | 
| storing result in query cache  | 0.000005 | 0.000000 |   0.000000 |            0 |             0 | 
| logging slow query             | 0.000001 | 0.000000 |   0.000000 |            0 |             0 | 
| cleaning up                    | 0.000004 | 0.000000 |   0.000000 |            0 |             0 | 
+--------------------------------+----------+----------+------------+--------------+---------------+


n+1情况
+--------------------------------+----------+----------+------------+--------------+---------------+
| Status                         | Duration | CPU_user | CPU_system | Block_ops_in | Block_ops_out |
+--------------------------------+----------+----------+------------+--------------+---------------+
| starting                       | 0.000015 | 0.000000 |   0.000000 |            0 |             0 | 
| checking query cache for query | 0.000123 | 0.000000 |   0.000000 |            0 |             0 | 
| Opening tables                 | 0.000573 | 0.000000 |   0.000000 |            0 |             0 | 
| System lock                    | 0.000004 | 0.000000 |   0.000000 |            0 |             0 | 
| Table lock                     | 0.000607 | 0.001000 |   0.000000 |            0 |             0 | 
| optimizing                     | 0.000012 | 0.000000 |   0.000000 |            0 |             0 | 
| statistics                     | 0.000057 | 0.000000 |   0.000000 |            0 |             0 | 
| preparing                      | 0.000007 | 0.000000 |   0.000000 |            0 |             0 | 
| executing                      | 0.000002 | 0.000000 |   0.000000 |            0 |             0 | 
| Sending data                   | 0.000033 | 0.000000 |   0.000000 |            0 |             0 | 
| optimizing                     | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| statistics                     | 0.000031 | 0.000000 |   0.000000 |            0 |             0 | 
| preparing                      | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| executing                      | 0.000002 | 0.000000 |   0.000000 |            0 |             0 | 
| Sending data                   | 0.000015 | 0.000000 |   0.000000 |            0 |             0 | 
| optimizing                     | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| statistics                     | 0.000026 | 0.000000 |   0.000000 |            0 |             0 | 
| preparing                      | 0.000002 | 0.000000 |   0.000000 |            0 |             0 | 
| executing                      | 0.000001 | 0.000000 |   0.000000 |            0 |             0 | 
| Sending data                   | 0.000017 | 0.000000 |   0.000000 |            0 |             0 | 
| optimizing                     | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| statistics                     | 0.000021 | 0.000000 |   0.000000 |            0 |             0 | 
| preparing                      | 0.000002 | 0.000000 |   0.000000 |            0 |             0 | 
| executing                      | 0.000001 | 0.000000 |   0.000000 |            0 |             0 | 
| optimizing                     | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| statistics                     | 0.000028 | 0.000000 |   0.000000 |            0 |             0 | 
| preparing                      | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| executing                      | 0.000002 | 0.000000 |   0.000000 |            0 |             0 | 
| Sending data                   | 0.000024 | 0.000000 |   0.000000 |            0 |             0 | 
| optimizing                     | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| statistics                     | 0.000030 | 0.000000 |   0.000000 |            0 |             0 | 
| preparing                      | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| executing                      | 0.000001 | 0.000000 |   0.000000 |            0 |             0 | 
| Sending data                   | 0.000016 | 0.000000 |   0.000000 |            0 |             0 | 
| optimizing                     | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| statistics                     | 0.000029 | 0.000000 |   0.000000 |            0 |             0 | 
| preparing                      | 0.000002 | 0.000000 |   0.000000 |            0 |             0 | 
| executing                      | 0.000002 | 0.000000 |   0.000000 |            0 |             0 | 
| Sending data                   | 0.000022 | 0.000000 |   0.000000 |            0 |             0 | 
| optimizing                     | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| statistics                     | 0.000024 | 0.000000 |   0.000000 |            0 |             0 | 
| preparing                      | 0.000002 | 0.000000 |   0.000000 |            0 |             0 | 
| executing                      | 0.000002 | 0.000000 |   0.000000 |            0 |             0 | 
| Sending data                   | 0.000016 | 0.000000 |   0.000000 |            0 |             0 | 
| optimizing                     | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| statistics                     | 0.000032 | 0.000000 |   0.000000 |            0 |             0 | 
| preparing                      | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| executing                      | 0.000001 | 0.000000 |   0.000000 |            0 |             0 | 
| Sending data                   | 0.000016 | 0.000000 |   0.000000 |            0 |             0 | 
| optimizing                     | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| statistics                     | 0.000025 | 0.000000 |   0.000000 |            0 |             0 | 
| preparing                      | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| executing                      | 0.000001 | 0.000000 |   0.000000 |            0 |             0 | 
| Sending data                   | 0.000021 | 0.000000 |   0.000000 |            0 |             0 | 
| optimizing                     | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| statistics                     | 0.000033 | 0.000000 |   0.000000 |            0 |             0 | 
| preparing                      | 0.000002 | 0.000000 |   0.000000 |            0 |             0 | 
| executing                      | 0.000002 | 0.000000 |   0.000000 |            0 |             0 | 
| Sending data                   | 0.000022 | 0.000000 |   0.000000 |            0 |             0 | 
| optimizing                     | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| statistics                     | 0.000027 | 0.000999 |   0.000000 |            0 |             0 | 
| preparing                      | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| executing                      | 0.000001 | 0.000000 |   0.000000 |            0 |             0 | 
| Sending data                   | 0.000016 | 0.000000 |   0.000000 |            0 |             0 | 
| optimizing                     | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| statistics                     | 0.000031 | 0.000000 |   0.000000 |            0 |             0 | 
| preparing                      | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| executing                      | 0.000002 | 0.000000 |   0.000000 |            0 |             0 | 
| Sending data                   | 0.000022 | 0.000000 |   0.000000 |            0 |             0 | 
| optimizing                     | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| statistics                     | 0.000029 | 0.000000 |   0.000000 |            0 |             0 | 
| preparing                      | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| executing                      | 0.000001 | 0.000000 |   0.000000 |            0 |             0 | 
| Sending data                   | 0.000017 | 0.000000 |   0.000000 |            0 |             0 | 
| optimizing                     | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| statistics                     | 0.000028 | 0.000000 |   0.000000 |            0 |             0 | 
| preparing                      | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| executing                      | 0.000001 | 0.000000 |   0.000000 |            0 |             0 | 
| Sending data                   | 0.000018 | 0.000000 |   0.000000 |            0 |             0 | 
| optimizing                     | 0.000002 | 0.000000 |   0.000000 |            0 |             0 | 
| statistics                     | 0.000034 | 0.000000 |   0.000000 |            0 |             0 | 
| preparing                      | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| executing                      | 0.000002 | 0.000000 |   0.000000 |            0 |             0 | 
| Sending data                   | 0.000019 | 0.000000 |   0.000000 |            0 |             0 | 
| optimizing                     | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| statistics                     | 0.000032 | 0.000000 |   0.000000 |            0 |             0 | 
| preparing                      | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| executing                      | 0.000002 | 0.000000 |   0.000000 |            0 |             0 | 
| Sending data                   | 0.000016 | 0.000000 |   0.000000 |            0 |             0 | 
| optimizing                     | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| statistics                     | 0.000028 | 0.000000 |   0.000000 |            0 |             0 | 
| preparing                      | 0.000002 | 0.000000 |   0.000000 |            0 |             0 | 
| executing                      | 0.000002 | 0.000000 |   0.000000 |            0 |             0 | 
| Sending data                   | 0.000016 | 0.000000 |   0.000000 |            0 |             0 | 
| optimizing                     | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| statistics                     | 0.000028 | 0.000000 |   0.000000 |            0 |             0 | 
| preparing                      | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| executing                      | 0.000001 | 0.000000 |   0.000000 |            0 |             0 | 
| Sending data                   | 0.000024 | 0.000000 |   0.000000 |            0 |             0 | 
| optimizing                     | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| statistics                     | 0.000024 | 0.000000 |   0.000000 |            0 |             0 | 
| preparing                      | 0.000002 | 0.000000 |   0.000000 |            0 |             0 | 
| executing                      | 0.000010 | 0.000000 |   0.000000 |            0 |             0 | 
| optimizing                     | 0.000002 | 0.000000 |   0.000000 |            0 |             0 | 
| statistics                     | 0.000005 | 0.000000 |   0.000000 |            0 |             0 | 
| preparing                      | 0.000004 | 0.000000 |   0.000000 |            0 |             0 | 
| executing                      | 0.000001 | 0.000000 |   0.000000 |            0 |             0 | 
| Sending data                   | 0.000143 | 0.000000 |   0.000000 |            0 |             0 | 
| removing tmp table             | 0.000004 | 0.000000 |   0.000000 |            0 |             0 | 
| Sending data                   | 0.000007 | 0.000000 |   0.000000 |            0 |             0 | 
| query end                      | 0.000003 | 0.000000 |   0.000000 |            0 |             0 | 
| freeing items                  | 0.000048 | 0.000000 |   0.000000 |            0 |             0 | 
| storing result in query cache  | 0.000018 | 0.000000 |   0.000000 |            0 |             0 | 
| logging slow query             | 0.000001 | 0.000000 |   0.000000 |            0 |             0 | 
| logging slow query             | 0.000043 | 0.000000 |   0.000000 |            0 |             0 | 
| cleaning up                    | 0.000004 | 0.000000 |   0.000000 |            0 |             0 | 
+--------------------------------+----------+----------+------------+--------------+---------------+


in的话主要耗费在sending data上,而n+1比较稳定并且比in多了临时表,sending data包括索引的查找以及数据的传输,我想in慢在查找上,因为是innodb而且是主键,只要找到主键就可以得到数据。
至于,in是怎么实现查找的,这个就不清楚了。

郁闷
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2 楼 willko 2009-07-08  
mayongzhan 写道
测试200w的数据.是n+1的方法速度快.不知道你上次的实验是怎么做出来的,不过这n+1代码太恶心了..语句太长了.

希望能出现第三篇总结的文章.

这次,我调整了一下配置。。。
1 楼 mayongzhan 2009-07-06  
测试200w的数据.是n+1的方法速度快.不知道你上次的实验是怎么做出来的,不过这n+1代码太恶心了..语句太长了.

希望能出现第三篇总结的文章.

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