mysql插入竞争条件 [英] mysql insert race condition
问题描述
如何在MySQL中停止竞争条件?眼前的问题是由一个简单的算法引起的:
How do you stop race conditions in MySQL? the problem at hand is caused by a simple algorithm:
- 从表中选择一行
- 如果不存在，请插入
，然后您得到重复的行，或者如果您通过唯一/主键阻止它，则会出现错误.
and then either you get a duplicate row, or if you prevent it via unique/primary keys, an error.
现在通常我认为事务在这里有用，但是因为该行不存在，所以事务实际上并没有帮助(或者我遗漏了什么?).
Now normally I'd think transactions help here, but because the row doesn't exist, the transaction don't actually help (or am I missing something?).
LOCK TABLE听起来有些矫kill过正，尤其是如果该表每秒更新多次.
LOCK TABLE sounds like an overkill, especially if the table is updated multiple times per second.
我能想到的唯一其他解决方案是对每个不同的id使用GET_LOCK()，但是没有更好的方法吗?这里也没有可伸缩性问题吗?而且，对每个表执行此操作听起来有点不自然，因为这对我而言在高并发数据库中听起来是一个非常普遍的问题.
The only other solution I can think of is GET_LOCK() for every different id, but isn't there a better way? Are there no scalability issues here as well? And also, doing it for every table sounds a bit unnatural, as it sounds like a very common problem in high-concurrency databases to me.
推荐答案
您想要的是锁定表
或者如果看起来过分的话插入IGNORE 与检查该行是否已实际插入.
or if that seems excessive how about INSERT IGNORE with a check that the row was actually inserted.
如果使用IGNORE关键字，则会出现错误 在执行INSERT时发生的情况 声明被视为警告 代替.
If you use the IGNORE keyword, errors that occur while executing the INSERT statement are treated as warnings instead.
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