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ab测试 - php这串代码为什么并发时有的会写不进去

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Release： 2016-06-06 20:24:56
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拿AB压测了下 -n1000 -c10 每次写进的数量都不一样。

 file_put_contents("a.txt","a",FILE_APPEND);
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?>

回复内容：

拿AB压测了下 -n1000 -c10 每次写进的数量都不一样。

 file_put_contents("a.txt","a",FILE_APPEND);
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?>

因为并发状态下，用户1进来读取到的a.txt是100个字符，如果用2进来读取到的a.txt也是100个字符，则用户1会在101位置处写入，用户2也会在此位置写入，所以结果可能会比想要的结果少几个字符，所以每次数量都不一样,可以在写文件时加锁，如下

file_put_contents("a.txt", "a", FILE_APPEND | LOCK_EX);
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Related labels：
ab test php concurrent
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