希望发起对douban/libmc#75 的讨论，pr内容可以先不看，我下面会简单介绍。
1，首先引入对multi thread logging 的支持。对于dae-go这种有自己的pool实现，里面放了golibmc的Client。这样一来 多个goruntine可能会拿多个Client同时操作。需要有线程唯一的mutex来保证log不会串。同理对于python多线程程序(或gevent)来讲 如果要用libmc也会面临类似问题。引入plog能够解决这一点。
https://github.com/SergiusTheBest/plog/blob/master/include/plog/Appenders/ConsoleAppender.h#L28
现象:
dae-go的一个项目elves，通过elves的sentry发现，通常（最近观察到的都是）在AM 1:00 到AM: 9:00 会出现大量的recv error，elves的开发者一直在追问是什么情况。
elves的用法如下
begin := time.Now()
if rated, err = mc.IncrUint64(key, 1); err != nil && err.Error() == LIBMC_CACHE_MISS_ERROR {
rated = 1
| chenlijun@redis00 /tmp/test_warn $ python tmp.py | |
| see each key the first time | |
| File "tmp.py", line 5, in <module> | |
| func1("aaa") | |
| File "/tmp/test_warn/app_code.py", line 5, in func1 | |
| get1(val) | |
| File "/tmp/test_warn/fake_libmc.py", line 14, in get1 | |
| warnings.warn(val) | |
| File "/tmp/test_warn/fake_libmc.py", line 7, in warn_with_traceback | |
| traceback.print_stack(file=log) |
| 125046514 function calls in 233.965 seconds | |
| Ordered by: standard name | |
| ncalls tottime percall cumtime percall filename:lineno(function) | |
| 1214379 6.203 0.000 9.627 0.000 __init__.py:6368(__init__) | |
| 1214379 2.753 0.000 8.325 0.000 __init__.py:6379(_get_document) | |
| - 141990135 function calls in 4517.825 seconds | |
| + 141990135 function calls in 305.731 seconds | |
| - 15732127 35.384 0.000 41.229 0.000 __init__.py:6549(__init__) | |
| + 15732127 27.876 0.000 32.483 0.000 __init__.py:6549(__init__) | |
| class TermListItem(object): | |
| def __init__(self, iter, term): | |
| self._iter = iter | |
| self.term = term | |
| self._wdf = None |
| --- 1.txt 2013-11-20 21:24:35.000000000 +0800 | |
| +++ 3.txt 2013-11-20 21:24:35.000000000 +0800 | |
| @@ -1,4 +1,4 @@ | |
| - 309378992 function calls in 596.173 seconds | |
| + 309378996 function calls in 9818.898 seconds | |
| Ordered by: standard name | |
| @@ -33,7 +33,7 @@ | |
| 1 0.000 0.000 0.000 0.000 __init__.py:2732(ExpandDecider) |
| --- 1.txt 2013-11-20 21:24:35.000000000 +0800 | |
| +++ 2.txt 2013-11-20 21:24:35.000000000 +0800 | |
| @@ -1,4 +1,4 @@ | |
| - 309378992 function calls in 596.173 seconds | |
| + 309378992 function calls in 592.411 seconds | |
| Ordered by: standard name | |
| @@ -89,13 +89,13 @@ | |
| 1 0.000 0.000 0.000 0.000 __init__.py:705(NetworkError) |
| In [88]: class C: | |
| ....: def foo(self): | |
| ....: pass | |
| ....: foo = classmethod(foo) | |
| ....: | |
| In [89]: C.__dict__ | |
| Out[89]: | |
| {'__doc__': None, | |
| '__module__': '__main__', |
| In [29]: class foo(): | |
| ....: def __init__(self): | |
| ....: self.__x = 1 | |
| ....: | |
| In [30]: r1 = foo() | |
| In [31]: r1.__x | |
| --------------------------------------------------------------------------- | |
| AttributeError Traceback (most recent call last) |