Error like this:

Collecting misaka==2.1.1 (from -r requirements.txt (line 12))
  Downloading https://pypi.tuna.tsinghua.edu.cn/packages/fa/87/b1020510a00aba1b936477e54180b143df654c565b84936b0b3e85272cf2/misaka-2.1.1.tar.gz (125kB)
    ERROR: Complete output from command python setup.py egg_info:
    ERROR: 
        No working compiler found, or bogus compiler options passed to
        the compiler from Python's standard "distutils" module.  See
        the error messages above.  Likely, the problem is not related
        to CFFI but generic to the setup.py of any Python package that
        tries to compile C code.  (Hints: on OS/X 10.8, for errors about
        -mno-fused-madd see http://stackoverflow.com/questions/22313407/
        Otherwise, see https://wiki.python.org/moin/CompLangPython or
        the IRC channel #python on irc.freenode.net.)
    
        Trying to continue anyway.  If you are trying to install CFFI from
        a build done in a different context, you can ignore this warning.
    
    Traceback (most recent call last):
      File "/usr/local/lib/python3.7/distutils/unixccompiler.py", line 118, in _compile
        extra_postargs)
      File "/usr/local/lib/python3.7/distutils/ccompiler.py", line 909, in spawn
        spawn(cmd, dry_run=self.dry_run)
      File "/usr/local/lib/python3.7/distutils/spawn.py", line 36, in spawn
        _spawn_posix(cmd, search_path, dry_run=dry_run)
      File "/usr/local/lib/python3.7/distutils/spawn.py", line 159, in _spawn_posix
        % (cmd, exit_status))
    distutils.errors.DistutilsExecError: command 'gcc' failed with exit status 1

And my Dockerfile is here:

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以前的写法是这样的,

from pymongo import MongoClient
client = MongoClient(host='127.0.0.1')
db = client['dbname']
db.authenticate(user, password)

不过上面的已经废弃

warning:: Starting in MongoDB 3.6, calling :meth:authenticate
invalidates all existing cursors. It may also leave logical sessions
open on the server for up to 30 minutes until they time out.



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MySql经常用,但是通常就是ORM中间件来CRUD操作,很少关注索引问题,可能是我近些年很少用MySQL做大型的系统了。
现在一面试就遇到所有领域的问题来都来一个问一遍,MySQL的复合索引其实也就一知半解。

面试官的问类似于select语句里where a>100 and b=3 and c=1 能否命中创建的(a, b, c)这种索引,还有a>100能否命中这个复合索引。

我想当然就说,a>100 and b=3 and c=1 只能命令(a, b, c)这种索引, a>100不能命中。唉呀,人家笑了。我说我可能说的不对,我下来试试。好吧查资料,建表,亲自实操一把。


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