使用Python操作MysqL数据库的时候常使用MySQLdb这个模块。
今天在开发的过程发现MysqLdb.connect有些参数没法设置。通过这个页面我们可以看到在connect的时候,可以设置的option和client_flags和MysqL c api相比差不少。
一个很重要的参数 MysqL_OPT_READ_TIMEOUT没法设置,这个参数如果不设置,极致状况MysqL处于hang住,自动切换IP漂移,客户端无法重连到新MysqL。
给MysqLdb加Option很简单,只要修改_MysqL.c这个把Python对象映射到MysqL操作的文件,添加参数,再加一段MysqL_option即可。
?View Code BASH diff --git a/_MysqL.c b/_MysqL.c index d42cc54..61a9b34 100644 --- a/_MysqL.c +++ b/_MysqL.c @@ -489,9 +489,10 @@ _MysqL_ConnectionObject_Initialize( "named_pipe","init_command","read_default_file","read_default_group","client_flag","ssl",- "local_infile",+ "local_infile","read_timeout",NULL } ; int connect_timeout = 0; + int read_timeout = 0; int compress = -1,named_pipe = -1,local_infile = -1; char *init_command=NULL,*read_default_file=NULL,@@ -500,7 +501,7 @@ _MysqL_ConnectionObject_Initialize( self->converter = NULL; self->open = 0; check_server_init(-1); - if (!PyArg_ParseTupleAndKeywords(args,kwargs,"|ssssisOiiisssiOi:connect",+ if (!PyArg_ParseTupleAndKeywords(args,"|ssssisOiiisssiOii:connect",kwlist,&host,&user,&passwd,&db,&port,&unix_socket,&conv,@@ -509,7 +510,8 @@ _MysqL_ConnectionObject_Initialize( &init_command,&read_default_file,&read_default_group,&client_flag,&ssl,- &local_infile /* DO NOT PATCH FOR RECONNECT,IdioTS + &local_infile,&read_timeout + /* DO NOT PATCH FOR RECONNECT,IdioTS IF YOU DO THIS,I WILL NOT SUPPORT YOUR PACKAGES. */ )) return -1; @@ -540,6 +542,12 @@ _MysqL_ConnectionObject_Initialize( MysqL_options(&(self->connection),MysqL_OPT_CONNECT_TIMEOUT,(char *)&timeout); } + + if (read_timeout) { + unsigned int timeout = read_timeout; + MysqL_options(&(self->connection),MysqL_OPT_READ_TIMEOUT,(char *)&timeout); + } + if (compress != -1) { MysqL_options(&(self->connection),MysqL_OPT_COMPRESS,0); client_flag |= CLIENT_COMPRESS;
代码修改完毕,python setup.py install 即可,如果出现MysqL_config找不到的问题。你还要修改setup_posix.py文件。
hoterran@hoterran-laptop:~/Projects/MysqL-python-1.2.3$ git diff setup_posix.py diff --git a/setup_posix.py b/setup_posix.py index 86432f5..f4f08f1 100644 --- a/setup_posix.py +++ b/setup_posix.py @@ -23,7 +23,7 @@ def MysqL_config(what): if ret/256 > 1: raise EnvironmentError("%s not found" % (MysqL_config.path,)) return data -MysqL_config.path = "MysqL_config" +MysqL_config.path = "/usr/local/MysqL/bin/MysqL_config" def get_config(): import os,sys
编译通过,我们来试试添加的read_timeout这个参数。
conn = MysqLdb.connect(host = DB_SERVER,user = DB_USERNAME,passwd = DB_PASSWORD,db = DB_NAME,port=int(DB_PORT),client_flag = 2,read_timeout = 10)
然后执行语句前,你试着把MysqL用gdb hang住10s后,python就会异常抛错
OperationalError: (2013,'Lost connection to MysqL server during query') >/home/hoterran/Projects/dbaas/trunk/dbtest.py(18)() >mydb.execute_sql(conn,sql) (Pdb) --Return-- > /home/hoterran/Projects/dbaas/trunk/dbtest.py(18)()->None > mydb.execute_sql(conn,sql) (Pdb) OperationalError: (2013,'Lost connection to MysqL server during query') > <string>(1)<module>()->None