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使用Python操作MySQL數(shù)據(jù)庫的時候常使用MySQLdb這個模塊。
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今天在開發(fā)的過程發(fā)現(xiàn)MySQLdb.connect有些參數(shù)沒法設(shè)置。通過這個頁面我們可以看到在connect的時候，可以設(shè)置的option和client_flags和MySQL c api相比差不少。
一個很重要的參數(shù) MYSQL_OPT_READ_TIMEOUT沒法設(shè)置，這個參數(shù)如果不設(shè)置，***狀況MySQL處于hang住，自動切換IP漂移，客戶端無法重連到新MySQL。
給MySQLdb加Option很簡單，只要修改_mysql.c這個把Python對象映射到MySQL操作的文件，添加參數(shù)，再加一段mysql_option即可。
下面是修改后的git diff 文件
- 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, kwargs, "|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;
代碼修改完畢，python setup.py install 即可，如果出現(xiàn)mysql_config找不到的問題。你還要修改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
編譯通過，我們來試試添加的read_timeout這個參數(shù)。
- 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)
然后執(zhí)行語句前，你試著把mysql用gdb hang住10s后，python就會異常拋錯
- 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')
- > (1)()->None
原文出處：http://ourmysql.com/archives/932
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文章標(biāo)題：如何給Python的MySQL模塊加功能
文章URL：http://www.dlmjj.cn/article/coidjop.html
