In python, frequently used MySQLdboperations MySQL database.
In the implementation, MySQLdbnot the pure python, but encapsulates the MySQL C API library _mysql.

Whether MySQLdb support read_timeout, its manual did not mention this parameter. So, read_timeoutit really is available, the existence of doubt. It was also above the stack overflow asked the same question .

Next, we from MySQLdbthe source library MySQLdb-python github address begin, look at support read_timeout.

`MySQLdb`Source

Look at the code library HISTORYfile :

beta 4
======

Added support for the MySQL read_timeout option. Contributed by
Jean Schurger ([email protected]).

Added a workaround so that the MySQL character set utf8mb4 works with Python; utf8 is substituted
on the Python side.

Which has been clearly mentioned that the parameters have been read_timeoutprovided support.

The look, the underlying code is how to achieve _mysql.c :

/* According to https://dev.mysql.com/doc/refman/5.1/en/mysql-options.html
   The MYSQL_OPT_READ_TIMEOUT apear in the version 5.1.12 */
#if MYSQL_VERSION_ID > 50112
#define HAVE_MYSQL_OPT_TIMEOUTS 1
#endif


#ifdef HAVE_MYSQL_OPT_TIMEOUTS
    if (read_timeout) {
        unsigned int timeout = read_timeout;
        mysql_options(&(self->connection), MYSQL_OPT_READ_TIMEOUT,
                (char *)&timeout);
    }
    if (write_timeout) {
        unsigned int timeout = write_timeout;
        mysql_options(&(self->connection), MYSQL_OPT_WRITE_TIMEOUT,
                (char *)&timeout);
    }
#endif

From the code, you can see, MySQL is supported from version 5.1.12 read_timeout.

MySQLdbIn the specific implementation, by
mysql_options()setting parameters MYSQL_OPT_READ_TIMEOUT, to achieve read out.

On MYSQL_OPT_READ_TIMEOUTand MYSQL_OPT_WRITE_TIMEOUTyou can refer to the official MySQL documentation
mysql_options () .

Let's look at MySQLdb-pythonthe read_timeouthow.

`read_timeout`example

In the following example, we set read_timeoutas 5s, sql statement is executed and more than 5s.
View the results of its execution.

import MySQLdb
from datetime import datetime


host = "127.0.0.1"
port = 3306
sql = "select sleep(10)"
user = "root"
passwd = "Aa123456"

conn = MySQLdb.connect(host=host, port=port, user=user,passwd=passwd, connect_timeout=2, read_timeout=5, charset="utf8")
cursor = conn.cursor()

print("now:", datetime.now())

try:
        cursor.execute(sql)
except Exception as e:
        print("now:", datetime.now())
        print("except:", e)
        raise

ret = cursor.fetchone()
print("result:", ret)

cursor.close()
conn.close()
print("end")

output:

now: 2019-07-28 15:57:40.424942
now: 2019-07-28 15:57:45.425193
except: (2013, 'Lost connection to MySQL server during query')
Traceback (most recent call last):
  File "read_timeout.py", line 19, in <module>
    cursor.execute(sql)
  File "/Users/lanyang/workspace/orange-service/.venv/lib/python3.6/site-packages/MySQLdb/cursors.py", line 198, in execute
    res = self._query(query)
  File "/Users/lanyang/workspace/orange-service/.venv/lib/python3.6/site-packages/MySQLdb/cursors.py", line 304, in _query
    db.query(q)
  File "/Users/lanyang/workspace/orange-service/.venv/lib/python3.6/site-packages/MySQLdb/connections.py", line 217, in query
    _mysql.connection.query(self, query)
MySQLdb._exceptions.OperationalError: (2013, 'Lost connection to MySQL server during query')

It can be seen when the sql statement is executed more than 5s, the connection is broken.
It has reached the desired effect.