python - PyMySQL can't connect to MySQL on localhost

Question

I'm trying to connect to MySQL on localhost using PyMySQL:

import pymysql
conn = pymysql.connect(db='base', user='root', passwd='pwd', host='localhost')

but (both on Python 2.7 and Python 3.2) I get the error:

socket.error: [Errno 111] Connection refused

pymysql.err.OperationalError: (2003, "Can't connect to MySQL server on 'localhost' (111)")

I'm sure mysqld is running because I can connect using mysql command or phpMyAdmin. Moreover, I can connect using MySQLdb on Python 2 with nearly the same code:

import MySQLdb
conn = MySQLdb.connect(db='base', user='root', passwd='pwd', host='localhost')

It seems that the problem is on PyMySQL side rather than MySQL but I have no idea how to solve it.

Answer 1

Two guesses:

1. Run mysqladmin variables | grep socket to get where the socket is located, and try setting up a connection like so:

   pymysql.connect(db='base', user='root', passwd='pwd', unix_socket="/tmp/mysql.sock")
   

2. Run mysqladmin variables | grep port and verify that the port is 3306. If not, you can set the port manually like so:

   pymysql.connect(db='base', user='root', passwd='pwd', host='localhost', port=XXXX)
   

Answer 2

Seems like changing localhost to 127.0.0.1 fixes the error, at least in my configuration. If it doesn't, I would look for errors in tcp sockets connection and, of course, post it as a bug in pymysql bugtrack.

Answer 3

I solved the issue by replacing localhost with 127.0.0.1 and changing the password to my MYSQL database password as shown below;

conn = pymysql.connect(
    host = '127.0.0.1',
    port = 3306,
    user = 'root',
    passwd = 'XXXXXXXXX',
    db = 'mysql'
)

Answer 4

I met the same question and my solution is as follows:

1. Run ssh -fN -L 3307:mysql_host:3306 ssh_user@ssh_host in my terminal.
2. Then input your ssh password
3. conn = pymysql.connect(db='base', user='root', passwd='pwd', host='localhost')

This error occurs because database does not support link directly.

Answer 5

I asked why socket worked but not TCP and the answer was that bind-address in /etc/my.cnf was not set correctly. This could be your problem too since the socket methods works just fine but the TCP one does not.

Answer 6

Those who are strugging to connect localhost MySQL from dockerised flask-sqlalchemy or using pymysql, pls look into this thread, very usefull How to connect locally hosted MySQL database with the docker container

Answer 7

This worked for me:

import pymysql

db = pymysql.connect(host="localhost",port=8889,user="root",passwd="root")
cursor=db.cursor()
cursor.execute("SHOW DATABASES")
results=cursor.fetchall()
for result in results:
    print (result)

if you want to find the port # go to mysql in terminal, and type:

SHOW VARIABLES WHERE Variable_name = 'hostname';
SHOW VARIABLES WHERE Variable_name = 'port';

Answer 8

You need to add the port to the connection as well. Try this and it works fine.

pymysql(Module Name).connect(host="localhost", user="root", passwd="root", port=8889, db="db_name")