“Login timeout expired” error when accessing MS SQL db via sqlalchemy and pyodbc

问题

So I have some trouble getting sqlalchemy and pyodbc working with a remote MS SQL Server. Local sqlcmd worked properly but not when I try to read the db via python code. Any help would be appreciated.

Environment:

Centos 7
SQLCmd version: Version 17.1.0000.1 Linux
MS SQL Server 6.01.7601.17514
Python 2.7

The following sqlcmd worked properly

sqlcmd -S {Host},{Port} -U {USER} -P {PWD} -Q "use {Database};"

Attempts to work with sqlalchemy or pyodbc directly didn't work. Error:

pyodbc.OperationalError: ('HYT00', u'[HYT00] [unixODBC][Microsoft][ODBC Driver 17 for SQL Server]Login timeout expired (0) (SQLDriverConnect)')

Code: Attempt with pyodbc

conn = pyodbc.connect(
    r'DRIVER={ODBC Driver 17 for SQL Server};'
    r'SERVER=HOST,PORT;'
    r'DATABASE=DATABASE;'
    r'UID=UID;'
    r'PWD=PWD'
    )

Attempt with sqlalchemy:

create_engine('mssql+pyodbc://{user}:{password}@{host}:{port}/{database}?driver={driver}'.format(
        user=user,
        password=password,
        host=host,
        database=database,
        port=port,
        driver="ODBC+Driver+17+for+SQL+Server"
    )).connect()

I can reproduce the error with sqlcmd if I remove the port from the command, so maybe the conn_string I am passing to pyodbc is not in the correct format?

回答1:

The problem might be DNS related, as you can read here.
Try to use an IP address, instead of the hostname, in the connection string, or check your DNS configuration.

回答2:

What does your python code do? Problem might be multiple Connections calls. Dont open the connection in a loop. Or conn.close() at the wrong point. Other problem could be a firewall rule issue, check it.

I use pymssql to acces to my sql server. Read the documentation and install pymssql and freetds-dev on your centos system. Maybe u need to edit freetds.conf and add the ip and port of your sql server.

来源：https://stackoverflow.com/questions/50996079/login-timeout-expired-error-when-accessing-ms-sql-db-via-sqlalchemy-and-pyodbc

标签

sql-server

sqlalchemy

pyodbc

sqlcmd