Random Errors with pyodbc and ODBC Driver 17 for SQL Server when Connecting to MSSQL Database

Question

I keep getting random errors while creating connections to mssql db like the below.

Those happen randomly and if I restart my jobs, it works again, until it doesn't and starts throwing similar errors again. I use pyodbc with {ODBC Driver 17 for SQL Server}.

Not sure what the problem is. Any ideas? Most common error i see is the "Communication link failure".

('08S01', '[08S01] [Microsoft][ODBC Driver 17 for SQL Server]Communication link failure (0) (SQLExecDirectW)')

('Connection aborted.', ConnectionAbortedError(10053, 'An established connection was aborted by the software in your host machine', None, 10053, None))

('IM002', '[IM002] [Microsoft][ODBC Driver Manager] Data source name not found and no default driver specified (0) (SQLDriverConnect)')

('08S01', '[08S01] [Microsoft][ODBC Driver 17 for SQL Server]Communication link failure (0) (SQLSetConnectAttr(SQL_ATTR_AUTOCOMMIT)); [08S01] [Microsoft][ODBC Driver 17 for SQL Server]The connection is broken and recovery is not possible. The client driver attempted to recover the connection one or more times and all attempts failed. Increase the value of ConnectRetryCount to increase the number of recovery attempts. (0)')

Answer 1

Hi Bill9x •,

Welcome to Microsoft Q&A forum.

As I understand, you are getting Communication link failure for SQL Server when Connecting to MSSQL Database.

Try below:

• Look for network issues.
• Check performance on target/application server
• Implement the retry-logic at connection and command execution.

Refer to complete blogpost to handle such error: https://techcommunity.microsoft.com/t5/azure-database-support-blog/lesson-learned-215-hands-on-labs-communication-link-failed-error/ba-p/3565011

Also, update ODBC driver, check firewall, network connectivity, logs etc

Let us know if this helped.

If not, we will continue to engage more on this for troubleshoot.

Thanks

Answer 2

Because the established connection was aborted by the software in your host machine, you must check your antivirus/firewall to find the reason of interrupting.

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