AWS Aurora issues with MySQL.Data connector for .NET clients

Hello,

The 'Got an error reading communication packets' is a generic warning message and could appear due to a variety of reasons including improper termination of a client connection, sleeping connections exceeding the 'wait_timeout' or the 'interactive_timeout' values and consequently being forcibly closed by the Aurora MySQL server, the client exceeding the 'max_allowed_packet' value for queries etc.

Some of the common reasons for such error messages are as follows:

1. It takes more than connect_timeout seconds to obtain a connect packet.
2. The client had been sleeping more than wait_timeout or interactive_timeout seconds without issuing any requests to the server. I can see that you have increased the time out values for these parameters.
3. The max_allowed_packet variable value is too small or queries require more memory than you have allocated for mysqld.
4. The client program did not call mysql_close() before exiting.
5. The client program ended abruptly in the middle of a data transfer.
6. A connection packet does not contain the right information.

These are some checks that could be made:

• show full processlist;
• SHOW GLOBAL STATUS like '%aborted%';
• select * from innodb_locks;
• select * from innodb_trx;
• select * from innodb_lock_waits;
• Show engine InnoDB Status

This will give you some extra information in order to dive into this issue since the information about the status of the connections is internal and due to security reasons we do not have access to this data.

Here are some possible remediation methods that might help you resolve/reduce the occurrence of these errors :

1. Close the connection properly on the application side rather than waiting for it to timeout. We strongly recommend changing the application logic to properly close connections at the end of an operation, this can be done by calling the close() function from within your application.
2. Set 'wait_timeout' to a higher value (max. value possible) [+] https://dev.mysql.com/doc/refman/5.7/en/server-system-variables.html#sysvar_wait_timeout
3. Set max_allowed_packet to a higher value [+] https://dev.mysql.com/doc/refman/5.7/en/server-system-variables.html#sysvar_max_allowed_packet
4. If you are using an application to connect, make sure the timeout value on the application end is not shorter than the 'wait_timeout' otherwise connections will be aborted abruptly from the application end thus causing this error.

You may also refer to the following links for more information:

• How do I resolve the "Got an error reading communication packets" error in Amazon RDS MySQL? : https://aws.amazon.com/premiumsupport/knowledge-center/rds-mysql-communication-packet-error/ • https://www.percona.com/blog/2016/05/16/mysql-got-an-error-reading-communication-packet-errors/
• https://www.percona.com/blog/2008/08/23/how-to-track-down-the-source-of-aborted_connects/
• https://aws.amazon.com/blogs/database/best-practices-for-configuring-parameters-for-amazon-rds-for-mysql-part-3-parameters-related-to-security-operational-manageability-and-connectivity-timeout/
• Aurora MySQL database engine updates 2022-10-25 (version 2.11.0) : https://docs.aws.amazon.com/AmazonRDS/latest/AuroraMySQLReleaseNotes/AuroraMySQL.Updates.2110.html • MySQL bugs fixed by Aurora MySQL database engine updates : https://docs.aws.amazon.com/AmazonRDS/latest/AuroraMySQLReleaseNotes/AuroraMySQL.Updates.MySQLBugs.html

I hope the above information helps!

Thank you and wishing you a great day ahead!