Common MYSQL Error – Lost connection to MySQL server
There are three likely causes for this error message.
Usually it indicates network connectivity trouble and you should check the condition of your network if this error occurs frequently. If the error message includes “during query,” this is probably the case you are experiencing.
Sometimes the “during query” form happens when millions of rows are being sent as part of one or more queries. If you know that this is happening, you should try increasing net_read_timeout from its default of 30 seconds to 60 seconds or longer, sufficient for the data transfer to complete.
More rarely, it can happen when the client is attempting the initial connection to the server. In this case, if your connect_timeout value is set to only a few seconds, you may be able to resolve the problem by increasing it to ten seconds, perhaps more if you have a very long distance or slow connection. You can determine whether you are experiencing this more uncommon cause by using SHOW GLOBAL STATUS LIKE ‘Aborted_connects’. It will increase by one for each initial connection attempt that the server aborts. You may see “reading authorization packet” as part of the error message; if so, that also suggests that this is the solution that you need.
If the cause is none of those just described, you may be experiencing a problem with BLOB values that are larger than max_allowed_packet, which can cause this error with some clients. Sometime you may see “packet too large” as part of the error message, and that confirms that you need to increase max_allowed_packet.
What are MYSQL Errors?
MySQL programs have access to several types of error information when the server returns an error.
The MYSQL message displayed contains three types of information:
A numeric error code. This number is MySQL-specific and is not portable to other database systems.
A five-character SQLSTATE value. The values are specified by ANSI SQL and ODBC and are more standardized. Not all MySQL error numbers are mapped to SQLSTATE error codes.
A message string that provides a textual description of the error.
When an error occurs, you can access the MySQL error code, the SQLSTATE value, and the message string using C API functions:
MySQL error code: Call mysql_errno()
SQLSTATE value: Call mysql_sqlstate()
Error message: Call mysql_error()
Hope this was helpful.
Information about MYSQL Error Codes and Error Messages or Warnings on Windows, Linux Operating Systems.