Sporadic invalid connection error in a web server

[MaticVerbic]

Issue description

Exec() and Query() methods (seemingly) randomly return ErrInvalidConnection with no explanation. I have been unsuccessful in trying to replicate this issue locally.

I've gone through #654 and #836: but I don't seem to find a way to work around this from the user side.

Example code

//Execute - execute type query
func (h *Handler) Execute(query string, args []interface{}) (IDBResult, error) {
	var rsp sql.Result
	var err error

	rsp, err = h.conn.Exec(query, args...)
	if err != nil {
		return nil, err
	}

	return rsp, err
}

Error log

No error log since the only error that's returned is invalid connection.

Configuration

Driver version (or git SHA): 1.4.1

Go version: 1.14

[shogo82148]

Please read https://github.com/go-sql-driver/mysql/wiki/Support at first.
You should ask such questions in Gopher Slack, Stack Overflow, or somewhere else.

[MaticVerbic]

@shogo82148 I have done as you have suggested and opened a question on StackOverflow.

Admittedly I chose to skip that step before since we believe that this issue is caused by this driver (v1.4.1 and v1.5.0) and thus opened this issue.

No matter in which way I tried to produce this error, I could not, thus leading me to believe this is happening due to some internal driver implementation.

The other point that lead me to that belief is that this specific error is only thrown if some unexported flags within the driver itself are set, specifically mysqlConn.closed.

[methane]

Continue in https://stackoverflow.com/questions/64968877/sporadic-mysql-invalid-connection-error-in-a-web-server

[himanshupandey-cpi]

@methane the stackoverflow link provided is dead. I am also facing this problem, is there a fix for it already in new driver versions. I am using 1.4.0

[MaticVerbic]

@methane the stackoverflow link provided is dead. I am also facing this problem, is there a fix for it already in new driver versions. I am using 1.4.0

We found out the error was actually on the system side with the MySQL database itsellf. I can't provide further help though, besides the fact that updating it helped.