fix: concurrency issue in stdConnOpener (#918)

clickhouse_std.go

@@ -77,8 +77,6 @@ func (o *stdConnOpener) Connect(ctx context.Context) (_ driver.Conn, err error)
 		return nil, ErrAcquireConnNoAddress
 	}
 
-	o.setClientInfoDefaults()
-
 	for i := range o.opt.Addr {
 		var num int
 		switch o.opt.ConnOpenStrategy {
@@ -104,10 +102,6 @@ func (o *stdConnOpener) Connect(ctx context.Context) (_ driver.Conn, err error)
 	return nil, err
 }
 
-func (o *stdConnOpener) setClientInfoDefaults() {
-	o.opt.ClientInfo.comment = []string{"database/sql"}
-}
-
 func init() {
 	var debugf = func(format string, v ...interface{}) {}
 	sql.Register("clickhouse", &stdDriver{debugf: debugf})
@@ -197,6 +191,7 @@ func (std *stdDriver) Open(dsn string) (_ driver.Conn, err error) {
 	if o.Debug {
 		debugf = log.New(os.Stdout, fmt.Sprintf("[clickhouse-std][opener] "), 0).Printf
 	}
+	o.ClientInfo.comment = []string{"database/sql"}
 	return (&stdConnOpener{opt: o, debugf: debugf}).Connect(context.Background())
 }