retrieve connection type information

Signed-off-by: Harshit Gangal <[email protected]>

go/mysql/conn.go

@@ -1624,12 +1624,18 @@ func (c *Conn) TLSEnabled() bool {
 	return c.Capabilities&CapabilityClientSSL > 0
 }
 
-// IsUnixSocket returns true if this connection is over a Unix socket.
+// IsUnixSocket returns true if the server connection is over a Unix socket.
 func (c *Conn) IsUnixSocket() bool {
 	_, ok := c.listener.listener.(*net.UnixListener)
 	return ok
 }
 
+// IsClientUnixSocket returns true if the client connection is over a Unix socket with the server.
+func (c *Conn) IsClientUnixSocket() bool {
+	_, ok := c.conn.(*net.UnixConn)
+	return ok
+}
+
 // GetRawConn returns the raw net.Conn for nefarious purposes.
 func (c *Conn) GetRawConn() net.Conn {
 	return c.conn

go/vt/vttablet/tabletserver/connpool/dbconn.go

@@ -600,5 +600,5 @@ func (dbc *Conn) applySameSetting(ctx context.Context) error {
 }
 
 func (dbc *Conn) IsUnixSocket() bool {
-	return dbc.conn.Conn.IsUnixSocket()
+	return dbc.conn.IsClientUnixSocket()
 }

go/vt/vttablet/tabletserver/dt_executor.go

@@ -67,7 +67,9 @@ func (dte *DTExecutor) Prepare(transactionID int64, dtid string) error {
 		return nil
 	}
 
-	if !conn.dbConn.Conn.IsUnixSocket() {
+	// We can only prepare on a Unix socket connection.
+	// Unix socket are reliable and we can be sure that the connection is not lost with the server after prepare.
+	if !conn.IsUnixSocket() {
 		dte.te.txPool.RollbackAndRelease(dte.ctx, conn)
 		return vterrors.VT10002("cannot prepare the transaction on a network connection")
 	}

go/vt/vttablet/tabletserver/stateful_connection.go

@@ -264,7 +264,7 @@ func (sc *StatefulConnection) IsTainted() bool {
 // LogTransaction logs transaction related stats
 func (sc *StatefulConnection) LogTransaction(reason tx.ReleaseReason) {
 	if sc.txProps == nil {
-		return //Nothing to log as no transaction exists on this connection.
+		return // Nothing to log as no transaction exists on this connection.
 	}
 	sc.txProps.Conclusion = reason.Name()
 	sc.txProps.EndTime = time.Now()
@@ -288,7 +288,7 @@ func (sc *StatefulConnection) SetTimeout(timeout time.Duration) {
 // logReservedConn logs reserved connection related stats.
 func (sc *StatefulConnection) logReservedConn() {
 	if sc.reservedProps == nil {
-		return //Nothing to log as this connection is not reserved.
+		return // Nothing to log as this connection is not reserved.
 	}
 	duration := time.Since(sc.reservedProps.StartTime)
 	username := sc.getUsername()
@@ -315,3 +315,8 @@ func (sc *StatefulConnection) ApplySetting(ctx context.Context, setting *smartco
 func (sc *StatefulConnection) resetExpiryTime() {
 	sc.expiryTime = time.Now().Add(sc.timeout)
 }
+
+// IsUnixSocket returns true if the connection is using a unix socket
+func (sc *StatefulConnection) IsUnixSocket() bool {
+	return sc.dbConn.Conn.IsUnixSocket()
+}