pr-451 with additional tests and some documentation editing

AUTHORS

@@ -18,6 +18,7 @@ Asta Xie <xiemengjun at gmail.com>
 Bulat Gaifullin <gaifullinbf at gmail.com>
 Carlos Nieto <jose.carlos at menteslibres.net>
 Chris Moos <chris at tech9computers.com>
+Chris Piraino <piraino.chris at gmail.com>
 Daniel Nichter <nil at codenode.com>
 Daniël van Eeden <git at myname.nl>
 Dave Protasowski <dprotaso at gmail.com>
@@ -34,6 +35,7 @@ INADA Naoki <songofacandy at gmail.com>
 Jacek Szwec <szwec.jacek at gmail.com>
 James Harr <james.harr at gmail.com>
 Jian Zhen <zhenjl at gmail.com>
+John Shahid <jvshahid at gmail.com>
 Joshua Prunier <joshua.prunier at gmail.com>
 Julien Lefevre <julien.lefevr at gmail.com>
 Julien Schmidt <go-sql-driver at julienschmidt.com>
@@ -58,6 +60,7 @@ Runrioter Wung <runrioter at gmail.com>
 Soroush Pour <me at soroushjp.com>
 Stan Putrya <root.vagner at gmail.com>
 Stanley Gunawan <gunawan.stanley at gmail.com>
+Thomas Parrott <tomp at tomp.uk>
 Xiangyu Hu <xiangyu.hu at outlook.com>
 Xiaobing Jiang <s7v7nislands at gmail.com>
 Xiuming Chen <cc at cxm.cc>

driver_test.go

@@ -1773,6 +1773,88 @@ func TestCustomDial(t *testing.T) {
 	}
 }
 
+// Ensure mariadb's ER_CONNECTION_KILLED will cause the query to be restarted
+func TestConnectionLost(t *testing.T) {
+	if !available {
+		t.Skipf("MySQL server not running on %s", netAddr)
+	}
+
+	var proxyConn net.Conn
+
+	killCh := make(chan struct{})
+
+	// our custom dial function which justs wraps net.Dial here
+	RegisterDial("mydial", func(addr string) (net.Conn, error) {
+		conn, err := net.Dial(prot, addr)
+		if err != nil {
+			return nil, err
+		}
+
+		var clientConn net.Conn
+		proxyConn, clientConn = net.Pipe()
+		go io.Copy(conn, proxyConn)
+
+		bytesCh := make(chan []byte)
+		go func() {
+			for {
+				bs := make([]byte, 1024)
+				n, err := conn.Read(bs)
+				if err == io.EOF {
+					return
+				}
+				if err != nil {
+					panic(err)
+				}
+				bytesCh <- bs[:n]
+			}
+		}()
+		go func() {
+			for {
+				select {
+				case bs := <-bytesCh:
+					_, err := proxyConn.Write(bs)
+					if err == io.ErrClosedPipe {
+						return
+					}
+					if err != nil {
+						panic(err)
+					}
+				case <-killCh:
+					go func() {
+						proxyConn.Write([]byte{
+							0x08, // packet size
+							0x00,
+							0x00,
+							0x00, // sequence 0
+							0xFF, // err_packet
+							0x87, // ER_CONNECTION_KILLED error
+							0x07,
+							0x00, // sql_state_marker
+						})
+					}()
+				}
+			}
+		}()
+		return clientConn, err
+	})
+
+	db, err := sql.Open("mysql", fmt.Sprintf("%s:%s@mydial(%s)/%s?timeout=30s&strict=true", user, pass, addr, dbname))
+	if err != nil {
+		t.Fatalf("error connecting: %s", err.Error())
+	}
+	defer db.Close()
+
+	if _, err = db.Exec("DO 1"); err != nil {
+		t.Fatalf("connection failed: %s", err.Error())
+	}
+
+	killCh <- struct{}{}
+
+	if _, err = db.Exec("DO 1"); err != nil {
+		t.Fatalf("connection failed: %s", err.Error())
+	}
+}
+
 func TestSQLInjection(t *testing.T) {
 	createTest := func(arg string) func(dbt *DBTest) {
 		return func(dbt *DBTest) {

packets.go

@@ -46,8 +46,15 @@ func (mc *mysqlConn) readPacket() ([]byte, error) {
 			if data[3] > mc.sequence {
 				return nil, ErrPktSyncMul
 			}
-			return nil, ErrPktSync
+
+			// The MariaDB server sends an error packet with sequence numer 0 during
+			// server shutdown. Continue to process it so the specific error can be
+			// detected.
+			if data[3] != 0 {
+				return nil, ErrPktSync
+			}
 		}
+
 		mc.sequence++
 
 		// packets with length 0 terminate a previous packet which is a
@@ -585,6 +592,13 @@ func (mc *mysqlConn) handleErrorPacket(data []byte) error {
 		pos = 9
 	}
 
+	// If error code is for ER_CONNECTION_KILLED, then mark connection as bad.
+	// https://mariadb.com/kb/en/mariadb/mariadb-error-codes/
+	if errno == 1927 {
+		errLog.Print("Error ", errno, ": ", string(data[pos:]))
+		return driver.ErrBadConn
+	}
+
 	// Error Message [string]
 	return &MySQLError{
 		Number:  errno,

packets_test.go

@@ -115,9 +115,9 @@ func TestReadPacketWrongSequenceID(t *testing.T) {
 	}
 
 	// too low sequence id
-	conn.data = []byte{0x01, 0x00, 0x00, 0x00, 0xff}
+	conn.data = []byte{0x01, 0x00, 0x00, 0x01, 0xff}
 	conn.maxReads = 1
-	mc.sequence = 1
+	mc.sequence = 2
 	_, err := mc.readPacket()
 	if err != ErrPktSync {
 		t.Errorf("expected ErrPktSync, got %v", err)