fix up constants for server cursor types and add a support for PARAMETER_COUNT_AVAILABLE cursor

go/mysql/conn.go

@@ -1609,7 +1609,7 @@ func (c *Conn) execQuery(ctx context.Context, query string, handler Handler, mul
 // requests to write the rows from the result set.
 func (c *Conn) execPrepareStatement(ctx context.Context, stmtID uint32, cursorType byte, handler Handler) error {
 	prepare := c.PrepareData[stmtID]
-	if cursorType == NoCursor {
+	if cursorType == NoCursor || cursorType == ParameterCountAvailable {
 		fieldSent := false
 		sendFinished := false // sendFinished is set if the response should just be an OK packet.
 
@@ -1664,74 +1664,72 @@ func (c *Conn) execPrepareStatement(ctx context.Context, stmtID uint32, cursorTy
 		}
 
 		return nil
-	} else {
-		next := make(chan *sqltypes.Result)
-		done, quit := make(chan error), make(chan error)
+	}
+	next := make(chan *sqltypes.Result)
+	done, quit := make(chan error), make(chan error)
 
-		go func() {
-			var err error
-			defer func() {
-				// pass along error, even if there's a panic
-				if r := recover(); r != nil {
-					err = fmt.Errorf("panic while running query for server-side cursor: %v", r)
-				}
-				close(next)
-				done <- err
-				close(done)
-			}()
-			err = handler.ComStmtExecute(ctx, c, prepare, func(qr *sqltypes.Result) error {
-				// block until query results are sent or receive signal to quit
-				var qerr error
-				select {
-				case next <- qr:
-				case qerr = <-quit:
-				}
-				return qerr
-			})
+	go func() {
+		var err error
+		defer func() {
+			// pass along error, even if there's a panic
+			if r := recover(); r != nil {
+				err = fmt.Errorf("panic while running query for server-side cursor: %v", r)
+			}
+			close(next)
+			done <- err
+			close(done)
 		}()
-
-		// Immediately receive the very first query result to write the fields
-		qr, ok := <-next
-		if !ok {
-			<-done
-			if werr := c.writeErrorPacket(ERUnknownError, SSUnknownSQLState, "unknown error: %v", "missing result set"); werr != nil {
-				log.Errorf("Error writing query error to %s: %v", c, werr)
-				return werr
+		err = handler.ComStmtExecute(ctx, c, prepare, func(qr *sqltypes.Result) error {
+			// block until query results are sent or receive signal to quit
+			var qerr error
+			select {
+			case next <- qr:
+			case qerr = <-quit:
 			}
-			return nil
-		}
+			return qerr
+		})
+	}()
 
-		if len(qr.Fields) == 0 {
-			// DML or something without a result set. We do not open a cursor here.
-			<-done
-			return c.writeOKPacket(qr.RowsAffected, qr.InsertID, c.StatusFlags, 0)
-		} else {
-			// Open the cursor and write the fields.
-			c.StatusFlags |= uint16(ServerCursorExists)
-			if err := c.writeFieldsWithoutEOF(qr); err != nil {
-				log.Errorf("Error writing fields to %s: %v", c, err)
-				return err
-			}
-			// TODO: Look into whether accessing WarningCount
-			// here after passing `c` to ComStmtExecute in the
-			// goroutine above races.
-			if werr := c.writeEndResult(false, 0, 0, handler.WarningCount(c)); werr != nil {
-				log.Errorf("Error writing result to %s: %v", c, werr)
-				return werr
-			}
-			// After writing the EOF_Packet/OK_Packet above, we
-			// have told the client the cursor is open.
-			c.StatusFlags &= ^uint16(ServerCursorExists)
-			c.cs = &cursorState{
-				stmtID:  stmtID,
-				next:    next,
-				done:    done,
-				quit:    quit,
-				pending: qr,
-			}
-			return nil
+	// Immediately receive the very first query result to write the fields
+	qr, ok := <-next
+	if !ok {
+		<-done
+		if werr := c.writeErrorPacket(ERUnknownError, SSUnknownSQLState, "unknown error: %v", "missing result set"); werr != nil {
+			log.Errorf("Error writing query error to %s: %v", c, werr)
+			return werr
 		}
+		return nil
+	}
+
+	if len(qr.Fields) == 0 {
+		// DML or something without a result set. We do not open a cursor here.
+		<-done
+		return c.writeOKPacket(qr.RowsAffected, qr.InsertID, c.StatusFlags, 0)
 	}
+	// Open the cursor and write the fields.
+	c.StatusFlags |= uint16(ServerCursorExists)
+	if err := c.writeFieldsWithoutEOF(qr); err != nil {
+		log.Errorf("Error writing fields to %s: %v", c, err)
+		return err
+	}
+	// TODO: Look into whether accessing WarningCount
+	// here after passing `c` to ComStmtExecute in the
+	// goroutine above races.
+	if werr := c.writeEndResult(false, 0, 0, handler.WarningCount(c)); werr != nil {
+		log.Errorf("Error writing result to %s: %v", c, werr)
+		return werr
+	}
+	// After writing the EOF_Packet/OK_Packet above, we
+	// have told the client the cursor is open.
+	c.StatusFlags &= ^uint16(ServerCursorExists)
+	c.cs = &cursorState{
+		stmtID:  stmtID,
+		next:    next,
+		done:    done,
+		quit:    quit,
+		pending: qr,
+	}
+	return nil
 }
 
 //

go/mysql/constants.go

@@ -168,12 +168,13 @@ const (
 )
 
 // Cursor Types. They are received on COM_STMT_EXECUTE()
-// See https://mariadb.com/kb/en/com_stmt_execute/
+// See https://dev.mysql.com/doc/dev/mysql-server/9.3.0/mysql__com_8h.html#a3e5e9e744ff6f7b989a604fd669977da
 const (
-	NoCursor = iota
-	ReadOnly
-	CursorForUpdate
-	ScrollableCursor
+	NoCursor uint8 = 0x00
+	ReadOnly uint8 = 0x01
+	ForUpdate uint8 = 0x02
+	Scrollable uint8 = 0x04
+	ParameterCountAvailable uint8 = 0x08
 )
 
 // State Change Information