optimizer/plan: fix join panic (pingcap#1246)

* optimizer/plan: fix join panic

executor/executor_test.go

@@ -1304,3 +1304,12 @@ func (s *testSuite) TestDatumXAPI(c *C) {
 	result = tk.MustQuery("select * from t where b > '11:11:11.5'")
 	result.Check(testkit.Rows("11:11:12 11:11:12", "11:11:13 11:11:13"))
 }
+
+func (s *testSuite) TestJoinPanic(c *C) {
+	defer testleak.AfterTest(c)()
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("use test")
+	tk.MustExec("drop table if exists events")
+	tk.MustExec("create table events (clock int, source int)")
+	tk.MustQuery("SELECT * FROM events e JOIN (SELECT MAX(clock) AS clock FROM events e2 GROUP BY e2.source) e3 ON e3.clock=e.clock")
+}

optimizer/plan/planbuilder_join.go

@@ -220,6 +220,9 @@ func (p *joinPath) attachCondition(condition ast.ExprNode, availablePaths []*joi
 }
 
 func (p *joinPath) containsTable(table *ast.TableName) bool {
+	if table == nil {
+		return false
+	}
 	if p.table != nil {
 		return p.table == table
 	}
@@ -234,7 +237,6 @@ func (p *joinPath) containsTable(table *ast.TableName) bool {
 		}
 		return false
 	}
-
 	return p.outer.containsTable(table) || p.inner.containsTable(table)
 }
 

optimizer/validator.go

@@ -15,6 +15,7 @@ package optimizer
 
 import (
 	"math"
+	"strings"
 
 	"github.com/juju/errors"
 	"github.com/pingcap/tidb/ast"
@@ -183,11 +184,16 @@ func (v *validator) checkAutoIncrement(stmt *ast.CreateTableStmt) {
 	if count < 1 {
 		return
 	}
-
 	if !isKey {
 		isKey = isConstraintKeyTp(stmt.Constraints, autoIncrementCol)
 	}
-	if !isKey || count > 1 {
+	autoIncrementMustBeKey := true
+	for _, opt := range stmt.Options {
+		if opt.Tp == ast.TableOptionEngine && strings.EqualFold(opt.StrValue, "MyISAM") {
+			autoIncrementMustBeKey = false
+		}
+	}
+	if (autoIncrementMustBeKey && !isKey) || count > 1 {
 		v.err = errors.New("Incorrect table definition; there can be only one auto column and it must be defined as a key")
 	}
 

optimizer/validator_test.go

@@ -51,6 +51,7 @@ func (s *testValidatorSuite) TestValidator(c *C) {
 		{"create table t(id decimal auto_increment, key (id))", true,
 			errors.New("Incorrect column specifier for column 'id'")},
 		{"create table t(id float auto_increment, key (id))", true, nil},
+		{"create table t(id int auto_increment) ENGINE=MYISAM", true, nil},
 	}
 	store, err := tidb.NewStore(tidb.EngineGoLevelDBMemory)
 	c.Assert(err, IsNil)

server/conn.go

@@ -262,6 +262,11 @@ func (cc *clientConn) dispatch(data []byte) error {
 	}()
 
 	switch cmd {
+	case mysql.ComSleep:
+		// TODO: According to mysql document, this command is supposed to be used only internally.
+		// So it's just a temp fix, not sure if it's done right.
+		// Investigate this command and write test case later.
+		return nil
 	case mysql.ComQuit:
 		return io.EOF
 	case mysql.ComQuery: