*: fix data races detected by go test -race (pingcap#1407)

infoschema/infoschema.go

@@ -273,7 +273,6 @@ func newMemSchemaHandle() (*memSchemaHandle, error) {
 	if err != nil {
 		return nil, errors.Trace(err)
 	}
-	initMemoryTables(h)
 	h.perfHandle, err = perfschema.NewPerfHandle()
 	if err != nil {
 		return nil, errors.Trace(err)

perfschema/init.go

@@ -328,7 +328,11 @@ func (ps *perfSchema) initRecords(tbName string, records [][]types.Datum) error
 	return nil
 }
 
-var setupTimersRecords [][]types.Datum
+var setupTimersRecords = [][]types.Datum{
+	types.MakeDatums("stage", mysql.Enum{Name: "NANOSECOND", Value: 1}),
+	types.MakeDatums("statement", mysql.Enum{Name: "NANOSECOND", Value: 1}),
+	types.MakeDatums("transaction", mysql.Enum{Name: "NANOSECOND", Value: 1}),
+}
 
 func (ps *perfSchema) initialize() (err error) {
 	ps.tables = make(map[string]*model.TableInfo)
@@ -425,12 +429,6 @@ func (ps *perfSchema) initialize() (err error) {
 	if err != nil {
 		return errors.Trace(err)
 	}
-
-	setupTimersRecords = [][]types.Datum{
-		types.MakeDatums("stage", mysql.Enum{Name: "NANOSECOND", Value: 1}),
-		types.MakeDatums("statement", mysql.Enum{Name: "NANOSECOND", Value: 1}),
-		types.MakeDatums("transaction", mysql.Enum{Name: "NANOSECOND", Value: 1}),
-	}
 	err = ps.initRecords(TableSetupTimers, setupTimersRecords)
 	if err != nil {
 		return errors.Trace(err)

server/server.go

@@ -68,7 +68,11 @@ type Server struct {
 
 // ConnectionCount gets current connection count.
 func (s *Server) ConnectionCount() int {
-	return len(s.clients)
+	var cnt int
+	s.rwlock.RLock()
+	cnt = len(s.clients)
+	s.rwlock.RUnlock()
+	return cnt
 }
 
 func (s *Server) getToken() *Token {

server/tidb_test.go

@@ -29,6 +29,7 @@ type TidbTestSuite struct {
 var _ = Suite(new(TidbTestSuite))
 
 func (ts *TidbTestSuite) SetUpSuite(c *C) {
+	log.SetLevelByString("error")
 	store, err := tidb.NewStore("memory:///tmp/tidb")
 	c.Assert(err, IsNil)
 	ts.tidbdrv = NewTiDBDriver(store)
@@ -42,8 +43,6 @@ func (ts *TidbTestSuite) SetUpSuite(c *C) {
 	ts.server = server
 	go ts.server.Run()
 	time.Sleep(time.Millisecond * 100)
-
-	log.SetLevelByString("error")
 }
 
 func (ts *TidbTestSuite) TearDownSuite(c *C) {

session_test.go

@@ -20,7 +20,6 @@ import (
 	"sync/atomic"
 	"time"
 
-	"github.com/ngaut/log"
 	. "github.com/pingcap/check"
 	"github.com/pingcap/tidb/context"
 	"github.com/pingcap/tidb/executor"
@@ -58,7 +57,6 @@ func (s *testSessionSuite) SetUpSuite(c *C) {
 	s.dropTableSQL = `Drop TABLE if exists t;`
 	s.createTableSQL = `CREATE TABLE t(id TEXT);`
 	s.selectSQL = `SELECT * from t;`
-	log.SetLevelByString("error")
 }
 
 func (s *testSessionSuite) TearDownSuite(c *C) {

store/tikv/coprocessor.go

@@ -96,7 +96,9 @@ func (c *CopClient) Send(req *kv.Request) kv.Response {
 	}
 	it.errChan = make(chan error, 1)
 	if len(it.tasks) == 0 {
+		it.mu.Lock()
 		it.Close()
+		it.mu.Unlock()
 	}
 	it.run()
 	return it
@@ -269,9 +271,11 @@ func (it *copIterator) Next() (io.ReadCloser, error) {
 				break
 			}
 		}
-		it.mu.Unlock()
 		if task == nil {
 			it.Close()
+		}
+		it.mu.Unlock()
+		if task == nil {
 			return nil, nil
 		}
 		select {
@@ -282,12 +286,13 @@ func (it *copIterator) Next() (io.ReadCloser, error) {
 		task.status = taskDone
 		it.mu.Unlock()
 	}
+
+	it.mu.Lock()
+	defer it.mu.Unlock()
 	if err != nil {
 		it.Close()
 		return nil, err
 	}
-	it.mu.Lock()
-	defer it.mu.Unlock()
 	it.respGot++
 	if it.respGot == len(it.tasks) {
 		it.Close()

tidb_test.go

@@ -35,6 +35,7 @@ import (
 var store = flag.String("store", "memory", "registered store name, [memory, goleveldb, boltdb]")
 
 func TestT(t *testing.T) {
+	log.SetLevelByString("error")
 	TestingT(t)
 }
 
@@ -67,8 +68,6 @@ func (s *testMainSuite) SetUpSuite(c *C) {
     CREATE TABLE tbl_test2(id INT NOT NULL DEFAULT 3, name varchar(255), PRIMARY KEY(id));`
 	s.selectSQL = `SELECT * from tbl_test;`
 	runtime.GOMAXPROCS(runtime.NumCPU())
-
-	log.SetLevelByString("error")
 }
 
 func (s *testMainSuite) TearDownSuite(c *C) {