*: tidy code && prealloc some slice for performance

cmd/explaintest/main.go

@@ -140,11 +140,11 @@ LOOP:
 				break LOOP
 			default:
 				if strings.HasPrefix(s, "--error") {
-					t.expectedErrs = strings.Split(strings.TrimSpace(strings.TrimLeft(s, "--error")), ",")
+					t.expectedErrs = strings.Split(strings.TrimSpace(strings.TrimPrefix(s, "--error")), ",")
 				} else if strings.HasPrefix(s, "-- error") {
-					t.expectedErrs = strings.Split(strings.TrimSpace(strings.TrimLeft(s, "-- error")), ",")
+					t.expectedErrs = strings.Split(strings.TrimSpace(strings.TrimPrefix(s, "--error")), ",")
 				} else if strings.HasPrefix(s, "--echo") {
-					echo := strings.TrimSpace(strings.TrimLeft(s, "--echo"))
+					echo := strings.TrimSpace(strings.TrimPrefix(s, "--echo"))
 					t.buf.WriteString(echo)
 					t.buf.WriteString("\n")
 				}

ddl/callback_test.go

@@ -90,5 +90,5 @@ func (s *testDDLSuite) TestCallback(c *C) {
 	c.Assert(cb.OnChanged(nil), IsNil)
 	cb.OnJobRunBefore(nil)
 	cb.OnJobUpdated(nil)
-	cb.OnWatched(nil)
+	cb.OnWatched(context.TODO())
 }

ddl/db_test.go

@@ -3606,7 +3606,7 @@ func (s *testDBSuite2) TestTablesLockDelayClean(c *C) {
 		tk.Se.Close()
 		wg.Done()
 	}()
-	time.Sleep(50)
+	time.Sleep(50 * time.Nanosecond)
 	checkTableLock(c, tk.Se, "test", "t1", model.TableLockWrite)
 	wg.Wait()
 	c.Assert(time.Since(startTime).Seconds() > 0.1, IsTrue)

ddl/ddl_worker.go

@@ -448,7 +448,7 @@ func (w *worker) handleDDLJobQueue(d *ddlCtx) error {
 		// Here means the job enters another state (delete only, write only, public, etc...) or is cancelled.
 		// If the job is done or still running or rolling back, we will wait 2 * lease time to guarantee other servers to update
 		// the newest schema.
-		w.waitSchemaChanged(nil, d, waitTime, schemaVer, job)
+		w.waitSchemaChanged(context.TODO(), d, waitTime, schemaVer, job)
 		if job.IsSynced() || job.IsCancelled() {
 			asyncNotify(d.ddlJobDoneCh)
 		}

ddl/util/syncer_test.go

@@ -31,8 +31,8 @@ import (
 	"go.etcd.io/etcd/integration"
 	"go.etcd.io/etcd/mvcc/mvccpb"
 	goctx "golang.org/x/net/context"
-	"google.golang.org/grpc"
 	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
 )
 
 const minInterval = 10 * time.Nanosecond // It's used to test timeout.
@@ -225,7 +225,7 @@ func TestSyncerSimple(t *testing.T) {
 }
 
 func isTimeoutError(err error) bool {
-	if terror.ErrorEqual(err, goctx.DeadlineExceeded) || grpc.Code(errors.Cause(err)) == codes.DeadlineExceeded ||
+	if terror.ErrorEqual(err, goctx.DeadlineExceeded) || status.Code(errors.Cause(err)) == codes.DeadlineExceeded ||
 		terror.ErrorEqual(err, etcdserver.ErrTimeout) {
 		return true
 	}
@@ -245,7 +245,7 @@ func checkRespKV(t *testing.T, kvCount int, key, val string,
 	if string(kv.Key) != key {
 		t.Fatalf("key resp %s, exported %s", kv.Key, key)
 	}
-	if val != val {
+	if string(kv.Value) != val {
 		t.Fatalf("val resp %s, exported %s", kv.Value, val)
 	}
 }

executor/admin_test.go

@@ -445,6 +445,7 @@ func (s *testSuite2) TestAdminCheckPartitionTableFailed(c *C) {
 		_, err = indexOpr.Create(s.ctx, txn, types.MakeDatums(i), int64(i))
 		c.Assert(err, IsNil)
 		err = txn.Commit(context.Background())
+		c.Assert(err, IsNil)
 		tk.MustExec("admin check table admin_test_p")
 	}
 

go.sum

@@ -232,6 +232,7 @@ github.com/soheilhy/cmux v0.1.4 h1:0HKaf1o97UwFjHH9o5XsHUOF+tqmdA7KEzXLpiyaw0E=
 github.com/soheilhy/cmux v0.1.4/go.mod h1:IM3LyeVVIOuxMH7sFAkER9+bJ4dT7Ms6E4xg4kGIyLM=
 github.com/spaolacci/murmur3 v0.0.0-20180118202830-f09979ecbc72 h1:qLC7fQah7D6K1B0ujays3HV9gkFtllcxhzImRR7ArPQ=
 github.com/spaolacci/murmur3 v0.0.0-20180118202830-f09979ecbc72/go.mod h1:JwIasOWyU6f++ZhiEuf87xNszmSA2myDM2Kzu9HwQUA=
+github.com/spf13/cobra v0.0.3 h1:ZlrZ4XsMRm04Fr5pSFxBgfND2EBVa1nLpiy1stUsX/8=
 github.com/spf13/cobra v0.0.3/go.mod h1:1l0Ry5zgKvJasoi3XT1TypsSe7PqH0Sj9dhYf7v3XqQ=
 github.com/spf13/pflag v1.0.1 h1:aCvUg6QPl3ibpQUxyLkrEkCHtPqYJL4x9AuhqVqFis4=
 github.com/spf13/pflag v1.0.1/go.mod h1:DYY7MBk1bdzusC3SYhjObp+wFpr4gzcvqqNjLnInEg4=

statistics/feedback.go

@@ -460,6 +460,7 @@ func getOverlapFraction(fb Feedback, bkt bucket) (float64, float64) {
 // mergeFullyContainedFeedback merges the max fraction of non-overlapped feedbacks that are fully contained in the bucket.
 func (b *BucketFeedback) mergeFullyContainedFeedback(sc *stmtctx.StatementContext, bkt bucket) (float64, float64, bool) {
 	var feedbacks []Feedback
+	feedbacks = make([]Feedback, 0, len(b.feedback))
 	// Get all the fully contained feedbacks.
 	for _, fb := range b.feedback {
 		res, err := outOfRange(sc, bkt.Lower, bkt.Upper, fb.Lower)

util/rowDecoder/decoder.go

@@ -185,6 +185,7 @@ func SubstituteGenColsInDecodeColMap(decodeColMap map[int64]Column) {
 		colOffset int
 	}
 	var orderedCols []Pair
+	orderedCols = make([]Pair, 0, len(decodeColMap))
 	for colID, col := range decodeColMap {
 		orderedCols = append(orderedCols, Pair{colID, col.Col.Offset})
 	}

util/testkit/ctestkit.go

@@ -230,8 +230,9 @@ func (tk *CTestKit) ConcurrentRun(c *check.C, concurrent int, loops int,
 
 // PermInt returns, as a slice of n ints, a pseudo-random permutation of the integers [0,n).
 func (tk *CTestKit) PermInt(n int) []interface{} {
-	var v []interface{}
-	for _, i := range rand.Perm(n) {
+	randPermSlice := rand.Perm(n)
+	v := make([]interface{}, 0, len(randPermSlice))
+	for _, i := range randPermSlice {
 		v = append(v, i)
 	}
 	return v