address comment

tools/pd-simulator/simulator/cases/import_data.go

@@ -97,7 +97,6 @@ func newImportData() *Case {
 			}
 		}
 		if leaderTotal == 0 || peerTotal == 0 {
-			simutil.Logger.Info("scan zore region")
 			return false
 		}
 		leaderLog := "leader distribute (table2)"

tools/pd-simulator/simulator/raft.go

@@ -31,14 +31,14 @@ import (
 // RaftEngine records all raft infomations.
 type RaftEngine struct {
 	sync.RWMutex
-	regionsInfo      *core.RegionsInfo
-	conn             *Connection
-	regionChange     map[uint64][]uint64
-	schedulerStats   *schedulerStatistics
-	regionSplitSize  int64
-	regionSplitKeys  int64
-	storeConfig      *SimConfig
-	useTiDBEncodeKey bool
+	regionsInfo       *core.RegionsInfo
+	conn              *Connection
+	regionChange      map[uint64][]uint64
+	schedulerStats    *schedulerStatistics
+	regionSplitSize   int64
+	regionSplitKeys   int64
+	storeConfig       *SimConfig
+	useTiDBEncodedKey bool
 }
 
 // NewRaftEngine creates the initialized raft with the configuration.
@@ -55,7 +55,7 @@ func NewRaftEngine(conf *cases.Case, conn *Connection, storeConfig *SimConfig) *
 	var splitKeys []string
 	if conf.TableNumber > 0 {
 		splitKeys = generateTableKeys(conf.TableNumber, len(conf.Regions)-1)
-		r.useTiDBEncodeKey = true
+		r.useTiDBEncodedKey = true
 	} else {
 		splitKeys = generateKeys(len(conf.Regions) - 1)
 	}
@@ -135,8 +135,8 @@ func (r *RaftEngine) stepSplit(region *core.RegionInfo) {
 	}
 
 	var splitKey []byte
-	if r.useTiDBEncodeKey {
-		splitKey = generateMvccSplitKey(region.GetStartKey(), region.GetEndKey())
+	if r.useTiDBEncodedKey {
+		splitKey = generateTiDBEncodedSplitKey(region.GetStartKey(), region.GetEndKey())
 	} else {
 		splitKey = generateSplitKey(region.GetStartKey(), region.GetEndKey())
 	}
@@ -306,14 +306,11 @@ func generateTableKeys(tableCount, size int) []string {
 		id++
 		tableID := id
 		for rowID := 0; rowID < groupNumber && size > 0; rowID++ {
+			key := table.GenerateRowKey(int64(tableID), int64(rowID))
 			if rowID == 0 {
-				key := table.GenerateTableKey(int64(tableID))
-				key = table.EncodeBytes(key)
-				v = append(v, string(key))
-				size--
+				key = table.GenerateTableKey(int64(tableID))
 				continue
 			}
-			key := table.GenerateRowKey(int64(tableID), int64(rowID))
 			key = table.EncodeBytes(key)
 			v = append(v, string(key))
 			size--
@@ -356,14 +353,21 @@ func mustDecodeMvccKey(key []byte) []byte {
 	return res
 }
 
-func generateMvccSplitKey(start, end []byte) []byte {
+// generateTiDBEncodedSplitKey calculates the split key with start and end key,
+// the keys are encoded according to the TiDB encoding rules.
+// The algorithm is the computationally the logical median.
+func generateTiDBEncodedSplitKey(start, end []byte) []byte {
+	if bytes.Equal(start, end) {
+		simutil.Logger.Fatal("start key and end key should not be same")
+	}
 	start = mustDecodeMvccKey(start)
 	end = mustDecodeMvccKey(end)
 	if len(start) == 0 && len(end) == 0 {
 		// suppose use table key with table ID: 0
 		key := table.GenerateTableKey(int64(0))
 		return table.EncodeBytes(key)
 	}
+	// make the start and end in same length.
 	if len(end) == 0 {
 		end = make([]byte, len(start))
 	} else if len(start) < len(end) {
@@ -373,7 +377,9 @@ func generateMvccSplitKey(start, end []byte) []byte {
 		pad := make([]byte, len(start)-len(end))
 		end = append(end, pad...)
 	}
+
 	borrow := false
+	equalWithStart := true
 	var (
 		d uint16
 		e uint16
@@ -385,8 +391,12 @@ func generateMvccSplitKey(start, end []byte) []byte {
 		if borrow {
 			e += 0x100
 		}
+		// if can't divide 2, assume that the lowposition borrows one from the high position, and then can divide 2.
 		borrow = (uint16(s)+e)%2 != 0
 		d = (uint16(s) + e) / 2
+		if d != uint16(s) {
+			equalWithStart = false
+		}
 		if d >= 0x100 {
 			d -= 0x100
 			for j := i - 1; j >= 0; j-- {
@@ -398,7 +408,7 @@ func generateMvccSplitKey(start, end []byte) []byte {
 		}
 		res[i] = byte(d)
 	}
-	if bytes.Equal(res, start) {
+	if equalWithStart {
 		res = append(res, 0)
 	}
 

tools/pd-simulator/simulator/raft_test.go

@@ -1,4 +1,4 @@
-// Copyright 2017 PingCAP, Inc.
+// Copyright 2018 PingCAP, Inc.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -14,38 +14,36 @@
 package simulator
 
 import (
-	"bytes"
-	"strings"
 	"testing"
+
+	. "github.com/pingcap/check"
 )
 
-func TestGenerateTableKeys(t *testing.T) {
+func Test(t *testing.T) {
+	TestingT(t)
+}
+
+var _ = Suite(&testTableKeySuite{})
+
+type testTableKeySuite struct{}
+
+func (t *testTableKeySuite) TestGenerateTableKeys(c *C) {
 	tableCount := 3
 	size := 10
 	keys := generateTableKeys(tableCount, size)
-	if len(keys) != size {
-		t.Fatalf("keys length %d, expected %d", len(keys), size)
-	}
+	c.Assert(len(keys), Equals, size)
+
 	for i := 1; i < len(keys); i++ {
-		if strings.Compare(keys[i-1], keys[i]) >= 0 {
-			t.Fatal("not an increamental sequence")
-		}
-		splitKey := string(generateMvccSplitKey([]byte(keys[i-1]), []byte(keys[i])))
-		if strings.Compare(keys[i-1], splitKey) >= 0 {
-			t.Fatalf("not expected split key")
-		}
-		if strings.Compare(splitKey, keys[i]) >= 0 {
-			t.Fatalf("not expected split key")
-		}
+		c.Assert(keys[i-1], Less, keys[i])
+		splitKey := string(generateTiDBEncodedSplitKey([]byte(keys[i-1]), []byte(keys[i])))
+		c.Assert(keys[i-1], Less, splitKey)
+		c.Assert(splitKey, Less, keys[i])
 	}
 	// empty key
 	startKey := []byte("")
 	endKey := []byte{116, 128, 0, 0, 0, 0, 0, 0, 255, 1, 0, 0, 0, 0, 0, 0, 0, 248}
-	splitKey := generateMvccSplitKey(startKey, endKey)
-	if bytes.Compare(startKey, splitKey) >= 0 {
-		t.Fatalf("not expected split key")
-	}
-	if bytes.Compare(splitKey, endKey) >= 0 {
-		t.Fatalf("not expected split key")
-	}
+	splitKey := generateTiDBEncodedSplitKey(startKey, endKey)
+	c.Assert(startKey, Less, splitKey)
+	c.Assert(splitKey, Less, endKey)
+
 }