lightning: change MinRowID because ADD UNIQUE INDEX may be smaller

br/pkg/lightning/backend/kv/BUILD.bazel

@@ -42,6 +42,7 @@ go_library(
         "//pkg/tablecodec",
         "//pkg/types",
         "//pkg/util/chunk",
+        "//pkg/util/codec",
         "//pkg/util/topsql/stmtstats",
         "@com_github_docker_go_units//:go-units",
         "@com_github_pingcap_errors//:errors",

br/pkg/lightning/backend/kv/base.go

@@ -33,6 +33,7 @@ import (
 	"github.com/pingcap/tidb/pkg/table/tables"
 	"github.com/pingcap/tidb/pkg/types"
 	"github.com/pingcap/tidb/pkg/util/chunk"
+	"github.com/pingcap/tidb/pkg/util/codec"
 	"go.uber.org/zap"
 	"go.uber.org/zap/zapcore"
 )
@@ -201,7 +202,7 @@ func (e *BaseKVEncoder) Record2KV(record, originalRow []types.Datum, rowID int64
 	kvPairs := e.SessionCtx.TakeKvPairs()
 	for i := 0; i < len(kvPairs.Pairs); i++ {
 		var encoded [9]byte // The max length of encoded int64 is 9.
-		kvPairs.Pairs[i].RowID = common.EncodeIntRowIDToBuf(encoded[:0], rowID)
+		kvPairs.Pairs[i].RowID = codec.EncodeComparableVarint(encoded[:0], rowID)
 	}
 	e.recordCache = record[:0]
 	return kvPairs, nil

br/pkg/lightning/backend/local/iterator.go

@@ -180,15 +180,6 @@ type dupDBIter struct {
 	err        error
 }
 
-func (d *dupDBIter) Seek(key []byte) bool {
-	rawKey := d.keyAdapter.Encode(nil, key, common.ZeroRowID)
-	if d.err != nil || !d.iter.SeekGE(rawKey) {
-		return false
-	}
-	d.curKey, d.err = d.keyAdapter.Decode(d.curKey[:0], d.iter.Key())
-	return d.err == nil
-}
-
 func (d *dupDBIter) Error() error {
 	if d.err != nil {
 		return d.err

br/pkg/lightning/common/BUILD.bazel

@@ -112,7 +112,7 @@ go_test(
     ],
     embed = [":common"],
     flaky = True,
-    shard_count = 28,
+    shard_count = 29,
     deps = [
         "//br/pkg/errors",
         "//br/pkg/lightning/log",
@@ -127,6 +127,8 @@ go_test(
         "//pkg/store/driver/error",
         "//pkg/store/mockstore",
         "//pkg/testkit/testsetup",
+        "//pkg/types",
+        "//pkg/util/codec",
         "//pkg/util/dbutil",
         "//pkg/util/mock",
         "@com_github_data_dog_go_sqlmock//:go-sqlmock",

br/pkg/lightning/common/key_adapter.go

@@ -15,8 +15,6 @@
 package common
 
 import (
-	"math"
-
 	"github.com/pingcap/errors"
 	"github.com/pingcap/tidb/pkg/util/codec"
 )
@@ -114,8 +112,7 @@ func (DupDetectKeyAdapter) EncodedLen(key []byte, rowID []byte) int {
 
 var _ KeyAdapter = DupDetectKeyAdapter{}
 
-// static vars for rowID
 var (
-	MinRowID  = EncodeIntRowID(math.MinInt64)
-	ZeroRowID = EncodeIntRowID(0)
+	// MinRowID is the minimum rowID value after DupDetectKeyAdapter.Encode().
+	MinRowID = []byte{0, 0, 0, 0, 0, 0, 0, 0, 0}
 )

br/pkg/lightning/common/key_adapter_test.go

@@ -20,8 +20,12 @@ import (
 	"math"
 	"sort"
 	"testing"
+	"time"
 	"unsafe"
 
+	"github.com/pingcap/tidb/pkg/kv"
+	"github.com/pingcap/tidb/pkg/types"
+	"github.com/pingcap/tidb/pkg/util/codec"
 	"github.com/stretchr/testify/require"
 )
 
@@ -34,8 +38,9 @@ func randBytes(n int) []byte {
 func TestNoopKeyAdapter(t *testing.T) {
 	keyAdapter := NoopKeyAdapter{}
 	key := randBytes(32)
-	require.Len(t, key, keyAdapter.EncodedLen(key, ZeroRowID))
-	encodedKey := keyAdapter.Encode(nil, key, ZeroRowID)
+	rowID := randBytes(8)
+	require.Len(t, key, keyAdapter.EncodedLen(key, rowID))
+	encodedKey := keyAdapter.Encode(nil, key, rowID)
 	require.Equal(t, key, encodedKey)
 
 	decodedKey, err := keyAdapter.Decode(nil, encodedKey)
@@ -159,3 +164,49 @@ func TestDecodeKeyDstIsInsufficient(t *testing.T) {
 		require.Equal(t, key, buf2[4:])
 	}
 }
+
+func TestMinRowID(t *testing.T) {
+	keyApapter := DupDetectKeyAdapter{}
+	key := []byte("key")
+	val := []byte("val")
+	shouldBeMin := keyApapter.Encode(key, val, MinRowID)
+
+	rowIDs := make([][]byte, 0, 20)
+
+	// DDL
+
+	rowIDs = append(rowIDs, kv.IntHandle(math.MinInt64).Encoded())
+	rowIDs = append(rowIDs, kv.IntHandle(-1).Encoded())
+	rowIDs = append(rowIDs, kv.IntHandle(0).Encoded())
+	rowIDs = append(rowIDs, kv.IntHandle(math.MaxInt64).Encoded())
+	handleData := []types.Datum{
+		types.NewIntDatum(math.MinInt64),
+		types.NewIntDatum(-1),
+		types.NewIntDatum(0),
+		types.NewIntDatum(math.MaxInt64),
+		types.NewBytesDatum(make([]byte, 1)),
+		types.NewBytesDatum(make([]byte, 7)),
+		types.NewBytesDatum(make([]byte, 8)),
+		types.NewBytesDatum(make([]byte, 9)),
+		types.NewBytesDatum(make([]byte, 100)),
+	}
+	for _, d := range handleData {
+		encodedKey, err := codec.EncodeKey(time.Local, nil, d)
+		require.NoError(t, err)
+		ch, err := kv.NewCommonHandle(encodedKey)
+		require.NoError(t, err)
+		rowIDs = append(rowIDs, ch.Encoded())
+	}
+
+	// lightning, IMPORT INTO, ...
+
+	numRowIDs := []int64{math.MinInt64, -1, 0, math.MaxInt64}
+	for _, id := range numRowIDs {
+		rowIDs = append(rowIDs, codec.EncodeComparableVarint(nil, id))
+	}
+
+	for _, id := range rowIDs {
+		bs := keyApapter.Encode(key, val, id)
+		require.True(t, bytes.Compare(bs, shouldBeMin) >= 0)
+	}
+}

br/pkg/lightning/common/util.go

@@ -461,15 +461,16 @@ type KvPair struct {
 	Key []byte
 	// Val is the value of the KV pair
 	Val []byte
-	// RowID identifies a KvPair in case two KvPairs are equal in Key and Val. It's
-	// often set to the file offset of the KvPair in the source file or the record
-	// handle.
+	// RowID identifies a KvPair in case two KvPairs are equal in Key and Val. It has
+	// two sources:
+	//
+	// When the KvPair is generated from ADD INDEX, the RowID is the encoded handle.
+	//
+	// Otherwise, the RowID is related to the row number in the source files, and
+	// encode the number with `codec.EncodeComparableVarint`.
 	RowID []byte
 }
 
-// EncodeIntRowIDToBuf encodes an int64 row id to a buffer.
-var EncodeIntRowIDToBuf = codec.EncodeComparableVarint
-
 // EncodeIntRowID encodes an int64 row id.
 func EncodeIntRowID(rowID int64) []byte {
 	return codec.EncodeComparableVarint(nil, rowID)

tests/realtikvtest/addindextest/add_index_test.go

@@ -135,3 +135,15 @@ func TestIssue51162(t *testing.T) {
 	tk.MustExec("alter table tl add index idx_16(`col_48`,(cast(`col_45` as signed array)),`col_46`(5));")
 	tk.MustExec("admin check table tl")
 }
+
+func TestAddUKWithSmallIntHandles(t *testing.T) {
+	store := realtikvtest.CreateMockStoreAndSetup(t)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("drop database if exists small;")
+	tk.MustExec("create database small;")
+	tk.MustExec("use small;")
+	tk.MustExec(`set global tidb_ddl_enable_fast_reorg=1;`)
+	tk.MustExec("create table t (a bigint, b int, primary key (a) clustered)")
+	tk.MustExec("insert into t values (-9223372036854775808, 1),(-9223372036854775807, 1)")
+	tk.MustContainErrMsg("alter table t add unique index uk(b)", "Duplicate entry '1' for key 't.uk'")
+}