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sink(ticdc): add before field for avro protocol #12632

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3c26bfa
init
wk989898 May 9, 2026
0ff364f
chore
wk989898 May 9, 2026
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3 changes: 3 additions & 0 deletions cdc/api/v2/model.go
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Original file line number Diff line number Diff line change
Expand Up @@ -342,6 +342,7 @@ func (c *ReplicaConfig) toInternalReplicaConfigWithOriginConfig(
AvroEnableWatermark: oldConfig.AvroEnableWatermark,
AvroDecimalHandlingMode: oldConfig.AvroDecimalHandlingMode,
AvroBigintUnsignedHandlingMode: oldConfig.AvroBigintUnsignedHandlingMode,
AvroIncludeBeforeValue: oldConfig.AvroIncludeBeforeValue,
EncodingFormat: oldConfig.EncodingFormat,
}
}
Expand Down Expand Up @@ -614,6 +615,7 @@ func ToAPIReplicaConfig(c *config.ReplicaConfig) *ReplicaConfig {
AvroEnableWatermark: oldConfig.AvroEnableWatermark,
AvroDecimalHandlingMode: oldConfig.AvroDecimalHandlingMode,
AvroBigintUnsignedHandlingMode: oldConfig.AvroBigintUnsignedHandlingMode,
AvroIncludeBeforeValue: oldConfig.AvroIncludeBeforeValue,
EncodingFormat: oldConfig.EncodingFormat,
}
}
Expand Down Expand Up @@ -1192,6 +1194,7 @@ type CodecConfig struct {
AvroEnableWatermark *bool `json:"avro_enable_watermark,omitempty"`
AvroDecimalHandlingMode *string `json:"avro_decimal_handling_mode,omitempty"`
AvroBigintUnsignedHandlingMode *string `json:"avro_bigint_unsigned_handling_mode,omitempty"`
AvroIncludeBeforeValue *bool `json:"avro_include_before_value,omitempty"`
EncodingFormat *string `json:"encoding_format,omitempty"`
}

Expand Down
2 changes: 2 additions & 0 deletions pkg/config/config_test_data.go
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Original file line number Diff line number Diff line change
Expand Up @@ -292,6 +292,7 @@ const (
"avro-enable-watermark": true,
"avro-decimal-handling-mode": "string",
"avro-bigint-unsigned-handling-mode": "string",
"avro-include-before-value": true,
"encoding-format": "json"
},
"large-message-handle": {
Expand Down Expand Up @@ -469,6 +470,7 @@ const (
"avro-enable-watermark": true,
"avro-decimal-handling-mode": "string",
"avro-bigint-unsigned-handling-mode": "string",
"avro-include-before-value": true,
"encoding-format": "json"
},
"large-message-handle": {
Expand Down
1 change: 1 addition & 0 deletions pkg/config/replica_config_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -103,6 +103,7 @@ func TestReplicaConfigMarshal(t *testing.T) {
AvroEnableWatermark: aws.Bool(true),
AvroDecimalHandlingMode: aws.String("string"),
AvroBigintUnsignedHandlingMode: aws.String("string"),
AvroIncludeBeforeValue: aws.Bool(true),
EncodingFormat: aws.String("json"),
},
LargeMessageHandle: &LargeMessageHandleConfig{
Expand Down
1 change: 1 addition & 0 deletions pkg/config/sink.go
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Original file line number Diff line number Diff line change
Expand Up @@ -408,6 +408,7 @@ type CodecConfig struct {
AvroEnableWatermark *bool `toml:"avro-enable-watermark" json:"avro-enable-watermark"`
AvroDecimalHandlingMode *string `toml:"avro-decimal-handling-mode" json:"avro-decimal-handling-mode,omitempty"`
AvroBigintUnsignedHandlingMode *string `toml:"avro-bigint-unsigned-handling-mode" json:"avro-bigint-unsigned-handling-mode,omitempty"`
AvroIncludeBeforeValue *bool `toml:"avro-include-before-value" json:"avro-include-before-value,omitempty"`
EncodingFormat *string `toml:"encoding-format" json:"encoding-format,omitempty"`
}

Expand Down
68 changes: 68 additions & 0 deletions pkg/sink/codec/avro/avro.go
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Original file line number Diff line number Diff line change
Expand Up @@ -184,6 +184,12 @@ func (a *BatchEncoder) encodeValue(ctx context.Context, topic string, e *model.R
log.Error("avro: converting value to native failed", zap.Error(err))
return nil, errors.Trace(err)
}
if a.config.AvroIncludeBeforeValue {
native, err = a.nativeValueWithBeforeValue(native, e)
if err != nil {
return nil, errors.Trace(err)
}
}
if a.config.EnableTiDBExtension {
native = a.nativeValueWithExtension(native, e)
}
Expand Down Expand Up @@ -326,6 +332,41 @@ func getOperation(e *model.RowChangedEvent) string {
return ""
}

func beforeValueRecordName(tableName model.TableName) string {
return common.SanitizeName(tableName.Table) + "_before"
}

func (a *BatchEncoder) beforeValueRecordFullName(tableName model.TableName) string {
namespace := getAvroNamespace(a.namespace, tableName.Schema)
if namespace == "" {
return beforeValueRecordName(tableName)
}
return namespace + "." + beforeValueRecordName(tableName)
}

func (a *BatchEncoder) nativeValueWithBeforeValue(
native map[string]interface{},
e *model.RowChangedEvent,
) (map[string]interface{}, error) {
if !e.IsUpdate() {
native[ticdcBefore] = goavro.Union("null", nil)
return native, nil
}

input := avroEncodeInput{
TableInfo: e.TableInfo,
columns: e.PreColumns,
colInfos: e.TableInfo.GetColInfosForRowChangedEvent(),
}
before, err := a.columns2AvroData(input)
if err != nil {
log.Error("avro: converting before value to native failed", zap.Error(err))
return nil, errors.Trace(err)
}
native[ticdcBefore] = goavro.Union(a.beforeValueRecordFullName(e.TableInfo.TableName), before)
return native, nil
}

func (a *BatchEncoder) nativeValueWithExtension(
native map[string]interface{},
e *model.RowChangedEvent,
Expand Down Expand Up @@ -354,6 +395,7 @@ const (
tidbOp = "_tidb_op"
tidbCommitTs = "_tidb_commit_ts"
tidbPhysicalTime = "_tidb_commit_physical_time"
ticdcBefore = "_ticdc_before"

// row level checksum related fields
tidbRowLevelChecksum = "_tidb_row_level_checksum"
Expand Down Expand Up @@ -522,6 +564,25 @@ func (a *BatchEncoder) schemaWithExtension(
return top
}

func (a *BatchEncoder) schemaWithBeforeValue(
top *avroSchemaTop,
tableName model.TableName,
input avroEncodeInput,
) (*avroSchemaTop, error) {
beforeValue, err := a.columns2AvroSchema(tableName, input)
if err != nil {
return nil, err
}
beforeValue.Name = beforeValueRecordName(tableName)

top.Fields = append(top.Fields, map[string]interface{}{
"name": ticdcBefore,
"type": []interface{}{"null", beforeValue},
"default": nil,
})
return top, nil
}

func (a *BatchEncoder) columns2AvroSchema(tableName model.TableName, input avroEncodeInput) (*avroSchemaTop, error) {
top := &avroSchemaTop{
Tp: "record",
Expand Down Expand Up @@ -588,6 +649,13 @@ func (a *BatchEncoder) value2AvroSchema(tableName model.TableName, input avroEnc
return "", err
}

if a.config.AvroIncludeBeforeValue {
top, err = a.schemaWithBeforeValue(top, tableName, input)
if err != nil {
return "", err
}
}

if a.config.EnableTiDBExtension {
top = a.schemaWithExtension(top)
}
Expand Down
81 changes: 81 additions & 0 deletions pkg/sink/codec/avro/avro_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -243,6 +243,87 @@ func TestAvroEncode(t *testing.T) {
}
}

func TestAvroEncodeIncludeBeforeValue(t *testing.T) {
codecConfig := common.NewConfig(config.ProtocolAvro)
codecConfig.EnableTiDBExtension = true
codecConfig.AvroIncludeBeforeValue = true

ctx, cancel := context.WithCancel(context.Background())
defer cancel()

encoder, err := SetupEncoderAndSchemaRegistry4Testing(ctx, codecConfig)
defer TeardownEncoderAndSchemaRegistry4Testing()
require.NoError(t, err)
require.NotNil(t, encoder)

tableColumns := []*model.Column{
{Name: "id", Type: mysql.TypeLong, Flag: model.HandleKeyFlag | model.PrimaryKeyFlag},
{Name: "name", Type: mysql.TypeVarchar},
{Name: "age", Type: mysql.TypeLong},
}
tableInfo := model.BuildTableInfo("test", "person", tableColumns, [][]int{{0}})
beforeColumns := []*model.Column{
{Name: "id", Value: int64(1)},
{Name: "name", Value: "old"},
{Name: "age", Value: int64(18)},
}
afterColumns := []*model.Column{
{Name: "id", Value: int64(1)},
{Name: "name", Value: "new"},
{Name: "age", Value: int64(20)},
}
event := &model.RowChangedEvent{
CommitTs: 1024,
TableInfo: tableInfo,
PreColumns: model.Columns2ColumnDatas(beforeColumns, tableInfo),
Columns: model.Columns2ColumnDatas(afterColumns, tableInfo),
}

topic := "default"
bin, err := encoder.encodeValue(ctx, topic, event)
require.NoError(t, err)

cid, data, err := extractConfluentSchemaIDAndBinaryData(bin)
require.NoError(t, err)

avroValueCodec, err := encoder.schemaM.Lookup(ctx, topic, schemaID{confluentSchemaID: cid})
require.NoError(t, err)

res, _, err := avroValueCodec.NativeFromBinary(data)
require.NoError(t, err)
require.NotNil(t, res)

m, ok := res.(map[string]interface{})
require.True(t, ok)
require.Equal(t, int32(20), m["age"])
require.Equal(t, "new", m["name"])

beforeUnion, ok := m[ticdcBefore].(map[string]interface{})
require.True(t, ok)
before, ok := beforeUnion[encoder.beforeValueRecordFullName(tableInfo.TableName)].(map[string]interface{})
require.True(t, ok)
require.Equal(t, int32(18), before["age"])
require.Equal(t, "old", before["name"])

key, err := encoder.encodeKey(ctx, topic, event)
require.NoError(t, err)
decoder := NewDecoder(codecConfig, encoder.schemaM, topic, nil)
err = decoder.AddKeyValue(key, bin)
require.NoError(t, err)

messageType, exist, err := decoder.HasNext()
require.NoError(t, err)
require.True(t, exist)
require.Equal(t, model.MessageTypeRow, messageType)

decoded, err := decoder.NextRowChangedEvent()
require.NoError(t, err)
require.True(t, decoded.IsUpdate())
require.Equal(t, uint64(1024), decoded.CommitTs)
require.Equal(t, "old", decoded.GetPreColumns()[1].Value)
require.Equal(t, "new", decoded.GetColumns()[1].Value)
}

func TestAvroEnvelope(t *testing.T) {
t.Parallel()
cManager := &confluentSchemaManager{}
Expand Down
123 changes: 90 additions & 33 deletions pkg/sink/codec/avro/decoder.go
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Original file line number Diff line number Diff line change
Expand Up @@ -182,6 +182,93 @@ func assembleEvent(
return nil, errors.New("schema fields should be a map")
}

columns, err := avroData2Columns(keyMap, valueMap, fields)
if err != nil {
return nil, errors.Trace(err)
}

beforeMap, hasBefore, err := extractBeforeValueMap(valueMap)
if err != nil {
return nil, errors.Trace(err)
}
var beforeColumns []*model.Column
if hasBefore {
beforeColumns, err = avroData2Columns(keyMap, beforeMap, fields)
if err != nil {
return nil, errors.Trace(err)
}
}

// "namespace.schema"
namespace := schema["namespace"].(string)
schemaName := strings.Split(namespace, ".")[1]
tableName := schema["name"].(string)
Comment on lines +203 to +205
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@gemini-code-assist gemini-code-assist Bot May 9, 2026

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high

These type assertions and the string split operation are fragile and could lead to a panic if the schema metadata is unexpected (e.g., missing namespace or namespace without a dot). It is safer to use comma-ok assertions and check the length of the split result.

Suggested change
namespace := schema["namespace"].(string)
schemaName := strings.Split(namespace, ".")[1]
tableName := schema["name"].(string)
namespace, ok := schema["namespace"].(string)
if !ok {
return nil, errors.New("namespace not found or not a string")
}
parts := strings.Split(namespace, ".")
if len(parts) < 2 {
return nil, errors.New("invalid namespace format")
}
schemaName := parts[1]
tableName, ok := schema["name"].(string)
if !ok {
return nil, errors.New("table name not found or not a string")
}


var commitTs int64
if !isDelete {
o, ok := valueMap[tidbCommitTs]
if !ok {
return nil, errors.New("commit ts not found")
}
commitTs = o.(int64)
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@gemini-code-assist gemini-code-assist Bot May 9, 2026

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medium

This type assertion could panic if the value is not an int64. Using a comma-ok assertion is safer.

commitTs, ok = o.(int64)
		if !ok {
			return nil, errors.New("commit ts is not an int64")
		}

}

event := new(model.RowChangedEvent)
event.CommitTs = uint64(commitTs)
pkNameSet := make(map[string]struct{}, len(keyMap))
for name := range keyMap {
pkNameSet[name] = struct{}{}
}
event.TableInfo = model.BuildTableInfoWithPKNames4Test(schemaName, tableName, columns, pkNameSet)

if isDelete {
event.PreColumns = model.Columns2ColumnDatas(columns, event.TableInfo)
} else {
event.Columns = model.Columns2ColumnDatas(columns, event.TableInfo)
if hasBefore {
event.PreColumns = model.Columns2ColumnDatas(beforeColumns, event.TableInfo)
}
}

return event, nil
}

func isAvroExtensionField(name string) bool {
switch name {
case tidbOp, tidbCommitTs, tidbPhysicalTime, tidbRowLevelChecksum,
tidbChecksumVersion, tidbCorrupted, ticdcBefore:
return true
default:
return false
}
}

func extractBeforeValueMap(valueMap map[string]interface{}) (map[string]interface{}, bool, error) {
rawBefore, ok := valueMap[ticdcBefore]
if !ok || rawBefore == nil {
return nil, false, nil
}

beforeUnion, ok := rawBefore.(map[string]interface{})
if !ok {
return nil, false, errors.New("before value should be a map")
}
for unionName, value := range beforeUnion {
if unionName == "null" || value == nil {
return nil, false, nil
}
before, ok := value.(map[string]interface{})
if !ok {
return nil, false, errors.New("before record should be a map")
}
return before, true, nil
}
return nil, false, nil
}

func avroData2Columns(
keyMap, valueMap map[string]interface{}, fields []interface{},
) ([]*model.Column, error) {
columns := make([]*model.Column, 0, len(valueMap))
// fields is ordered by the column id, so iterate over it to build columns
// it's also the order to calculate the checksum.
Expand All @@ -191,10 +278,9 @@ func assembleEvent(
return nil, errors.New("schema field should be a map")
}

// `tidbOp` is the first extension field in the schema,
// it's not real columns, so break here.
// Extension fields are not real columns, so break here.
colName := field["name"].(string)
if colName == tidbOp {
if isAvroExtensionField(colName) {
break
}

Expand Down Expand Up @@ -241,36 +327,7 @@ func assembleEvent(
}
columns = append(columns, col)
}

// "namespace.schema"
namespace := schema["namespace"].(string)
schemaName := strings.Split(namespace, ".")[1]
tableName := schema["name"].(string)

var commitTs int64
if !isDelete {
o, ok := valueMap[tidbCommitTs]
if !ok {
return nil, errors.New("commit ts not found")
}
commitTs = o.(int64)
}

event := new(model.RowChangedEvent)
event.CommitTs = uint64(commitTs)
pkNameSet := make(map[string]struct{}, len(keyMap))
for name := range keyMap {
pkNameSet[name] = struct{}{}
}
event.TableInfo = model.BuildTableInfoWithPKNames4Test(schemaName, tableName, columns, pkNameSet)

if isDelete {
event.PreColumns = model.Columns2ColumnDatas(columns, event.TableInfo)
} else {
event.Columns = model.Columns2ColumnDatas(columns, event.TableInfo)
}

return event, nil
return columns, nil
}

func isCorrupted(valueMap map[string]interface{}) bool {
Expand Down
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