milvus/internal/storage/serde.go

// Licensed to the LF AI & Data foundation under one
// or more contributor license agreements. See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License. You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package storage

import (
	"encoding/binary"
	"fmt"
	"io"
	"math"
	"strconv"
	"sync"

	"github.com/apache/arrow/go/v12/arrow"
	"github.com/apache/arrow/go/v12/arrow/array"
	"github.com/apache/arrow/go/v12/parquet"
	"github.com/apache/arrow/go/v12/parquet/compress"
	"github.com/apache/arrow/go/v12/parquet/pqarrow"
	"github.com/cockroachdb/errors"
	"google.golang.org/protobuf/proto"

	"github.com/milvus-io/milvus-proto/go-api/v2/schemapb"
	"github.com/milvus-io/milvus/pkg/v2/common"
	"github.com/milvus-io/milvus/pkg/v2/util/typeutil"
)

type Record interface {
	Schema() map[FieldID]schemapb.DataType
	ArrowSchema() *arrow.Schema
	Column(i FieldID) arrow.Array
	Len() int
	Release()
	Slice(start, end int) Record
}

type RecordReader interface {
	Next() error
	Record() Record
	Close()
}

type RecordWriter interface {
	Write(r Record) error
	GetWrittenUncompressed() uint64
	Close()
}

type (
	Serializer[T any]   func([]T) (Record, error)
	Deserializer[T any] func(Record, []T) error
)

// compositeRecord is a record being composed of multiple records, in which each only have 1 column
type compositeRecord struct {
	recs   map[FieldID]arrow.Record
	schema map[FieldID]schemapb.DataType
}

var _ Record = (*compositeRecord)(nil)

func (r *compositeRecord) Column(i FieldID) arrow.Array {
	return r.recs[i].Column(0)
}

func (r *compositeRecord) Len() int {
	for _, rec := range r.recs {
		return rec.Column(0).Len()
	}
	return 0
}

func (r *compositeRecord) Release() {
	for _, rec := range r.recs {
		rec.Release()
	}
}

func (r *compositeRecord) Schema() map[FieldID]schemapb.DataType {
	return r.schema
}

func (r *compositeRecord) ArrowSchema() *arrow.Schema {
	var fields []arrow.Field
	for _, rec := range r.recs {
		fields = append(fields, rec.Schema().Field(0))
	}
	return arrow.NewSchema(fields, nil)
}

func (r *compositeRecord) Slice(start, end int) Record {
	slices := make(map[FieldID]arrow.Record)
	for i, rec := range r.recs {
		slices[i] = rec.NewSlice(int64(start), int64(end))
	}
	return &compositeRecord{
		recs:   slices,
		schema: r.schema,
	}
}

type serdeEntry struct {
	// arrowType returns the arrow type for the given dimension
	arrowType func(int) arrow.DataType
	// deserialize deserializes the i-th element in the array, returns the value and ok.
	//	null is deserialized to nil without checking the type nullability.
	deserialize func(arrow.Array, int) (any, bool)
	// serialize serializes the value to the builder, returns ok.
	// 	nil is serialized to null without checking the type nullability.
	serialize func(array.Builder, any) bool
}

var serdeMap = func() map[schemapb.DataType]serdeEntry {
	m := make(map[schemapb.DataType]serdeEntry)
	m[schemapb.DataType_Bool] = serdeEntry{
		func(i int) arrow.DataType {
			return arrow.FixedWidthTypes.Boolean
		},
		func(a arrow.Array, i int) (any, bool) {
			if a.IsNull(i) {
				return nil, true
			}
			if arr, ok := a.(*array.Boolean); ok && i < arr.Len() {
				return arr.Value(i), true
			}
			return nil, false
		},
		func(b array.Builder, v any) bool {
			if v == nil {
				b.AppendNull()
				return true
			}
			if builder, ok := b.(*array.BooleanBuilder); ok {
				if v, ok := v.(bool); ok {
					builder.Append(v)
					return true
				}
			}
			return false
		},
	}
	m[schemapb.DataType_Int8] = serdeEntry{
		func(i int) arrow.DataType {
			return arrow.PrimitiveTypes.Int8
		},
		func(a arrow.Array, i int) (any, bool) {
			if a.IsNull(i) {
				return nil, true
			}
			if arr, ok := a.(*array.Int8); ok && i < arr.Len() {
				return arr.Value(i), true
			}
			return nil, false
		},
		func(b array.Builder, v any) bool {
			if v == nil {
				b.AppendNull()
				return true
			}
			if builder, ok := b.(*array.Int8Builder); ok {
				if v, ok := v.(int8); ok {
					builder.Append(v)
					return true
				}
			}
			return false
		},
	}
	m[schemapb.DataType_Int16] = serdeEntry{
		func(i int) arrow.DataType {
			return arrow.PrimitiveTypes.Int16
		},
		func(a arrow.Array, i int) (any, bool) {
			if a.IsNull(i) {
				return nil, true
			}
			if arr, ok := a.(*array.Int16); ok && i < arr.Len() {
				return arr.Value(i), true
			}
			return nil, false
		},
		func(b array.Builder, v any) bool {
			if v == nil {
				b.AppendNull()
				return true
			}
			if builder, ok := b.(*array.Int16Builder); ok {
				if v, ok := v.(int16); ok {
					builder.Append(v)
					return true
				}
			}
			return false
		},
	}
	m[schemapb.DataType_Int32] = serdeEntry{
		func(i int) arrow.DataType {
			return arrow.PrimitiveTypes.Int32
		},
		func(a arrow.Array, i int) (any, bool) {
			if a.IsNull(i) {
				return nil, true
			}
			if arr, ok := a.(*array.Int32); ok && i < arr.Len() {
				return arr.Value(i), true
			}
			return nil, false
		},
		func(b array.Builder, v any) bool {
			if v == nil {
				b.AppendNull()
				return true
			}
			if builder, ok := b.(*array.Int32Builder); ok {
				if v, ok := v.(int32); ok {
					builder.Append(v)
					return true
				}
			}
			return false
		},
	}
	m[schemapb.DataType_Int64] = serdeEntry{
		func(i int) arrow.DataType {
			return arrow.PrimitiveTypes.Int64
		},
		func(a arrow.Array, i int) (any, bool) {
			if a.IsNull(i) {
				return nil, true
			}
			if arr, ok := a.(*array.Int64); ok && i < arr.Len() {
				return arr.Value(i), true
			}
			return nil, false
		},
		func(b array.Builder, v any) bool {
			if v == nil {
				b.AppendNull()
				return true
			}
			if builder, ok := b.(*array.Int64Builder); ok {
				if v, ok := v.(int64); ok {
					builder.Append(v)
					return true
				}
			}
			return false
		},
	}
	m[schemapb.DataType_Float] = serdeEntry{
		func(i int) arrow.DataType {
			return arrow.PrimitiveTypes.Float32
		},
		func(a arrow.Array, i int) (any, bool) {
			if a.IsNull(i) {
				return nil, true
			}
			if arr, ok := a.(*array.Float32); ok && i < arr.Len() {
				return arr.Value(i), true
			}
			return nil, false
		},
		func(b array.Builder, v any) bool {
			if v == nil {
				b.AppendNull()
				return true
			}
			if builder, ok := b.(*array.Float32Builder); ok {
				if v, ok := v.(float32); ok {
					builder.Append(v)
					return true
				}
			}
			return false
		},
	}
	m[schemapb.DataType_Double] = serdeEntry{
		func(i int) arrow.DataType {
			return arrow.PrimitiveTypes.Float64
		},
		func(a arrow.Array, i int) (any, bool) {
			if a.IsNull(i) {
				return nil, true
			}
			if arr, ok := a.(*array.Float64); ok && i < arr.Len() {
				return arr.Value(i), true
			}
			return nil, false
		},
		func(b array.Builder, v any) bool {
			if v == nil {
				b.AppendNull()
				return true
			}
			if builder, ok := b.(*array.Float64Builder); ok {
				if v, ok := v.(float64); ok {
					builder.Append(v)
					return true
				}
			}
			return false
		},
	}
	stringEntry := serdeEntry{
		func(i int) arrow.DataType {
			return arrow.BinaryTypes.String
		},
		func(a arrow.Array, i int) (any, bool) {
			if a.IsNull(i) {
				return nil, true
			}
			if arr, ok := a.(*array.String); ok && i < arr.Len() {
				return arr.Value(i), true
			}
			return nil, false
		},
		func(b array.Builder, v any) bool {
			if v == nil {
				b.AppendNull()
				return true
			}
			if builder, ok := b.(*array.StringBuilder); ok {
				if v, ok := v.(string); ok {
					builder.Append(v)
					return true
				}
			}
			return false
		},
	}

	m[schemapb.DataType_VarChar] = stringEntry
	m[schemapb.DataType_String] = stringEntry

	// We're not using the deserialized data in go, so we can skip the heavy pb serde.
	// If there is need in the future, just assign it to m[schemapb.DataType_Array]
	eagerArrayEntry := serdeEntry{
		func(i int) arrow.DataType {
			return arrow.BinaryTypes.Binary
		},
		func(a arrow.Array, i int) (any, bool) {
			if a.IsNull(i) {
				return nil, true
			}
			if arr, ok := a.(*array.Binary); ok && i < arr.Len() {
				v := &schemapb.ScalarField{}
				if err := proto.Unmarshal(arr.Value(i), v); err == nil {
					return v, true
				}
			}
			return nil, false
		},
		func(b array.Builder, v any) bool {
			if v == nil {
				b.AppendNull()
				return true
			}
			if builder, ok := b.(*array.BinaryBuilder); ok {
				if vv, ok := v.(*schemapb.ScalarField); ok {
					if bytes, err := proto.Marshal(vv); err == nil {
						builder.Append(bytes)
						return true
					}
				}
			}
			return false
		},
	}
	_ = eagerArrayEntry

	byteEntry := serdeEntry{
		func(i int) arrow.DataType {
			return arrow.BinaryTypes.Binary
		},
		func(a arrow.Array, i int) (any, bool) {
			if a.IsNull(i) {
				return nil, true
			}
			if arr, ok := a.(*array.Binary); ok && i < arr.Len() {
				return arr.Value(i), true
			}
			return nil, false
		},
		func(b array.Builder, v any) bool {
			if v == nil {
				b.AppendNull()
				return true
			}
			if builder, ok := b.(*array.BinaryBuilder); ok {
				if vv, ok := v.([]byte); ok {
					builder.Append(vv)
					return true
				}
				if vv, ok := v.(*schemapb.ScalarField); ok {
					if bytes, err := proto.Marshal(vv); err == nil {
						builder.Append(bytes)
						return true
					}
				}
			}
			return false
		},
	}

	m[schemapb.DataType_Array] = byteEntry
	m[schemapb.DataType_JSON] = byteEntry
	m[schemapb.DataType_Geometry] = byteEntry

	fixedSizeDeserializer := func(a arrow.Array, i int) (any, bool) {
		if a.IsNull(i) {
			return nil, true
		}
		if arr, ok := a.(*array.FixedSizeBinary); ok && i < arr.Len() {
			return arr.Value(i), true
		}
		return nil, false
	}
	fixedSizeSerializer := func(b array.Builder, v any) bool {
		if v == nil {
			b.AppendNull()
			return true
		}
		if builder, ok := b.(*array.FixedSizeBinaryBuilder); ok {
			if v, ok := v.([]byte); ok {
				builder.Append(v)
				return true
			}
		}
		return false
	}

	m[schemapb.DataType_BinaryVector] = serdeEntry{
		func(i int) arrow.DataType {
			return &arrow.FixedSizeBinaryType{ByteWidth: (i + 7) / 8}
		},
		fixedSizeDeserializer,
		fixedSizeSerializer,
	}
	m[schemapb.DataType_Float16Vector] = serdeEntry{
		func(i int) arrow.DataType {
			return &arrow.FixedSizeBinaryType{ByteWidth: i * 2}
		},
		fixedSizeDeserializer,
		fixedSizeSerializer,
	}
	m[schemapb.DataType_BFloat16Vector] = serdeEntry{
		func(i int) arrow.DataType {
			return &arrow.FixedSizeBinaryType{ByteWidth: i * 2}
		},
		fixedSizeDeserializer,
		fixedSizeSerializer,
	}
	m[schemapb.DataType_FloatVector] = serdeEntry{
		func(i int) arrow.DataType {
			return &arrow.FixedSizeBinaryType{ByteWidth: i * 4}
		},
		func(a arrow.Array, i int) (any, bool) {
			if a.IsNull(i) {
				return nil, true
			}
			if arr, ok := a.(*array.FixedSizeBinary); ok && i < arr.Len() {
				return arrow.Float32Traits.CastFromBytes(arr.Value(i)), true
			}
			return nil, false
		},
		func(b array.Builder, v any) bool {
			if v == nil {
				b.AppendNull()
				return true
			}
			if builder, ok := b.(*array.FixedSizeBinaryBuilder); ok {
				if vv, ok := v.([]float32); ok {
					dim := len(vv)
					byteLength := dim * 4
					bytesData := make([]byte, byteLength)
					for i, vec := range vv {
						bytes := math.Float32bits(vec)
						common.Endian.PutUint32(bytesData[i*4:], bytes)
					}
					builder.Append(bytesData)
					return true
				}
			}
			return false
		},
	}
	m[schemapb.DataType_SparseFloatVector] = byteEntry
	return m
}()

// Since parquet does not support custom fallback encoding for now,
// we disable dict encoding for primary key.
// It can be scale to all fields once parquet fallback encoding is available.
func getFieldWriterProps(field *schemapb.FieldSchema) *parquet.WriterProperties {
	if field.GetIsPrimaryKey() {
		return parquet.NewWriterProperties(
			parquet.WithCompression(compress.Codecs.Zstd),
			parquet.WithCompressionLevel(3),
			parquet.WithDictionaryDefault(false),
		)
	}
	return parquet.NewWriterProperties(
		parquet.WithCompression(compress.Codecs.Zstd),
		parquet.WithCompressionLevel(3),
	)
}

type DeserializeReader[T any] struct {
	rr           RecordReader
	deserializer Deserializer[T]
	rec          Record
	values       []T
	pos          int
}

// Iterate to next value, return error or EOF if no more value.
func (deser *DeserializeReader[T]) Next() error {
	if deser.rec == nil || deser.pos >= deser.rec.Len()-1 {
		if err := deser.rr.Next(); err != nil {
			return err
		}
		deser.pos = 0
		deser.rec = deser.rr.Record()

		deser.values = make([]T, deser.rec.Len())

		if err := deser.deserializer(deser.rec, deser.values); err != nil {
			return err
		}
	} else {
		deser.pos++
	}

	return nil
}

func (deser *DeserializeReader[T]) NextRecord() (Record, error) {
	if len(deser.values) != 0 {
		return nil, errors.New("deserialize result is not empty")
	}

	if err := deser.rr.Next(); err != nil {
		return nil, err
	}
	return deser.rr.Record(), nil
}

func (deser *DeserializeReader[T]) Value() T {
	return deser.values[deser.pos]
}

func (deser *DeserializeReader[T]) Close() {
	if deser.rec != nil {
		deser.rec.Release()
	}
	if deser.rr != nil {
		deser.rr.Close()
	}
}

func NewDeserializeReader[T any](rr RecordReader, deserializer Deserializer[T]) *DeserializeReader[T] {
	return &DeserializeReader[T]{
		rr:           rr,
		deserializer: deserializer,
	}
}

var _ Record = (*selectiveRecord)(nil)

// selectiveRecord is a Record that only contains a single field, reusing existing Record.
type selectiveRecord struct {
	r               Record
	selectedFieldId FieldID

	schema map[FieldID]schemapb.DataType
}

func (r *selectiveRecord) Schema() map[FieldID]schemapb.DataType {
	return r.schema
}

func (r *selectiveRecord) ArrowSchema() *arrow.Schema {
	return r.r.ArrowSchema()
}

func (r *selectiveRecord) Column(i FieldID) arrow.Array {
	if i == r.selectedFieldId {
		return r.r.Column(i)
	}
	return nil
}

func (r *selectiveRecord) Len() int {
	return r.r.Len()
}

func (r *selectiveRecord) Release() {
	// do nothing.
}

func (r *selectiveRecord) Slice(start, end int) Record {
	panic("not implemented")
}

func calculateArraySize(a arrow.Array) int {
	if a == nil || a.Data() == nil || a.Data().Buffers() == nil {
		return 0
	}

	var totalSize int
	offset := a.Data().Offset()
	length := a.Len()

	if len(a.NullBitmapBytes()) > 0 {
		totalSize += (length + 7) / 8
	}

	for i, buf := range a.Data().Buffers() {
		if buf == nil {
			continue
		}

		switch i {
		case 0:
			// Handle bitmap buffer, already handled
		case 1:
			switch a.DataType().ID() {
			case arrow.STRING, arrow.BINARY:
				// Handle variable-length types like STRING/BINARY
				startOffset := int(binary.LittleEndian.Uint32(buf.Bytes()[offset*4:]))
				endOffset := int(binary.LittleEndian.Uint32(buf.Bytes()[(offset+length)*4:]))
				totalSize += endOffset - startOffset
			case arrow.LIST:
				// Handle nest types like list
				for i := 0; i < length; i++ {
					startOffset := int(binary.LittleEndian.Uint32(buf.Bytes()[(offset+i)*4:]))
					endOffset := int(binary.LittleEndian.Uint32(buf.Bytes()[(offset+i+1)*4:]))
					elementSize := a.DataType().(*arrow.ListType).Elem().(arrow.FixedWidthDataType).Bytes()
					totalSize += (endOffset - startOffset) * elementSize
				}
			default:
				// Handle fixed-length types
				elementSize := a.DataType().(arrow.FixedWidthDataType).Bytes()
				totalSize += elementSize * length
			}
		}
	}
	return totalSize
}

func newSelectiveRecord(r Record, selectedFieldId FieldID) *selectiveRecord {
	dt, ok := r.Schema()[selectedFieldId]
	if !ok {
		return nil
	}
	schema := make(map[FieldID]schemapb.DataType, 1)
	schema[selectedFieldId] = dt
	return &selectiveRecord{
		r:               r,
		selectedFieldId: selectedFieldId,
		schema:          schema,
	}
}

var _ RecordWriter = (*CompositeRecordWriter)(nil)

type CompositeRecordWriter struct {
	writers map[FieldID]RecordWriter
}

func (crw *CompositeRecordWriter) GetWrittenUncompressed() uint64 {
	s := uint64(0)
	for _, w := range crw.writers {
		s += w.GetWrittenUncompressed()
	}
	return s
}

func (crw *CompositeRecordWriter) Write(r Record) error {
	if len(r.Schema()) != len(crw.writers) {
		return fmt.Errorf("schema length mismatch %d, expected %d", len(r.Schema()), len(crw.writers))
	}

	for fieldId, w := range crw.writers {
		sr := newSelectiveRecord(r, fieldId)
		if err := w.Write(sr); err != nil {
			return err
		}
	}
	return nil
}

func (crw *CompositeRecordWriter) Close() {
	if crw != nil {
		for _, w := range crw.writers {
			if w != nil {
				w.Close()
			}
		}
	}
}

func NewCompositeRecordWriter(writers map[FieldID]RecordWriter) *CompositeRecordWriter {
	return &CompositeRecordWriter{
		writers: writers,
	}
}

var _ RecordWriter = (*singleFieldRecordWriter)(nil)

type RecordWriterOptions func(*singleFieldRecordWriter)

func WithRecordWriterProps(writerProps *parquet.WriterProperties) RecordWriterOptions {
	return func(w *singleFieldRecordWriter) {
		w.writerProps = writerProps
	}
}

type singleFieldRecordWriter struct {
	fw          *pqarrow.FileWriter
	fieldId     FieldID
	schema      *arrow.Schema
	writerProps *parquet.WriterProperties

	numRows              int
	writtenUncompressed  uint64
	memoryExpansionRatio int
}

func (sfw *singleFieldRecordWriter) Write(r Record) error {
	sfw.numRows += r.Len()
	a := r.Column(sfw.fieldId)

	sfw.writtenUncompressed += uint64(calculateArraySize(a))
	rec := array.NewRecord(sfw.schema, []arrow.Array{a}, int64(r.Len()))
	defer rec.Release()
	return sfw.fw.WriteBuffered(rec)
}

func (sfw *singleFieldRecordWriter) GetWrittenUncompressed() uint64 {
	return sfw.writtenUncompressed * uint64(sfw.memoryExpansionRatio)
}

func (sfw *singleFieldRecordWriter) Close() {
	sfw.fw.Close()
}

func newSingleFieldRecordWriter(field *schemapb.FieldSchema, writer io.Writer, opts ...RecordWriterOptions) (*singleFieldRecordWriter, error) {
	// calculate memory expansion ratio
	// arrays are serialized by protobuf, where int values may be compacted, see https://protobuf.dev/reference/go/size
	// to correct the actual size, we need to multiply the memory expansion ratio accordingly.
	determineMemoryExpansionRatio := func(field *schemapb.FieldSchema) int {
		if field.DataType == schemapb.DataType_Array {
			switch field.GetElementType() {
			case schemapb.DataType_Int16:
				return 2
			case schemapb.DataType_Int32:
				return 4
			case schemapb.DataType_Int64:
				return 8
			}
		}
		return 1
	}
	dim, _ := typeutil.GetDim(field)
	w := &singleFieldRecordWriter{
		fieldId: field.FieldID,
		schema: arrow.NewSchema([]arrow.Field{
			{
				Name:     strconv.Itoa(int(field.FieldID)),
				Type:     serdeMap[field.DataType].arrowType(int(dim)),
				Nullable: true, // No nullable check here.
			},
		}, nil),
		writerProps: parquet.NewWriterProperties(
			parquet.WithMaxRowGroupLength(math.MaxInt64), // No additional grouping for now.
			parquet.WithCompression(compress.Codecs.Zstd),
			parquet.WithCompressionLevel(3)),
		memoryExpansionRatio: determineMemoryExpansionRatio(field),
	}
	for _, o := range opts {
		o(w)
	}
	fw, err := pqarrow.NewFileWriter(w.schema, writer, w.writerProps, pqarrow.DefaultWriterProps())
	if err != nil {
		return nil, err
	}
	w.fw = fw
	return w, nil
}

var _ RecordWriter = (*multiFieldRecordWriter)(nil)

type multiFieldRecordWriter struct {
	fw       *pqarrow.FileWriter
	fieldIDs []FieldID
	schema   *arrow.Schema

	numRows             int
	writtenUncompressed uint64
}

func (mfw *multiFieldRecordWriter) Write(r Record) error {
	mfw.numRows += r.Len()
	columns := make([]arrow.Array, len(mfw.fieldIDs))
	for i, fieldId := range mfw.fieldIDs {
		columns[i] = r.Column(fieldId)
		mfw.writtenUncompressed += uint64(calculateArraySize(columns[i]))
	}
	rec := array.NewRecord(mfw.schema, columns, int64(r.Len()))
	defer rec.Release()
	return mfw.fw.WriteBuffered(rec)
}

func (mfw *multiFieldRecordWriter) GetWrittenUncompressed() uint64 {
	return mfw.writtenUncompressed
}

func (mfw *multiFieldRecordWriter) Close() {
	mfw.fw.Close()
}

func newMultiFieldRecordWriter(fieldIDs []FieldID, fields []arrow.Field, writer io.Writer) (*multiFieldRecordWriter, error) {
	schema := arrow.NewSchema(fields, nil)
	fw, err := pqarrow.NewFileWriter(schema, writer,
		parquet.NewWriterProperties(parquet.WithMaxRowGroupLength(math.MaxInt64)), // No additional grouping for now.
		pqarrow.DefaultWriterProps())
	if err != nil {
		return nil, err
	}
	return &multiFieldRecordWriter{
		fw:       fw,
		fieldIDs: fieldIDs,
		schema:   schema,
	}, nil
}

type SerializeWriter[T any] struct {
	rw         RecordWriter
	serializer Serializer[T]
	batchSize  int
	mu         sync.Mutex

	buffer []T
	pos    int
}

func (sw *SerializeWriter[T]) Flush() error {
	sw.mu.Lock()
	defer sw.mu.Unlock()
	if sw.pos == 0 {
		return nil
	}
	buf := sw.buffer[:sw.pos]
	r, err := sw.serializer(buf)
	if err != nil {
		return err
	}
	defer r.Release()
	if err := sw.rw.Write(r); err != nil {
		return err
	}
	sw.pos = 0
	return nil
}

func (sw *SerializeWriter[T]) Write(value T) error {
	if sw.buffer == nil {
		sw.buffer = make([]T, sw.batchSize)
	}
	sw.buffer[sw.pos] = value
	sw.pos++
	if sw.pos == sw.batchSize {
		if err := sw.Flush(); err != nil {
			return err
		}
	}
	return nil
}

func (sw *SerializeWriter[T]) WriteRecord(r Record) error {
	sw.mu.Lock()
	defer sw.mu.Unlock()
	if len(sw.buffer) != 0 {
		return errors.New("serialize buffer is not empty")
	}

	if err := sw.rw.Write(r); err != nil {
		return err
	}

	return nil
}

func (sw *SerializeWriter[T]) WrittenMemorySize() uint64 {
	sw.mu.Lock()
	defer sw.mu.Unlock()
	return sw.rw.GetWrittenUncompressed()
}

func (sw *SerializeWriter[T]) Close() error {
	if err := sw.Flush(); err != nil {
		return err
	}
	sw.rw.Close()
	return nil
}

func NewSerializeRecordWriter[T any](rw RecordWriter, serializer Serializer[T], batchSize int) *SerializeWriter[T] {
	return &SerializeWriter[T]{
		rw:         rw,
		serializer: serializer,
		batchSize:  batchSize,
	}
}

type simpleArrowRecord struct {
	r      arrow.Record
	schema map[FieldID]schemapb.DataType

	field2Col map[FieldID]int
}

var _ Record = (*simpleArrowRecord)(nil)

func (sr *simpleArrowRecord) Schema() map[FieldID]schemapb.DataType {
	return sr.schema
}

func (sr *simpleArrowRecord) Column(i FieldID) arrow.Array {
	colIdx, ok := sr.field2Col[i]
	if !ok {
		panic("no such field")
	}
	return sr.r.Column(colIdx)
}

func (sr *simpleArrowRecord) Len() int {
	return int(sr.r.NumRows())
}

func (sr *simpleArrowRecord) Release() {
	sr.r.Release()
}

func (sr *simpleArrowRecord) ArrowSchema() *arrow.Schema {
	return sr.r.Schema()
}

func (sr *simpleArrowRecord) Slice(start, end int) Record {
	s := sr.r.NewSlice(int64(start), int64(end))
	return newSimpleArrowRecord(s, sr.schema, sr.field2Col)
}

func newSimpleArrowRecord(r arrow.Record, schema map[FieldID]schemapb.DataType, field2Col map[FieldID]int) *simpleArrowRecord {
	return &simpleArrowRecord{
		r:         r,
		schema:    schema,
		field2Col: field2Col,
	}
}