speed up the performance of s3select on csv (#7945)

pkg/s3select/csv/reader.go

@@ -82,10 +82,11 @@ func (rr *recordReader) Read(p []byte) (n int, err error) {
 
 // Reader - CSV record reader for S3Select.
 type Reader struct {
-	args        *ReaderArgs
+	args         *ReaderArgs
-	readCloser  io.ReadCloser
+	readCloser   io.ReadCloser
-	csvReader   *csv.Reader
+	csvReader    *csv.Reader
-	columnNames []string
+	columnNames  []string
+	nameIndexMap map[string]int64
 }
 
 // Read - reads single record.
@@ -99,23 +100,24 @@ func (r *Reader) Read() (sql.Record, error) {
 		return nil, err
 	}
 
-	columnNames := r.columnNames
+	if r.columnNames == nil {
-	if columnNames == nil {
+		r.columnNames = make([]string, len(csvRecord))
-		columnNames = make([]string, len(csvRecord))
 		for i := range csvRecord {
-			columnNames[i] = fmt.Sprintf("_%v", i+1)
+			r.columnNames[i] = fmt.Sprintf("_%v", i+1)
 		}
 	}
 
-	nameIndexMap := make(map[string]int64)
+	if r.nameIndexMap == nil {
-	for i := range columnNames {
+		r.nameIndexMap = make(map[string]int64)
-		nameIndexMap[columnNames[i]] = int64(i)
+		for i := range r.columnNames {
+			r.nameIndexMap[r.columnNames[i]] = int64(i)
+		}
 	}
 
 	return &Record{
-		columnNames:  columnNames,
+		columnNames:  r.columnNames,
 		csvRecord:    csvRecord,
-		nameIndexMap: nameIndexMap,
+		nameIndexMap: r.nameIndexMap,
 	}, nil
 }
 

pkg/s3select/csv/reader_test.go

@@ -17,6 +17,7 @@
 package csv
 
 import (
+	"bytes"
 	"io"
 	"io/ioutil"
 	"strings"
@@ -39,6 +40,7 @@ func TestRead(t *testing.T) {
 	for i, c := range cases {
 		var err error
 		var record sql.Record
+		var result bytes.Buffer
 
 		r, _ := NewReader(ioutil.NopCloser(strings.NewReader(c.content)), &ReaderArgs{
 			FileHeaderInfo:             none,
@@ -51,22 +53,22 @@ func TestRead(t *testing.T) {
 			unmarshaled:                true,
 		})
 
-		result := ""
 		for {
 			record, err = r.Read()
 			if err != nil {
 				break
 			}
-			s, _ := record.MarshalCSV([]rune(c.fieldDelimiter)[0])
+			record.WriteCSV(&result, []rune(c.fieldDelimiter)[0])
-			result += string(s) + c.recordDelimiter
+			result.Truncate(result.Len() - 1)
+			result.WriteString(c.recordDelimiter)
 		}
 		r.Close()
 		if err != io.EOF {
 			t.Fatalf("Case %d failed with %s", i, err)
 		}
 
-		if result != c.content {
+		if result.String() != c.content {
-			t.Errorf("Case %d failed: expected %v result %v", i, c.content, result)
+			t.Errorf("Case %d failed: expected %v result %v", i, c.content, result.String())
 		}
 	}
 }

pkg/s3select/csv/record.go

@@ -17,11 +17,11 @@
 package csv
 
 import (
-	"bytes"
 	"encoding/csv"
 	"encoding/json"
 	"errors"
 	"fmt"
+	"io"
 
 	"github.com/bcicen/jstream"
 	"github.com/minio/minio/pkg/s3select/sql"
@@ -61,30 +61,28 @@ func (r *Record) Set(name string, value *sql.Value) error {
 	return nil
 }
 
-// MarshalCSV - encodes to CSV data.
+// WriteCSV - encodes to CSV data.
-func (r *Record) MarshalCSV(fieldDelimiter rune) ([]byte, error) {
+func (r *Record) WriteCSV(writer io.Writer, fieldDelimiter rune) error {
-	buf := new(bytes.Buffer)
+	w := csv.NewWriter(writer)
-	w := csv.NewWriter(buf)
 	w.Comma = fieldDelimiter
 	if err := w.Write(r.csvRecord); err != nil {
-		return nil, err
+		return err
 	}
 	w.Flush()
 	if err := w.Error(); err != nil {
-		return nil, err
+		return err
 	}
 
-	data := buf.Bytes()
+	return nil
-	return data[:len(data)-1], nil
 }
 
-// MarshalJSON - encodes to JSON data.
+// WriteJSON - encodes to JSON data.
-func (r *Record) MarshalJSON() ([]byte, error) {
+func (r *Record) WriteJSON(writer io.Writer) error {
 	var kvs jstream.KVS = make([]jstream.KV, len(r.columnNames))
 	for i := 0; i < len(r.columnNames); i++ {
 		kvs[i] = jstream.KV{Key: r.columnNames[i], Value: r.csvRecord[i]}
 	}
-	return json.Marshal(kvs)
+	return json.NewEncoder(writer).Encode(kvs)
 }
 
 // Raw - returns the underlying data with format info.

pkg/s3select/json/record.go

@@ -17,11 +17,11 @@
 package json
 
 import (
-	"bytes"
 	"encoding/csv"
 	"encoding/json"
 	"errors"
 	"fmt"
+	"io"
 	"strings"
 
 	"github.com/bcicen/jstream"
@@ -77,8 +77,8 @@ func (r *Record) Set(name string, value *sql.Value) error {
 	return nil
 }
 
-// MarshalCSV - encodes to CSV data.
+// WriteCSV - encodes to CSV data.
-func (r *Record) MarshalCSV(fieldDelimiter rune) ([]byte, error) {
+func (r *Record) WriteCSV(writer io.Writer, fieldDelimiter rune) error {
 	var csvRecord []string
 	for _, kv := range r.KVS {
 		var columnValue string
@@ -90,24 +90,22 @@ func (r *Record) MarshalCSV(fieldDelimiter rune) ([]byte, error) {
 		case RawJSON:
 			columnValue = string([]byte(val))
 		default:
-			return nil, errors.New("Cannot marshal unhandled type")
+			return errors.New("Cannot marshal unhandled type")
 		}
 		csvRecord = append(csvRecord, columnValue)
 	}
 
-	buf := new(bytes.Buffer)
+	w := csv.NewWriter(writer)
-	w := csv.NewWriter(buf)
 	w.Comma = fieldDelimiter
 	if err := w.Write(csvRecord); err != nil {
-		return nil, err
+		return err
 	}
 	w.Flush()
 	if err := w.Error(); err != nil {
-		return nil, err
+		return err
 	}
 
-	data := buf.Bytes()
+	return nil
-	return data[:len(data)-1], nil
 }
 
 // Raw - returns the underlying representation.
@@ -115,9 +113,9 @@ func (r *Record) Raw() (sql.SelectObjectFormat, interface{}) {
 	return r.SelectFormat, r.KVS
 }
 
-// MarshalJSON - encodes to JSON data.
+// WriteJSON - encodes to JSON data.
-func (r *Record) MarshalJSON() ([]byte, error) {
+func (r *Record) WriteJSON(writer io.Writer) error {
-	return json.Marshal(r.KVS)
+	return json.NewEncoder(writer).Encode(r.KVS)
 }
 
 // Replace the underlying buffer of json data.

pkg/s3select/message.go

@@ -242,7 +242,7 @@ type messageWriter struct {
 
 	payloadBuffer      []byte
 	payloadBufferIndex int
-	payloadCh          chan []byte
+	payloadCh          chan *bytes.Buffer
 
 	finBytesScanned, finBytesProcessed int64
 
@@ -308,10 +308,10 @@ func (writer *messageWriter) start() {
 				}
 				writer.write(endMessage)
 			} else {
-				for len(payload) > 0 {
+				for payload.Len() > 0 {
-					copiedLen := copy(writer.payloadBuffer[writer.payloadBufferIndex:], payload)
+					copiedLen := copy(writer.payloadBuffer[writer.payloadBufferIndex:], payload.Bytes())
 					writer.payloadBufferIndex += copiedLen
-					payload = payload[copiedLen:]
+					payload.Next(copiedLen)
 
 					// If buffer is filled, flush it now!
 					freeSpace := bufLength - writer.payloadBufferIndex
@@ -322,6 +322,8 @@ func (writer *messageWriter) start() {
 						}
 					}
 				}
+
+				bufPool.Put(payload)
 			}
 
 		case <-recordStagingTicker.C:
@@ -349,10 +351,16 @@ func (writer *messageWriter) start() {
 	if progressTicker != nil {
 		progressTicker.Stop()
 	}
+
+	// Whatever drain the payloadCh to prevent from memory leaking.
+	for len(writer.payloadCh) > 0 {
+		payload := <-writer.payloadCh
+		bufPool.Put(payload)
+	}
 }
 
 // Sends a single whole record.
-func (writer *messageWriter) SendRecord(payload []byte) error {
+func (writer *messageWriter) SendRecord(payload *bytes.Buffer) error {
 	select {
 	case writer.payloadCh <- payload:
 		return nil
@@ -409,7 +417,7 @@ func newMessageWriter(w http.ResponseWriter, getProgressFunc func() (bytesScanne
 		getProgressFunc: getProgressFunc,
 
 		payloadBuffer: make([]byte, bufLength),
-		payloadCh:     make(chan []byte),
+		payloadCh:     make(chan *bytes.Buffer),
 
 		errCh:  make(chan []byte),
 		doneCh: make(chan struct{}),

pkg/s3select/select.go

@@ -17,11 +17,15 @@
 package s3select
 
 import (
+	"bufio"
+	"bytes"
 	"encoding/xml"
 	"fmt"
 	"io"
+	"io/ioutil"
 	"net/http"
 	"strings"
+	"sync"
 
 	"github.com/minio/minio/pkg/s3select/csv"
 	"github.com/minio/minio/pkg/s3select/json"
@@ -53,6 +57,20 @@ const (
 	maxRecordSize = 1 << 20 // 1 MiB
 )
 
+var bufPool = sync.Pool{
+	New: func() interface{} {
+		return new(bytes.Buffer)
+	},
+}
+
+var bufioWriterPool = sync.Pool{
+	New: func() interface{} {
+		// ioutil.Discard is just used to create the writer. Actual destination
+		// writer is set later by Reset() before using it.
+		return bufio.NewWriter(ioutil.Discard)
+	},
+}
+
 // UnmarshalXML - decodes XML data.
 func (c *CompressionType) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
 	var s string
@@ -306,22 +324,36 @@ func (s3Select *S3Select) Open(getReader func(offset, length int64) (io.ReadClos
 	panic(fmt.Errorf("unknown input format '%v'", s3Select.Input.format))
 }
 
-func (s3Select *S3Select) marshal(record sql.Record) ([]byte, error) {
+func (s3Select *S3Select) marshal(buf *bytes.Buffer, record sql.Record) error {
 	switch s3Select.Output.format {
 	case csvFormat:
-		data, err := record.MarshalCSV([]rune(s3Select.Output.CSVArgs.FieldDelimiter)[0])
+		// Use bufio Writer to prevent csv.Writer from allocating a new buffer.
+		bufioWriter := bufioWriterPool.Get().(*bufio.Writer)
+		defer func() {
+			bufioWriter.Reset(ioutil.Discard)
+			bufioWriterPool.Put(bufioWriter)
+		}()
+
+		bufioWriter.Reset(buf)
+		err := record.WriteCSV(bufioWriter, []rune(s3Select.Output.CSVArgs.FieldDelimiter)[0])
 		if err != nil {
-			return nil, err
+			return err
 		}
 
-		return append(data, []byte(s3Select.Output.CSVArgs.RecordDelimiter)...), nil
+		buf.Truncate(buf.Len() - 1)
+		buf.WriteString(s3Select.Output.CSVArgs.RecordDelimiter)
+
+		return nil
 	case jsonFormat:
-		data, err := record.MarshalJSON()
+		err := record.WriteJSON(buf)
 		if err != nil {
-			return nil, err
+			return err
 		}
 
-		return append(data, []byte(s3Select.Output.JSONArgs.RecordDelimiter)...), nil
+		buf.Truncate(buf.Len() - 1)
+		buf.WriteString(s3Select.Output.JSONArgs.RecordDelimiter)
+
+		return nil
 	}
 
 	panic(fmt.Errorf("unknown output format '%v'", s3Select.Output.format))
@@ -338,24 +370,29 @@ func (s3Select *S3Select) Evaluate(w http.ResponseWriter) {
 	var inputRecord sql.Record
 	var outputRecord sql.Record
 	var err error
-	var data []byte
 	sendRecord := func() bool {
 		if outputRecord == nil {
 			return true
 		}
 
-		if data, err = s3Select.marshal(outputRecord); err != nil {
+		buf := bufPool.Get().(*bytes.Buffer)
+		buf.Reset()
+
+		if err = s3Select.marshal(buf, outputRecord); err != nil {
+			bufPool.Put(buf)
 			return false
 		}
 
-		if len(data) > maxRecordSize {
+		if buf.Len() > maxRecordSize {
 			writer.FinishWithError("OverMaxRecordSize", "The length of a record in the input or result is greater than maxCharsPerRecord of 1 MB.")
+			bufPool.Put(buf)
 			return false
 		}
 
-		if err = writer.SendRecord(data); err != nil {
+		if err = writer.SendRecord(buf); err != nil {
 			// FIXME: log this error.
 			err = nil
+			bufPool.Put(buf)
 			return false
 		}
 

pkg/s3select/select_benchmark_test.go

@@ -99,26 +99,28 @@ func benchmarkSelect(b *testing.B, count int, query string) {
 </SelectObjectContentRequest>
 `)
 
-	s3Select, err := NewS3Select(bytes.NewReader(requestXML))
-	if err != nil {
-		b.Fatal(err)
-	}
-
 	csvData := genSampleCSVData(count)
 
 	b.ResetTimer()
 	b.ReportAllocs()
 
-	for i := 0; i < b.N; i++ {
+	b.RunParallel(func(pb *testing.PB) {
-		if err = s3Select.Open(func(offset, length int64) (io.ReadCloser, error) {
+		for pb.Next() {
-			return ioutil.NopCloser(bytes.NewReader(csvData)), nil
+			s3Select, err := NewS3Select(bytes.NewReader(requestXML))
-		}); err != nil {
+			if err != nil {
-			b.Fatal(err)
+				b.Fatal(err)
-		}
+			}
 
-		s3Select.Evaluate(&nullResponseWriter{})
+			if err = s3Select.Open(func(offset, length int64) (io.ReadCloser, error) {
-		s3Select.Close()
+				return ioutil.NopCloser(bytes.NewReader(csvData)), nil
-	}
+			}); err != nil {
+				b.Fatal(err)
+			}
+
+			s3Select.Evaluate(&nullResponseWriter{})
+			s3Select.Close()
+		}
+	})
 }
 
 func benchmarkSelectAll(b *testing.B, count int) {

pkg/s3select/sql/record.go

@@ -16,7 +16,11 @@
 
 package sql
 
-import "github.com/bcicen/jstream"
+import (
+	"io"
+
+	"github.com/bcicen/jstream"
+)
 
 // SelectObjectFormat specifies the format of the underlying data
 type SelectObjectFormat int
@@ -36,8 +40,8 @@ const (
 type Record interface {
 	Get(name string) (*Value, error)
 	Set(name string, value *Value) error
-	MarshalCSV(fieldDelimiter rune) ([]byte, error)
+	WriteCSV(writer io.Writer, fieldDelimiter rune) error
-	MarshalJSON() ([]byte, error)
+	WriteJSON(writer io.Writer) error
 
 	// Returns underlying representation
 	Raw() (SelectObjectFormat, interface{})