lib/storage: remove interface conversion in hot path during block merging

This should improve merge speed a bit for parts with big number of small blocks.

lib/storage/block_stream_reader.go

@@ -25,8 +25,12 @@ type blockStreamReader struct {
 
 	ph partHeader
 
-	timestampsReader filestream.ReadCloser
-	valuesReader     filestream.ReadCloser
+	// Use io.Reader type for timestampsReader and valuesReader
+	// in order to remove I2I conversion in readBlock
+	// when passing them to fs.ReadFullData
+	timestampsReader io.Reader
+	valuesReader     io.Reader
+
 	indexReader filestream.ReadCloser
 
 	mrs []metaindexRow
@@ -56,6 +60,11 @@ type blockStreamReader struct {
 	err error
 }
 
+func (bsr *blockStreamReader) assertWriteClosers() {
+	_ = bsr.timestampsReader.(filestream.ReadCloser)
+	_ = bsr.valuesReader.(filestream.ReadCloser)
+}
+
 func (bsr *blockStreamReader) reset() {
 	bsr.Block.Reset()
 
@@ -108,6 +117,8 @@ func (bsr *blockStreamReader) InitFromInmemoryPart(mp *inmemoryPart) {
 	if err != nil {
 		logger.Panicf("BUG: cannot unmarshal metaindex rows from inmemoryPart: %s", err)
 	}
+
+	bsr.assertWriteClosers()
 }
 
 // InitFromFilePart initializes bsr from a file-based part on the given path.
@@ -167,6 +178,8 @@ func (bsr *blockStreamReader) InitFromFilePart(path string) error {
 	bsr.indexReader = indexFile
 	bsr.mrs = mrs
 
+	bsr.assertWriteClosers()
+
 	return nil
 }
 
@@ -174,8 +187,8 @@ func (bsr *blockStreamReader) InitFromFilePart(path string) error {
 //
 // It closes *Reader files passed to Init.
 func (bsr *blockStreamReader) MustClose() {
-	bsr.timestampsReader.MustClose()
-	bsr.valuesReader.MustClose()
+	bsr.timestampsReader.(filestream.ReadCloser).MustClose()
+	bsr.valuesReader.(filestream.ReadCloser).MustClose()
 	bsr.indexReader.MustClose()
 
 	bsr.reset()

lib/storage/block_stream_writer.go

@@ -2,6 +2,7 @@ package storage
 
 import (
 	"fmt"
+	"io"
 	"path/filepath"
 	"sync"
 	"sync/atomic"
@@ -17,8 +18,12 @@ type blockStreamWriter struct {
 	compressLevel int
 	path          string
 
-	timestampsWriter filestream.WriteCloser
-	valuesWriter     filestream.WriteCloser
+	// Use io.Writer type for timestampsWriter and valuesWriter
+	// in order to remove I2I conversion in WriteExternalBlock
+	// when passing them to fs.MustWriteData
+	timestampsWriter io.Writer
+	valuesWriter     io.Writer
+
 	indexWriter     filestream.WriteCloser
 	metaindexWriter filestream.WriteCloser
 
@@ -35,6 +40,11 @@ type blockStreamWriter struct {
 	compressedMetaindexData []byte
 }
 
+func (bsw *blockStreamWriter) assertWriteClosers() {
+	_ = bsw.timestampsWriter.(filestream.WriteCloser)
+	_ = bsw.valuesWriter.(filestream.WriteCloser)
+}
+
 // Init initializes bsw with the given writers.
 func (bsw *blockStreamWriter) reset() {
 	bsw.compressLevel = 0
@@ -67,6 +77,8 @@ func (bsw *blockStreamWriter) InitFromInmemoryPart(mp *inmemoryPart) {
 	bsw.valuesWriter = &mp.valuesData
 	bsw.indexWriter = &mp.indexData
 	bsw.metaindexWriter = &mp.metaindexData
+
+	bsw.assertWriteClosers()
 }
 
 // InitFromFilePart initializes bsw from a file-based part on the given path.
@@ -126,6 +138,8 @@ func (bsw *blockStreamWriter) InitFromFilePart(path string, nocache bool, compre
 	bsw.indexWriter = indexFile
 	bsw.metaindexWriter = metaindexFile
 
+	bsw.assertWriteClosers()
+
 	return nil
 }
 
@@ -141,8 +155,8 @@ func (bsw *blockStreamWriter) MustClose() {
 	fs.MustWriteData(bsw.metaindexWriter, bsw.compressedMetaindexData)
 
 	// Close writers.
-	bsw.timestampsWriter.MustClose()
-	bsw.valuesWriter.MustClose()
+	bsw.timestampsWriter.(filestream.WriteCloser).MustClose()
+	bsw.valuesWriter.(filestream.WriteCloser).MustClose()
 	bsw.indexWriter.MustClose()
 	bsw.metaindexWriter.MustClose()