VictoriaMetrics/lib/mergeset/block_stream_writer.go
Aliaksandr Valialkin 5d69ba630e
lib/mergeset: properly record the firstItem in metaindexRow at blockStreamWriter.WriteBlock
The 3c246cdf00 added an optimization where the previous metaindexRow
could be saved to disk when the current block header couldn't be added indexBlock because the resulting
indexBlock size became too big. This could result in an empty metaindexRow.firstItem for the next metaindexRow.
2024-02-12 18:06:50 +02:00

200 lines
5.6 KiB
Go

package mergeset
import (
"path/filepath"
"sync"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/encoding"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/filestream"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/fs"
)
type blockStreamWriter struct {
compressLevel int
metaindexWriter filestream.WriteCloser
indexWriter filestream.WriteCloser
itemsWriter filestream.WriteCloser
lensWriter filestream.WriteCloser
sb storageBlock
bh blockHeader
mr metaindexRow
unpackedIndexBlockBuf []byte
packedIndexBlockBuf []byte
unpackedMetaindexBuf []byte
packedMetaindexBuf []byte
itemsBlockOffset uint64
lensBlockOffset uint64
indexBlockOffset uint64
// whether the first item for mr has been caught.
mrFirstItemCaught bool
}
func (bsw *blockStreamWriter) reset() {
bsw.compressLevel = 0
bsw.metaindexWriter = nil
bsw.indexWriter = nil
bsw.itemsWriter = nil
bsw.lensWriter = nil
bsw.sb.Reset()
bsw.bh.Reset()
bsw.mr.Reset()
bsw.unpackedIndexBlockBuf = bsw.unpackedIndexBlockBuf[:0]
bsw.packedIndexBlockBuf = bsw.packedIndexBlockBuf[:0]
bsw.unpackedMetaindexBuf = bsw.unpackedMetaindexBuf[:0]
bsw.packedMetaindexBuf = bsw.packedMetaindexBuf[:0]
bsw.itemsBlockOffset = 0
bsw.lensBlockOffset = 0
bsw.indexBlockOffset = 0
bsw.mrFirstItemCaught = false
}
func (bsw *blockStreamWriter) MustInitFromInmemoryPart(mp *inmemoryPart, compressLevel int) {
bsw.reset()
bsw.compressLevel = compressLevel
bsw.metaindexWriter = &mp.metaindexData
bsw.indexWriter = &mp.indexData
bsw.itemsWriter = &mp.itemsData
bsw.lensWriter = &mp.lensData
}
// MustInitFromFilePart initializes bsw from a file-based part on the given path.
//
// The bsw doesn't pollute OS page cache if nocache is set.
func (bsw *blockStreamWriter) MustInitFromFilePart(path string, nocache bool, compressLevel int) {
path = filepath.Clean(path)
// Create the directory
fs.MustMkdirFailIfExist(path)
// Create part files in the directory.
// Always cache metaindex file in OS page cache, since it is immediately
// read after the merge.
metaindexPath := filepath.Join(path, metaindexFilename)
metaindexFile := filestream.MustCreate(metaindexPath, false)
indexPath := filepath.Join(path, indexFilename)
indexFile := filestream.MustCreate(indexPath, nocache)
itemsPath := filepath.Join(path, itemsFilename)
itemsFile := filestream.MustCreate(itemsPath, nocache)
lensPath := filepath.Join(path, lensFilename)
lensFile := filestream.MustCreate(lensPath, nocache)
bsw.reset()
bsw.compressLevel = compressLevel
bsw.metaindexWriter = metaindexFile
bsw.indexWriter = indexFile
bsw.itemsWriter = itemsFile
bsw.lensWriter = lensFile
}
// MustClose closes the bsw.
//
// It closes *Writer files passed to Init*.
func (bsw *blockStreamWriter) MustClose() {
// Flush the remaining data.
bsw.flushIndexData()
// Compress and write metaindex.
bsw.packedMetaindexBuf = encoding.CompressZSTDLevel(bsw.packedMetaindexBuf[:0], bsw.unpackedMetaindexBuf, bsw.compressLevel)
fs.MustWriteData(bsw.metaindexWriter, bsw.packedMetaindexBuf)
// Close all the writers.
bsw.metaindexWriter.MustClose()
bsw.indexWriter.MustClose()
bsw.itemsWriter.MustClose()
bsw.lensWriter.MustClose()
bsw.reset()
}
// WriteBlock writes ib to bsw.
//
// ib must be sorted.
func (bsw *blockStreamWriter) WriteBlock(ib *inmemoryBlock) {
bsw.bh.firstItem, bsw.bh.commonPrefix, bsw.bh.itemsCount, bsw.bh.marshalType = ib.MarshalSortedData(&bsw.sb, bsw.bh.firstItem[:0], bsw.bh.commonPrefix[:0], bsw.compressLevel)
// Write itemsData
fs.MustWriteData(bsw.itemsWriter, bsw.sb.itemsData)
bsw.bh.itemsBlockSize = uint32(len(bsw.sb.itemsData))
bsw.bh.itemsBlockOffset = bsw.itemsBlockOffset
bsw.itemsBlockOffset += uint64(bsw.bh.itemsBlockSize)
// Write lensData
fs.MustWriteData(bsw.lensWriter, bsw.sb.lensData)
bsw.bh.lensBlockSize = uint32(len(bsw.sb.lensData))
bsw.bh.lensBlockOffset = bsw.lensBlockOffset
bsw.lensBlockOffset += uint64(bsw.bh.lensBlockSize)
// Write blockHeader
unpackedIndexBlockBufLen := len(bsw.unpackedIndexBlockBuf)
bsw.unpackedIndexBlockBuf = bsw.bh.Marshal(bsw.unpackedIndexBlockBuf)
if len(bsw.unpackedIndexBlockBuf) > maxIndexBlockSize {
bsw.unpackedIndexBlockBuf = bsw.unpackedIndexBlockBuf[:unpackedIndexBlockBufLen]
bsw.flushIndexData()
bsw.unpackedIndexBlockBuf = bsw.bh.Marshal(bsw.unpackedIndexBlockBuf)
}
if !bsw.mrFirstItemCaught {
bsw.mr.firstItem = append(bsw.mr.firstItem[:0], bsw.bh.firstItem...)
bsw.mrFirstItemCaught = true
}
bsw.bh.Reset()
bsw.mr.blockHeadersCount++
}
// The maximum size of index block with multiple blockHeaders.
const maxIndexBlockSize = 64 * 1024
func (bsw *blockStreamWriter) flushIndexData() {
if len(bsw.unpackedIndexBlockBuf) == 0 {
// Nothing to flush.
return
}
// Write indexBlock.
bsw.packedIndexBlockBuf = encoding.CompressZSTDLevel(bsw.packedIndexBlockBuf[:0], bsw.unpackedIndexBlockBuf, bsw.compressLevel)
fs.MustWriteData(bsw.indexWriter, bsw.packedIndexBlockBuf)
bsw.mr.indexBlockSize = uint32(len(bsw.packedIndexBlockBuf))
bsw.mr.indexBlockOffset = bsw.indexBlockOffset
bsw.indexBlockOffset += uint64(bsw.mr.indexBlockSize)
bsw.unpackedIndexBlockBuf = bsw.unpackedIndexBlockBuf[:0]
// Write metaindexRow.
bsw.unpackedMetaindexBuf = bsw.mr.Marshal(bsw.unpackedMetaindexBuf)
bsw.mr.Reset()
// Notify that the next call to WriteBlock must catch the first item.
bsw.mrFirstItemCaught = false
}
func getBlockStreamWriter() *blockStreamWriter {
v := bswPool.Get()
if v == nil {
return &blockStreamWriter{}
}
return v.(*blockStreamWriter)
}
func putBlockStreamWriter(bsw *blockStreamWriter) {
bsw.reset()
bswPool.Put(bsw)
}
var bswPool sync.Pool