Use cached tags when applying series entries

tsdb/index/tsi1/log_file.go

@@ -36,13 +36,14 @@ const (
 
 // LogFile represents an on-disk write-ahead log file.
 type LogFile struct {
-	mu   sync.RWMutex
-	wg   sync.WaitGroup // ref count
-	id   int            // file sequence identifier
-	data []byte         // mmap
-	file *os.File       // writer
-	w    *bufio.Writer  // buffered writer
-	buf  []byte         // marshaling buffer
+	mu     sync.RWMutex
+	wg     sync.WaitGroup // ref count
+	id     int            // file sequence identifier
+	data   []byte         // mmap
+	file   *os.File       // writer
+	w      *bufio.Writer  // buffered writer
+	buf    []byte         // marshaling buffer
+	keyBuf []byte
 
 	sfile   *tsdb.SeriesFile // series lookup
 	size    int64            // tracks current file size
@@ -478,7 +479,7 @@ func (f *LogFile) AddSeriesList(seriesSet *tsdb.SeriesIDSet, names [][]byte, tag
 			continue
 		}
 		writeRequired = true
-		entries = append(entries, LogEntry{SeriesID: seriesIDs[i]})
+		entries = append(entries, LogEntry{SeriesID: seriesIDs[i], name: names[i], tags: tagsSlice[i], cached: true})
 	}
 	seriesSet.RUnlock()
 
@@ -607,7 +608,17 @@ func (f *LogFile) execDeleteTagValueEntry(e *LogEntry) {
 }
 
 func (f *LogFile) execSeriesEntry(e *LogEntry) {
-	seriesKey := f.sfile.SeriesKey(e.SeriesID)
+	var seriesKey []byte
+	if e.cached {
+		sz := tsdb.SeriesKeySize(e.name, e.tags)
+		if len(f.keyBuf) < sz {
+			f.keyBuf = make([]byte, 0, sz)
+		}
+		seriesKey = tsdb.AppendSeriesKey(f.keyBuf[:0], e.name, e.tags)
+	} else {
+		seriesKey = f.sfile.SeriesKey(e.SeriesID)
+	}
+
 	assert(seriesKey != nil, fmt.Sprintf("series key for ID: %d not found", e.SeriesID))
 
 	// Check if deleted.
@@ -966,6 +977,10 @@ type LogEntry struct {
 	Value    []byte // tag value
 	Checksum uint32 // checksum of flag/name/tags.
 	Size     int    // total size of record, in bytes.
+
+	cached bool        // Hint to LogFile that series data is already parsed
+	name   []byte      // series naem, this is a cached copy of the parsed measurement name
+	tags   models.Tags // series tags, this is a cached copied of the parsed tags
 }
 
 // UnmarshalBinary unmarshals data into e.