db: consolidate point and range bytes annotators

Using two annotators leads to two traversals and twice the allocated
objects per node. Consolidate into a single annotator.

Author: RaduBerinde

compaction_picker.go

@@ -987,15 +987,13 @@ func (p *compactionPickerByScore) calculateLevelScores(
 	}
 	sizeAdjust := calculateSizeAdjust(inProgressCompactions)
 	for level := 1; level < numLevels; level++ {
-		compensatedLevelSize :=
-			// Actual file size.
-			p.vers.Levels[level].AggregateSize() +
-				// Point deletions.
-				*pointDeletionsBytesEstimateAnnotator.LevelAnnotation(p.vers.Levels[level]) +
-				// Range deletions.
-				*rangeDeletionsBytesEstimateAnnotator.LevelAnnotation(p.vers.Levels[level]) +
-				// Adjustments for in-progress compactions.
-				sizeAdjust[level].compensated()
+		// Actual file size.
+		compensatedLevelSize := p.vers.Levels[level].AggregateSize()
+		// Deletions.
+		delBytes := deletionBytesAnnotator.LevelAnnotation(p.vers.Levels[level])
+		compensatedLevelSize += delBytes.PointDels + delBytes.RangeDels
+		// Adjustments for in-progress compactions.
+		compensatedLevelSize += sizeAdjust[level].compensated()
 		scores[level].compensatedFillFactor = float64(compensatedLevelSize) / float64(p.levelMaxBytes[level])
 		scores[level].fillFactor = float64(p.vers.Levels[level].AggregateSize()+sizeAdjust[level].actual()) / float64(p.levelMaxBytes[level])
 	}
@@ -1343,9 +1341,8 @@ func (p *compactionPickerByScore) getCompactionConcurrency() int {
 	compactableGarbageCompactions := 0
 	garbageFractionLimit := p.opts.Experimental.CompactionGarbageFractionForMaxConcurrency()
 	if garbageFractionLimit > 0 && p.dbSizeBytes > 0 {
-		compactableGarbageBytes :=
-			*pointDeletionsBytesEstimateAnnotator.MultiLevelAnnotation(p.vers.Levels[:]) +
-				*rangeDeletionsBytesEstimateAnnotator.MultiLevelAnnotation(p.vers.Levels[:])
+		delBytes := deletionBytesAnnotator.MultiLevelAnnotation(p.vers.Levels[:])
+		compactableGarbageBytes := delBytes.PointDels + delBytes.RangeDels
 		garbageFraction := float64(compactableGarbageBytes) / float64(p.dbSizeBytes)
 		compactableGarbageCompactions =
 			int((garbageFraction / garbageFractionLimit) * float64(upper-lower))

db.go

@@ -1880,10 +1880,9 @@ func (d *DB) Metrics() *Metrics {
 	metrics.Keys.RangeKeySetsCount = *rangeKeySetsAnnotator.MultiLevelAnnotation(vers.RangeKeyLevels[:])
 	metrics.Keys.TombstoneCount = *tombstonesAnnotator.MultiLevelAnnotation(vers.Levels[:])
 
-	metrics.Table.Garbage.PointDeletionsBytesEstimate =
-		*pointDeletionsBytesEstimateAnnotator.MultiLevelAnnotation(vers.Levels[:])
-	metrics.Table.Garbage.RangeDeletionsBytesEstimate =
-		*rangeDeletionsBytesEstimateAnnotator.MultiLevelAnnotation(vers.Levels[:])
+	delBytes := deletionBytesAnnotator.MultiLevelAnnotation(vers.Levels[:])
+	metrics.Table.Garbage.PointDeletionsBytesEstimate = delBytes.PointDels
+	metrics.Table.Garbage.RangeDeletionsBytesEstimate = delBytes.RangeDels
 
 	d.mu.versions.logLock()
 	metrics.private.manifestFileSize = uint64(d.mu.versions.manifest.Size())

table_stats.go

@@ -1106,26 +1106,27 @@ var valueBlockSizeAnnotator = manifest.SumAnnotator(func(f *manifest.TableMetada
 	return 0, false
 })
 
-// pointDeletionsBytesEstimateAnnotator is a manifest.TableAnnotator that annotates
-// B-Tree nodes with the sum of the files' PointDeletionsBytesEstimate. This
-// value may change once a table's stats are loaded asynchronously, so its
-// values are marked as cacheable only if a file's stats have been loaded.
-var pointDeletionsBytesEstimateAnnotator = manifest.SumAnnotator(func(f *manifest.TableMetadata) (uint64, bool) {
-	if stats, ok := f.Stats(); ok {
-		return stats.PointDeletionsBytesEstimate, true
-	}
-	return 0, false
-})
+type deletionBytes struct {
+	// PointDels contains a sum of TableStats.PointDeletionsBytesEstimate.
+	PointDels uint64
+	// RangeDels contains a sum of TableStats.RangeDeletionsBytesEstimate.
+	RangeDels uint64
+}
 
-// rangeDeletionsBytesEstimateAnnotator is a manifest.TableAnnotator that annotates
-// B-Tree nodes with the sum of the files' RangeDeletionsBytesEstimate. This
-// value may change once a table's stats are loaded asynchronously, so its
-// values are marked as cacheable only if a file's stats have been loaded.
-var rangeDeletionsBytesEstimateAnnotator = manifest.SumAnnotator(func(f *manifest.TableMetadata) (uint64, bool) {
-	if stats, ok := f.Stats(); ok {
-		return stats.RangeDeletionsBytesEstimate, true
-	}
-	return 0, false
+var deletionBytesAnnotator = manifest.NewTableAnnotator[deletionBytes](manifest.SumAggregator[deletionBytes]{
+	AddFunc: func(src, dst *deletionBytes) {
+		dst.PointDels += src.PointDels
+		dst.RangeDels += src.RangeDels
+	},
+	AccumulateFunc: func(f *manifest.TableMetadata) (v deletionBytes, cacheOK bool) {
+		if stats, ok := f.Stats(); ok {
+			return deletionBytes{
+				PointDels: stats.PointDeletionsBytesEstimate,
+				RangeDels: stats.RangeDeletionsBytesEstimate,
+			}, true
+		}
+		return deletionBytes{}, false
+	},
 })
 
 // compressionStatsAnnotator is a manifest.TableAnnotator that annotates B-tree nodes