app/vmstorage: expose vm_indexdb_items_added_total and vm_indexdb_items_added_size_bytes_total counters at /metrics page

These counters can be used for monitoring the rate of addition of new entries in indexdb (aka inverted index).

See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2471

app/vmstorage/main.go

@@ -500,6 +500,13 @@ func registerStorageMetrics() {
 		return float64(idbm().AssistedMerges)
 	})
 
+	metrics.NewGauge(`vm_indexdb_items_added_total`, func() float64 {
+		return float64(idbm().ItemsAdded)
+	})
+	metrics.NewGauge(`vm_indexdb_items_added_size_bytes_total`, func() float64 {
+		return float64(idbm().ItemsAddedSizeBytes)
+	})
+
 	// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/686
 	metrics.NewGauge(`vm_merge_need_free_disk_space{type="storage/small"}`, func() float64 {
 		return float64(tm().SmallMergeNeedFreeDiskSpace)

docs/CHANGELOG.md

@@ -22,6 +22,7 @@ The following tip changes can be tested by building VictoriaMetrics components f
 * FEATURE: allow specifying TLS cipher suites for incoming https requests via `-tlsCipherSuites` command-line flag. See [this feature request](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2404).
 * FEATURE: allow specifying TLS cipher suites for mTLS connections between cluster components via `-cluster.tlsCipherSuites` command-line flag. See [these docs](https://docs.victoriametrics.com/Cluster-VictoriaMetrics.html#mtls-protection).
 * FEATURE: [vmui](https://docs.victoriametrics.com/#vmui): shown an empty graph on the selected time range when there is no data on it. Previously `No data to show` placeholder was shown instead of the graph in this case. This prevented from zooming and scrolling of such a graph.
+* FEATURE: expose `vm_indexdb_items_added_total` and `vm_indexdb_items_added_size_bytes_total` counters at `/metrics` page, which can be used for monitoring the rate for addition of new entries in `indexdb` (aka `inverted index`) alongside the total size in bytes for the added entries. See [this feature request](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2471).
 
 * BUGFIX: [vmctl](https://docs.victoriametrics.com/vmctl.html): return non-zero exit code on error. This allows handling `vmctl` errors in shell scripts. Previously `vmctl` was returning 0 exit code on error. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2322).
 * BUGFIX: [vmagent](https://docs.victoriametrics.com/vmagent.html): properly show `scrape_timeout` and `scrape_interval` options at `http://vmagent:8429/config` page. Previously these options weren't displayed even if they were set in `-promscrape.config`.

lib/mergeset/table.go

@@ -75,10 +75,12 @@ type Table struct {
 	// aligned to 8 bytes on 32-bit architectures.
 	// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/212
 
-	activeMerges   uint64
-	mergesCount    uint64
-	itemsMerged    uint64
-	assistedMerges uint64
+	activeMerges        uint64
+	mergesCount         uint64
+	itemsMerged         uint64
+	assistedMerges      uint64
+	itemsAdded          uint64
+	itemsAddedSizeBytes uint64
 
 	mergeIdx uint64
 
@@ -396,10 +398,12 @@ func (tb *Table) Path() string {
 
 // TableMetrics contains essential metrics for the Table.
 type TableMetrics struct {
-	ActiveMerges   uint64
-	MergesCount    uint64
-	ItemsMerged    uint64
-	AssistedMerges uint64
+	ActiveMerges        uint64
+	MergesCount         uint64
+	ItemsMerged         uint64
+	AssistedMerges      uint64
+	ItemsAdded          uint64
+	ItemsAddedSizeBytes uint64
 
 	PendingItems uint64
 
@@ -430,6 +434,8 @@ func (tb *Table) UpdateMetrics(m *TableMetrics) {
 	m.MergesCount += atomic.LoadUint64(&tb.mergesCount)
 	m.ItemsMerged += atomic.LoadUint64(&tb.itemsMerged)
 	m.AssistedMerges += atomic.LoadUint64(&tb.assistedMerges)
+	m.ItemsAdded += atomic.LoadUint64(&tb.itemsAdded)
+	m.ItemsAddedSizeBytes += atomic.LoadUint64(&tb.itemsAddedSizeBytes)
 
 	m.PendingItems += uint64(tb.rawItems.Len())
 
@@ -464,6 +470,12 @@ func (tb *Table) AddItems(items [][]byte) error {
 	if err := tb.rawItems.addItems(tb, items); err != nil {
 		return fmt.Errorf("cannot insert data into %q: %w", tb.path, err)
 	}
+	atomic.AddUint64(&tb.itemsAdded, uint64(len(items)))
+	n := 0
+	for _, item := range items {
+		n += len(item)
+	}
+	atomic.AddUint64(&tb.itemsAddedSizeBytes, uint64(n))
 	return nil
 }