diff --git a/app/vmstorage/main.go b/app/vmstorage/main.go
index 5ba759a45..24874ad70 100644
--- a/app/vmstorage/main.go
+++ b/app/vmstorage/main.go
@@ -430,6 +430,13 @@ func registerStorageMetrics() {
 		return float64(idbm().DateRangeSearchHits)
 	})
 
+	metrics.NewGauge(`vm_date_metric_id_cache_syncs_total`, func() float64 {
+		return float64(m().DateMetricIDCacheSyncsCount)
+	})
+	metrics.NewGauge(`vm_date_metric_id_cache_resets_total`, func() float64 {
+		return float64(m().DateMetricIDCacheResetsCount)
+	})
+
 	metrics.NewGauge(`vm_cache_entries{type="storage/tsid"}`, func() float64 {
 		return float64(m().TSIDCacheSize)
 	})
diff --git a/lib/storage/index_db.go b/lib/storage/index_db.go
index 87270fffc..5a9dd3068 100644
--- a/lib/storage/index_db.go
+++ b/lib/storage/index_db.go
@@ -919,7 +919,7 @@ func (db *indexDB) DeleteTSIDs(tfss []*TagFilters) (int, error) {
 		MaxTimestamp: (1 << 63) - 1,
 	}
 	is := db.getIndexSearch()
-	metricIDs, err := is.searchMetricIDs(tfss, tr, 1e12)
+	metricIDs, err := is.searchMetricIDs(tfss, tr, 2e9)
 	db.putIndexSearch(is)
 	if err != nil {
 		return 0, err
diff --git a/lib/storage/storage.go b/lib/storage/storage.go
index 9a9f1bca7..6b211c7ce 100644
--- a/lib/storage/storage.go
+++ b/lib/storage/storage.go
@@ -312,7 +312,9 @@ type Metrics struct {
 	MetricNameCacheMisses     uint64
 	MetricNameCacheCollisions uint64
 
-	DateMetricIDCacheSize uint64
+	DateMetricIDCacheSize        uint64
+	DateMetricIDCacheSyncsCount  uint64
+	DateMetricIDCacheResetsCount uint64
 
 	HourMetricIDCacheSize uint64
 
@@ -365,6 +367,8 @@ func (s *Storage) UpdateMetrics(m *Metrics) {
 	m.MetricNameCacheCollisions += cs.Collisions
 
 	m.DateMetricIDCacheSize += uint64(s.dateMetricIDCache.EntriesCount())
+	m.DateMetricIDCacheSyncsCount += atomic.LoadUint64(&s.dateMetricIDCache.syncsCount)
+	m.DateMetricIDCacheResetsCount += atomic.LoadUint64(&s.dateMetricIDCache.resetsCount)
 
 	hmCurr := s.currHourMetricIDs.Load().(*hourMetricIDs)
 	hmPrev := s.prevHourMetricIDs.Load().(*hourMetricIDs)
@@ -943,6 +947,10 @@ func (s *Storage) updatePerDateData(rows []rawRow, lastError error) error {
 //
 // It should be faster than map[date]*uint64set.Set on multicore systems.
 type dateMetricIDCache struct {
+	// 64-bit counters must be at the top of the structure to be properly aligned on 32-bit arches.
+	syncsCount  uint64
+	resetsCount uint64
+
 	// Contains immutable map
 	byDate atomic.Value
 
@@ -960,9 +968,13 @@ func newDateMetricIDCache() *dateMetricIDCache {
 
 func (dmc *dateMetricIDCache) Reset() {
 	dmc.mu.Lock()
+	// Do not reset syncsCount and resetsCount
 	dmc.byDate.Store(newByDateMetricIDMap())
 	dmc.byDateMutable = newByDateMetricIDMap()
+	dmc.lastSyncTime = time.Now()
 	dmc.mu.Unlock()
+
+	atomic.AddUint64(&dmc.resetsCount, 1)
 }
 
 func (dmc *dateMetricIDCache) EntriesCount() int {
@@ -1017,10 +1029,11 @@ func (dmc *dateMetricIDCache) sync() {
 		e.v.Union(v)
 	}
 	dmc.byDate.Store(dmc.byDateMutable)
-	byDateMutable := newByDateMetricIDMap()
-	dmc.byDateMutable = byDateMutable
+	dmc.byDateMutable = newByDateMetricIDMap()
 	dmc.mu.Unlock()
 
+	atomic.AddUint64(&dmc.syncsCount, 1)
+
 	if dmc.EntriesCount() > memory.Allowed()/128 {
 		dmc.Reset()
 	}
diff --git a/lib/storage/storage_test.go b/lib/storage/storage_test.go
index 3c130d21c..5e97bcd82 100644
--- a/lib/storage/storage_test.go
+++ b/lib/storage/storage_test.go
@@ -13,6 +13,88 @@ import (
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/uint64set"
 )
 
+func TestDateMetricIDCacheSerial(t *testing.T) {
+	c := newDateMetricIDCache()
+	if err := testDateMetricIDCache(c, false); err != nil {
+		t.Fatalf("unexpected error: %s", err)
+	}
+}
+
+func TestDateMetricIDCacheConcurrent(t *testing.T) {
+	c := newDateMetricIDCache()
+	ch := make(chan error, 5)
+	for i := 0; i < 5; i++ {
+		go func() {
+			ch <- testDateMetricIDCache(c, true)
+		}()
+	}
+	for i := 0; i < 5; i++ {
+		select {
+		case err := <-ch:
+			if err != nil {
+				t.Fatalf("unexpected error: %s", err)
+			}
+		case <-time.After(time.Second * 5):
+			t.Fatalf("timeout")
+		}
+	}
+}
+
+func testDateMetricIDCache(c *dateMetricIDCache, concurrent bool) error {
+	type dmk struct {
+		date     uint64
+		metricID uint64
+	}
+	m := make(map[dmk]bool)
+	for i := 0; i < 1e5; i++ {
+		date := uint64(i) % 3
+		metricID := uint64(i) % 1237
+		if !concurrent && c.Has(date, metricID) {
+			if !m[dmk{date, metricID}] {
+				return fmt.Errorf("c.Has(%d, %d) must return false, but returned true", date, metricID)
+			}
+			continue
+		}
+		c.Set(date, metricID)
+		m[dmk{date, metricID}] = true
+		if !concurrent && !c.Has(date, metricID) {
+			return fmt.Errorf("c.Has(%d, %d) must return true, but returned false", date, metricID)
+		}
+		if i%11234 == 0 {
+			c.sync()
+		}
+		if i%34323 == 0 {
+			c.Reset()
+			m = make(map[dmk]bool)
+		}
+	}
+
+	// Verify fast path after sync.
+	for i := 0; i < 1e5; i++ {
+		date := uint64(i) % 3
+		metricID := uint64(i) % 123
+		c.Set(date, metricID)
+	}
+	c.sync()
+	for i := 0; i < 1e5; i++ {
+		date := uint64(i) % 3
+		metricID := uint64(i) % 123
+		if !concurrent && !c.Has(date, metricID) {
+			return fmt.Errorf("c.Has(%d, %d) must return true after sync", date, metricID)
+		}
+	}
+
+	// Verify c.Reset
+	if n := c.EntriesCount(); !concurrent && n < 123 {
+		return fmt.Errorf("c.EntriesCount must return at least 123; returned %d", n)
+	}
+	c.Reset()
+	if n := c.EntriesCount(); !concurrent && n > 0 {
+		return fmt.Errorf("c.EntriesCount must return 0 after reset; returned %d", n)
+	}
+	return nil
+}
+
 func TestUpdateCurrHourMetricIDs(t *testing.T) {
 	newStorage := func() *Storage {
 		var s Storage