diff --git a/app/vmselect/promql/eval.go b/app/vmselect/promql/eval.go
index 91a8873af..a62e87474 100644
--- a/app/vmselect/promql/eval.go
+++ b/app/vmselect/promql/eval.go
@@ -218,7 +218,8 @@ func getTimestamps(start, end, step int64) []int64 {
 
 func evalExpr(qt *querytracer.Tracer, ec *EvalConfig, e metricsql.Expr) ([]*timeseries, error) {
 	if qt.Enabled() {
-		query := e.AppendString(nil)
+		query := string(e.AppendString(nil))
+		query = bytesutil.LimitStringLen(query, 300)
 		mayCache := ec.mayCache()
 		qt = qt.NewChild("eval: query=%s, timeRange=%s, step=%d, mayCache=%v", query, ec.timeRangeString(), ec.Step, mayCache)
 	}
diff --git a/app/vmselect/promql/rollup_result_cache.go b/app/vmselect/promql/rollup_result_cache.go
index 5068e0542..c76ef241e 100644
--- a/app/vmselect/promql/rollup_result_cache.go
+++ b/app/vmselect/promql/rollup_result_cache.go
@@ -155,7 +155,8 @@ func ResetRollupResultCache() {
 
 func (rrc *rollupResultCache) Get(qt *querytracer.Tracer, ec *EvalConfig, expr metricsql.Expr, window int64) (tss []*timeseries, newStart int64) {
 	if qt.Enabled() {
-		query := expr.AppendString(nil)
+		query := string(expr.AppendString(nil))
+		query = bytesutil.LimitStringLen(query, 300)
 		qt = qt.NewChild("rollup cache get: query=%s, timeRange=%s, step=%d, window=%d", query, ec.timeRangeString(), ec.Step, window)
 		defer qt.Done()
 	}
@@ -255,7 +256,8 @@ var resultBufPool bytesutil.ByteBufferPool
 
 func (rrc *rollupResultCache) Put(qt *querytracer.Tracer, ec *EvalConfig, expr metricsql.Expr, window int64, tss []*timeseries) {
 	if qt.Enabled() {
-		query := expr.AppendString(nil)
+		query := string(expr.AppendString(nil))
+		query = bytesutil.LimitStringLen(query, 300)
 		qt = qt.NewChild("rollup cache put: query=%s, timeRange=%s, step=%d, window=%d, series=%d", query, ec.timeRangeString(), ec.Step, window, len(tss))
 		defer qt.Done()
 	}
diff --git a/lib/bytesutil/bytesutil.go b/lib/bytesutil/bytesutil.go
index daa01232d..8d9d1c560 100644
--- a/lib/bytesutil/bytesutil.go
+++ b/lib/bytesutil/bytesutil.go
@@ -79,3 +79,14 @@ func ToUnsafeBytes(s string) (b []byte) {
 	slh.Cap = sh.Len
 	return b
 }
+
+// LimitStringLen limits the length of s to maxLen.
+//
+// If len(s) > maxLen, then the function concatenates s prefix with s suffix.
+func LimitStringLen(s string, maxLen int) string {
+	if maxLen <= 4 || len(s) <= maxLen {
+		return s
+	}
+	n := maxLen/2 - 1
+	return s[:n] + ".." + s[len(s)-n:]
+}
diff --git a/lib/storage/index_db.go b/lib/storage/index_db.go
index 60c4d883a..35189bf35 100644
--- a/lib/storage/index_db.go
+++ b/lib/storage/index_db.go
@@ -422,7 +422,7 @@ func (is *indexSearch) maybeCreateIndexes(tsid *TSID, metricNameRaw []byte, date
 		return false, fmt.Errorf("cannot create global indexes: %w", err)
 	}
 	if err := is.createPerDayIndexes(date, tsid.MetricID, mn); err != nil {
-		return false, fmt.Errorf("cannot create per-day indexes for date=%d: %w", date, err)
+		return false, fmt.Errorf("cannot create per-day indexes for date=%s: %w", dateToString(date), err)
 	}
 	PutMetricName(mn)
 	atomic.AddUint64(&is.db.timeseriesRepopulated, 1)
@@ -615,7 +615,7 @@ func (is *indexSearch) createTSIDByName(dst *TSID, metricName, metricNameRaw []b
 		return fmt.Errorf("cannot create global indexes: %w", err)
 	}
 	if err := is.createPerDayIndexes(date, dst.MetricID, mn); err != nil {
-		return fmt.Errorf("cannot create per-day indexes for date=%d: %w", date, err)
+		return fmt.Errorf("cannot create per-day indexes for date=%s: %w", dateToString(date), err)
 	}
 
 	// There is no need in invalidating tag cache, since it is invalidated
@@ -800,7 +800,7 @@ func (is *indexSearch) searchLabelNamesWithFiltersOnTimeRange(qt *querytracer.Tr
 	qt = qt.NewChild("parallel search for label names: filters=%s, timeRange=%s", tfss, &tr)
 	for date := minDate; date <= maxDate; date++ {
 		wg.Add(1)
-		qtChild := qt.NewChild("search for label names: filters=%s, date=%d", tfss, date)
+		qtChild := qt.NewChild("search for label names: filters=%s, date=%s", tfss, dateToString(date))
 		go func(date uint64) {
 			defer func() {
 				qtChild.Done()
@@ -956,7 +956,7 @@ func (is *indexSearch) searchLabelValuesWithFiltersOnTimeRange(qt *querytracer.T
 	qt = qt.NewChild("parallel search for label values: labelName=%q, filters=%s, timeRange=%s", labelName, tfss, &tr)
 	for date := minDate; date <= maxDate; date++ {
 		wg.Add(1)
-		qtChild := qt.NewChild("search for label names: filters=%s, date=%d", tfss, date)
+		qtChild := qt.NewChild("search for label names: filters=%s, date=%s", tfss, dateToString(date))
 		go func(date uint64) {
 			defer func() {
 				qtChild.Done()
@@ -2486,7 +2486,7 @@ func (is *indexSearch) tryUpdatingMetricIDsForDateRange(qt *querytracer.Tracer,
 	var errGlobal error
 	var mu sync.Mutex // protects metricIDs + errGlobal vars from concurrent access below
 	for minDate <= maxDate {
-		qtChild := qt.NewChild("parallel thread for date=%d", minDate)
+		qtChild := qt.NewChild("parallel thread for date=%s", dateToString(minDate))
 		wg.Add(1)
 		go func(date uint64) {
 			defer func() {
@@ -2522,8 +2522,10 @@ func (is *indexSearch) tryUpdatingMetricIDsForDateRange(qt *querytracer.Tracer,
 }
 
 func (is *indexSearch) getMetricIDsForDateAndFilters(qt *querytracer.Tracer, date uint64, tfs *TagFilters, maxMetrics int) (*uint64set.Set, error) {
-	qt = qt.NewChild("search for metric ids on a particular day: filters=%s, date=%d, maxMetrics=%d", tfs, date, maxMetrics)
-	defer qt.Done()
+	if qt.Enabled() {
+		qt = qt.NewChild("search for metric ids on a particular day: filters=%s, date=%s, maxMetrics=%d", tfs, dateToString(date), maxMetrics)
+		defer qt.Done()
+	}
 	// Sort tfs by loopsCount needed for performing each filter.
 	// This stats is usually collected from the previous queries.
 	// This way we limit the amount of work below by applying fast filters at first.
@@ -2869,18 +2871,20 @@ func (is *indexSearch) hasDateMetricID(date, metricID uint64, accountID, project
 		if err == io.EOF {
 			return false, nil
 		}
-		return false, fmt.Errorf("error when searching for (date=%d, metricID=%d) entry: %w", date, metricID, err)
+		return false, fmt.Errorf("error when searching for (date=%s, metricID=%d) entry: %w", dateToString(date), metricID, err)
 	}
 	if string(ts.Item) != string(kb.B) {
-		return false, fmt.Errorf("unexpected entry for (date=%d, metricID=%d); got %q; want %q", date, metricID, ts.Item, kb.B)
+		return false, fmt.Errorf("unexpected entry for (date=%s, metricID=%d); got %q; want %q", dateToString(date), metricID, ts.Item, kb.B)
 	}
 	return true, nil
 }
 
 func (is *indexSearch) getMetricIDsForDateTagFilter(qt *querytracer.Tracer, tf *tagFilter, date uint64, commonPrefix []byte,
 	maxMetrics int, maxLoopsCount int64) (*uint64set.Set, int64, error) {
-	qt = qt.NewChild("get metric ids for filter and date: filter={%s}, date=%d, maxMetrics=%d, maxLoopsCount=%d", tf, date, maxMetrics, maxLoopsCount)
-	defer qt.Done()
+	if qt.Enabled() {
+		qt = qt.NewChild("get metric ids for filter and date: filter={%s}, date=%s, maxMetrics=%d, maxLoopsCount=%d", tf, dateToString(date), maxMetrics, maxLoopsCount)
+		defer qt.Done()
+	}
 	if !bytes.HasPrefix(tf.prefix, commonPrefix) {
 		logger.Panicf("BUG: unexpected tf.prefix %q; must start with commonPrefix %q", tf.prefix, commonPrefix)
 	}
diff --git a/lib/storage/search.go b/lib/storage/search.go
index c4ff994e7..13b6461e2 100644
--- a/lib/storage/search.go
+++ b/lib/storage/search.go
@@ -295,10 +295,11 @@ type TagFilter struct {
 // String returns string representation of tf.
 func (tf *TagFilter) String() string {
 	op := tf.getOp()
+	value := bytesutil.LimitStringLen(string(tf.Value), 60)
 	if len(tf.Key) == 0 {
-		return fmt.Sprintf("__name__%s%q", op, tf.Value)
+		return fmt.Sprintf("__name__%s%q", op, value)
 	}
-	return fmt.Sprintf("%s%s%q", tf.Key, op, tf.Value)
+	return fmt.Sprintf("%s%s%q", tf.Key, op, value)
 }
 
 func (tf *TagFilter) getOp() string {
diff --git a/lib/storage/storage.go b/lib/storage/storage.go
index 31205d7d5..34913ed4c 100644
--- a/lib/storage/storage.go
+++ b/lib/storage/storage.go
@@ -2235,8 +2235,8 @@ func (s *Storage) updatePerDateData(rows []rawRow, mrs []*MetricRow) error {
 		ok, err := is.hasDateMetricID(date, metricID, dmid.accountID, dmid.projectID)
 		if err != nil {
 			if firstError == nil {
-				firstError = fmt.Errorf("error when locating (date=%d, metricID=%d, accountID=%d, projectID=%d) in database: %w",
-					date, metricID, dmid.accountID, dmid.projectID, err)
+				firstError = fmt.Errorf("error when locating (date=%s, metricID=%d, accountID=%d, projectID=%d) in database: %w",
+					dateToString(date), metricID, dmid.accountID, dmid.projectID, err)
 			}
 			continue
 		}
@@ -2253,7 +2253,7 @@ func (s *Storage) updatePerDateData(rows []rawRow, mrs []*MetricRow) error {
 			mn.sortTags()
 			if err := is.createPerDayIndexes(date, metricID, mn); err != nil {
 				if firstError == nil {
-					firstError = fmt.Errorf("error when storing per-date inverted index for (date=%d, metricID=%d): %w", date, metricID, err)
+					firstError = fmt.Errorf("error when storing per-date inverted index for (date=%s, metricID=%d): %w", dateToString(date), metricID, err)
 				}
 				continue
 			}
diff --git a/lib/storage/tag_filters.go b/lib/storage/tag_filters.go
index 92e43b00f..4e6899504 100644
--- a/lib/storage/tag_filters.go
+++ b/lib/storage/tag_filters.go
@@ -299,30 +299,35 @@ func (tf *tagFilter) Less(other *tagFilter) bool {
 
 // String returns human-readable tf value.
 func (tf *tagFilter) String() string {
-	op := "="
-	if tf.isNegative {
-		op = "!="
-		if tf.isRegexp {
-			op = "!~"
-		}
-	} else if tf.isRegexp {
-		op = "=~"
-	}
+	op := tf.getOp()
+	value := bytesutil.LimitStringLen(string(tf.value), 60)
 	if bytes.Equal(tf.key, graphiteReverseTagKey) {
-		return fmt.Sprintf("__graphite_reverse__%s%q", op, tf.value)
+		return fmt.Sprintf("__graphite_reverse__%s%q", op, value)
 	}
 	if tf.isComposite() {
 		metricName, key, err := unmarshalCompositeTagKey(tf.key)
 		if err != nil {
 			logger.Panicf("BUG: cannot unmarshal composite tag key: %s", err)
 		}
-		return fmt.Sprintf("composite(%s,%s)%s%q", metricName, key, op, tf.value)
+		return fmt.Sprintf("composite(%s,%s)%s%q", metricName, key, op, value)
 	}
-	key := tf.key
-	if len(key) == 0 {
-		key = []byte("__name__")
+	if len(tf.key) == 0 {
+		return fmt.Sprintf("__name__%s%q", op, value)
 	}
-	return fmt.Sprintf("%s%s%q", key, op, tf.value)
+	return fmt.Sprintf("%s%s%q", tf.key, op, value)
+}
+
+func (tf *tagFilter) getOp() string {
+	if tf.isNegative {
+		if tf.isRegexp {
+			return "!~"
+		}
+		return "!="
+	}
+	if tf.isRegexp {
+		return "=~"
+	}
+	return "="
 }
 
 func (tf *tagFilter) Marshal(dst []byte, accountID, projectID uint32) []byte {
diff --git a/lib/storage/time.go b/lib/storage/time.go
index 83da3db98..9be28b241 100644
--- a/lib/storage/time.go
+++ b/lib/storage/time.go
@@ -5,6 +5,14 @@ import (
 	"time"
 )
 
+func dateToString(date uint64) string {
+	if date == 0 {
+		return "1970-01-01"
+	}
+	t := time.Unix(int64(date*24*3600), 0).UTC()
+	return t.Format("2006-01-02")
+}
+
 // timestampToTime returns time representation of the given timestamp.
 //
 // The returned time is in UTC timezone.