lib/storage: remove obsolete code

lib/storage/index_db.go

@@ -1210,15 +1210,6 @@ func mergeTSIDs(a, b []TSID) []TSID {
 }
 
 func (is *indexSearch) searchTSIDs(tfss []*TagFilters, tr TimeRange, maxMetrics int) ([]TSID, error) {
-	// Verify whether `is` contains data for the given tr.
-	ok, err := is.containsTimeRange(tr)
-	if err != nil {
-		return nil, fmt.Errorf("error in containsTimeRange(%s): %s", &tr, err)
-	}
-	if !ok {
-		// Fast path: nothing to search.
-		return nil, nil
-	}
 	metricIDs, err := is.searchMetricIDs(tfss, tr, maxMetrics)
 	if err != nil {
 		return nil, err
@@ -1700,14 +1691,14 @@ func (is *indexSearch) updateMetricIDsForTagFilters(metricIDs *uint64set.Set, tf
 		return bytes.Compare(a.prefix, b.prefix) < 0
 	})
 
-	ok, err := is.tryUpdatingMetricIDsForDateRange(metricIDs, tfs, tr, maxMetrics)
-	if err != nil {
-		return err
-	}
-	if ok {
+	err := is.tryUpdatingMetricIDsForDateRange(metricIDs, tfs, tr, maxMetrics)
+	if err == nil {
 		// Fast path: found metricIDs by date range.
 		return nil
 	}
+	if err != errFallbackToMetricNameMatch {
+		return err
+	}
 
 	// Slow path - try searching over the whole inverted index.
 	minTf, minMetricIDs, err := is.getTagFilterWithMinMetricIDsCountOptimized(tfs, tr, maxMetrics)
@@ -2051,30 +2042,41 @@ func (is *indexSearch) getMetricIDsForTimeRange(tr TimeRange, maxMetrics int) (*
 		// Too much dates must be covered. Give up.
 		return nil, errMissingMetricIDsForDate
 	}
+	if minDate == maxDate {
+		// Fast path - query on a single day.
+		metricIDs, err := is.getMetricIDsForDate(minDate, maxMetrics)
+		if err != nil {
+			return nil, err
+		}
+		atomic.AddUint64(&is.db.dateMetricIDsSearchHits, 1)
+		return metricIDs, nil
+	}
 
-	// Search for metricIDs for each day in parallel.
+	// Slower path - query over multiple days in parallel.
 	metricIDs = &uint64set.Set{}
 	var wg sync.WaitGroup
 	var errGlobal error
 	var mu sync.Mutex // protects metricIDs + errGlobal from concurrent access below.
 	for minDate <= maxDate {
-		date := minDate
-		isLocal := is.db.getIndexSearch()
 		wg.Add(1)
-		go func() {
+		go func(date uint64) {
 			defer wg.Done()
+			isLocal := is.db.getIndexSearch()
 			defer is.db.putIndexSearch(isLocal)
-			var result uint64set.Set
-			err := isLocal.getMetricIDsForDate(date, &result, maxMetrics)
+			m, err := isLocal.getMetricIDsForDate(date, maxMetrics)
 			mu.Lock()
-			if metricIDs.Len() < maxMetrics {
-				metricIDs.UnionMayOwn(&result)
+			defer mu.Unlock()
+			if errGlobal != nil {
+				return
 			}
 			if err != nil {
 				errGlobal = err
+				return
 			}
-			mu.Unlock()
-		}()
+			if metricIDs.Len() < maxMetrics {
+				metricIDs.UnionMayOwn(m)
+			}
+		}(minDate)
 		minDate++
 	}
 	wg.Wait()
@@ -2085,57 +2087,72 @@ func (is *indexSearch) getMetricIDsForTimeRange(tr TimeRange, maxMetrics int) (*
 	return metricIDs, nil
 }
 
-func (is *indexSearch) tryUpdatingMetricIDsForDateRange(metricIDs *uint64set.Set, tfs *TagFilters, tr TimeRange, maxMetrics int) (bool, error) {
+func (is *indexSearch) tryUpdatingMetricIDsForDateRange(metricIDs *uint64set.Set, tfs *TagFilters, tr TimeRange, maxMetrics int) error {
 	atomic.AddUint64(&is.db.dateRangeSearchCalls, 1)
 	minDate := uint64(tr.MinTimestamp) / msecPerDay
 	maxDate := uint64(tr.MaxTimestamp) / msecPerDay
 	if minDate < is.db.startDateForPerDayInvertedIndex || maxDate < minDate {
 		// Per-day inverted index doesn't cover the selected date range.
-		return false, nil
+		return errFallbackToMetricNameMatch
 	}
 	if maxDate-minDate > maxDaysForDateMetricIDs {
 		// Too much dates must be covered. Give up, since it may be slow.
-		return false, nil
+		return errFallbackToMetricNameMatch
+	}
+	if minDate == maxDate {
+		// Fast path - query only a single date.
+		m, err := is.getMetricIDsForDateAndFilters(minDate, tfs, maxMetrics)
+		if err != nil {
+			return err
+		}
+		metricIDs.UnionMayOwn(m)
+		atomic.AddUint64(&is.db.dateRangeSearchHits, 1)
+		return nil
 	}
 
-	// Search for metricIDs for each day in parallel.
+	// Slower path - search for metricIDs for each day in parallel.
 	var wg sync.WaitGroup
 	var errGlobal error
-	okGlobal := true
-	var mu sync.Mutex // protects metricIDs + *Global vars from concurrent access below
+	var mu sync.Mutex // protects metricIDs + errGlobal vars from concurrent access below
 	for minDate <= maxDate {
-		date := minDate
-		isLocal := is.db.getIndexSearch()
 		wg.Add(1)
-		go func() {
+		go func(date uint64) {
 			defer wg.Done()
+			isLocal := is.db.getIndexSearch()
 			defer is.db.putIndexSearch(isLocal)
-			var result uint64set.Set
-			ok, err := isLocal.tryUpdatingMetricIDsForDate(date, &result, tfs, maxMetrics)
+			m, err := isLocal.getMetricIDsForDateAndFilters(date, tfs, maxMetrics)
 			mu.Lock()
-			if metricIDs.Len() < maxMetrics {
-				metricIDs.UnionMayOwn(&result)
-			}
-			if !ok {
-				okGlobal = ok
+			defer mu.Unlock()
+			if errGlobal != nil {
+				return
 			}
 			if err != nil {
+				if err == errFallbackToMetricNameMatch {
+					// The per-date search is too expensive. Probably it is faster to perform global search
+					// using metric name match.
+					errGlobal = err
+					return
+				}
 				dateStr := time.Unix(int64(date*24*3600), 0)
 				errGlobal = fmt.Errorf("cannot search for metricIDs for %s: %s", dateStr, err)
+				return
 			}
-			mu.Unlock()
-		}()
+			if metricIDs.Len() < maxMetrics {
+				metricIDs.UnionMayOwn(m)
+			}
+		}(minDate)
 		minDate++
 	}
 	wg.Wait()
 	if errGlobal != nil {
-		return false, errGlobal
+		return errGlobal
 	}
 	atomic.AddUint64(&is.db.dateRangeSearchHits, 1)
-	return okGlobal, nil
+	return nil
 }
 
-func (is *indexSearch) tryUpdatingMetricIDsForDate(date uint64, metricIDs *uint64set.Set, tfs *TagFilters, maxMetrics int) (bool, error) {
+func (is *indexSearch) getMetricIDsForDateAndFilters(date uint64, tfs *TagFilters, maxMetrics int) (*uint64set.Set, error) {
+	// Populate metricIDs with the first non-negative filter.
 	var tfFirst *tagFilter
 	for i := range tfs.tfs {
 		tf := &tfs.tfs[i]
@@ -2145,37 +2162,36 @@ func (is *indexSearch) tryUpdatingMetricIDsForDate(date uint64, metricIDs *uint6
 		tfFirst = tf
 		break
 	}
-
-	var result *uint64set.Set
+	var metricIDs *uint64set.Set
 	maxDateMetrics := maxMetrics * 50
 	if tfFirst == nil {
-		result = &uint64set.Set{}
-		if err := is.updateMetricIDsForDateAll(result, date, maxDateMetrics); err != nil {
+		// All the filters in tfs are negative. Populate all the metricIDs for the given (date),
+		// so later they can be filtered out with negative filters.
+		m, err := is.getMetricIDsForDate(date, maxDateMetrics)
+		if err != nil {
 			if err == errMissingMetricIDsForDate {
-				// Zero data points were written on the given date.
+				// Zero time series were written on the given date.
 				// It is OK, since (date, metricID) entries must exist for the given date
 				// according to startDateForPerDayInvertedIndex.
-				return true, nil
+				return nil, nil
 			}
-			return false, fmt.Errorf("cannot obtain all the metricIDs: %s", err)
+			return nil, fmt.Errorf("cannot obtain all the metricIDs: %s", err)
 		}
+		metricIDs = m
 	} else {
+		// Populate metricIDs for the given tfFirst on the given (date)
 		m, err := is.getMetricIDsForDateTagFilter(tfFirst, date, tfs.commonPrefix, maxDateMetrics)
 		if err != nil {
-			if err == errFallbackToMetricNameMatch {
-				// The per-date search is too expensive. Probably it is better to perform global search
-				// using metric name match.
-				return false, nil
+			return nil, err
 		}
-			return false, err
+		metricIDs = m
 	}
-		result = m
-	}
-	if result.Len() >= maxDateMetrics {
+	if metricIDs.Len() >= maxDateMetrics {
 		// Too many time series found by a single tag filter. Fall back to global search.
-		return false, nil
+		return nil, errFallbackToMetricNameMatch
 	}
 
+	// Intersect metricIDs with the rest of filters.
 	for i := range tfs.tfs {
 		tf := &tfs.tfs[i]
 		if tf == tfFirst {
@@ -2183,28 +2199,23 @@ func (is *indexSearch) tryUpdatingMetricIDsForDate(date uint64, metricIDs *uint6
 		}
 		m, err := is.getMetricIDsForDateTagFilter(tf, date, tfs.commonPrefix, maxDateMetrics)
 		if err != nil {
-			if err == errFallbackToMetricNameMatch {
-				// The per-date search is too expensive. Probably it is better to perform global search
-				// using metric name match.
-				return false, nil
-			}
-			return false, err
+			return nil, err
 		}
 		if m.Len() >= maxDateMetrics {
 			// Too many time series found by a single tag filter. Fall back to global search.
-			return false, nil
+			return nil, errFallbackToMetricNameMatch
 		}
 		if tf.isNegative {
-			result.Subtract(m)
+			metricIDs.Subtract(m)
 		} else {
-			result.Intersect(m)
+			metricIDs.Intersect(m)
 		}
-		if result.Len() == 0 {
-			return true, nil
+		if metricIDs.Len() == 0 {
+			// Short circuit - there is no need in applying the remaining filters to empty set.
+			return nil, nil
 		}
 	}
-	metricIDs.UnionMayOwn(result)
-	return true, nil
+	return metricIDs, nil
 }
 
 func (is *indexSearch) getMetricIDsForRecentHours(tr TimeRange, maxMetrics int) (*uint64set.Set, bool) {
@@ -2332,67 +2343,23 @@ func (is *indexSearch) getMetricIDsForDateTagFilter(tf *tagFilter, date uint64,
 	return is.getMetricIDsForTagFilter(&tfNew, maxMetrics)
 }
 
-func (is *indexSearch) getMetricIDsForDate(date uint64, metricIDs *uint64set.Set, maxMetrics int) error {
-	ts := &is.ts
-	kb := &is.kb
-	kb.B = marshalCommonPrefix(kb.B[:0], nsPrefixDateToMetricID)
-	kb.B = encoding.MarshalUint64(kb.B, date)
-	ts.Seek(kb.B)
-	items := 0
-	for metricIDs.Len() < maxMetrics && ts.NextItem() {
-		if !bytes.HasPrefix(ts.Item, kb.B) {
-			break
-		}
-		// Extract MetricID from ts.Item (the last 8 bytes).
-		v := ts.Item[len(kb.B):]
-		if len(v) != 8 {
-			return fmt.Errorf("cannot extract metricID from k; want %d bytes; got %d bytes", 8, len(v))
-		}
-		metricID := encoding.UnmarshalUint64(v)
-		metricIDs.Add(metricID)
-		items++
-	}
-	if err := ts.Error(); err != nil {
-		return fmt.Errorf("error when searching for metricIDs for date %d: %s", date, err)
-	}
-	if items == 0 {
-		// There are no metricIDs for the given date.
-		// This may be the case for old data when Date -> MetricID wasn't available.
-		return errMissingMetricIDsForDate
-	}
-	return nil
-}
-
-func (is *indexSearch) containsTimeRange(tr TimeRange) (bool, error) {
-	ts := &is.ts
-	kb := &is.kb
-
-	// Verify whether the maximum date in `ts` covers tr.MinTimestamp.
-	minDate := uint64(tr.MinTimestamp) / msecPerDay
-	kb.B = marshalCommonPrefix(kb.B[:0], nsPrefixDateToMetricID)
-	kb.B = encoding.MarshalUint64(kb.B, minDate)
-	ts.Seek(kb.B)
-	if !ts.NextItem() {
-		if err := ts.Error(); err != nil {
-			return false, fmt.Errorf("error when searching for minDate=%d, prefix %q: %s", minDate, kb.B, err)
-		}
-		return false, nil
-	}
-	if !bytes.HasPrefix(ts.Item, kb.B[:1]) {
-		// minDate exceeds max date from ts.
-		return false, nil
-	}
-	return true, nil
-}
-
-func (is *indexSearch) updateMetricIDsForDateAll(metricIDs *uint64set.Set, date uint64, maxMetrics int) error {
+func (is *indexSearch) getMetricIDsForDate(date uint64, maxMetrics int) (*uint64set.Set, error) {
 	// Extract all the metricIDs from (date, __name__=value)->metricIDs entries.
 	kb := kbPool.Get()
 	defer kbPool.Put(kb)
-	kb.B = marshalCommonPrefix(kb.B[:0], nsPrefixTagToMetricIDs)
+	kb.B = marshalCommonPrefix(kb.B[:0], nsPrefixDateTagToMetricIDs)
 	kb.B = encoding.MarshalUint64(kb.B, date)
 	kb.B = marshalTagValue(kb.B, nil)
-	return is.updateMetricIDsForPrefix(kb.B, metricIDs, maxMetrics)
+	var metricIDs uint64set.Set
+	if err := is.updateMetricIDsForPrefix(kb.B, &metricIDs, maxMetrics); err != nil {
+		return nil, err
+	}
+	if metricIDs.Len() == 0 {
+		// There are no metricIDs for the given date.
+		// This may be the case for old data where (data, __name__=value)->metricIDs entries weren't available.
+		return nil, errMissingMetricIDsForDate
+	}
+	return &metricIDs, nil
 }
 
 func (is *indexSearch) updateMetricIDsAll(metricIDs *uint64set.Set, maxMetrics int) error {