lib/storage: code prettifying after be5e1222f3

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/781

lib/storage/index_db.go

@@ -1962,7 +1962,7 @@ func (is *indexSearch) getTagFilterWithMinMetricIDsCount(tfs *TagFilters, maxMet
 			continue
 		}
 
-		metricIDs, err := is.getMetricIDsForTagFilter(tf, maxMetrics, nil)
+		metricIDs, err := is.getMetricIDsForTagFilter(tf, nil, maxMetrics)
 		if err != nil {
 			if err == errFallbackToMetricNameMatch {
 				// Skip tag filters requiring to scan for too many metrics.
@@ -2225,7 +2225,7 @@ const (
 
 var uselessTagFilterCacheValue = []byte("1")
 
-func (is *indexSearch) getMetricIDsForTagFilter(tf *tagFilter, maxMetrics int, filter *uint64set.Set) (*uint64set.Set, error) {
+func (is *indexSearch) getMetricIDsForTagFilter(tf *tagFilter, filter *uint64set.Set, maxMetrics int) (*uint64set.Set, error) {
 	if tf.isNegative {
 		logger.Panicf("BUG: isNegative must be false")
 	}
@@ -2243,11 +2243,7 @@ func (is *indexSearch) getMetricIDsForTagFilter(tf *tagFilter, maxMetrics int, f
 
 	// Slow path - scan for all the rows with the given prefix.
 	maxLoops := maxMetrics * maxIndexScanSlowLoopsPerMetric
-	err := is.getMetricIDsForTagFilterSlow(tf, maxLoops, filter, func(metricID uint64) bool {
+	if err := is.getMetricIDsForTagFilterSlow(tf, filter, maxLoops, metricIDs.Add); err != nil {
-		metricIDs.Add(metricID)
-		return metricIDs.Len() < maxMetrics
-	})
-	if err != nil {
 		if err == errFallbackToMetricNameMatch {
 			return nil, err
 		}
@@ -2256,7 +2252,7 @@ func (is *indexSearch) getMetricIDsForTagFilter(tf *tagFilter, maxMetrics int, f
 	return metricIDs, nil
 }
 
-func (is *indexSearch) getMetricIDsForTagFilterSlow(tf *tagFilter, maxLoops int, filter *uint64set.Set, f func(metricID uint64) bool) error {
+func (is *indexSearch) getMetricIDsForTagFilterSlow(tf *tagFilter, filter *uint64set.Set, maxLoops int, f func(metricID uint64)) error {
 	if len(tf.orSuffixes) > 0 {
 		logger.Panicf("BUG: the getMetricIDsForTagFilterSlow must be called only for empty tf.orSuffixes; got %s", tf.orSuffixes)
 	}
@@ -2293,24 +2289,7 @@ func (is *indexSearch) getMetricIDsForTagFilterSlow(tf *tagFilter, maxLoops int,
 		if err := mp.InitOnlyTail(item, tail); err != nil {
 			return err
 		}
-
 		mp.ParseMetricIDs()
-
-		// Fast path: use the filter to skip items that don't need to be matched.
-		if filter != nil {
-			hasCommonMetric := false
-			for _, metricID := range mp.MetricIDs {
-				if filter.Has(metricID) {
-					hasCommonMetric = true
-					break
-				}
-			}
-			// For both complement and intersection calculations, the result and filter need to have elements in common.
-			if !hasCommonMetric {
-				continue
-			}
-		}
-
 		if prevMatch && string(suffix) == string(prevMatchingSuffix) {
 			// Fast path: the same tag value found.
 			// There is no need in checking it again with potentially
@@ -2320,12 +2299,18 @@ func (is *indexSearch) getMetricIDsForTagFilterSlow(tf *tagFilter, maxLoops int,
 				return errFallbackToMetricNameMatch
 			}
 			for _, metricID := range mp.MetricIDs {
-				if !f(metricID) {
+				if filter != nil && !filter.Has(metricID) {
-					return nil
+					continue
 				}
+				f(metricID)
 			}
 			continue
 		}
+		if filter != nil && !mp.HasCommonMetricIDs(filter) {
+			// Faster path: there is no need in calling tf.matchSuffix,
+			// since the current row has no matching metricIDs.
+			continue
+		}
 
 		// Slow path: need tf.matchSuffix call.
 		ok, err := tf.matchSuffix(suffix)
@@ -2358,9 +2343,10 @@ func (is *indexSearch) getMetricIDsForTagFilterSlow(tf *tagFilter, maxLoops int,
 			return errFallbackToMetricNameMatch
 		}
 		for _, metricID := range mp.MetricIDs {
-			if !f(metricID) {
+			if filter != nil && !filter.Has(metricID) {
-				return nil
+				continue
 			}
+			f(metricID)
 		}
 	}
 	if err := ts.Error(); err != nil {
@@ -2700,7 +2686,7 @@ func (is *indexSearch) getMetricIDsForDateAndFilters(date uint64, tfs *TagFilter
 			tfsRemainingWithCount = append(tfsRemainingWithCount, tfsWithCount[i])
 			continue
 		}
-		m, err := is.getMetricIDsForDateTagFilter(tf, date, tfs.commonPrefix, maxDateMetrics, nil)
+		m, err := is.getMetricIDsForDateTagFilter(tf, date, tfs.commonPrefix, nil, maxDateMetrics)
 		if err != nil {
 			return nil, err
 		}
@@ -2751,7 +2737,7 @@ func (is *indexSearch) getMetricIDsForDateAndFilters(date uint64, tfs *TagFilter
 			break
 		}
 		tf := tfWithCount.tf
-		m, err := is.getMetricIDsForDateTagFilter(tf, date, tfs.commonPrefix, maxDateMetrics, metricIDs)
+		m, err := is.getMetricIDsForDateTagFilter(tf, date, tfs.commonPrefix, metricIDs, maxDateMetrics)
 		if err != nil {
 			return nil, err
 		}
@@ -2937,7 +2923,7 @@ func (is *indexSearch) hasDateMetricID(date, metricID uint64) (bool, error) {
 	return true, nil
 }
 
-func (is *indexSearch) getMetricIDsForDateTagFilter(tf *tagFilter, date uint64, commonPrefix []byte, maxMetrics int, filter *uint64set.Set) (*uint64set.Set, error) {
+func (is *indexSearch) getMetricIDsForDateTagFilter(tf *tagFilter, date uint64, commonPrefix []byte, filter *uint64set.Set, maxMetrics int) (*uint64set.Set, error) {
 	// Augument tag filter prefix for per-date search instead of global search.
 	if !bytes.HasPrefix(tf.prefix, commonPrefix) {
 		logger.Panicf("BUG: unexpected tf.prefix %q; must start with commonPrefix %q", tf.prefix, commonPrefix)
@@ -2951,21 +2937,21 @@ func (is *indexSearch) getMetricIDsForDateTagFilter(tf *tagFilter, date uint64,
 	tfNew := *tf
 	tfNew.isNegative = false // isNegative for the original tf is handled by the caller.
 	tfNew.prefix = kb.B
-	metricIDs, err := is.getMetricIDsForTagFilter(&tfNew, maxMetrics, filter)
+	metricIDs, err := is.getMetricIDsForTagFilter(&tfNew, filter, maxMetrics)
-
+	if filter != nil {
+		// Do not cache the number of matching metricIDs,
+		// since this number may be modified by filter.
+		return metricIDs, err
+	}
 	// Store the number of matching metricIDs in the cache in order to sort tag filters
 	// in ascending number of matching metricIDs on the next search.
 	is.kb.B = appendDateTagFilterCacheKey(is.kb.B[:0], date, tf, is.accountID, is.projectID)
-
+	metricIDsLen := uint64(metricIDs.Len())
-	var metricIDsLen uint64
+	if err != nil {
-	if err == nil {
-		metricIDsLen = uint64(metricIDs.Len())
-	} else {
 		// Set metricIDsLen to maxMetrics, so the given entry will be moved to the end
 		// of tag filters on the next search.
 		metricIDsLen = uint64(maxMetrics)
 	}
-
 	kb.B = encoding.MarshalUint64(kb.B[:0], metricIDsLen)
 	is.db.metricIDsPerDateTagFilterCache.Set(is.kb.B, kb.B)
 	return metricIDs, err
@@ -3098,16 +3084,13 @@ func (is *indexSearch) intersectMetricIDsWithTagFilterNocache(tf *tagFilter, fil
 
 	// Slow path - scan for all the rows with the given prefix.
 	maxLoops := filter.Len() * maxIndexScanSlowLoopsPerMetric
-	err := is.getMetricIDsForTagFilterSlow(tf, maxLoops, filter, func(metricID uint64) bool {
+	err := is.getMetricIDsForTagFilterSlow(tf, filter, maxLoops, func(metricID uint64) {
 		if tf.isNegative {
 			// filter must be equal to metricIDs
 			metricIDs.Del(metricID)
-			return true
+		} else {
-		}
-		if filter.Has(metricID) {
 			metricIDs.Add(metricID)
 		}
-		return true
 	})
 	if err != nil {
 		if err == errFallbackToMetricNameMatch {
@@ -3298,6 +3281,16 @@ func (mp *tagToMetricIDsRowParser) ParseMetricIDs() {
 	}
 }
 
+// HasCommonMetricIDs returns true if mp has at least one common metric id with filter.
+func (mp *tagToMetricIDsRowParser) HasCommonMetricIDs(filter *uint64set.Set) bool {
+	for _, metricID := range mp.MetricIDs {
+		if filter.Has(metricID) {
+			return true
+		}
+	}
+	return false
+}
+
 // IsDeletedTag verifies whether the tag from mp is deleted according to dmis.
 //
 // dmis must contain deleted MetricIDs.