Remove hardcoded labels in store shard matcher and inject unshardable label in query analyzer

CHANGELOG.md

@@ -25,6 +25,8 @@ We use *breaking :warning:* to mark changes that are not backward compatible (re
 - [#5255](https://github.com/thanos-io/thanos/pull/5296) Query: Use k-way merging for the proxying logic. The proxying sub-system now uses much less resources (~25-80% less CPU usage, ~30-50% less RAM usage according to our benchmarks). Reduces query duration by a few percent on queries with lots of series.
 - [#5690](https://github.com/thanos-io/thanos/pull/5690) Compact: update `--debug.accept-malformed-index` flag to apply to downsampling. Previously the flag only applied to compaction, and fatal errors would still occur when downsampling was attempted.
 - [#5707](https://github.com/thanos-io/thanos/pull/5707) Objstore: Update objstore to latest version which includes a refactored Azure Storage Account implementation with a new SDK.
+- [#5641](https://github.com/thanos-io/thanos/pull/5641) Store: Remove hardcoded labels in shard matcher.
+- [#5641](https://github.com/thanos-io/thanos/pull/5641) Query: Inject unshardable le label in query analyzer.
 - [#5685](https://github.com/thanos-io/thanos/pull/5685) Receive: Make active/head series limiting configuration per tenant by adding it to new limiting config.
 
 ### Removed

pkg/querysharding/analyzer.go

@@ -35,6 +35,7 @@ func NewQueryAnalyzer() *QueryAnalyzer {
 //   used in grouping expressions. If non-empty, treat the query
 //   as shardable by those labels.
 // * otherwise, treat the query as non-shardable.
+// The le label is excluded from sharding.
 func (a *QueryAnalyzer) Analyze(query string) (QueryAnalysis, error) {
 	expr, err := parser.ParseExpr(query)
 	if err != nil {
@@ -55,15 +56,15 @@ func (a *QueryAnalyzer) Analyze(query string) (QueryAnalysis, error) {
 			}
 		case *parser.BinaryExpr:
 			if n.VectorMatching != nil {
-				analysis = analysis.scopeToLabels(n.VectorMatching.MatchingLabels, n.VectorMatching.On)
+				shardingLabels := without(n.VectorMatching.MatchingLabels, []string{"le"})
+				analysis = analysis.scopeToLabels(shardingLabels, n.VectorMatching.On)
 			}
 		case *parser.AggregateExpr:
-			labels := make([]string, 0)
+			shardingLabels := make([]string, 0)
 			if len(n.Grouping) > 0 {
-				labels = n.Grouping
+				shardingLabels = without(n.Grouping, []string{"le"})
 			}
-
-			analysis = analysis.scopeToLabels(labels, !n.Without)
+			analysis = analysis.scopeToLabels(shardingLabels, !n.Without)
 		}
 
 		return nil
@@ -85,7 +86,8 @@ func analyzeRootExpression(node parser.Node) QueryAnalysis {
 	switch n := node.(type) {
 	case *parser.BinaryExpr:
 		if n.VectorMatching != nil && n.VectorMatching.On {
-			return newShardableByLabels(n.VectorMatching.MatchingLabels, n.VectorMatching.On)
+			shardingLabels := without(n.VectorMatching.MatchingLabels, []string{"le"})
+			return newShardableByLabels(shardingLabels, n.VectorMatching.On)
 		} else {
 			return nonShardableQuery()
 		}
@@ -94,7 +96,8 @@ func analyzeRootExpression(node parser.Node) QueryAnalysis {
 			return nonShardableQuery()
 		}
 
-		return newShardableByLabels(n.Grouping, !n.Without)
+		shardingLabels := without(n.Grouping, []string{"le"})
+		return newShardableByLabels(shardingLabels, !n.Without)
 	}
 
 	return nonShardableQuery()

pkg/querysharding/analyzer_test.go

@@ -156,6 +156,11 @@ sum by (container) (
 http_requests_total`,
 			shardingLabels: []string{"cluster", "pod"},
 		},
+		{
+			name:           "histogram quantile",
+			expression:     "histogram_quantile(0.95, sum(rate(metric[1m])) without (le, cluster))",
+			shardingLabels: []string{"cluster"},
+		},
 	}
 
 	for _, test := range nonShardable {

pkg/store/storepb/shard_info.go

@@ -42,11 +42,6 @@ func (s *ShardMatcher) MatchesZLabels(zLabels []labelpb.ZLabel) bool {
 
 	*s.buf = (*s.buf)[:0]
 	for _, lbl := range zLabels {
-		// Exclude metric name and le label from sharding
-		if lbl.Name == "__name__" || lbl.Name == "le" {
-			continue
-		}
-
 		if shardByLabel(s.shardingLabelset, lbl, s.by) {
 			*s.buf = append(*s.buf, lbl.Name...)
 			*s.buf = append(*s.buf, sep[0])