Logql/absent label optimization (#3299)

* absent_over_time does not extract unnecessary labels * rebase fix
grafana · Feb 9, 2021 · 5f0c06a · 5f0c06a
1 parent b848ac5
commit 5f0c06a
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diff --git a/pkg/logql/functions.go b/pkg/logql/functions.go
@@ -43,6 +43,12 @@ func (r rangeAggregationExpr) extractor(override *grouping) (log.SampleExtractor
 		}
 	}
 
+	// absent_over_time cannot be grouped (yet?), so set noLabels=true
+	// to make extraction more efficient and less likely to strip per query series limits.
+	if r.operation == OpRangeTypeAbsent {
+		noLabels = true
+	}
+
 	sort.Strings(groups)
 
 	var stages []log.Stage

diff --git a/pkg/logql/log/parser_hints_test.go b/pkg/logql/log/parser_hints_test.go
@@ -140,12 +140,48 @@ func Test_ParserHints(t *testing.T) {
 			15.0,
 			`{Ingester_TotalBatches="0", Ingester_TotalChunksMatched="0", caller="spanlogger.go:79", traceID="2e5c7234b8640997", ts="2021-02-02T14:35:05.983992774Z"}`,
 		},
+		{
+			`sum(rate({app="nginx"} | json | remote_user="foo" [1m]))`,
+			jsonLine,
+			true,
+			1.0,
+			`{}`,
+		},
+		{
+			`sum(rate({app="nginx"} | json | nonexistant_field="foo" [1m]))`,
+			jsonLine,
+			false,
+			0,
+			``,
+		},
+		{
+			`absent_over_time({app="nginx"} | json [1m])`,
+			jsonLine,
+			true,
+			1.0,
+			`{}`,
+		},
+		{
+			`absent_over_time({app="nginx"} | json | nonexistant_field="foo" [1m])`,
+			jsonLine,
+			false,
+			0,
+			``,
+		},
+		{
+			`absent_over_time({app="nginx"} | json | remote_user="foo" [1m])`,
+			jsonLine,
+			true,
+			1.0,
+			`{}`,
+		},
 	} {
 		tt := tt
 		t.Run(tt.expr, func(t *testing.T) {
 			t.Parallel()
 			expr, err := logql.ParseSampleExpr(tt.expr)
 			require.NoError(t, err)
+
 			ex, err := expr.Extractor()
 			require.NoError(t, err)
 			v, lbsRes, ok := ex.ForStream(lbs).Process(tt.line)