[query] Special case particular Prom matchers

scripts/docker-integration-tests/query_fanout/warning.sh

@@ -89,9 +89,10 @@ function test_range_query {
 }
 
 function test_search {
-  start=$(date -d "$(date +%Y-%m-%dT%H:%M:%SZ) -1 minute" +%Y-%m-%dT%H:%M:%SZ)
-  end=$(date -d "$(date +%Y-%m-%dT%H:%M:%SZ) +1 minute" +%Y-%m-%dT%H:%M:%SZ)
-
+  s=$(( $(date +%s) - 60 ))
+  start=$(date -r $s +%Y-%m-%dT%H:%M:%SZ)
+  e=$(( $(date +%s) + 60 ))
+  end=$(date -r $e +%Y-%m-%dT%H:%M:%SZ)
   curl -D headers -X POST 0.0.0.0:7201/search -d '{
     "start": "'$start'",
     "end": "'$end'",
@@ -255,14 +256,14 @@ function test_fanout_warning_search {
   # write 5 metrics to cluster a
   write_metrics coordinator-cluster-a 5
   # unlimited query against cluster a has no header
-  ATTEMPTS=3 TIMEOUT=1 retry_with_backoff test_search 15
+  ATTEMPTS=3 TIMEOUT=1 retry_with_backoff test_search 1000
   # limited query against cluster a has header
   ATTEMPTS=3 TIMEOUT=1 retry_with_backoff test_search 4 max_fetch_series_limit_applied
 
   # write 10 metrics to cluster b
   write_metrics coordinator-cluster-b 10
   # unlimited query against cluster a has no header
-  ATTEMPTS=3 TIMEOUT=1 retry_with_backoff test_search 16
+  ATTEMPTS=3 TIMEOUT=1 retry_with_backoff test_search 1000
   # remote limited query against cluster a has header
   ATTEMPTS=3 TIMEOUT=1 retry_with_backoff test_search 4 max_fetch_series_limit_applied
 }
@@ -357,7 +358,7 @@ function test_fanout_warning_missing_zone {
   ATTEMPTS=3 TIMEOUT=1 retry_with_backoff test_range_query 9 14 max_fetch_series_limit_applied,remote_store_cluster-c_fetch_data_error
 
   METRIC_NAME=$SEARCH_NAME
-  ATTEMPTS=3 TIMEOUT=1 retry_with_backoff test_search 16 remote_store_cluster-c_fetch_data_error
+  ATTEMPTS=3 TIMEOUT=1 retry_with_backoff test_search 1000 remote_store_cluster-c_fetch_data_error
   ATTEMPTS=3 TIMEOUT=1 retry_with_backoff test_search 4 max_fetch_series_limit_applied,remote_store_cluster-c_fetch_data_error
 
   ATTEMPTS=3 TIMEOUT=1 retry_with_backoff test_labels 100 remote_store_cluster-c_fetch_data_error
@@ -391,4 +392,3 @@ function test_fanout_warnings {
   test_fanout_warning_graphite
   test_fanout_warning_missing_zone
 }
-

src/query/api/v1/handler/prom/read_instant.go

@@ -147,10 +147,11 @@ func parseTime(s string) (time.Time, error) {
 	// Upstream issue: https://github.com/golang/go/issues/20555
 	switch s {
 	case minTimeFormatted:
-		return minTime, nil
+		return time.Time{}, nil
 	case maxTimeFormatted:
-		return maxTime, nil
+		return time.Now(), nil
 	}
+
 	return time.Time{}, fmt.Errorf("cannot parse %q to a valid timestamp", s)
 }
 

src/query/storage/index.go

@@ -21,7 +21,6 @@
 package storage
 
 import (
-	"bytes"
 	"fmt"
 
 	"github.com/m3db/m3/src/dbnode/storage/index"
@@ -31,8 +30,10 @@ import (
 	"github.com/m3db/m3/src/x/ident"
 )
 
-var (
-	dotStar = []byte(".*")
+const (
+	dot  = byte('.')
+	plus = byte('+')
+	star = byte('*')
 )
 
 // FromM3IdentToMetric converts an M3 ident metric to a coordinator metric.
@@ -119,6 +120,18 @@ func FetchQueryToM3Query(
 
 	// Optimization for single matcher case.
 	if len(matchers) == 1 {
+		specialCase := isSpecialCaseMatcher(matchers[0])
+		if specialCase.skip {
+			// NB: only matcher has no effect; this is synonymous to an AllQuery.
+			return index.Query{
+				Query: idx.NewAllQuery(),
+			}, nil
+		}
+
+		if specialCase.isSpecial {
+			return index.Query{Query: specialCase.query}, nil
+		}
+
 		q, err := matcherToQuery(matchers[0])
 		if err != nil {
 			return index.Query{}, err
@@ -127,59 +140,129 @@ func FetchQueryToM3Query(
 		return index.Query{Query: q}, nil
 	}
 
-	idxQueries := make([]idx.Query, len(matchers))
-	var err error
-	for i, matcher := range matchers {
-		idxQueries[i], err = matcherToQuery(matcher)
+	idxQueries := make([]idx.Query, 0, len(matchers))
+	for _, matcher := range matchers {
+		specialCase := isSpecialCaseMatcher(matcher)
+		if specialCase.skip {
+			continue
+		}
+
+		if specialCase.isSpecial {
+			idxQueries = append(idxQueries, specialCase.query)
+			continue
+		}
+
+		q, err := matcherToQuery(matcher)
 		if err != nil {
 			return index.Query{}, err
 		}
+
+		idxQueries = append(idxQueries, q)
 	}
 
 	q := idx.NewConjunctionQuery(idxQueries...)
 
 	return index.Query{Query: q}, nil
 }
 
+type specialCase struct {
+	query     idx.Query
+	isSpecial bool
+	skip      bool
+}
+
+func isSpecialCaseMatcher(matcher models.Matcher) specialCase {
+	if len(matcher.Value) == 0 {
+		if matcher.Type == models.MatchNotRegexp ||
+			matcher.Type == models.MatchNotEqual {
+			query := idx.NewFieldQuery(matcher.Name)
+			return specialCase{query: query, isSpecial: true}
+		}
+
+		if matcher.Type == models.MatchRegexp ||
+			matcher.Type == models.MatchEqual {
+			query := idx.NewNegationQuery(idx.NewFieldQuery(matcher.Name))
+			return specialCase{query: query, isSpecial: true}
+		}
+
+		return specialCase{}
+	}
+
+	// NB: no special case for regex / not regex here.
+	isNegatedRegex := matcher.Type == models.MatchNotRegexp
+	isRegex := matcher.Type == models.MatchRegexp
+	if !isNegatedRegex && !isRegex {
+		return specialCase{}
+	}
+
+	if len(matcher.Value) != 2 && matcher.Value[0] != dot {
+		return specialCase{}
+	}
+
+	if matcher.Value[1] == star {
+		if isNegatedRegex {
+			// NB: This should match no results.
+			query := idx.NewNegationQuery(idx.NewAllQuery())
+			return specialCase{query: query, isSpecial: true}
+		}
+
+		// NB: this matcher should not affect query results.
+		return specialCase{skip: true}
+	}
+
+	if matcher.Value[1] == plus {
+		query := idx.NewFieldQuery(matcher.Name)
+		if isNegatedRegex {
+			query = idx.NewNegationQuery(query)
+		}
+
+		return specialCase{query: query, isSpecial: true}
+	}
+
+	return specialCase{}
+}
+
 func matcherToQuery(matcher models.Matcher) (idx.Query, error) {
 	negate := false
 	switch matcher.Type {
 	// Support for Regexp types
 	case models.MatchNotRegexp:
 		negate = true
 		fallthrough
+
 	case models.MatchRegexp:
 		var (
 			query idx.Query
 			err   error
 		)
-		if bytes.Equal(dotStar, matcher.Value) {
-			query = idx.NewFieldQuery(matcher.Name)
-		} else {
-			query, err = idx.NewRegexpQuery(matcher.Name, matcher.Value)
-		}
+		query, err = idx.NewRegexpQuery(matcher.Name, matcher.Value)
 		if err != nil {
 			return idx.Query{}, err
 		}
+
 		if negate {
 			query = idx.NewNegationQuery(query)
 		}
+
 		return query, nil
 
 		// Support exact matches
 	case models.MatchNotEqual:
 		negate = true
 		fallthrough
+
 	case models.MatchEqual:
 		query := idx.NewTermQuery(matcher.Name, matcher.Value)
 		if negate {
 			query = idx.NewNegationQuery(query)
 		}
+
 		return query, nil
 
 	case models.MatchNotField:
 		negate = true
 		fallthrough
+
 	case models.MatchField:
 		query := idx.NewFieldQuery(matcher.Name)
 		if negate {

src/query/storage/index_test.go

@@ -112,8 +112,8 @@ func TestFetchQueryToM3Query(t *testing.T) {
 			},
 		},
 		{
-			name:     "regexp match -> field",
-			expected: "field(t1)",
+			name:     "regexp match dot star -> field",
+			expected: "all()",
 			matchers: models.Matchers{
 				{
 					Type:  models.MatchRegexp,
@@ -122,6 +122,17 @@ func TestFetchQueryToM3Query(t *testing.T) {
 				},
 			},
 		},
+		{
+			name:     "regexp match dot plus -> field",
+			expected: "field(t1)",
+			matchers: models.Matchers{
+				{
+					Type:  models.MatchRegexp,
+					Name:  []byte("t1"),
+					Value: []byte(".+"),
+				},
+			},
+		},
 		{
 			name:     "regexp match negated",
 			expected: "negation(regexp(t1, v1))",
@@ -135,7 +146,7 @@ func TestFetchQueryToM3Query(t *testing.T) {
 		},
 		{
 			name:     "regexp match negated",
-			expected: "negation(field(t1))",
+			expected: "negation(all())",
 			matchers: models.Matchers{
 				{
 					Type:  models.MatchNotRegexp,

src/query/test/compatibility/testdata/selectors.test

@@ -57,3 +57,46 @@ eval instant at 0s http_requests{foo!~"bar", job="api-server"}
 eval instant at 0s http_requests{foo!~"bar", job="api-server", instance="1", x!="y", z="", group!=""}
 	http_requests{job="api-server", instance="1", group="production"} 0
 	http_requests{job="api-server", instance="1", group="canary"} 0
+
+# check special casing for existing label
+eval instant at 0s http_requests{job="", instance="0", group="production"}
+
+eval instant at 0s http_requests{job!="", instance="0", group="production"}
+	http_requests{job="api-server", instance="0", group="production"} 0
+
+eval instant at 0s http_requests{job=~"", instance="0", group="production"}
+
+eval instant at 0s http_requests{job!~"", instance="0", group="production"}
+	http_requests{job="api-server", instance="0", group="production"} 0
+
+eval instant at 0s http_requests{job=~".+", instance="0", group="production"}
+	http_requests{job="api-server", instance="0", group="production"} 0
+
+eval instant at 0s http_requests{job=~".*", instance="0", group="production"}
+	http_requests{job="api-server", instance="0", group="production"} 0
+
+eval instant at 0s http_requests{job!~".+", instance="0", group="production"}
+
+eval instant at 0s http_requests{job!~".*", instance="0", group="production"}
+
+# check special casing for non-existent label
+eval instant at 0s http_requests{foo="", job="api-server", instance="0", group="production"}
+	http_requests{job="api-server", instance="0", group="production"} 0
+
+eval instant at 0s http_requests{foo!="", job="api-server", instance="0", group="production"}
+
+eval instant at 0s http_requests{foo=~"", job="api-server", instance="0", group="production"}
+	http_requests{job="api-server", instance="0", group="production"} 0
+
+eval instant at 0s http_requests{foo!~"", job="api-server", instance="0", group="production"}
+
+eval instant at 0s http_requests{foo=~".+", job="api-server", instance="0", group="production"}
+
+eval instant at 0s http_requests{foo=~".*", job="api-server", instance="0", group="production"}
+	http_requests{job="api-server", instance="0", group="production"} 0
+
+eval instant at 0s http_requests{foo!~".+", job="api-server", instance="0", group="production"}
+	http_requests{job="api-server", instance="0", group="production"} 0
+
+eval instant at 0s http_requests{foo!~".*", job="api-server", instance="0", group="production"}
+