Add TestAnalyzeRealQueries (#443)

* Add TestAnalyzeRealQueries

Signed-off-by: Marco Pracucci <marco@pracucci.com>

* Add nolint directive

Signed-off-by: Marco Pracucci <marco@pracucci.com>

---------

Signed-off-by: Marco Pracucci <marco@pracucci.com>

model/labels/regexp.go

@@ -57,6 +57,14 @@ func NewFastRegexMatcher(v string) (*FastRegexMatcher, error) {
 	return m, nil
 }
 
+// isOptimized returns true if any fast-path optimization is applied to the
+// regex matcher.
+//
+//nolint:unused
+func (m *FastRegexMatcher) isOptimized() bool {
+	return len(m.setMatches) > 0 || m.stringMatcher != nil || m.prefix != "" || m.suffix != "" || m.contains != ""
+}
+
 // findSetMatches extract equality matches from a regexp.
 // Returns nil if we can't replace the regexp by only equality matchers or the regexp contains
 // a mix of case sensitive and case insensitive matchers.

model/labels/regexp_test.go

@@ -14,11 +14,14 @@
 package labels
 
 import (
+	"bufio"
 	"math/rand"
+	"os"
 	"strings"
 	"testing"
 	"time"
 
+	"github.com/grafana/regexp"
 	"github.com/grafana/regexp/syntax"
 	"github.com/stretchr/testify/require"
 )
@@ -374,3 +377,54 @@ func FuzzFastRegexMatcher_WithFuzzyRegularExpressions(f *testing.F) {
 		require.Equalf(t, m.re.MatchString(text), m.MatchString(text), "regexp: %s text: %s", m.re.String(), text)
 	})
 }
+
+// This test can be used to analyze real queries from Mimir logs. You can extract real queries with a regexp matcher
+// running the following command:
+//
+// logcli --addr=XXX --username=YYY --password=ZZZ query '{namespace=~"(cortex|mimir).*",name="query-frontend"} |= "query stats" |= "=~" --limit=100000 > logs.txt
+func TestAnalyzeRealQueries(t *testing.T) {
+	t.Skip("Decomment this test only to manually analyze real queries")
+
+	labelValueRE := regexp.MustCompile(`=~\\"([^"]+)\\"`)
+	labelValues := make(map[string]struct{})
+
+	// Read the logs file line-by-line, and find all values for regex label matchers.
+	readFile, err := os.Open("logs.txt")
+	require.NoError(t, err)
+
+	fileScanner := bufio.NewScanner(readFile)
+	fileScanner.Split(bufio.ScanLines)
+
+	for fileScanner.Scan() {
+		line := fileScanner.Text()
+		matches := labelValueRE.FindAllStringSubmatch(line, -1)
+
+		for _, match := range matches {
+			labelValues[match[1]] = struct{}{}
+		}
+	}
+
+	require.NoError(t, readFile.Close())
+	t.Logf("Found %d unique regexp matchers", len(labelValues))
+
+	// Check if each regexp matcher is supported by our optimization.
+	numChecked := 0
+	numOptimized := 0
+
+	for re := range labelValues {
+		m, err := NewFastRegexMatcher(re)
+		if err != nil {
+			// Ignore it, because we may have failed to extract the label matcher.
+			continue
+		}
+
+		numChecked++
+		if m.isOptimized() {
+			numOptimized++
+		} else {
+			t.Logf("Not optimized matcher: %s", re)
+		}
+	}
+
+	t.Logf("Found %d (%.2f%%) optimized matchers out of %d", numOptimized, (float64(numOptimized)/float64(numChecked))*100, numChecked)
+}