Collect and log search stats. (#114107)

* Collect and log search stats.

* Fix compilation problems.

pkg/storage/unified/resource/stats.go

@@ -0,0 +1,65 @@
+package resource
+
+import "time"
+
+type SearchStats struct {
+	operation string
+	startTime time.Time // Time when the operation.
+
+	indexBuildTime  time.Duration // Time to build indexes if it wasn't open before.
+	indexUpdateTime time.Duration // Time to update indexes to the latest state.
+
+	requestConversion time.Duration // How long does it take to convert search request to the bleve query
+
+	searchTime        time.Duration
+	totalHits         int // Total hits across all pages
+	returnedDocuments int // Hits returned in this page
+
+	resultsConversionTime time.Duration // How long does it take to convert search results to final results.
+}
+
+func NewSearchStats(op string) *SearchStats {
+	return &SearchStats{operation: op, startTime: time.Now()}
+}
+
+func (s *SearchStats) AddIndexBuildTime(d time.Duration) {
+	if s != nil {
+		s.indexBuildTime += d
+	}
+}
+
+func (s *SearchStats) AddIndexUpdateTime(d time.Duration) {
+	if s != nil {
+		s.indexUpdateTime += d
+	}
+}
+
+func (s *SearchStats) AddRequestConversionTime(d time.Duration) {
+	if s != nil {
+		s.requestConversion += d
+	}
+}
+
+func (s *SearchStats) AddSearchTime(d time.Duration) {
+	if s != nil {
+		s.searchTime += d
+	}
+}
+
+func (s *SearchStats) AddTotalHits(total int) {
+	if s != nil {
+		s.totalHits += total
+	}
+}
+
+func (s *SearchStats) AddReturnedDocuments(docs int) {
+	if s != nil {
+		s.returnedDocuments += docs
+	}
+}
+
+func (s *SearchStats) AddResultsConversionTime(d time.Duration) {
+	if s != nil {
+		s.resultsConversionTime += d
+	}
+}