Make compatibility computation happen in go routine

util.go

@@ -26,6 +26,7 @@ import (
 	"log"
 	"math"
 	"strconv"
+	"sync"
 
 	"github.com/kellydunn/golang-geo"
 )
@@ -159,7 +160,7 @@ func project(entries records, features featureMap, modes modeMap, featureName st
 	return projection
 }
 
-func computeRecordGeo(entries records, context queryContext) {
+func computeRecordsGeo(entries records, context queryContext) {
 	distUserMin := math.MaxFloat64
 	distUserMax := 0.0
 
@@ -195,10 +196,7 @@ func computeRecordGeo(entries records, context queryContext) {
 	}
 }
 
-func computeRecordCompat(entries records, context queryContext) {
+func computeRecordCompat(entry *record, context queryContext, wg *sync.WaitGroup) {
-	for index := range entries {
-		entry := &entries[index]
-
 	historyRows, err := db.Query("SELECT id FROM history WHERE reviewId = (?)", entry.id)
 	if err != nil {
 		log.Fatal(err)
@@ -245,6 +243,28 @@ func computeRecordCompat(entries records, context queryContext) {
 	if groupCount > 0 {
 		entry.compatibility = groupSum / float64(groupCount)
 	}
+
+	wg.Done()
+}
+
+func computeRecordsCompat(entries records, context queryContext) {
+	count := len(entries)
+	limit := 32
+
+	for i := 0; i < count; i += limit {
+		batch := count - i
+		if batch > limit {
+			batch = limit
+		}
+
+		var wg sync.WaitGroup
+		wg.Add(batch)
+
+		for j := 0; j < batch; j++ {
+			go computeRecordCompat(&entries[i+j], context, &wg)
+		}
+
+		wg.Wait()
 	}
 }
 
@@ -296,8 +316,8 @@ func getRecords(context queryContext) records {
 		log.Fatal(err)
 	}
 
-	computeRecordCompat(entries, context)
+	computeRecordsCompat(entries, context)
-	computeRecordGeo(entries, context)
+	computeRecordsGeo(entries, context)
 
 	return entries
 }