Prepare columns in go routines

server.go

@@ -30,6 +30,7 @@ import (
 	"log"
 	"math"
 	"net/http"
+	"runtime"
 	"strings"
 
 	"github.com/GaryBoone/GoStats/stats"
@@ -38,40 +39,15 @@ import (
 
 var db *sql.DB
 
-func executeQuery(rw http.ResponseWriter, req *http.Request) {
+func prepareColumn(request jsonQueryRequest, entries, foundEntries records, features featureMap, modes modeMap, name string, value float64, columns chan jsonColumn) {
-	var request jsonQueryRequest
+	mode := modes[name]
-	if err := json.NewDecoder(req.Body).Decode(&request); err != nil {
-		http.Error(rw, err.Error(), http.StatusInternalServerError)
-		return
-	}
-
-	var geo *geoData
-	if request.Geo != nil {
-		geo = &geoData{request.Geo.Latitude, request.Geo.Longitude}
-	}
-
-	entries := getRecords(queryContext{geo, request.Profile, request.WalkingDist})
-	features := fixFeatures(request.Features)
-	modes := fixModes(request.Modes)
-
-	foundEntries := findRecords(entries, features, modes, request.MinScore)
-	sorter := recordSorter{entries: foundEntries, key: request.SortKey, ascending: request.SortAsc}
-	sorter.sort()
-
-	response := jsonQueryResponse{
-		Columns:  make(map[string]jsonColumn),
-		Count:    len(foundEntries),
-		MinScore: request.MinScore,
-		Records:  make([]jsonRecord, 0)}
-
-	for name, value := range features {
-		mode, _ := modes[name]
 
 	column := jsonColumn{
 		Bracket: jsonBracket{Max: -1.0, Min: 1.0},
 		Mode:    mode.String(),
 		Steps:   request.Resolution,
-			Value:   value}
+		Value:   value,
+		name:    name}
 
 	hints := project(
 		entries,
@@ -105,7 +81,43 @@ func executeQuery(rw http.ResponseWriter, req *http.Request) {
 		column.Bracket.Min = math.Max(mean-dev, d.Min())
 	}
 
-		response.Columns[name] = column
+	columns <- column
+}
+
+func executeQuery(rw http.ResponseWriter, req *http.Request) {
+	var request jsonQueryRequest
+	if err := json.NewDecoder(req.Body).Decode(&request); err != nil {
+		http.Error(rw, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	var geo *geoData
+	if request.Geo != nil {
+		geo = &geoData{request.Geo.Latitude, request.Geo.Longitude}
+	}
+
+	entries := getRecords(queryContext{geo, request.Profile, request.WalkingDist})
+	features := fixFeatures(request.Features)
+	modes := fixModes(request.Modes)
+
+	foundEntries := findRecords(entries, features, modes, request.MinScore)
+	sorter := recordSorter{entries: foundEntries, key: request.SortKey, ascending: request.SortAsc}
+	sorter.sort()
+
+	response := jsonQueryResponse{
+		Columns:  make(map[string]jsonColumn),
+		Count:    len(foundEntries),
+		MinScore: request.MinScore,
+		Records:  make([]jsonRecord, 0)}
+
+	columns := make(chan jsonColumn, len(features))
+	for name, value := range features {
+		go prepareColumn(request, entries, foundEntries, features, modes, name, value, columns)
+	}
+
+	for i := 0; i < len(features); i++ {
+		column := <-columns
+		response.Columns[column.name] = column
 	}
 
 	for index, record := range foundEntries {
@@ -288,6 +300,8 @@ func clearHistory(rw http.ResponseWriter, req *http.Request) {
 }
 
 func main() {
+	runtime.GOMAXPROCS(runtime.NumCPU())
+
 	staticDir := flag.String("static", "static", "path to static files")
 	portNum := flag.Int("port", 8080, "port to serve content on")
 	dataSrc := flag.String("data", "hscd@/hscd", "data source for database")

types.go

@@ -66,6 +66,7 @@ type jsonColumn struct {
 	Mode    string           `json:"mode"`
 	Steps   int              `json:"steps"`
 	Value   float64          `json:"value"`
+	name    string
 }
 
 type jsonProjection struct {