bench.diff

diff --git a/go/src/hello/hello.go b/go/src/hello/hello.go
index 5f54709..b843e19 100644
--- a/go/src/hello/hello.go
+++ b/go/src/hello/hello.go
@@ -10,6 +10,7 @@ import (
        "runtime"
        "sort"
        "strconv"
+       "sync"

        _ "github.com/go-sql-driver/mysql"
 )
@@ -52,12 +53,15 @@ var (
        updateStatement  *sql.Stmt

        helloWorldBytes = []byte(helloWorldString)
+       db              *sql.DB
+       queryChan       chan (*queryRequest)
 )

 func main() {
        runtime.GOMAXPROCS(runtime.NumCPU())

-       db, err := sql.Open("mysql", connectionString)
+       var err error
+       db, err = sql.Open("mysql", connectionString)
        if err != nil {
                log.Fatalf("Error opening database: %v", err)
        }
@@ -75,6 +79,12 @@ func main() {
                log.Fatal(err)
        }

+       queryChan = make(chan *queryRequest)
+       numQueryRunners := runtime.NumCPU() * 2
+       for i := 0; i < numQueryRunners; i++ {
+               go queryRunner(queryChan)
+       }
+
        http.HandleFunc("/db", dbHandler)
        http.HandleFunc("/queries", queriesHandler)
        http.HandleFunc("/json", jsonHandler)
@@ -102,6 +112,38 @@ func dbHandler(w http.ResponseWriter, r *http.Request) {
        json.NewEncoder(w).Encode(&world)
 }

+type queryRequest struct {
+       n      int
+       wg     *sync.WaitGroup
+       result World
+       err    error
+}
+
+func setupQueryRequest(r *queryRequest, wg *sync.WaitGroup) {
+       r.n = rand.Intn(worldRowCount) + 1
+       r.wg = wg
+}
+
+func (q *queryRequest) MarshalJSON() ([]byte, error) {
+       return json.Marshal(q.result)
+}
+
+func (r *queryRequest) runQuery(stmt *sql.Stmt) {
+       defer r.wg.Done()
+       r.err = stmt.QueryRow(r.n).Scan(&r.result.Id, &r.result.RandomNumber)
+}
+
+func queryRunner(c chan *queryRequest) {
+       stmt, err := db.Prepare(worldSelect)
+       if err != nil {
+               log.Fatal(err)
+       }
+       defer stmt.Close()
+       for r := range c {
+               r.runQuery(stmt)
+       }
+}
+
 // Test 3: Multiple database queries
 func queriesHandler(w http.ResponseWriter, r *http.Request) {
        n := 1
@@ -114,16 +156,23 @@ func queriesHandler(w http.ResponseWriter, r *http.Request) {
                return
        }

-       world := make([]World, n)
+       var wg sync.WaitGroup
+       queries := make([]queryRequest, n)
+       wg.Add(n)
        for i := 0; i < n; i++ {
-               err := worldStatement.QueryRow(rand.Intn(worldRowCount)+1).Scan(&world[i].Id, &world[
-               if err != nil {
-                       log.Fatalf("Error scanning world row: %s", err.Error())
+               setupQueryRequest(&queries[i], &wg)
+               queryChan <- &queries[i]
+       }
+       wg.Wait()
+
+       for i := range queries {
+               if queries[i].err != nil {
+                       log.Fatalf("Error scanning world row: %d %s", queries[i].n, queries[i].err.Er
                }
        }

        w.Header().Set("Content-Type", "application/json")
-       json.NewEncoder(w).Encode(world)
+       json.NewEncoder(w).Encode(queries)
 }

 // Test 4: Fortunes