database/sql: improve standard deviation response time under high concurrency
See https://github.com/raggi/go-and-java for runtime benchmark.
The patch reduces the amount of map key search, moving connection oriented
variables onto the connection structs.
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/8092045
diff --git a/src/pkg/database/sql/sql_test.go b/src/pkg/database/sql/sql_test.go
index 54aad3a..6b91783 100644
--- a/src/pkg/database/sql/sql_test.go
+++ b/src/pkg/database/sql/sql_test.go
@@ -7,7 +7,9 @@
import (
"fmt"
"reflect"
+ "runtime"
"strings"
+ "sync"
"testing"
"time"
)
@@ -36,7 +38,14 @@
var chrisBirthday = time.Unix(123456789, 0)
-func newTestDB(t *testing.T, name string) *DB {
+type testOrBench interface {
+ Fatalf(string, ...interface{})
+ Errorf(string, ...interface{})
+ Fatal(...interface{})
+ Error(...interface{})
+}
+
+func newTestDB(t testOrBench, name string) *DB {
db, err := Open("test", fakeDBName)
if err != nil {
t.Fatalf("Open: %v", err)
@@ -53,14 +62,14 @@
return db
}
-func exec(t *testing.T, db *DB, query string, args ...interface{}) {
+func exec(t testOrBench, db *DB, query string, args ...interface{}) {
_, err := db.Exec(query, args...)
if err != nil {
t.Fatalf("Exec of %q: %v", query, err)
}
}
-func closeDB(t *testing.T, db *DB) {
+func closeDB(t testOrBench, db *DB) {
if e := recover(); e != nil {
fmt.Printf("Panic: %v\n", e)
panic(e)
@@ -844,3 +853,63 @@
t.Errorf("after Stmt Close, driverConn's Conn interface should be nil")
}
}
+
+func manyConcurrentQueries(t testOrBench) {
+ maxProcs, numReqs := 16, 500
+ if testing.Short() {
+ maxProcs, numReqs = 4, 50
+ }
+ defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(maxProcs))
+
+ db := newTestDB(t, "people")
+ defer closeDB(t, db)
+
+ stmt, err := db.Prepare("SELECT|people|name|")
+ if err != nil {
+ t.Fatal(err)
+ }
+
+ var wg sync.WaitGroup
+ wg.Add(numReqs)
+
+ reqs := make(chan bool)
+ defer close(reqs)
+
+ for i := 0; i < maxProcs*2; i++ {
+ go func() {
+ for _ = range reqs {
+ rows, err := stmt.Query()
+ if err != nil {
+ t.Errorf("error on query: %v", err)
+ wg.Done()
+ continue
+ }
+
+ var name string
+ for rows.Next() {
+ rows.Scan(&name)
+ }
+ rows.Close()
+
+ wg.Done()
+ }
+ }()
+ }
+
+ for i := 0; i < numReqs; i++ {
+ reqs <- true
+ }
+
+ wg.Wait()
+}
+
+func TestConcurrency(t *testing.T) {
+ manyConcurrentQueries(t)
+}
+
+func BenchmarkConcurrency(b *testing.B) {
+ b.ReportAllocs()
+ for i := 0; i < b.N; i++ {
+ manyConcurrentQueries(b)
+ }
+}
