runtime: Remove now unnecessary pad field from ParFor.

It is not needed due to the removal of the ctx field.
    
    Reviewed-on: https://go-review.googlesource.com/16525

From-SVN: r229616

libgo/go/database/sql/sql_test.go

@@ -497,7 +497,7 @@ func TestTxStmt(t *testing.T) {
 	}
 }
 
-// Issue: http://golang.org/issue/2784
+// Issue: https://golang.org/issue/2784
 // This test didn't fail before because we got lucky with the fakedb driver.
 // It was failing, and now not, in github.com/bradfitz/go-sql-test
 func TestTxQuery(t *testing.T) {
@@ -1070,6 +1070,57 @@ func TestMaxOpenConns(t *testing.T) {
 	}
 }
 
+// Issue 9453: tests that SetMaxOpenConns can be lowered at runtime
+// and affects the subsequent release of connections.
+func TestMaxOpenConnsOnBusy(t *testing.T) {
+	defer setHookpostCloseConn(nil)
+	setHookpostCloseConn(func(_ *fakeConn, err error) {
+		if err != nil {
+			t.Errorf("Error closing fakeConn: %v", err)
+		}
+	})
+
+	db := newTestDB(t, "magicquery")
+	defer closeDB(t, db)
+
+	db.SetMaxOpenConns(3)
+
+	conn0, err := db.conn(cachedOrNewConn)
+	if err != nil {
+		t.Fatalf("db open conn fail: %v", err)
+	}
+
+	conn1, err := db.conn(cachedOrNewConn)
+	if err != nil {
+		t.Fatalf("db open conn fail: %v", err)
+	}
+
+	conn2, err := db.conn(cachedOrNewConn)
+	if err != nil {
+		t.Fatalf("db open conn fail: %v", err)
+	}
+
+	if g, w := db.numOpen, 3; g != w {
+		t.Errorf("free conns = %d; want %d", g, w)
+	}
+
+	db.SetMaxOpenConns(2)
+	if g, w := db.numOpen, 3; g != w {
+		t.Errorf("free conns = %d; want %d", g, w)
+	}
+
+	conn0.releaseConn(nil)
+	conn1.releaseConn(nil)
+	if g, w := db.numOpen, 2; g != w {
+		t.Errorf("free conns = %d; want %d", g, w)
+	}
+
+	conn2.releaseConn(nil)
+	if g, w := db.numOpen, 2; g != w {
+		t.Errorf("free conns = %d; want %d", g, w)
+	}
+}
+
 func TestSingleOpenConn(t *testing.T) {
 	db := newTestDB(t, "people")
 	defer closeDB(t, db)
@@ -1093,6 +1144,26 @@ func TestSingleOpenConn(t *testing.T) {
 	}
 }
 
+func TestStats(t *testing.T) {
+	db := newTestDB(t, "people")
+	stats := db.Stats()
+	if got := stats.OpenConnections; got != 1 {
+		t.Errorf("stats.OpenConnections = %d; want 1", got)
+	}
+
+	tx, err := db.Begin()
+	if err != nil {
+		t.Fatal(err)
+	}
+	tx.Commit()
+
+	closeDB(t, db)
+	stats = db.Stats()
+	if got := stats.OpenConnections; got != 0 {
+		t.Errorf("stats.OpenConnections = %d; want 0", got)
+	}
+}
+
 // golang.org/issue/5323
 func TestStmtCloseDeps(t *testing.T) {
 	if testing.Short() {
@@ -1314,7 +1385,80 @@ func TestStmtCloseOrder(t *testing.T) {
 	}
 }
 
-// golang.org/issue/5781
+// Test cases where there's more than maxBadConnRetries bad connections in the
+// pool (issue 8834)
+func TestManyErrBadConn(t *testing.T) {
+	manyErrBadConnSetup := func() *DB {
+		db := newTestDB(t, "people")
+
+		nconn := maxBadConnRetries + 1
+		db.SetMaxIdleConns(nconn)
+		db.SetMaxOpenConns(nconn)
+		// open enough connections
+		func() {
+			for i := 0; i < nconn; i++ {
+				rows, err := db.Query("SELECT|people|age,name|")
+				if err != nil {
+					t.Fatal(err)
+				}
+				defer rows.Close()
+			}
+		}()
+
+		if db.numOpen != nconn {
+			t.Fatalf("unexpected numOpen %d (was expecting %d)", db.numOpen, nconn)
+		} else if len(db.freeConn) != nconn {
+			t.Fatalf("unexpected len(db.freeConn) %d (was expecting %d)", len(db.freeConn), nconn)
+		}
+		for _, conn := range db.freeConn {
+			conn.ci.(*fakeConn).stickyBad = true
+		}
+		return db
+	}
+
+	// Query
+	db := manyErrBadConnSetup()
+	defer closeDB(t, db)
+	rows, err := db.Query("SELECT|people|age,name|")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err = rows.Close(); err != nil {
+		t.Fatal(err)
+	}
+
+	// Exec
+	db = manyErrBadConnSetup()
+	defer closeDB(t, db)
+	_, err = db.Exec("INSERT|people|name=Julia,age=19")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Begin
+	db = manyErrBadConnSetup()
+	defer closeDB(t, db)
+	tx, err := db.Begin()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err = tx.Rollback(); err != nil {
+		t.Fatal(err)
+	}
+
+	// Prepare
+	db = manyErrBadConnSetup()
+	defer closeDB(t, db)
+	stmt, err := db.Prepare("SELECT|people|age,name|")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err = stmt.Close(); err != nil {
+		t.Fatal(err)
+	}
+}
+
+// golang.org/issue/5718
 func TestErrBadConnReconnect(t *testing.T) {
 	db := newTestDB(t, "foo")
 	defer closeDB(t, db)
@@ -1764,56 +1908,6 @@ func doConcurrentTest(t testing.TB, ct concurrentTest) {
 	wg.Wait()
 }
 
-func manyConcurrentQueries(t testing.TB) {
-	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)
-	}
-	defer stmt.Close()
-
-	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 TestIssue6081(t *testing.T) {
 	db := newTestDB(t, "people")
 	defer closeDB(t, db)
@@ -1985,3 +2079,31 @@ func BenchmarkConcurrentRandom(b *testing.B) {
 		doConcurrentTest(b, ct)
 	}
 }
+
+func BenchmarkManyConcurrentQueries(b *testing.B) {
+	b.ReportAllocs()
+	// To see lock contention in Go 1.4, 16~ cores and 128~ goroutines are required.
+	const parallelism = 16
+
+	db := newTestDB(b, "magicquery")
+	defer closeDB(b, db)
+	db.SetMaxIdleConns(runtime.GOMAXPROCS(0) * parallelism)
+
+	stmt, err := db.Prepare("SELECT|magicquery|op|op=?,millis=?")
+	if err != nil {
+		b.Fatal(err)
+	}
+	defer stmt.Close()
+
+	b.SetParallelism(parallelism)
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			rows, err := stmt.Query("sleep", 1)
+			if err != nil {
+				b.Error(err)
+				return
+			}
+			rows.Close()
+		}
+	})
+}