如下代码，TestPreloadSkipCache能通过， TestPreload会失败：

type TestRole struct {
	gorm.Model
	Name string
}

type TestUser struct {
	gorm.Model
	UserName string `gorm:"size:32"`
	Password string `gorm:"size:32"`
	Age      int
	Status   int
	Roles    []TestRole `gorm:"many2many:test_user_roles;"`
}

func init() {
	var e error
	addr := "user=lab password=lab dbname=lab port=5432 sslmode=disable"
	db, e = gorm.Open("postgres", addr)
	if e != nil {
		panic(e)
	}
	db.AutoMigrate(&TestRole{})
	db.AutoMigrate(&TestUser{})
	db.AutoMigrate(&TestEmail{})

	opt := gcache.DefaultOption{}
	opt.Expires = 300              //缓存时间，默认60秒。范围 30-900
	opt.Level = gcache.LevelSearch //缓存级别，默认LevelSearch。LevelDisable:关闭缓存，LevelModel:模型缓存， LevelSearch:查询缓存
	opt.AsyncWrite = false         //异步缓存更新, 默认false。 insert update delete 成功后是否异步更新缓存
	opt.PenetrationSafe = false    //开启防穿透, 默认false。

	//缓存中间件 注入到Gorm
	cachePlugin = gcache.AttachDB(db, &opt, &gcache.RedisOption{Addr: "localhost:6379"})

	InitData()
	//开启Debug，查看日志
	db.LogMode(true)
	cachePlugin.Debug()
}

func InitData() {
	cachePlugin.FlushDB()
	db.Exec("truncate test_user_roles")
	db.Exec("truncate test_roles")
	db.Exec("truncate test_users")
	db.Exec("truncate test_emails")

	roleAdmin := &TestRole{
		Name: "ADMIN",
	}
	db.Save(roleAdmin)

	roleUser := &TestRole{
		Name: "USER",
	}
	db.Save(roleUser)

	for index := 1; index < 21; index++ {
		user := &TestUser{}
		user.UserName = fmt.Sprintf("%s_%d", "name", index)
		user.Password = fmt.Sprintf("%s_%d", "password", index)
		user.Age = 20 + index
		user.Status = rand.Intn(3)
		user.Roles = []TestRole{*roleUser, *roleAdmin}
		db.Save(user)

		email := &TestEmail{}
		email.TypeID = index
		email.TestUserID = index
		db.Save(email)
	}
}

func TestPreloadSkipCache(t *testing.T) {
	var tc TestUser
	db.First(&tc, "user_name = ?", "name_1")
	assert.Equal(t, "name_1", tc.UserName)
	assert.Equal(t, 0, len(tc.Roles))

	cachePlugin.SkipCache().Preload("Roles").Find(&tc)
	assert.Equal(t, 2, len(tc.Roles))
}

func TestPreload(t *testing.T) {
	var tc TestUser
	db.First(&tc, "user_name = ?", "name_1")
	assert.Equal(t, "name_1", tc.UserName)
	assert.Equal(t, 0, len(tc.Roles))

	db.Preload("Roles").Find(&tc)
	assert.Equal(t, 2, len(tc.Roles)) // FAIL
}

类似的错误很容易发生，能看出来是什么原因吗：

panic: reflect: call of reflect.Value.FieldByName on ptr Value

goroutine 67 [running]:
github.com/jinzhu/gorm.(*Scope).callCallbacks.func1(0xc000113d80)
	/root/go/pkg/mod/github.com/jinzhu/[email protected]/scope.go:865 +0xb0
panic(0x13b4ea0, 0xc00063cbc0)
	/home/jenkins/tools/org.jenkinsci.plugins.golang.GolangInstallation/go-lang-1.13/src/runtime/panic.go:679 +0x1b2
reflect.flag.mustBe(...)
	/home/jenkins/tools/org.jenkinsci.plugins.golang.GolangInstallation/go-lang-1.13/src/reflect/value.go:208
reflect.Value.FieldByName(0x13aad00, 0xc00063cba0, 0x196, 0x121f13c, 0x2, 0xc00063cba0, 0x196, 0xc00060d640)
	/home/jenkins/tools/org.jenkinsci.plugins.golang.GolangInstallation/go-lang-1.13/src/reflect/value.go:890 +0x1ed
github.com/8treenet/gcache/internal.(*easyScope).EasyPrimarys(0xc0004ccb00, 0x1616ed8, 0x8, 0xc0000486c0, 0x3c, 0xc00060d630)
	/root/go/pkg/mod/github.com/8treenet/[email protected]/internal/easy_scope.go:497 +0xbcf
github.com/8treenet/gcache/internal.(*queryHandle).BySearch(0xc0000196f8, 0xc0004ccb00, 0xc00063c080, 0x197, 0x203000, 0x203000, 0x203000)
	/root/go/pkg/mod/github.com/8treenet/[email protected]/internal/handle_query.go:109 +0xf7
github.com/8treenet/gcache/internal.(*callQuery).bySearch(0xc0003cc340, 0xc0004ccb00, 0x0, 0x0, 0x0, 0x0)
	/root/go/pkg/mod/github.com/8treenet/[email protected]/internal/call_query.go:118 +0xd6
github.com/8treenet/gcache/internal.(*callQuery).invoke.func1(0x413031, 0xd0, 0x14a1860, 0xfba41cc9035f6801)
	/root/go/pkg/mod/github.com/8treenet/[email protected]/internal/call_query.go:53 +0x75
github.com/8treenet/gcache/internal.(*Group).doCall(0xc0003cc348, 0xc000491f20, 0xc000040690, 0x4c, 0xc0000198a0)
	/root/go/pkg/mod/github.com/8treenet/[email protected]/internal/singleflight.go:91 +0x2e
github.com/8treenet/gcache/internal.(*Group).Do(0xc0003cc348, 0xc000040690, 0x4c, 0xc0000198a0, 0xe, 0xc00060d5c8, 0x2, 0xc000040690, 0x4c)
	/root/go/pkg/mod/github.com/8treenet/[email protected]/internal/singleflight.go:61 +0x1ba
github.com/8treenet/gcache/internal.(*callQuery).invoke(0xc0003cc340, 0xc000113d80)
	/root/go/pkg/mod/github.com/8treenet/[email protected]/internal/call_query.go:46 +0x1a8
github.com/jinzhu/gorm.(*Scope).callCallbacks(0xc000113d80, 0xc0003cce20, 0x4, 0x4, 0x0)
	/root/go/pkg/mod/github.com/jinzhu/[email protected]/scope.go:869 +0x92
github.com/jinzhu/gorm.(*DB).Find(0xc0003e8270, 0x12caea0, 0xc00063c080, 0xc000633950, 0x3, 0x3, 0xc000633950)
	/root/go/pkg/mod/github.com/jinzhu/[email protected]/main.go:354 +0x98
gitlab.com/example/dal/reader.(*Reader).GetProducts(0xc00048f580, 0xc000633950, 0x3, 0x3, 0xc00063c060, 0x2, 0x2, 0x2, 0xc0004d4240)
	/home/jenkins/workspace/example/dal/reader/product.go:19 +0xb4
gitlab.com/sensestar/example/payment/controllers.(*PaymentController).GetProducts(0x27c54b0, 0x19ed8e0, 0xc0005006c0, 0xc0004d4240, 0x27c54b0, 0xc0005006c0, 0xc000027b58)
	/home/jenkins/workspace/example/payment/controllers/payment.go:72 +0x4ee
gitlab.com/sensestar/example/payment._PaymentService_GetProducts_Handler(0x15ede00, 0x27c54b0, 0x19ed8e0, 0xc0005006c0, 0xc000490f60, 0x0, 0x19ed8e0, 0xc0005006c0, 0xc0004deb10, 0x10)
	/home/jenkins/workspace/example/payment/payment.pb.go:5483 +0x217
google.golang.org/grpc.(*Server).processUnaryRPC(0xc000210d00, 0x1a04620, 0xc0000ebe00, 0xc0004cc300, 0xc000089800, 0x2788aa0, 0x0, 0x0, 0x0)
	/root/go/pkg/mod/google.golang.org/[email protected]/server.go:1082 +0x4fd
google.golang.org/grpc.(*Server).handleStream(0xc000210d00, 0x1a04620, 0xc0000ebe00, 0xc0004cc300, 0x0)
	/root/go/pkg/mod/google.golang.org/[email protected]/server.go:1405 +0xd27
google.golang.org/grpc.(*Server).serveStreams.func1.1(0xc0004de9b0, 0xc000210d00, 0x1a04620, 0xc0000ebe00, 0xc0004cc300)
	/root/go/pkg/mod/google.golang.org/[email protected]/server.go:746 +0xbb
created by google.golang.org/grpc.(*Server).serveStreams.func1
	/root/go/pkg/mod/google.golang.org/[email protected]/server.go:744 +0xa1

在执行 golang: querys:=db.Table("dsp_campaign_frequercy").Find(&dCF).Scan(&dCF)

sql : select *from dsp_campaign_frequercy; 发现，并没有将查询出来的数据，插入到redis中，请问如何将全表数据，一次插入到redis中。

测试代码如下：

func TestAssociation(t *testing.T) {
	var tc TestUser
	db.First(&tc, "user_name = ?", "name_1")
	assert.Equal(t, "name_1", tc.UserName)
	assert.Equal(t, 0, len(tc.Roles))

	cachePlugin.SkipCache().Preload("Roles").Find(&tc)
	assert.Equal(t, 2, len(tc.Roles))

	db.Preload("Roles").Find(&tc)
	assert.Equal(t, 2, len(tc.Roles))

	var adminRole TestRole
	db.Model(&adminRole).Where("name = ?", "ADMIN").First(&adminRole)
	assert.Equal(t, "ADMIN", adminRole.Name)

	db.Model(tc).Association("Roles").Delete(adminRole) // panic: reflect.Value.Addr of unaddressable value
}

这个删除操作会导致 panic: reflect.Value.Addr of unaddressable value，测试了去掉 gcache 是能通过测试的。

Other code see #16, full code see https://github.com/8treenet/gcache/compare/master...sutra:testAssociation?expand=1

src\github.com\8treenet\gcache\internal\easy_scope.go:295:10: es.IsCompleteParentheses undefined (type *easyScope has no field or method IsCompleteParentheses)