Can't get space length via tarantool.crud

[Vlad97vsv]

Can't get space length via crud.len

I get an error: array len doesn't match: 1

db - is connected ConnectionPool

func getLen() uint64 {
	space := "test_space"
	req := tarantoolcrud.MakeLenRequest(space)
	data := tarantoolcrud.LenResult{}
	if err := db.Do(req, tarantoolpool.ANY).GetTyped(&data); err != nil {
		panic(err)
	}
	fmt.Println(data.Value)
	return data.Value
}

>>> panic: array len doesn't match: 1

When I use Count query everything is ok.

func getCount() uint64 {
	space := "test_space"
	req := tarantoolcrud.MakeCountRequest(space)
	data := tarantoolcrud.CountResult{}
	if err := db.Do(req, tarantoolpool.ANY).GetTyped(&data); err != nil {
		panic(err)
	}
	fmt.Println(data.Value)
	return data.Value
}
`>>> 10000`

---

If you look at what arrives, you can see that only 1 entry in the array arrives for crud.len. And for count there are 2 entries:

func (r *MetaTntRepositoryVShard) getCount2() {
	space := "test_space"
	req := crud.MakeCountRequest(space)
	if data, err := db.Do(req, tarantoolpool.ANY).Get(); err != nil {
		panic(err)
	} else {
		fmt.Printf("%+v\n", data)
	}
}

The error occurs precisely during serialization. Therefore the code below works

func (r *MetaTntRepositoryVShard) getLen2() {
	space := "test_space"
	req := crud.MakeLenRequest(space)
	if data, err := db.Do(req, tarantoolpool.ANY).Get(); err != nil {
		panic(err)
	} else {
		fmt.Printf("%+v\n", data)
	}
}

---

Crud is installed, everything works correctly via tarantoolctl crud.len works.

---

The error seems clear, but I can’t understand why tarantool returns 1 field when asking for length.

---

golang version: 1.21.1
lib: go-tarantool/v2 2.0.0
OS: MacOs
tarantool version: 2.11

[DifferentialOrange]

The error seems clear, but I can’t understand why tarantool returns 1 field when asking for length.

To be honest, it's more weird that every (or almost every) other method returns explicit result, nil in case of success.

[oleg-jukovec]

Thank you for the issue, are you sure that go-tarantool version is exactly v2.0.0? It should be fixed with:
c3ba5b5

Please, write a crud version because I can’t reproduce the problem. It works fine for me:

// ExampleLenRequest demonstrates how to execute a LenRequest.
func ExampleLenRequest() {
	conn := exampleConnect()
	req := crud.MakeLenRequest(exampleSpace)

	ret := crud.LenResult{}
	if err := conn.Do(req).GetTyped(&ret); err != nil {
		fmt.Printf("Failed to execute request: %s", err)
		return
	}

	fmt.Println(ret.Value)
	// Output:
	// 4
}

Please, make sure that go-tarantool version is release and v2.0.0 at least (or you could use v2.1.0 to make sure).

[Vlad97vsv]

I use github.com/tarantool/go-tarantool/v2 v2.0.0-20230823074441-d8df65dcd0f2.

---

Thank you. I'll try to update to 2.1.0 and will be back with feedback

[Vlad97vsv]

With the update to version 2.1.0 the problem disappeared.

Thank you very much for the quick response