嵌套数组结构的指针或无指针之间的混淆

Question

I have read some of the stack overflow question related to "why pointer and why not pointer", but I could not understand much.

So, want to understand based on my example below

I have a list of users and I am finding a hard time to understand which approach is better and faster for the purpose of nesting array struct of users inside another struct.

For an example -

type loc struct {
    Type string
    Point []float64
}

type User struct {
    ID string
    Name string
    Location loc
    ... // 30 more fields
}

Case A - Using pointer for nested array struct

type Games struct {
    ID string
    Owner []*User
    Player []*User
}

// and storing it as

G:= Games{
    ID: "1",
    Owner: []*User{
        &User {
            ID: "2",
            Name: "User A",
        },
    },
}

Case B - Should I use above approach or below approach to

type Games struct {
    ID string
    Owner []User
    Player []User
}

// storing it as

G := Games {
    ID: "1",
    Owner: []User{
        {
            ID: "2",
            Name: "User A",
        },
    },
}

Considering the situation, I do not have to change data for Owner or Player after creating value for Games above and Player can sometimes remain Nil, should I use only User or it's better to use *User

I have following confusion based on above 2 cases

• Performance - which one is better & why?
• Garbage Collection - which one is better & why?
• Any Memory effects?
• Any other effects!

Please help me out understanding based on the above example, which method would you have chosen above and why?

Answer 1

use option B

but if you want avoid allocation during iterations or change the content, you need to do it like this:

 for i:=range G.Games{
       G.Games[i]....
 }

this way a copy will be created in every iteration

for _,game:=range G.Games{
      game....
 }

this looks like premature optimization. write in the most simple/readable way and if is not fast enough, take a look at this in order to find the bottleneck