[Lua] How good is the garbage collector?

[HerlySQR]

Hello, I ask this question because I wanna know how viable is create a vector "class" with Lua, because taking advantage of the garbage collector will make easier do geometry.
I read threads about this but I didn't get a clear answer.
I know there exists [Lua] - Leak Preventer, but tables are easier to work than the locations, or maybe I can do something similar to this like "recycling tables", what can you tell me?
Edit: I discovered [Lua] - Lua wGeometry, but I have other plans.

 

[Wrda]

I believe that the fundamental core of the garbage collector is that once all references (non-local variables, in most cases) to an object (table) are nil, the object will be recycled.
However, there are moments that if you create objects at a constantly, let's say at a periodic timer of 0.03, then the garbage collector won't clean those because you're not letting it a room to breathe. Take this statement with a grain of salt.

[Lua] Process memory leaking at high GC pressure

Disclaimer: This is not something you would ever encounter under normal circumstances. TLDR: At very high GC pressure processes' memory will grow. If the GC catches up, the memory will not be released to OS. I'm currently attempting to debug a memory leak in a big trigger-heavy map I'm porting...

www.hiveworkshop.com

[lua] garbage collection issues

Hello guys, With the advent of lua I thought things would become easier, as destruction of tables was no longer required. However, while playing with it I found that things a bit less so... I've been trying to make sense of the garbage collection system, but am really having trouble to do so...

www.hiveworkshop.com

 

[HerlySQR]

After reading I have understood that the garbage collector runs after time, but when you create objects too fast will never be recycled or just is not that fast and if you stop they eventually will be collected, or I'm wrong?

 

[Wrda]

Too fast and constant = never recycled.
That's what I mainly understand from it.

 

[HerlySQR]

But, I also have understood that local values are always collected, or if I overwrite the previous local value, right?

 

[Wrda]

Yes, overwriting the previous value isn't a leak.

But, I also have understood that local values are always collected

Depends.

do
    local somevalue = "ba"

    function somefunc()
        print(somevalue)
    end
   
    function Test()
        local Testtrig = CreateTrigger()
        TriggerRegisterTimerEventPeriodic(Testtrig, 0.01)
        TriggerAddAction(Testtrig, function()
            local t = {}
            for i = 0, 1000 do t[i] = {} end
        end)
    end
end

The variable somevalue will never be collected, because there's still a location where it is used.
Test function generates 1000 tables very fast non-stop, the garbage collector won't catch up to collect them even if they're local.
Also, if an object is referenced in more than 1 variable, simplying nilling 1 of them doesn't collect the object, it's just removing a reference.
Lastly, there's also other things at hand like weak keys and values, but that I barely know.

 

[HerlySQR]

the garbage collector catch up to collect them even if they're local.

Wait, yes or no?

 

[Wrda]

Wait, yes or no?

Eh, I missed a a word "won't" there. This is one of the instances when what I write doesn't match what I'm thinking.