Performance Tab does not show memory getting garbage collected

Bug Reports Studio Bugs
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1

Setting the keys of a dictionary table to a part and then setting those keys to nil does not garbage collect or the Performance tab does not update accordingly

The code:
image

The Performance tab in action:

Expected behavior

The PhysicsPart memory category should go back down to the same level as it was, after the parts are destroyed and references are nilled out.

2

Its probably because roblox doesnt really delete parts entirely, just the physical instance

3

I believe you’re still holding a reference to the original BasePart by using it as a table key. If you set the entire ListOfParts to {}, does the memory get correctly GC’ed?

4

You can see at line 17 all the keys within the table are set to nil. I have tried multiple combinations including the one you suggested and still the memory persists in the performance tab.

5

When I check the graph after the following code runs:

local Lighting = game:GetService("Lighting")

task.wait(6)
print("Started")

local ListOfParts = {}

for _ = 1, 250 do
	for _ = 1, 100 do
		local BasePart = Instance.new("Part")
		BasePart.Parent = Lighting
		ListOfParts[BasePart] = {"data", true}
	end
	task.wait()
end

print(`Rem in 5 seconds`)

task.wait(5)

warn(`Removing...`)

Lighting:ClearAllChildren()

for BasePart, Data in ListOfParts do
	ListOfParts[BasePart] = nil
end

--ListOfParts = {}

print(`Done.`)

It looks like this:

image
image1164Ă—254 46.4 KB

It first rises to 50 MBs, before then dropping to 1.7 after 5 seconds. Are you sure you just didn’t wait long enough for the system to figure out it can get rid of the parts?

:Destroy removes a part from memory as long as there are no remaining “references” to it, it’ll also disconnect any script connections to the part, such as .Touched.

EDIT: Hmm, the memory leak seems to only happen if run from the Command Bar in Edit mode. It even persists between Play Tests!

6

Performance tab versus the developer console:

image
image1514Ă—862 126 KB

1 Like
7

Here I run your code. All code is ran on the server in a script, not via the command bar.

image
image1642Ă—376 143 KB

It displays 53MB in the developer console also.

8

Thanks for the report! Forwarding to the team.

1 Like
9

Garbage collection does not necessarily happen immediately. It can happen at arbitrary times in the future. Other studio systems/plugins can hold references to the Parts too.

This is expected behavior, will close this ticket.

1 Like