How the Garbage Collector Works in Java, Python, and Go!

Animation tools: Adobe Illustrator and After Effects.

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[jacob_s]

Small tip for anyone. For languages that use GC, if you're dealing with variables that hold arbitrary sized or external data (such as reading from a file, database, or user input), once you're done working with that data, null out the variable that points to it. If it's contained with a struct/object you're still using, just null out the member alone. It can help that memory be reclaimed faster, and helps to prevent situations where closures might keep the data accessible longer than you intended.
It's not strictly speaking necessary obviously, but I think it's a good habit to get into.

ex.
let fileData = readFile(filename.txt);
// work with the file data here
fileData = null;

[ugib]

This was a really cool look at garbage collection. I am purely a hobbyist at this point, but was still curious what was going on under the hood. Thanks for the informative and to the point video.

[ClearerThanMud]

Among the disadvantages of garbage collection:
1. Poorer latency, especially maximum latency.
2. More memory required for the same work; the heap needs space to copy into.
3. Generally lower performance (because marking and sweeping take time and cause MMU page faults).
4. Large runtime required.
5. Need to tune GC for good performance.
6. Delay in deallocation-triggered tasks, which happen when the GC discovers that memory is no longer in use.
For some types of applications, these are tolerable; for others, e.g. small embedded systems, they are a deal-killer.

[aethermass]

Great!! Now do memory in Rust, C++. The other side.

[gus]

One of the more helpful explanations in this series! Thanks 😎✌️

[IAMGregEVA]

Very appropriate - basic but essential topic that so many know nothing about. Thank you!

[abubakaramasa]

Prepping for an interview at the moment from a pdf just studied this few hours ago…and just popped on my YouTube suggestion, crazy

[Hellbending]

Some feedback Sir,

Regarding color choices when it comes to the infographics & they ‘key’ colours; specifically the delineation between each one of them.
The colours are quite close and I (and perhaps others?) find it difficult to scan your diagrams and differentiate between one aspect and the other- take for instance 4:38 ‘s diagram and the green hues used as an example.

I’d like to see (where possible given the color palette & styles you use) a larger difference in the colours as it makes comparing my understanding to your diagrams and explanations a lot clearer and easier.

Thank you for working on these brother 💙💪

[matthiasvanderhallen]

With regards to generational garbage collection, this citation from Wikipedia may be crucial to see how generational GC can be both sound (no objects are unjustly removed) and more performant (by not scanning the entire heap) in a tracing based GC (iso. e.g. ref counting):

"Furthermore, the runtime system maintains knowledge of when references cross generations by observing the creation and overwriting of references. When the garbage collector runs, it may be able to use this knowledge to prove that some objects in the initial white set are unreachable without having to traverse the entire reference tree. If the generational hypothesis holds, this results in much faster collection cycles while still reclaiming most unreachable objects."

This is necessary bookkeeping, because if you simply start from the GC roots but only recurse over objects in the young generation, objects may be marked for deletion incorrectly because they are only reachable from a GC root by recursing and expanding an object in an older generation (thus, requiring *every* older object to be returned on)

[pumpkinnnzoey]

Really cool video! Anyone know how they did these animations?

[Zmey]

The video helped me understand the difference in garbage collection approaches between Java, Python and Go. Very informative!

[basarat]

Why not add JS to the list?

Not popular enough or some other reason 😂

[Youkakun]

From this video i got the impression GC is just bad because of the overhead. RAII in C++ or Rust also frees memory in a comfortable way.
Isn't there an advantage like VMs allocate & free much memory at once which is better for the hardware & OS?

[ronpdf]

canal incrivel! agora com audio em portugues ficou melhor ainda.

[junyuan]

i'm calling boomers 'metaspace' from this point on

[saiskanda]

I was little annoyed by the white, grey, black but atleast the roles are reversed compared to say a whitelist and black list.

We really should be replacing all of these terms in technology.

[jamesT]

Why i love to watch ByteByteGo...precise to the topic, quality content and beautiful presentation no bla bla time waste❤

[tylercone]

Such an underated topic; fantastic work as always @ByteByteGo