Golang

2217 readers

1 users here now

This is a community dedicated to the go programming language.

Useful Links:

Rules:

Posts must be relevant to Go
No NSFW content
No hate speech, bigotry, etc
Try to keep discussions on topic
No spam of tools/companies/advertisements
It’s OK to post your own stuff part of the time, but the primary use of the community should not be self-promotion.

founded 1 year ago

MODERATORS

Ategon

RandomDevOpsDude

austin

Comparing memory usage between node.js object and go map[string]interface{} (self.golang)

submitted 1 month ago by bia to c/golang

4 comments fedilink hide all child comments

I'm fairly new to go and I've recently migrated a in-memory cache from node to go for concurrency improvements, but the memory usage difference between the two are huge. I've tried to read up on the map memory model in go but haven't been able to find a reason for the difference. I can't see that I'm doing anything special, so I'm looking for guidance here.

The documents that are stored are around 8 KB in size as a JSON file. In node the memory usage for 50000 documents stored as objects is 1,5 GB, and for go maps it is 10 GB.

To me, this doesn't seem reasonable but I can't find the source of the difference. Could anyone here give their take on this?

you are viewing a single comment's thread
view the rest of the comments

[–] nemith 6 points 1 month ago (1 children)

How are you measuring memory storage size? Are you sure you are looking as resident memory size and not just the virtual memory size?

Actual storage of the structures should be nothing. Interfaces are "fat pointers" but that should really just be an extra word which node would have at least that if not more.

My guess is that if you are looking at virtual memory that more memory/garbage is produced in PARSING and not storing and that the virtual memory size allocated is high even after garbage collection but RSS should be different.

[–] bia 1 points 1 month ago

I'm looking at the memory reported by metrics-server in EKS, as that what I base the container resource scaling on. Maybe the go process is reporting memory in a way that doesn't represent the "actual" usage. But I'm not sure it matters here, unless I can get it to change the reported memory usage.

Please see the heap dump I added for 10000 devices. Reported memory is 1,1 GB.