This example demonstrates the issues:
We re-init some graph that uses a few gigabytes of heap on initialization. Old data never used after re-initialization (there are no any links) but memory consumption increases anyway.
Each iteration leads to heap_sys/heap_idle increasing and finally to 137 exit code (out of memory).
I reproduced this issue on mac os host machine (Catalina 10.15.7) and Ubuntu 18.04 (5.4.0-51-generic and 5.5.0-050500-generic)
Make sure you have go version >= v1.13 set as default (or edit Makefile) and Docker installed on your system.
$ make build
$ make run
You will see something like this:
$ make build
go version go1.15.1 darwin/amd64
CGOENABLED=0 GOOS=linux GOARCH=amd64 go build ./main.go
docker build --memory 10Gb --memory-swap 10Gb -t mem_leak_issue_example .
Sending build context to Docker daemon 53.38MB
Step 1/4 : FROM ubuntu:latest
---> 775349758637
Step 2/4 : COPY ./main .
---> f2df7c102986
Step 3/4 : COPY ./edges.json .
---> d21215b8d8de
Step 4/4 : CMD ["/main"]
---> Running in a1765ec8a72c
Removing intermediate container a1765ec8a72c
---> 550ae674af6d
Successfully built 550ae674af6d
Successfully tagged mem_leak_issue_example:latest
$ make run
docker run -i -t --rm --memory 10Gb --memory-swap 10Gb --name="mem_leak_issue_example" mem_leak_issue_example
=> JSON parsed! 13695 edges found (data size: 1 Mb)
---
Alloc = 4 MiB TotalAlloc = 5 MiB StackInuse = 0 MiB StackSys = 0 MiB Sys = 69 MiB
HeapInuse = 4 MiB HeapSys = 63 MiB HeapIdle = 59 MiB HeapReleased = 58 MiB NumGC = 1
---
=> loading graph: 1 time
=> main dijkstra graph created!
=> all shortest created!
---
Alloc = 3110 MiB TotalAlloc = 3116 MiB StackInuse = 0 MiB StackSys = 0 MiB Sys = 3266 MiB
HeapInuse = 3113 MiB HeapSys = 3135 MiB HeapIdle = 22 MiB HeapReleased = 22 MiB NumGC = 5
---
---
Alloc = 3110 MiB TotalAlloc = 3116 MiB StackInuse = 0 MiB StackSys = 0 MiB Sys = 3266 MiB
HeapInuse = 3113 MiB HeapSys = 3135 MiB HeapIdle = 22 MiB HeapReleased = 22 MiB NumGC = 5
---
=> time spent for #1 iteration: 13.849821349s
=> loading graph: 2 time
=> main dijkstra graph created!
=> all shortest created!
---
Alloc = 5286 MiB TotalAlloc = 6228 MiB StackInuse = 0 MiB StackSys = 0 MiB Sys = 5525 MiB
HeapInuse = 5289 MiB HeapSys = 5311 MiB HeapIdle = 22 MiB HeapReleased = 22 MiB NumGC = 6
---
---
Alloc = 5286 MiB TotalAlloc = 6228 MiB StackInuse = 0 MiB StackSys = 0 MiB Sys = 5525 MiB
HeapInuse = 5289 MiB HeapSys = 5311 MiB HeapIdle = 22 MiB HeapReleased = 22 MiB NumGC = 6
---
=> time spent for #2 iteration: 15.055379515s
=> loading graph: 3 time
=> main dijkstra graph created!
=> all shortest created!
---
Alloc = 8398 MiB TotalAlloc = 9339 MiB StackInuse = 0 MiB StackSys = 0 MiB Sys = 8788 MiB
HeapInuse = 8402 MiB HeapSys = 8447 MiB HeapIdle = 44 MiB HeapReleased = 44 MiB NumGC = 6
---
---
Alloc = 8398 MiB TotalAlloc = 9339 MiB StackInuse = 0 MiB StackSys = 0 MiB Sys = 8788 MiB
HeapInuse = 8402 MiB HeapSys = 8447 MiB HeapIdle = 44 MiB HeapReleased = 44 MiB NumGC = 6
---
=> time spent for #3 iteration: 25.699820995s
=> loading graph: 4 time
=> main dijkstra graph created!
=> all shortest created!
---
Alloc = 7539 MiB TotalAlloc = 12451 MiB StackInuse = 0 MiB StackSys = 0 MiB Sys = 9398 MiB
HeapInuse = 7543 MiB HeapSys = 9023 MiB HeapIdle = 1480 MiB HeapReleased = 93 MiB NumGC = 7
---
---
Alloc = 7539 MiB TotalAlloc = 12451 MiB StackInuse = 0 MiB StackSys = 0 MiB Sys = 9398 MiB
HeapInuse = 7543 MiB HeapSys = 9023 MiB HeapIdle = 1480 MiB HeapReleased = 93 MiB NumGC = 7
---
=> time spent for #4 iteration: 14.367221161s
=> loading graph: 5 time
=> main dijkstra graph created!
make: *** [run] Error 137
Container is terminated by OOM killer.