Re: Garbage collection does not mean releasing memory

[Mark Hamburg <mhamburg.ml@...>]

As I understand it, erasing never causes a structure to get smaller. I forget which operations will cause a structure to compact.

Mark

> On Jun 4, 2015, at 12:56 PM, Dirk Laurie <dirk.laurie@gmail.com> wrote:
> 
> If you create a sequence with length 2^n, erase all the elements
> except those with keys 1,2,4,8,16,...,2^n, and call collectgarbage(),
> Lua does not release the memory.
> 
> n=20; t={}; for k=1,2^n do t[k]=k end
> for k=1,#t do if math.log(k,2)%1 ~=0 then t[k]=nil end end
> print("memory in use before 'collectgarbage()': "..(collectgarbage"count"))
> collectgarbage()
> print("memory in use after 'collectgarbage()': "..(collectgarbage"count"))
> 
> Output:
> 
> memory in use before 'collectgarbage()': 16409.73828125
> memory in use after 'collectgarbage()': 16406.772460938
> 
> There's probably some subtlety I don't understand.
>