# Is there a package to list memory consumption of selected data objects?

**URL:** https://discourse.julialang.org/t/is-there-a-package-to-list-memory-consumption-of-selected-data-objects/85019
**Category:** General Usage
**Tags:** memory
**Created:** [July 30, 2022, 2:54am UTC](https://discourse.julialang.org/t/is-there-a-package-to-list-memory-consumption-of-selected-data-objects/85019 "2022-07-30T02:54:30Z")
**Posts on this page:** 1
**Showing post:** 16

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### Author: ![Benny](https://avatars.discourse-cdn.com/v4/letter/b/49beb7/32.png) [@Benny](https://discourse.julialang.org/u/Benny)
#### Post date: [August 2, 2022, 6:16am UTC](https://discourse.julialang.org/t/is-there-a-package-to-list-memory-consumption-of-selected-data-objects/85019/16 "2022-08-02T06:16:27Z")

</div>

I couldn’t find out how to measure dictionary memory, and I wasn’t comfortable with large heterogeneous tuples that can store its elements in various ways, so I went with a simpler `Vector{Any}` as the container.

It appears that `Base.summarysize` doesn’t actually report all the memory used by a `Vector{Any}`. I know there should be boxes containing element type information, but it only seems to count the elements and the vector’s pointers to them. Also, if you allocate a `v = collect(1:100000)` then `empty!(v)`, the underlying buffer does not shrink if I recall correctly, but `sizeof` and `summarysize` reports a reduction to minimal memory. So `summarysize` might actually be unsuitable for measuring allocated heap memory; maybe we could say it measures the portion of allocated memory that represents accessible data?

Still, this might make it easier to remove the overhead of the `Vector{Any}` containing the `@locals` instances. Bear in mind the following only worked on a few small examples, I have not rigorously tested this and do not know how.

```julia
julia> function valuessize(v::Vector{Any})
           (Base.summarysize(v) # doesn't seem to count boxes
           - Base.summarysize(Any[]) # Vector overhead
           - sizeof(Int)*length(v) ) # element pointers
       end
valuessize (generic function with 1 method)

julia> function valuessize(d::Dict{Symbol, Any})
           valuessize(collect(values(d)))
       end
valuessize (generic function with 2 methods)

julia> x = Dict{Symbol, Any}(:x => 1, :y => 2.3, :z => [3])
Dict{Symbol, Any} with 3 entries:
  :y => 2.3
  :z => [3]
  :x => 1

julia> valuessize(x)
64

julia> sum(Base.summarysize.(values(x))) # elements don't share data
64

julia> Base.summarysize(collect(values(x))) # plus Vector{Any} overhead
128

julia> Base.summarysize(values(x)) # plus values/Dict{Symbol,Any} overhead
528

```

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