# How to GC a SharedArray

**URL:** https://discourse.julialang.org/t/how-to-gc-a-sharedarray/48699
**Category:** General Usage
**Tags:** distributed, sharedarrays
**Created:** [October 20, 2020, 7:24pm UTC](https://discourse.julialang.org/t/how-to-gc-a-sharedarray/48699 "2020-10-20T19:24:03Z")
**Posts on this page:** 1
**Showing post:** 6

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### Author: ![dridz](https://avatars.discourse-cdn.com/v4/letter/d/e47774/32.png) [@dridz](https://discourse.julialang.org/u/dridz)
#### Post date: [October 27, 2020, 3:56pm UTC](https://discourse.julialang.org/t/how-to-gc-a-sharedarray/48699/6 "2020-10-27T15:56:56Z")

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Hi,  
I think I am facing a similar issue. Here is another MWE:

```julia
using Distributed, SharedArrays

function parallel_compute()
    shared_array = SharedArray{Float64,1}(100_000)
    @sync @distributed for i in 1:100_000
        shared_array[i] = randn()
    end
    return sum(shared_array)
end

addprocs(4)

for t = 1:10
    x = parallel_compute()
    println(Sys.free_memory()/2^20)
end

rmprocs(workers())

```

when I run this code, the amount of free RAM available (printed in MiB in the main loop) keeps decreasing:

```julia
493.28515625
492.31640625
491.46875
478.390625
477.6640625
476.81640625
463.73828125
463.01171875
462.52734375
461.55859375

```

If I push it further (with more iterations and a more complex `parallel_compute` function), my code breaks because of memory shortage. I would also expect that the GC would help getting some free space after `parallel_compute` is called but it seems that it doesn’t. I tried `sharred_array = nothing; GC.gc()` at the end of `parallel_compute` but it didn’t help. Is this the expected behavior ? Am I missing something ?

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