GC.start在Pry中无效，但在IRB中有效 [英] GC.start has no effect in Pry, but does in IRB

问题描述

我在Pry中玩垃圾收集，并注意到由于某种原因它似乎不起作用.我正在尝试不同的方式将大数组设置为nil等，同时打破了这个问题:为什么我根本无法使用GC.start释放异常内存?"

I was playing with garbage collection in Pry, and noticed that for some reason it doesn't seem to work. I was trying different ways to set my big array as nil, etc, while breaking my head on the question "why in the world I simply cannot deallocate the freaking memory with GC.start?"

然后我去了IRB，突然工作了！我想知道是什么原因引起的，如果您不知道答案却找到了答案，我也想知道如何解决.

Then I went to IRB and suddenly it worked! I'm wondering what could cause this, and if you didn't know the answer but found it, I'd also like to know how.

我的简单代码(我在1.9.3-p327上，请注意，这将消耗1-2个演出):

My simple code (I'm on 1.9.3-p327, and beware, this will eat up 1-2 gigs):

a = []
for i in (1..1000000)
   a[i] = 'x' * 100
end

在这里，我观察到内存增加，然后再观察:

here, I observed the memory increase, and then later:

for i in (1..1000000)
   a[i] = i
end

然后

GC.start

推荐答案

这是因为.因此，您的对象仍会被引用，除非运行了足够的命令将其从Pry的输出历史记录中推出，否则不会对其进行垃圾收集.

This is because Pry stores the output of the last 100 commands by default. As a result, your object is still referenced and will not be garbage collected until enough commands have been run to push it out of Pry’s output history.

您应该能够使用

You should be able to find your object in the current Pry instance’s output history using _out_:

_out_.to_a

您可以通过调用 Pry.memory_size= 在您的~/.pryrc :

You can alter the default number of previous results saved by calling Pry.memory_size= in your ~/.pryrc:

Pry.memory_size = 1

或暂时在正在运行的撬中(也会删除所有现有的历史记录):

or temporarily in a running Pry (will erase all existing history as well):

_pry_.memory_size = 1

我们可以看到它像这样工作:

We can see this working like so:

$ pry
_pry_.memory_size = 100  # default
class C; end

C.new
ObjectSpace.each_object.grep(C).count  #=> 1

GC.start
ObjectSpace.each_object.grep(C).count  #=> 1

$ pry
_pry_.memory_size = 0
class C; end

C.new
ObjectSpace.each_object.grep(C).count  #=> 1

GC.start
ObjectSpace.each_object.grep(C).count  #=> 0

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