如何在Perl中查找哈希占用的物理内存量？ [英] How to find the amount of physical memory occupied by a hash in Perl?

问题描述

我有一个Perl脚本，使用哈希表维护一个非常简单的缓存。我想在哈希占用超过n个字节时清除哈希值，以避免Perl（32位）耗尽内存并导致崩溃。

我可以检查键值对的数量：

 <$ c （标量键％cache> $ maxSize）
 {
％cache =（）; 
} 
  

但是有可能检查哈希占用的实际内存吗？

解决方案

Devel :: Size 是你的问题的答案。 （请注意，Devel :: Size将在处理大型数据结构时临时分配大量内存，因此它不适合用于此目的。）

然而， Cache :: SizeAwareMemoryCache 和 Tie :: Cache 已经实现了你正在寻找的东西（具有不同的接口），并且可以帮你避免重新发明轮子。 >

记事是一个模块，缓存函数的返回值。它没有实现基于大小的缓存限制，但应该可以使用Tie :: Cache作为Memoize的后端。

I have a Perl script where I maintain a very simple cache using a hash table. I would like to clear the hash once it occupies more than n bytes, to avoid Perl (32-bit) running out of memory and crashing.

I can do a check on the number of keys-value pairs:

if (scalar keys %cache > $maxSize)
 {
 %cache = ();
 }

But is it possible to check the actual memory occupied by the hash?

解决方案

Devel::Size is the answer to your question. (Note that Devel::Size will temporarily allocate a significant amount of memory when processing a large data structure, so it's not really well suited to this purpose.)

However, Cache::SizeAwareMemoryCache and Tie::Cache already implement what you're looking for (with somewhat different interfaces), and could save you from reinventing the wheel.

Memoize is a module that makes it simple to cache the return value from a function. It doesn't implement a size-based cache limit, but it should be possible to use Tie::Cache as a backend for Memoize.

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