From: "Eregon (Benoit Daloze) via ruby-core" <ruby-core@...>
Date: 2023-01-13T16:34:05+00:00
Subject: [ruby-core:111804] [Ruby master Bug#19334] Defining many instance variables and accessing them is slow in Ruby 3.2.0

Issue #19334 has been updated by Eregon (Benoit Daloze).


Is there real code doing this?
Otherwise IMHO it's complexity and significant footprint increase to solve an irrelevant issue (misuse of instance variables).

----------------------------------------
Bug #19334: Defining many instance variables and accessing them is slow in Ruby 3.2.0
https://bugs.ruby-lang.org/issues/19334#change-101215

* Author: mame (Yusuke Endoh)
* Status: Open
* Priority: Normal
* Assignee: tenderlovemaking (Aaron Patterson)
* Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN
----------------------------------------
```
class C
  eval("def initialize; #{ (0..100000).map { "@x#{ _1 } = 0; " }.join } end")
  attr_reader :x50000
end
p :start
C.new.x50000
```

This script takes less than one second in Ruby 3.1.3, and does more than ten second in Ruby 3.2.0.

```
$ time ruby -v test.rb
ruby 3.1.3p185 (2022-11-24 revision 1a6b16756e) [x86_64-linux]
:start

real    0m0.210s
user    0m0.167s
sys     0m0.044s
```

```
$ time ruby -v test.rb
ruby 3.2.0 (2022-12-25 revision a528908271) [x86_64-linux]
:start

real    0m11.026s
user    0m10.950s
sys     0m0.040s
```

This problem is not critical, but is there any room for improvement?



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