From: jean.boussier@... Date: 2020-01-23T11:49:47+00:00 Subject: [ruby-core:96979] [Ruby master Feature#16557] Deduplicate Regexp literals Issue #16557 has been reported by byroot (Jean Boussier). ---------------------------------------- Feature #16557: Deduplicate Regexp literals https://bugs.ruby-lang.org/issues/16557 * Author: byroot (Jean Boussier) * Status: Open * Priority: Normal * Assignee: * Target version: ---------------------------------------- Pull Request: https://github.com/ruby/ruby/pull/2859 ### Context Real world application contain many duplicated Regexp literals. From a rails/console in Redmine: ``` >> ObjectSpace.each_object(Regexp).count => 6828 >> ObjectSpace.each_object(Regexp).uniq.count => 4162 >> ObjectSpace.each_object(Regexp).to_a.map { |r| ObjectSpace.memsize_of(r) }.sum => 4611957 # 4.4 MB total >> ObjectSpace.each_object(Regexp).to_a.map { |r| ObjectSpace.memsize_of(r) }.sum - ObjectSpace.each_object(Regexp).to_a.uniq.map { |r| ObjectSpace.memsize_of(r) }.sum => 1490601 # 1.42 MB could be saved ``` Here's the to 10 duplicated regexps in Redmine: ``` 147: /"/ 107: /\s+/ 103: // 89: /\n/ 83: /'/ 76: /\s+/m 37: /\d+/ 35: /\[/ 33: /./ 33: /\\./ ``` Any empty Rails application will have a similar amount of regexps. ### The feature Since https://bugs.ruby-lang.org/issues/16377 made literal regexps frozen, it is possible to deduplicate literal regexps without changing any semantic and save a decent amount of resident memory. ### The patch I tried implementing this feature in a way very similar to the `frozen_strings` table, it's functional but I'm having trouble with a segfault on Linux: https://github.com/ruby/ruby/pull/2859 -- https://bugs.ruby-lang.org/ Unsubscribe: