Patch #28940

Use Regexp#match? to reduce allocations of MatchData object

Added by Pavel Rosický about 3 years ago. Updated about 2 years ago.

Status:ClosedStart date:
Priority:NormalDue date:
Assignee:Go MAEDA% Done:

0%

Category:Performance
Target version:4.1.0

Description

since Rails 5.1+ we can use match? on a regex class safely even on older rubies
https://github.com/rails/rails/blob/5-1-stable/activesupport/lib/active_support/core_ext/regexp.rb

but the performance benefit is visible only on ruby 2.4+
https://bugs.ruby-lang.org/issues/8110

require 'benchmark/ips'
Benchmark.ips do |x|
  x.report('match') { /test\d/.match 'test5'.freeze }
  x.report('match?') { /test\d/.match? 'test5'.freeze }
  x.compare!
end

Comparison:
match?:  4493322.3 i/s
match:    926754.9 i/s - 4.85x  slower

rake test is about 5% faster

match.patch Magnifier (34 KB) Pavel Rosický, 2018-06-04 01:19

match_adapters.patch Magnifier (3.23 KB) Pavel Rosický, 2018-06-04 02:18

match-adapters-v2.diff Magnifier (1.97 KB) Go MAEDA, 2018-06-04 04:53

match-v2.diff Magnifier (13.6 KB) Go MAEDA, 2018-06-04 06:54

match_final.patch Magnifier (27.7 KB) Pavel Rosický, 2018-06-17 18:14

match_final.patch Magnifier - r18001 (28.3 KB) Pavel Rosický, 2019-03-21 23:01

Related issues

Related to Redmine - Patch #28939: replace regexp with casecmp Closed

Associated revisions

Revision 18011
Added by Go MAEDA about 2 years ago

Use Regexp#match? to reduce allocations of MatchData object (#28940).

Patch by Pavel Rosický.

History

#2 Updated by Go MAEDA about 3 years ago

It is a very interesting patch. But MailHandlerTest fails on my environment (Ruby 2.3).

$ ruby test/unit/mail_handler_test.rb
Run options: --seed 1974

# Running:

......................E

Error:
MailHandlerTest#test_truncate_emails_with_a_single_quoted_reply_should_truncate_the_email_at_the_delimiter_with_the_quoted_reply_symbols_(>):
NoMethodError: undefined method `match?' for #<String:0x007f91d84ebe90>
Did you mean?  match
    test/unit/mail_handler_test.rb:1005:in `block (2 levels) in <class:MailHandlerTest>'
    test/test_helper.rb:93:in `with_settings'
    test/unit/mail_handler_test.rb:1001:in `block in <class:MailHandlerTest>'

bin/rails test test/unit/mail_handler_test.rb:1000

........E

Error:
MailHandlerTest#test_truncate_emails_with_multiple_quoted_replies_should_truncate_the_email_at_the_delimiter_with_the_quoted_reply_symbols_(>):
NoMethodError: undefined method `match?' for #<String:0x007f91e3ad4d38>
Did you mean?  match
    test/unit/mail_handler_test.rb:1015:in `block (2 levels) in <class:MailHandlerTest>'
    test/test_helper.rb:93:in `with_settings'
    test/unit/mail_handler_test.rb:1011:in `block in <class:MailHandlerTest>'

bin/rails test test/unit/mail_handler_test.rb:1010

...........................................................

Finished in 21.213978s, 4.2896 runs/s, 20.2697 assertions/s.
91 runs, 430 assertions, 0 failures, 2 errors, 0 skips

The following sentence causes one of the error. Regexp.escape returns a String object. ActiveSupport defines Regexp#match? but does not String#match?.

      assert !Regexp.escape("--- Reply above. Do not remove this line. ---").match?(journal.notes)

#3 Updated by Pavel Rosický about 3 years ago

You're right. I will revert lines with Regexp.escape tomorrow, but otherwise it should work.

#4 Updated by Mizuki ISHIKAWA about 3 years ago

+1
Redmine uses a lot of match methods.
I think it's wonderful that the test will be 5% faster.

#5 Updated by Go MAEDA about 3 years ago

  • Related to Patch #28939: replace regexp with casecmp added

#6 Updated by Go MAEDA about 3 years ago

I have updated match-adapters.patch. The patch does not work due to syntax errors. "ActiveRecord::Base.connection.connection.adapter_name" must be replaced with "ActiveRecord::Base.connection.adapter_name" (one extra ".connection").

#7 Updated by Go MAEDA about 3 years ago

Pavel Rosický wrote:

I will revert lines with Regexp.escape tomorrow,

Done. I am attaching an updated patch.

#8 Updated by Go MAEDA about 3 years ago

  • Target version set to Candidate for next major release

#9 Updated by Go MAEDA about 3 years ago

  • Target version changed from Candidate for next major release to 4.1.0

Setting target version to 4.1.0.

#10 Updated by Pavel Rosický almost 3 years ago

I combined all patches into a single file and I retested it on Ruby 2.3 and Ruby 2.4

#12 Updated by Go MAEDA about 2 years ago

Pavel Rosický wrote:

I combined all patches into a single file and I retested it on Ruby 2.3 and Ruby 2.4

Thank you for updating the patch. I have confirmed that the patch passes all test in r18003.

Regexp#match? is faster than Regexp#match or =~ in most cases because it does not allocate MatchData object. I think there is no reason not to merge this patch.

#13 Updated by Go MAEDA about 2 years ago

  • Subject changed from reduce allocations to Use Regexp#match? to reduce allocations of MatchData object
  • Assignee set to Go MAEDA

Committed the patch. Thank you for posting many performance-tuning patches.

#14 Updated by Go MAEDA about 2 years ago

  • Status changed from New to Closed

Also available in: Atom PDF