Skip to content

java.lang.OutOfMemoryError error occurs when StringScanner keeps storing << and scan results in an array. (JRuby only, not CRuby) #83

@naitoh

Description

@naitoh

java.lang.OutOfMemoryError error occurs when StringScanner keeps storing << and scan results in an array.
(JRuby only, not CRuby)

No Problem Code

  • string_scanner_scan_string.rb
require 'strscan'

s = StringScanner.new('')

N = 100000

a = []
N.times do
  s.string = s.rest + "1234567890"
  a << s.scan(/.*/)
end
$ ruby string_scanner_scan_string.rb 
$

Problem Code

  • string_scanner_scan.rb
require 'strscan'

s = StringScanner.new('')

N = 100000

a = []
N.times do
  s << "1234567890"
  a << s.scan(/.*/)
end
$ ruby string_scanner_scan.rb 
Error: Your application used more memory than the automatic cap of 3758MB.
Specify -J-Xmx####M to increase it (#### = cap size in MB).
Specify -w for full java.lang.OutOfMemoryError: Java heap space stack trace

Estimated memory requirements

100,000 x 10 [Byte] = 1,000,000 [Byte] = 1 [MB]

The above is required for Array and StringScanner.

1 [MB] x 2 = 2 [MB]

3758MB is not needed, so a memory leak is likely to occur.

Environment

$ ruby -v
jruby 9.4.5.0 (3.1.4) 2023-11-02 1abae2700f Java HotSpot(TM) 64-Bit Server VM 25.121-b13 on 1.8.0_121-b13 +jit [x86_64-darwin]
$ gem list strscan

*** LOCAL GEMS ***

strscan (3.0.8 java, default: 3.0.7 java)

Metadata

Metadata

Assignees

No one assigned

    Labels

    No labels
    No labels

    Type

    No type

    Projects

    No projects

    Milestone

    No milestone

    Relationships

    None yet

    Development

    No branches or pull requests

    Issue actions