Gem :: load error while migrating from MySQL to MongoDB - mysql

Question

I am trying to migrate the Mysql DB to MongoDB using tool Mongify by referring the
documentation :
i have seen , there are few posts already present regarding such migration but they mentioned issues with rails application and some dependencies on rails. however, in my case , it is just simple migration without rails.
Environment details:
windows enterprise 7
Mysql community server : 5.7
Mongo db server : 4.0
ruby : ruby 2.5.1p57 (2018-03-29 revision 63029) [i386-mingw32]
Mysql c Connector (32 bit)
mysql server and mongo db server are working fine as a service.
rubygems environment details as follows :
RubyGems Environment:
- RUBYGEMS VERSION: 2.7.6
- RUBY VERSION: 2.5.1 (2018-03-29 patchlevel 57) [i386-mingw32]
- INSTALLATION DIRECTORY: C:/Ruby25/lib/ruby/gems/2.5.0
- USER INSTALLATION DIRECTORY: C:/Users/irfan.sayed/.gem/ruby/2.5.0
- RUBY EXECUTABLE: C:/Ruby25/bin/ruby.exe
- EXECUTABLE DIRECTORY: C:/Ruby25/bin
- SPEC CACHE DIRECTORY: C:/Users/irfan.sayed/.gem/specs
- SYSTEM CONFIGURATION DIRECTORY: C:/ProgramData
- RUBYGEMS PLATFORMS:
- ruby
- x86-mingw32
- GEM PATHS:
- C:/Ruby25/lib/ruby/gems/2.5.0
- C:/Users/irfan.sayed/.gem/ruby/2.5.0
- GEM CONFIGURATION:
- :update_sources => true
- :verbose => true
- :backtrace => false
- :bulk_threshold => 1000
- REMOTE SOURCES:
- https://rubygems.org/
- SHELL PATH:
- C:\windows\system32
- C:\windows
- C:\windows\System32\Wbem
- C:\Program Files (x86)\Microsoft Application Virtualization Client
- C:\Program Files\PuTTY\
- C:\apache-maven-3.5.2-bin\apache-maven-3.5.2\bin
- "C:\Program Files\Java\jdk1.8.0_151\bin"
- C:\Program Files\Git\cmd
- C:\HashiCorp\Vagrant\bin
- C:\windows\System32\WindowsPowerShell\v1.0\
- C:\windows\System32\WindowsPowerShell\v1.0\
- C:\Ruby25\bin
- C:\Program Files\MySQL\MySQL Server 8.0\bin
- C:\Program Files\MongoDB\Server\4.0\bin
locally installed Gems are as follows :
activemodel (5.2.1, 4.2.10)
activerecord (5.2.1, 4.2.10)
activerecord-mysql2-adapter (0.0.3)
activesupport (5.2.1, 4.2.10)
arel (9.0.0, 6.0.4)
awesome_print (1.8.0)
backports (3.11.3)
bigdecimal (default: 1.3.4)
bson (1.12.5)
bson_ext (1.12.5)
builder (3.2.3)
bundler (1.16.3)
byebug (10.0.2)
cmath (default: 1.0.0)
coderay (1.1.2)
concurrent-ruby (1.0.5)
coolline (0.5.0)
csv (default: 1.0.0)
cucumber (3.1.2)
cucumber-core (3.2.0)
cucumber-expressions (6.0.1)
cucumber-tag_expressions (1.1.1)
cucumber-wire (0.0.1)
date (default: 1.0.0)
dbm (default: 1.0.0)
did_you_mean (1.2.0)
diff-lcs (1.3)
etc (default: 1.0.0)
fcntl (default: 1.0.0)
fiddle (default: 1.0.0)
fileutils (default: 1.0.2)
gdbm (default: 2.0.0)
gherkin (5.1.0)
highline (1.7.8)
i18n (0.9.5, 0.7.0)
io-console (default: 0.4.6)
ipaddr (default: 1.2.0)
jazz_fingers (5.0.0)
json (default: 2.1.0)
metaclass (0.0.4)
method_source (0.9.0)
minitest (5.11.3, 5.10.3)
mocha (1.6.0)
mongify (1.3.2)
mongo (1.12.5)
multi_json (1.13.1)
multi_test (0.1.2)
mysql (2.9.1 x86-mingw32)
mysql2 (0.5.2 x86-mingw32)
net-telnet (0.1.1)
openssl (default: 2.1.0)
pg (1.0.0 x86-mingw32)
power_assert (1.1.1)
pry (0.11.3)
pry-byebug (3.6.0)
pry-coolline (0.2.5)
psych (default: 3.0.2)
rake (12.3.1, 12.3.0, 11.3.0)
rdoc (default: 6.0.1)
rspec (2.99.0)
rspec-collection_matchers (1.1.3)
rspec-core (2.99.2)
rspec-expectations (2.99.2)
rspec-mocks (2.99.4)
scanf (default: 1.0.0)
sdbm (default: 1.0.0)
sqlite3 (1.3.13 x86-mingw32)
stringio (default: 0.0.1)
strscan (default: 1.0.0)
test-unit (3.2.7)
thread_safe (0.3.6)
tzinfo (1.2.5)
unicode_utils (1.4.0)
watchr (0.7)
webrick (default: 1.4.2)
xmlrpc (0.3.0)
yard (0.9.15)
zlib (default: 1.0.0)
bundle install and bundle update commands are just working fine. all the dependencies are gems are resolved properly and available in default folder of ruby.
database.config file used as below :
sql_connection do
adapter "mysql2"
host "localhost"
username "root"
password "<password>"
database "abc"
end
mongodb_connection do
host "localhost"
database "db"
end
however getting following error :
mongify check database.config
Traceback (most recent call last):
10: from C:/Ruby25/bin/mongify:23:in `<main>'
9: from C:/Ruby25/bin/mongify:23:in `load'
8: from C:/Ruby25/lib/ruby/gems/2.5.0/gems/mongify-1.3.2/bin/mongify:17
:in `<top (required)>'
7: from C:/Ruby25/lib/ruby/gems/2.5.0/gems/mongify-1.3.2/lib/mongify/cl
i/application.rb:28:in `execute!'
6: from C:/Ruby25/lib/ruby/gems/2.5.0/gems/mongify-1.3.2/lib/mongify/cl
i/command/worker.rb:68:in `execute'
5: from C:/Ruby25/lib/ruby/gems/2.5.0/gems/mongify-1.3.2/lib/mongify/cl
i/command/worker.rb:99:in `check_sql_connection'
4: from C:/Ruby25/lib/ruby/gems/2.5.0/gems/mongify-1.3.2/lib/mongify/da
tabase/sql_connection.rb:56:in `has_connection?'
3: from C:/Ruby25/lib/ruby/gems/2.5.0/gems/mongify-1.3.2/lib/mongify/da
tabase/sql_connection.rb:40:in `setup_connection_adapter'
2: from C:/Ruby25/lib/ruby/gems/2.5.0/gems/activerecord-4.2.10/lib/acti
ve_record/connection_handling.rb:50:in `establish_connection'
1: from C:/Ruby25/lib/ruby/gems/2.5.0/gems/activerecord-4.2.10/lib/acti
ve_record/connection_adapters/connection_specification.rb:174:in `spec'
C:/Ruby25/lib/ruby/gems/2.5.0/gems/activerecord-4.2.10/lib/active_record/connect
ion_adapters/connection_specification.rb:177:in `rescue in spec': Specified 'mys
ql2' for database adapter, but the gem is not loaded. Add `gem 'mysql2'` to your
Gemfile (and ensure its version is at the minimum required by ActiveRecord). (G
em::LoadError)
not able to understand what is still missing. is the issue with MySQL adapter OR some version compatibility issue
EDIT : further update per suggestion from matthewd
i edited Gemfile and added following line
s.add_development_dependency('mysql2', '~> 0.4.10')
ran the bundle update --force , bundle install --force but it was still installing the 0.5.x version of mysql2 gem only
so i manually installed mysql2 gem of version 0.4.10 using following command
gem install mysql2 -v 0.4.10
but now it is giving following error
11: from C:/Ruby25/lib/ruby/gems/2.5.0/gems/mysql2-0.4.10-x86-mingw32/li
b/mysql2.rb:31:in `<top (required)>'
10: from C:/Ruby25/lib/ruby/gems/2.5.0/gems/activesupport-4.2.10/lib/act
ive_support/dependencies.rb:274:in `require'
9: from C:/Ruby25/lib/ruby/gems/2.5.0/gems/activesupport-4.2.10/lib/act
ive_support/dependencies.rb:240:in `load_dependency'
8: from C:/Ruby25/lib/ruby/gems/2.5.0/gems/activesupport-4.2.10/lib/act
ive_support/dependencies.rb:274:in `block in require'
7: from C:/Ruby25/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59
:in `require'
6: from C:/Ruby25/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59
:in `require'
5: from C:/Ruby25/lib/ruby/gems/2.5.0/gems/mysql2-0.4.10-x86-mingw32/li
b/mysql2/mysql2.rb:2:in `<top (required)>'
4: from C:/Ruby25/lib/ruby/gems/2.5.0/gems/activesupport-4.2.10/lib/act
ive_support/dependencies.rb:274:in `require'
3: from C:/Ruby25/lib/ruby/gems/2.5.0/gems/activesupport-4.2.10/lib/act
ive_support/dependencies.rb:240:in `load_dependency'
2: from C:/Ruby25/lib/ruby/gems/2.5.0/gems/activesupport-4.2.10/lib/act
ive_support/dependencies.rb:274:in `block in require'
1: from C:/Ruby25/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59
:in `require'
C:/Ruby25/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require': Co
uld not load 'active_record/connection_adapters/mysql2_adapter'. Make sure that
the adapter in config/database.yml is valid. If you use an adapter other than 'm
ysql', 'mysql2', 'postgresql' or 'sqlite3' add the necessary adapter gem to the
Gemfile. (LoadError)

Answer 1

The error message is misleading: you're using a version of the mysql2 gem that's too new for Active Record 4.2.10 (the latest version mongify supports).
The simplest solution is to explicitly use an older version of mysql2 by including a version constraint in your Gemfile entry:
gem "mysql2", "< 0.5"

Answer 2

Finally it is resolved. it has the issue with ruby version and 32 bit libraries. ruby 2.3 was properly tested and works fine with mongify gem. i was using latest version of ruby and was the issue.