Result returned from INSERT is nil

[bradrf]

Upgrading from v1.6.0 to v1.7.0, I'm seeing the following failure when trying to call save! on a bulk worker (using mysql2 v0.4.5 database connector against mysql v5.7.23 server):

D, [2018-10-11T09:17:07.739444 #72035] DEBUG -- : 2018-10-11 09:17:07.734938 D [72035:70195788170560] (0.727ms) ActiveRecord::Base -- SQL -- {:sql=>"INSERT  INTO `recent_files` (`repo_id`,`md5`,`size`,`created_at`,`updated_at`) VALUES (1,'ae3e83e2fab3a7d8683d8eefabd1e74d',3,'2018-10-11 16:17:07','2018-10-11 16:17:07')"}
E, [2018-10-11T09:17:07.740832 #72035] ERROR -- : 2018-10-11 09:17:07.735079 E [72035:70195788170560 bulk_insert_thread.rb:29] BulkInsertThread -- Exception: NoMethodError: undefined method `fields' for nil:NilClass
.../gems/activerecord-4.2.10/lib/active_record/connection_adapters/mysql2_adapter.rb:222:in `exec_query'
.../gems/bulk_insert-1.7.0/lib/bulk_insert/worker.rb:92:in `execute_query'
.../gems/bulk_insert-1.7.0/lib/bulk_insert/worker.rb:82:in `save!'
.../lib/modules/bulk_insert_thread.rb:27:in `block in initialize'

[philister]

+1

[mberlanda]

hey @bradrf @bradrf could you provide a snippet to reproduce the issue?
E.g.

• table creation migration
• buik insert statement

https://github.com/rails/rails/blob/4-2-stable/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb#L220-L223

[rfbezerra]

I have the same issue. Seems to be related to older versions of ActiveRecrod (4.2.10 is mine).

def exec_query(sql, name = 'SQL', binds = [])
  result = execute(sql, name)
  ActiveRecord::Result.new(result.fields, result.to_a)
end

The problem is that, the return of execute method is nil, so when result.fields is accessed throws error
When I have time, Ill investigate if there is a way to return the ids.

Maybe it occurrs because of sql nature, with multiple values in single query

[waynerobinson]

We've just run into this issue when attempting to add this library to our project.

It's rails 4.2.11.3 and mysql2 0.5.3.

[darthwiz]

I have the same issue with activerecord 3.2.22.2 and mysql2 0.3.21 - very old application, sorry.

Taking a hint from the original post I tried to downgrade bulk_insert to commit 4313c04 (1.6.0 with AR 3.2 compatibility) but that didn't solve the problem.

[mberlanda]

hi @darthwiz , is your project open source? As of today AR 3 compatibility should not be broken but there is no regression test. I am reviving this old PR to make sure that I put some regression tests for future contributions #61 (it would be great eventually to have the reference of a sample rails 3 application to add to the test cases)

@rfbezerra @waynerobinson would you able to provide a patch working with your active record version?
I will be happy to address your issue

[mberlanda]

The main difference I can see in this diff v1.6.0...v1.7.0 is calling @connection.exec_query instead of @connection.execute.

If I remember correctly, this was done to support returning primary keys for postgresql connections #32 .

We can eventually restore the previous behaviour under some special conditions: e.g. when AR < 5 and the connection is mysql.
What do you think?

[mberlanda]

In #77 I added some unit tests using mysql adapter.
I could reproduce the issue you were describing with tests allowed to fail:

  1) Error:
BulkInsertWorkerTest#test_explicit_nil_should_override_defaults:
NoMethodError: undefined method `fields' for nil:NilClass
    /home/travis/.rvm/gems/ruby-2.3.8/gems/activerecord-4.2.11.3/lib/active_record/connection_adapters/mysql2_adapter.rb:222:in `exec_query'
    /home/travis/build/jamis/bulk_insert/lib/bulk_insert/worker.rb:96:in `execute_query'
    /home/travis/build/jamis/bulk_insert/lib/bulk_insert/worker.rb:86:in `save!'
    /home/travis/build/jamis/bulk_insert/test/bulk_insert/worker_test.rb:67:in `block in <class:BulkInsertWorkerTest>'

The test is failing both for rails 3 and 4.
I am going to merge this testing pr as it is and fix the issue in a follow up pr

[mberlanda]

This issue was resolved in release 1.9.0.

Please feel free to confirm after the gem update and to re-open the issue if you still face the same problem