I've been working on upgrading rspec tests in a Rails 6.0.4 application using activerecord-oracle_enhanced-adapter v6.0.6. This update demonstrates a bug we encountered and a potential fix. The bug RuntimeError: executing in another thread occurs for us after the following:
configuring rspec to use rails System tests
setting config.use_transactional_fixtures = true
running a system spec configured with js: true that contains ajax requests and many interactions with the database
The error seems to be a race condition and is difficult to reproduce consistently. After tracing through the code, I think it is related to a feature added in Rails 5.1 to support transactions in system tests: https://github.com/rails/rails/pull/28083
It seems that some methods in the oracle adapter are not synchronized. For our project, the errors traced back to the OracleEnhanced::Connection#describe method in connection.rb. I was able to fix the error with calls to @lock.synchronize around any method using describe. Those changes are included in this commit.
I'm not deeply familiar with this adapter or ruby threads so this is more of a quick patch and proof-of-concept. I included a test case that usually reproduces the error without the fix. Hopefully someone more familiar with these codebases could take a look.
I've been working on upgrading rspec tests in a Rails 6.0.4 application using activerecord-oracle_enhanced-adapter v6.0.6. This update demonstrates a bug we encountered and a potential fix. The bug
RuntimeError: executing in another threadoccurs for us after the following:config.use_transactional_fixtures = truejs: truethat contains ajax requests and many interactions with the databaseThe error seems to be a race condition and is difficult to reproduce consistently. After tracing through the code, I think it is related to a feature added in Rails 5.1 to support transactions in system tests: https://github.com/rails/rails/pull/28083
The update made all threads share the same database connection in tests. It uses Monitor and
synchronizeto avoid simultaneous requests from different threads. For example, anything using thelogmethod is wrapped with a call to synchronize: https://github.com/rails/rails/blob/v7.0.2.3/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb#L765It seems that some methods in the oracle adapter are not synchronized. For our project, the errors traced back to the
OracleEnhanced::Connection#describemethod in connection.rb. I was able to fix the error with calls to@lock.synchronizearound any method using describe. Those changes are included in this commit.I'm not deeply familiar with this adapter or ruby threads so this is more of a quick patch and proof-of-concept. I included a test case that usually reproduces the error without the fix. Hopefully someone more familiar with these codebases could take a look.
Thanks!