I'm using Two databases in my project using default rails 6 support.
database.yml:-
default: &default
adapter: postgresql
migrations_paths: "db/migrate/primary"
encoding: unicode
min_messages: warning
username: ########
password: ########
pool: 5
timeout: 5000
host_name: localhost
development:
primary:
<<: *default
database: primary_db
hrm:
<<: *default
database: hrm_db
migrations_paths: "db/migrate/hrm"
Model'l of Secondary database are like:
class HRM::ServiceHistory < ApplicationRecord
connects_to database: { writing: :hrm, reading: :hrm }
belongs_to :employee
belongs_to :designation
.
.
Migration file:-
class ModifyDesigs < ActiveRecord::Migration[6.0]
def change
add_column :service_histories, :basic_scale, :integer
remove_column :employees, :designation_id
add_column :employees, :current_position_id, :integer
HRM::ServiceHistory.reset_column_information
HRM::Employee.reset_column_information
puts "\n\n=================== #{HRM::Employee.first.name} \n\n"
HRM::Employee.all.each do |emp|
emp.service_histories.each do |sh|
des = sh.designation
sh.basic_scale = des.basic_scale
sh.save!
end
sh = emp.service_histories.order('appointment_date desc').limit(1).first
if sh
emp.current_position = sh
emp.save!
end
end
end
end
All normal DDL statements are running file, even HRM::Employee.first.name doesn't raise error but further statements raise errors:
== 20200409162158 ModifyDesigs: migrating =====================================
-- add_column(:service_histories, :basic_scale, :integer) -> 0.0041s
-- add_column(:service_histories, :scale, :integer) -> 0.0005s
-- add_column(:service_histories, :scale_type, :string, {:limit=>1}) -> 0.0005s
-- remove_column(:employees, :designation_id) -> 0.0050s
-- add_column(:employees, :current_position_id, :integer) -> 0.0004s
-- add_index(:employees, :current_position_id) -> 0.0114s
-- add_foreign_key(:employees, :service_histories, {:column=>:current_position_id}) -> 0.0044s
=================== Employee Name
rails aborted!
ActiveRecord::StatementInvalid: PG::ConnectionBad: connection is closed
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activerecord-6.0.2.1/lib/active_record/connection_adapters/postgresql/database_statements.rb:65:in `exec'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activerecord-6.0.2.1/lib/active_record/connection_adapters/postgresql/database_statements.rb:65:in `block (2 levels) in query'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activesupport-6.0.2.1/lib/active_support/dependencies/interlock.rb:48:in `block in permit_concurrent_loads'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activesupport-6.0.2.1/lib/active_support/concurrency/share_lock.rb:187:in `yield_shares'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activesupport-6.0.2.1/lib/active_support/dependencies/interlock.rb:47:in `permit_concurrent_loads'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activerecord-6.0.2.1/lib/active_record/connection_adapters/postgresql/database_statements.rb:64:in `block in query'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activerecord-6.0.2.1/lib/active_record/connection_adapters/abstract_adapter.rb:718:in `block (2 levels) in log'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activerecord-6.0.2.1/lib/active_record/connection_adapters/abstract_adapter.rb:717:in `block in log'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activesupport-6.0.2.1/lib/active_support/notifications/instrumenter.rb:24:in `instrument'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activerecord-6.0.2.1/lib/active_record/connection_adapters/abstract_adapter.rb:708:in `log'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activerecord-6.0.2.1/lib/active_record/connection_adapters/postgresql/database_statements.rb:63:in `query'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activerecord-6.0.2.1/lib/active_record/connection_adapters/abstract/database_statements.rb:98:in `query_value'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activerecord-6.0.2.1/lib/active_record/connection_adapters/postgresql_adapter.rb:383:in `release_advisory_lock'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activerecord-6.0.2.1/lib/active_record/migration.rb:1384:in `ensure in with_advisory_lock'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activerecord-6.0.2.1/lib/active_record/migration.rb:1385:in `with_advisory_lock'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activerecord-6.0.2.1/lib/active_record/migration.rb:1229:in `migrate'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activerecord-6.0.2.1/lib/active_record/migration.rb:1061:in `up'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activerecord-6.0.2.1/lib/active_record/migration.rb:1036:in `migrate'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activerecord-6.0.2.1/lib/active_record/tasks/database_tasks.rb:238:in `migrate'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activerecord-6.0.2.1/lib/active_record/railties/databases.rake:114:in `block (4 levels) in <top (required)>'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/railties-6.0.2.1/lib/rails/commands/rake/rake_command.rb:23:in `block in perform'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/railties-6.0.2.1/lib/rails/commands/rake/rake_command.rb:20:in `perform'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/railties-6.0.2.1/lib/rails/command.rb:48:in `invoke'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/railties-6.0.2.1/lib/rails/commands.rb:18:in `<top (required)>'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `require'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `block in require_with_bootsnap_lfi'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/loaded_features_index.rb:92:in `register'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:21:in `require_with_bootsnap_lfi'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:30:in `require'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activesupport-6.0.2.1/lib/active_support/dependencies.rb:325:in `block in require'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activesupport-6.0.2.1/lib/active_support/dependencies.rb:291:in `load_dependency'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activesupport-6.0.2.1/lib/active_support/dependencies.rb:325:in `require'...
Caused by:
PG::ConnectionBad: connection is closed
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activerecord-6.0.2.1/lib/active_record/connection_adapters/postgresql/database_statements.rb:65:in `exec'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activerecord-6.0.2.1/lib/active_record/connection_adapters/postgresql/database_statements.rb:65:in `block (2 levels) in query'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activesupport-6.0.2.1/lib/active_support/dependencies/interlock.rb:48:in `block in permit_concurrent_loads'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activesupport-6.0.2.1/lib/active_support/concurrency/share_lock.rb:187:in `yield_shares'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activesupport-6.0.2.1/lib/active_support/dependencies/interlock.rb:47:in `permit_concurrent_loads'...
.
.
Caused by:
StandardError: An error has occurred, this and all later migrations canceled:
PG::ConnectionBad: connection is closed
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activerecord-6.0.2.1/lib/active_record/connection_adapters/postgresql/database_statements.rb:92:in `exec'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activerecord-6.0.2.1/lib/active_record/connection_adapters/postgresql/database_statements.rb:92:in `block (2 levels) in execute'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activesupport-6.0.2.1/lib/active_support/dependencies/interlock.rb:48:in `block in permit_concurrent_loads'...
.
.
Caused by:
ActiveRecord::StatementInvalid: PG::ConnectionBad: connection is closed
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activerecord-6.0.2.1/lib/active_record/connection_adapters/postgresql/database_statements.rb:92:in `exec'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activerecord-6.0.2.1/lib/active_record/connection_adapters/postgresql/database_statements.rb:92:in `block (2 levels) in execute'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activesupport-6.0.2.1/lib/active_support/dependencies/interlock.rb:48:in `block in permit_concurrent_loads'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activesupport-6.0.2.1/lib/active_support/concurrency/share_lock.rb:187:in `yield_shares'...
.
.
Caused by:
PG::ConnectionBad: connection is closed
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activerecord-6.0.2.1/lib/active_record/connection_adapters/postgresql/database_statements.rb:92:in `exec'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activerecord-6.0.2.1/lib/active_record/connection_adapters/postgresql/database_statements.rb:92:in `block (2 levels) in execute'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activesupport-6.0.2.1/lib/active_support/dependencies/interlock.rb:48:in `block in permit_concurrent_loads'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activesupport-6.0.2.1/lib/active_support/concurrency/share_lock.rb:187:in `yield_shares'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activesupport-6.0.2.1/lib/active_support/dependencies/interlock.rb:47:in `permit_concurrent_loads'...
.
.
Caused by:
NoMethodError: undefined method `basic_scale=' for #<HRM::ServiceHistory:0x000000000f3b7c98>
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activemodel-6.0.2.1/lib/active_model/attribute_methods.rb:431:in `method_missing'
/var/www/dris/releases/315/db/migrate/hrm/20200409162158_modify_desigs.rb:20:in `block (3 levels) in change'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activerecord-6.0.2.1/lib/active_record/relation/delegation.rb:85:in `each'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activerecord-6.0.2.1/lib/active_record/relation/delegation.rb:85:in `each'
/var/www/dris/releases/315/db/migrate/hrm/20200409162158_modify_desigs.rb:18:in `block (2 levels) in change'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activerecord-6.0.2.1/lib/active_record/relation/delegation.rb:85:in `each'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activerecord-6.0.2.1/lib/active_record/relation/delegation.rb:85:in `each'
/var/www/dris/releases/315/db/migrate/hrm/20200409162158_modify_desigs.rb:17:in `block in change'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activerecord-6.0.2.1/lib/active_record/connection_handling.rb:269:in `swap_connection_handler'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activerecord-6.0.2.1/lib/active_record/connection_handling.rb:176:in `with_handler'
/home/deployer/.rvm/gems/ruby-2.5.1/gems/activerecord-6.0.2.1/lib/active_record/connection_handling.rb:132:in `connected_to'
/var/www/dris/releases/315/db/migrate/hrm/20200409162158_modify_desigs.rb:15:in `change'..
.
.
This is error of just single run. I tried many times, sometimes task hangs on puts HRM::Employee.first.name and sometimes error as shown above.Looks like concurrent migrations were running, but they shouldn't. Although last paragraph of error log describes some mistake in my iterations, but basic_scale= is defined and I've tested in console. Even this migration is running successfully from rails console.
I've never faced such issue before using two databases and before migrating to Rails 6.
Edit: I tried splitting migration at the point of DML statements, and migrations run successfully. If I'm resetting column information in a single migration, it shouldn't cause this issue. It's quite strange why splitting migrations resolves the issue.
This seems to happen when invoking a model's own connection (like calling model.save or Model.connection.execute) inside the migration together with calling any ActiveRecord::Migration methods like create_table, etc. It breaks Rails' internal connection handling and causes weird behaviour. I've personally run into connection closed errors, but also it wrote to the wrong schema_information table.
Rails team is notified of this bug and it should be fixed as for Rails 7.1. If you can't upgrade: splitting up your migration into 2 will solve this issue: one for your modifying the database and the other for calling models (.save etc) (just like mentioned)
Example:
# First modify table
class ModifyTables < ActiveRecord::Migration[7.0]
def change
add_column :foo, :bar, :string
drop_column :foo, :baz
end
end
# THEN modify data
class ModifyData < ActiveRecord::Migration[7.0]
def up
Foo.find_each do |foo|
foo.update!(bar: "baz")
end
end
end