Comply with database related API changes

Within Rails 6.1 there have been a lot of work related to
database and how to make sharding possible. Some methods
have been removed/renamed. Let's comply with those changes.

ee/lib/gitlab/geo/database_tasks.rb

@@ -114,7 +114,7 @@ module Gitlab
               ['up', version, '********** NO FILE **********']
             end
             # output
-            puts "\ndatabase: #{ActiveRecord::Base.connection_config[:database]}\n\n"
+            puts "\ndatabase: #{ActiveRecord::Base.connection_db_config.database}\n\n"
             puts "#{'Status'.center(8)}  #{'Migration ID'.ljust(14)}  Migration Name"
             puts "-" * 50
             (db_list + file_list).sort_by { |_, version, _| version }.each do |status, version, name|

lib/gitlab/database.rb

@@ -61,7 +61,7 @@ module Gitlab
     end
 
     def self.config
-      default_config_hash = ActiveRecord::Base.configurations.find_db_config(Rails.env)&.config || {}
+      default_config_hash = ActiveRecord::Base.configurations.find_db_config(Rails.env)&.configuration_hash || {}
 
       default_config_hash.with_indifferent_access.tap do |hash|
         # Match config/initializers/database_config.rb

lib/gitlab/metrics/samplers/database_sampler.rb

@@ -45,8 +45,8 @@ module Gitlab
 
         def labels_for_class(klass)
           {
-            host: klass.connection_config[:host],
-            port: klass.connection_config[:port],
+            host: klass.connection_db_config.host,
+            port: klass.connection_db_config.configuration_hash[:port],
             class: klass.to_s
           }
         end

spec/db/schema_spec.rb

@@ -269,7 +269,7 @@ RSpec.describe 'Database schema' do
     sql = <<~SQL
         SELECT table_name, column_name, data_type
           FROM information_schema.columns
-        WHERE table_catalog = '#{ApplicationRecord.connection_config[:database]}'
+        WHERE table_catalog = '#{ApplicationRecord.connection_db_config.database}'
           AND table_schema = 'public'
           AND table_name NOT LIKE 'pg_%'
           AND data_type = 'jsonb'

spec/lib/gitlab/database/load_balancing/load_balancer_spec.rb

@@ -3,8 +3,7 @@
 require 'spec_helper'
 
 RSpec.describe Gitlab::Database::LoadBalancing::LoadBalancer, :request_store do
-  let(:pool_spec) { ActiveRecord::Base.connection_pool.spec }
-  let(:pool) { ActiveRecord::ConnectionAdapters::ConnectionPool.new(pool_spec) }
+  let(:pool) { Gitlab::Database.create_connection_pool(2) }
   let(:conflict_error) { Class.new(RuntimeError) }
 
   let(:lb) { described_class.new(%w(localhost localhost)) }

spec/lib/gitlab/database/with_lock_retries_spec.rb

@@ -242,10 +242,10 @@ RSpec.describe Gitlab::Database::WithLockRetries do
     let(:timing_configuration) { [[0.015.seconds, 0.025.seconds], [0.015.seconds, 0.025.seconds]] } # 15ms, 25ms
 
     it 'executes `SET LOCAL lock_timeout` using the configured timeout value in milliseconds' do
-      expect(ActiveRecord::Base.connection).to receive(:execute).with("SAVEPOINT active_record_1").and_call_original
-      expect(ActiveRecord::Base.connection).to receive(:execute).with('RESET idle_in_transaction_session_timeout; RESET lock_timeout').and_call_original
+      expect(ActiveRecord::Base.connection).to receive(:execute).with("RESET idle_in_transaction_session_timeout; RESET lock_timeout").and_call_original
+      expect(ActiveRecord::Base.connection).to receive(:execute).with("SAVEPOINT active_record_1", "TRANSACTION").and_call_original
       expect(ActiveRecord::Base.connection).to receive(:execute).with("SET LOCAL lock_timeout TO '15ms'").and_call_original
-      expect(ActiveRecord::Base.connection).to receive(:execute).with("RELEASE SAVEPOINT active_record_1").and_call_original
+      expect(ActiveRecord::Base.connection).to receive(:execute).with("RELEASE SAVEPOINT active_record_1", "TRANSACTION").and_call_original
 
       subject.run { }
     end

spec/lib/gitlab/database_spec.rb

@@ -329,7 +329,7 @@ RSpec.describe Gitlab::Database do
         expect(pool)
           .to be_kind_of(ActiveRecord::ConnectionAdapters::ConnectionPool)
 
-        expect(pool.spec.config[:pool]).to eq(5)
+        expect(pool.db_config.pool).to eq(5)
       ensure
         pool.disconnect!
       end
@@ -339,7 +339,7 @@ RSpec.describe Gitlab::Database do
       pool = described_class.create_connection_pool(5, '127.0.0.1')
 
       begin
-        expect(pool.spec.config[:host]).to eq('127.0.0.1')
+        expect(pool.db_config.host).to eq('127.0.0.1')
       ensure
         pool.disconnect!
       end
@@ -349,8 +349,8 @@ RSpec.describe Gitlab::Database do
       pool = described_class.create_connection_pool(5, '127.0.0.1', 5432)
 
       begin
-        expect(pool.spec.config[:host]).to eq('127.0.0.1')
-        expect(pool.spec.config[:port]).to eq(5432)
+        expect(pool.db_config.host).to eq('127.0.0.1')
+        expect(pool.db_config.configuration_hash[:port]).to eq(5432)
       ensure
         pool.disconnect!
       end