Merge branch 'cablett-concurrent-validate-false' into 'master'

Optional skip validation for concurrent foreign key

See merge request gitlab-org/gitlab!22282

lib/gitlab/database/migration_helpers.rb

@@ -158,7 +158,7 @@ module Gitlab
       # name - The name of the foreign key.
       #
       # rubocop:disable Gitlab/RailsLogger
-      def add_concurrent_foreign_key(source, target, column:, on_delete: :cascade, name: nil)
+      def add_concurrent_foreign_key(source, target, column:, on_delete: :cascade, name: nil, validate: true)
         # Transactions would result in ALTER TABLE locks being held for the
         # duration of the transaction, defeating the purpose of this method.
         if transaction_open?
@@ -197,12 +197,18 @@ module Gitlab
         # Validate the existing constraint. This can potentially take a very
         # long time to complete, but fortunately does not lock the source table
         # while running.
+        # Disable this check by passing `validate: false` to the method call
+        # The check will be enforced for new data (inserts) coming in,
+        # but validating existing data is delayed.
         #
         # Note this is a no-op in case the constraint is VALID already
+
+        if validate
           disable_statement_timeout do
             execute("ALTER TABLE #{source} VALIDATE CONSTRAINT #{options[:name]};")
           end
         end
+      end
       # rubocop:enable Gitlab/RailsLogger
 
       def foreign_key_exists?(source, target = nil, **options)

spec/lib/gitlab/database/migration_helpers_spec.rb

@@ -325,6 +325,25 @@ describe Gitlab::Database::MigrationHelpers do
           end
         end
       end
+
+      describe 'validate option' do
+        let(:args) { [:projects, :users] }
+        let(:options) { { column: :user_id, on_delete: nil } }
+
+        context 'when validate is supplied with a falsey value' do
+          it_behaves_like 'skips validation', validate: false
+          it_behaves_like 'skips validation', validate: nil
+        end
+
+        context 'when validate is supplied with a truthy value' do
+          it_behaves_like 'performs validation', validate: true
+          it_behaves_like 'performs validation', validate: :whatever
+        end
+
+        context 'when validate is not supplied' do
+          it_behaves_like 'performs validation', {}
+        end
+      end
     end
   end
 

spec/support/shared_examples/migration_helpers_examples.rb

+# frozen_string_literal: true
+
+shared_examples 'skips validation' do |validation_option|
+  it 'skips validation' do
+    expect(model).not_to receive(:disable_statement_timeout)
+    expect(model).to receive(:execute).with(/ADD CONSTRAINT/)
+    expect(model).not_to receive(:execute).with(/VALIDATE CONSTRAINT/)
+
+    model.add_concurrent_foreign_key(*args, **options.merge(validation_option))
+  end
+end
+
+shared_examples 'performs validation' do |validation_option|
+  it 'performs validation' do
+    expect(model).to receive(:disable_statement_timeout).and_call_original
+    expect(model).to receive(:execute).with(/statement_timeout/)
+    expect(model).to receive(:execute).ordered.with(/NOT VALID/)
+    expect(model).to receive(:execute).ordered.with(/VALIDATE CONSTRAINT/)
+    expect(model).to receive(:execute).with(/RESET ALL/)
+
+    model.add_concurrent_foreign_key(*args, **options.merge(validation_option))
+  end
+end