Merge branch 'prepare-async-index-no-subtxn' into 'master'

Update prepare_async_index migration helper to avoid subtransaction

See merge request gitlab-org/gitlab!69262

lib/gitlab/database/async_indexes/migration_helpers.rb

@@ -55,11 +55,14 @@ module Gitlab
           schema_creation = ActiveRecord::ConnectionAdapters::PostgreSQL::SchemaCreation.new(ApplicationRecord.connection)
           definition = schema_creation.accept(create_index)
 
-          async_index = PostgresAsyncIndex.safe_find_or_create_by!(name: index_name) do |rec|
+          async_index = PostgresAsyncIndex.find_or_create_by!(name: index_name) do |rec|
             rec.table_name = table_name
             rec.definition = definition
           end
 
+          async_index.definition = definition
+          async_index.save! # No-op if definition is not changed
+
           Gitlab::AppLogger.info(
             message: 'Prepared index for async creation',
             table_name: async_index.table_name,

spec/lib/gitlab/database/async_indexes/migration_helpers_spec.rb

@@ -150,6 +150,23 @@ RSpec.describe Gitlab::Database::AsyncIndexes::MigrationHelpers do
             migration.prepare_async_index(table_name, 'id')
           end.not_to change { index_model.where(name: index_name).count }
         end
+
+        it 'updates definition if changed' do
+          index = create(:postgres_async_index, table_name: table_name, name: index_name, definition: '...')
+
+          expect do
+            migration.prepare_async_index(table_name, 'id', name: index_name)
+          end.to change { index.reload.definition }
+        end
+
+        it 'does not update definition if not changed' do
+          definition = "CREATE INDEX CONCURRENTLY \"index_#{table_name}_on_id\" ON \"#{table_name}\" (\"id\")"
+          index = create(:postgres_async_index, table_name: table_name, name: index_name, definition: definition)
+
+          expect do
+            migration.prepare_async_index(table_name, 'id', name: index_name)
+          end.not_to change { index.reload.updated_at }
+        end
       end
 
       context 'when the async index table does not exist' do