Finalize converting deployments to bigint

Ensure the `deployable_id` to `deployable_id_convert_to_bigint`
conversion is completed

Copy the index on (deployable_type, deployable_id)

Swap the columns

See https://gitlab.com/gitlab-org/gitlab/-/issues/334824

Changelog: other

db/post_migrate/20210802131812_finalize_convert_deployments_bigint.rb

+# frozen_string_literal: true
+
+class FinalizeConvertDeploymentsBigint < ActiveRecord::Migration[6.1]
+  include Gitlab::Database::MigrationHelpers
+
+  disable_ddl_transaction!
+
+  TABLE_NAME = 'deployments'
+  COLUMN_NAME = 'deployable_id'
+  COLUMN_NAME_BIGINT = "#{COLUMN_NAME}_convert_to_bigint"
+  def up
+    ensure_batched_background_migration_is_finished(
+      job_class_name: 'CopyColumnUsingBackgroundMigrationJob',
+      table_name: TABLE_NAME,
+      column_name: 'id',
+      job_arguments: [[COLUMN_NAME], [COLUMN_NAME_BIGINT]]
+    )
+
+    swap
+  end
+
+  def down
+    swap
+  end
+
+  def swap
+    old_index_name = 'index_deployments_on_deployable_type_and_deployable_id'
+    bigint_index_name = 'index_deployments_on_deployable_type_and_deployable_id_bigint'
+    add_concurrent_index TABLE_NAME, ['deployable_type', COLUMN_NAME_BIGINT], name: bigint_index_name
+
+    with_lock_retries(raise_on_exhaustion: true) do
+      # Swap columns
+      temp_name = "#{COLUMN_NAME}_tmp"
+      execute "ALTER TABLE #{TABLE_NAME} RENAME COLUMN #{quote_column_name(COLUMN_NAME)} TO #{quote_column_name(temp_name)}"
+      execute "ALTER TABLE #{TABLE_NAME} RENAME COLUMN #{quote_column_name(COLUMN_NAME_BIGINT)} TO #{quote_column_name(COLUMN_NAME)}"
+      execute "ALTER TABLE #{TABLE_NAME} RENAME COLUMN #{quote_column_name(temp_name)} TO #{quote_column_name(COLUMN_NAME_BIGINT)}"
+
+      function_name = Gitlab::Database::UnidirectionalCopyTrigger.on_table(TABLE_NAME).name(COLUMN_NAME, COLUMN_NAME_BIGINT)
+      execute "ALTER FUNCTION #{quote_table_name(function_name)} RESET ALL"
+
+      execute "DROP INDEX #{old_index_name}"
+      rename_index TABLE_NAME, bigint_index_name, old_index_name
+    end
+  end
+end

db/schema_migrations/20210802131812

+a686e5df8b1528fa4d8d1c7b65b234837443d0cc249d08a38694f83263bb0532
\ No newline at end of file

db/structure.sql

@@ -12414,7 +12414,7 @@ CREATE TABLE deployments (
     tag boolean NOT NULL,
     sha character varying NOT NULL,
     user_id integer,
-    deployable_id integer,
+    deployable_id_convert_to_bigint integer,
     deployable_type character varying,
     created_at timestamp without time zone,
     updated_at timestamp without time zone,
@@ -12422,7 +12422,7 @@ CREATE TABLE deployments (
     status smallint NOT NULL,
     finished_at timestamp with time zone,
     cluster_id integer,
-    deployable_id_convert_to_bigint bigint
+    deployable_id bigint
 );
 
 CREATE SEQUENCE deployments_id_seq