Finalize conversion of ci_stages.id to bigint

1. Ensure the `id` to `id_convert_to_bigint` conversion is completed
2. Copy indexes and foreign keys
3. Swap columns

See https://gitlab.com/gitlab-org/gitlab/-/issues/327623

Changelog: other

db/post_migrate/20210707210916_finalize_ci_stages_bigint_conversion.rb

+# frozen_string_literal: true
+
+# See https://docs.gitlab.com/ee/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class FinalizeCiStagesBigintConversion < ActiveRecord::Migration[6.1]
+  include Gitlab::Database::MigrationHelpers
+  disable_ddl_transaction!
+
+  TABLE_NAME = 'ci_stages'
+
+  def up
+    ensure_batched_background_migration_is_finished(
+      job_class_name: 'CopyColumnUsingBackgroundMigrationJob',
+      table_name: TABLE_NAME,
+      column_name: 'id',
+      job_arguments: [['id'], ['id_convert_to_bigint']]
+    )
+
+    swap
+  end
+
+  def down
+    swap
+  end
+
+  def swap
+    # This will replace the existing ci_stages_pkey index for the primary key
+    add_concurrent_index TABLE_NAME, :id_convert_to_bigint, unique: true, name: 'index_ci_stages_on_id_convert_to_bigint'
+
+    # This will replace the existing ci_stages_on_pipeline_id_and_id index
+    add_concurrent_index TABLE_NAME, [:pipeline_id, :id_convert_to_bigint],
+                         name: 'index_ci_stages_on_pipeline_id_and_id_convert_to_bigint',
+                         where: 'status in (0, 1, 2, 8, 9, 10)'
+
+    # Add a foreign key on ci_builds(stage_id_convert_to_bigint), which we'll rename later. Give it the correct final name
+    fk_stage_id = concurrent_foreign_key_name(:ci_builds, :stage_id)
+    fk_stage_id_tmp = "#{fk_stage_id}_tmp"
+    add_concurrent_foreign_key :ci_builds, :ci_stages, column: :stage_id,
+                               target_column: :id_convert_to_bigint,
+                               name: fk_stage_id_tmp,
+                               on_delete: :cascade,
+                               reverse_lock_order: true
+
+    # Now it's time to do things in a transaction
+    with_lock_retries(raise_on_exhaustion: true) do
+      execute "LOCK TABLE #{TABLE_NAME}, ci_builds IN ACCESS EXCLUSIVE MODE"
+
+      temp_name = quote_column_name('id_tmp')
+      id_name = quote_column_name(:id)
+      id_convert_to_bigint_name = quote_column_name(:id_convert_to_bigint)
+      execute "ALTER TABLE #{TABLE_NAME} RENAME COLUMN #{id_name} TO #{temp_name}"
+      execute "ALTER TABLE #{TABLE_NAME} RENAME COLUMN #{id_convert_to_bigint_name} TO #{id_name}"
+      execute "ALTER TABLE #{TABLE_NAME} RENAME COLUMN #{temp_name} TO #{id_convert_to_bigint_name}"
+
+      function_name = Gitlab::Database::UnidirectionalCopyTrigger.on_table(TABLE_NAME).name(:id, :id_convert_to_bigint)
+      execute "ALTER FUNCTION #{quote_table_name(function_name)} RESET ALL"
+
+      # Swap defaults
+      execute "ALTER SEQUENCE ci_stages_id_seq OWNED BY #{TABLE_NAME}.id"
+      change_column_default TABLE_NAME, :id, -> { "nextval('ci_stages_id_seq'::regclass)"}
+      change_column_default TABLE_NAME, :id_convert_to_bigint, 0
+
+      # Swap pkey constraint
+      # This will drop fk_3a9eaa254d (ci_builds(stage_id) references ci_stages(id))
+      execute "ALTER TABLE #{TABLE_NAME} DROP CONSTRAINT ci_stages_pkey CASCADE"
+      rename_index TABLE_NAME, 'index_ci_stages_on_id_convert_to_bigint', 'ci_stages_pkey'
+      execute "ALTER TABLE #{TABLE_NAME} ADD CONSTRAINT ci_stages_pkey PRIMARY KEY USING INDEX ci_stages_pkey"
+
+      # Rename the other indexes
+      execute "DROP INDEX index_ci_stages_on_pipeline_id_and_id"
+      rename_index TABLE_NAME, 'index_ci_stages_on_pipeline_id_and_id_convert_to_bigint', 'index_ci_stages_on_pipeline_id_and_id'
+
+      rename_constraint(:ci_builds, fk_stage_id_tmp, fk_stage_id)
+    end
+  end
+end

db/schema_migrations/20210707210916

+0681e068672621fbaa513cadd86e6137709413bb370ae9d416fc562b19f11ff6
\ No newline at end of file

db/structure.sql

@@ -11299,7 +11299,7 @@ CREATE SEQUENCE ci_sources_projects_id_seq
 ALTER SEQUENCE ci_sources_projects_id_seq OWNED BY ci_sources_projects.id;
 
 CREATE TABLE ci_stages (
-    id integer NOT NULL,
+    id_convert_to_bigint integer DEFAULT 0 NOT NULL,
     project_id integer,
     pipeline_id integer,
     created_at timestamp without time zone,
@@ -11308,7 +11308,7 @@ CREATE TABLE ci_stages (
     status integer,
     lock_version integer DEFAULT 0,
     "position" integer,
-    id_convert_to_bigint bigint DEFAULT 0 NOT NULL,
+    id bigint NOT NULL,
     CONSTRAINT check_81b431e49b CHECK ((lock_version IS NOT NULL))
 );