Address the PK Overflow risk for the ci_builds_runner_session - Step 3

- Remove build_id_convert_to_bigint column
- Remove trigger_51ab7cef8934 trigger

Related to https://gitlab.com/gitlab-org/gitlab/-/issues/338057

Changelog: added

db/post_migrate/20210819145000_drop_temporary_columns_and_triggers_for_ci_builds_runner_session.rb

+# frozen_string_literal: true
+
+class DropTemporaryColumnsAndTriggersForCiBuildsRunnerSession < ActiveRecord::Migration[6.1]
+  include Gitlab::Database::MigrationHelpers
+
+  disable_ddl_transaction!
+
+  TABLE = 'ci_builds_runner_session'
+  TEMPORARY_COLUMN = 'build_id_convert_to_bigint'
+  MAIN_COLUMN = 'build_id'
+
+  # rubocop:disable Migration/WithLockRetriesDisallowedMethod
+  def up
+    with_lock_retries do
+      cleanup_conversion_of_integer_to_bigint(TABLE, MAIN_COLUMN)
+    end
+  end
+
+  def down
+    check_trigger_permissions!(TABLE)
+
+    with_lock_retries do
+      add_column(TABLE, TEMPORARY_COLUMN, :int, default: 0, null: false)
+      install_rename_triggers(TABLE, MAIN_COLUMN, TEMPORARY_COLUMN)
+    end
+  end
+  # rubocop:enable Migration/WithLockRetriesDisallowedMethod
+end

db/schema_migrations/20210819145000

+a73a33d30af332c8c01cd9d55618a1b84bc9074ffe4d06fd72c8eb37cd264954
\ No newline at end of file

db/structure.sql

@@ -71,15 +71,6 @@ BEGIN
 END;
 $$;
 
-CREATE FUNCTION trigger_51ab7cef8934() RETURNS trigger
-    LANGUAGE plpgsql
-    AS $$
-BEGIN
-  NEW."build_id_convert_to_bigint" := NEW."build_id";
-  RETURN NEW;
-END;
-$$;
-
 CREATE FUNCTION trigger_542d6c2ad72e() RETURNS trigger
     LANGUAGE plpgsql
     AS $$
@@ -11396,7 +11387,6 @@ ALTER SEQUENCE ci_builds_metadata_id_seq OWNED BY ci_builds_metadata.id;
 
 CREATE TABLE ci_builds_runner_session (
     id bigint NOT NULL,
-    build_id_convert_to_bigint integer DEFAULT 0 NOT NULL,
     url character varying NOT NULL,
     certificate character varying,
     "authorization" character varying,
@@ -27288,8 +27278,6 @@ CREATE TRIGGER trigger_21e7a2602957 BEFORE INSERT OR UPDATE ON ci_build_needs FO
 
 CREATE TRIGGER trigger_3f6129be01d2 BEFORE INSERT OR UPDATE ON ci_builds FOR EACH ROW EXECUTE FUNCTION trigger_3f6129be01d2();
 
-CREATE TRIGGER trigger_51ab7cef8934 BEFORE INSERT OR UPDATE ON ci_builds_runner_session FOR EACH ROW EXECUTE FUNCTION trigger_51ab7cef8934();
-
 CREATE TRIGGER trigger_542d6c2ad72e BEFORE INSERT OR UPDATE ON ci_builds_metadata FOR EACH ROW EXECUTE FUNCTION trigger_542d6c2ad72e();
 
 CREATE TRIGGER trigger_8487d4de3e7b BEFORE INSERT OR UPDATE ON ci_builds_metadata FOR EACH ROW EXECUTE FUNCTION trigger_8487d4de3e7b();

spec/migrations/20210819145000_drop_temporary_columns_and_triggers_for_ci_builds_runner_session_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+require_migration!('drop_temporary_columns_and_triggers_for_ci_builds_runner_session')
+
+RSpec.describe DropTemporaryColumnsAndTriggersForCiBuildsRunnerSession, :migration do
+  let(:ci_builds_runner_session_table) { table(:ci_builds_runner_session) }
+
+  it 'correctly migrates up and down' do
+    reversible_migration do |migration|
+      migration.before -> {
+        expect(ci_builds_runner_session_table.column_names).to include('build_id_convert_to_bigint')
+      }
+
+      migration.after -> {
+        ci_builds_runner_session_table.reset_column_information
+        expect(ci_builds_runner_session_table.column_names).not_to include('build_id_convert_to_bigint')
+      }
+    end
+  end
+end