Remove updated_at column from audit_events table

This field is not needed for append-only table. We are required to
update the partition trigger and corresponding partitioned table schema.

changelogs/unreleased/217941-drop-updated-at-on-audit-events.yml

+---
+title: Remove updated_at column on audit_events table
+merge_request: 35690
+author:
+type: other

db/post_migrate/20200724100421_remove_updated_at_from_audit_events.rb

+# frozen_string_literal: true
+
+class RemoveUpdatedAtFromAuditEvents < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::SchemaHelpers
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+  SOURCE_TABLE_NAME = 'audit_events'
+  PARTITIONED_TABLE_NAME = 'audit_events_part_5fc467ac26'
+  TRIGGER_FUNCTION_NAME = 'table_sync_function_2be879775d'
+
+  def up
+    with_lock_retries do
+      remove_column SOURCE_TABLE_NAME, :updated_at
+
+      create_trigger_function(TRIGGER_FUNCTION_NAME, replace: true) do
+        <<~SQL
+          IF (TG_OP = 'DELETE') THEN
+            DELETE FROM #{PARTITIONED_TABLE_NAME} where id = OLD.id;
+          ELSIF (TG_OP = 'UPDATE') THEN
+            UPDATE #{PARTITIONED_TABLE_NAME}
+            SET author_id = NEW.author_id,
+              type = NEW.type,
+              entity_id = NEW.entity_id,
+              entity_type = NEW.entity_type,
+              details = NEW.details,
+              ip_address = NEW.ip_address,
+              author_name = NEW.author_name,
+              entity_path = NEW.entity_path,
+              target_details = NEW.target_details,
+              created_at = NEW.created_at
+            WHERE #{PARTITIONED_TABLE_NAME}.id = NEW.id;
+          ELSIF (TG_OP = 'INSERT') THEN
+            INSERT INTO #{PARTITIONED_TABLE_NAME} (id,
+              author_id,
+              type,
+              entity_id,
+              entity_type,
+              details,
+              ip_address,
+              author_name,
+              entity_path,
+              target_details,
+              created_at)
+            VALUES (NEW.id,
+              NEW.author_id,
+              NEW.type,
+              NEW.entity_id,
+              NEW.entity_type,
+              NEW.details,
+              NEW.ip_address,
+              NEW.author_name,
+              NEW.entity_path,
+              NEW.target_details,
+              NEW.created_at);
+          END IF;
+          RETURN NULL;
+        SQL
+      end
+
+      remove_column PARTITIONED_TABLE_NAME, :updated_at
+    end
+  end
+
+  def down
+    with_lock_retries do
+      add_column SOURCE_TABLE_NAME, :updated_at, :datetime # rubocop:disable Migration/Datetime
+      add_column PARTITIONED_TABLE_NAME, :updated_at, :datetime # rubocop:disable Migration/Datetime
+
+      create_trigger_function(TRIGGER_FUNCTION_NAME, replace: true) do
+        <<~SQL
+          IF (TG_OP = 'DELETE') THEN
+            DELETE FROM #{PARTITIONED_TABLE_NAME} where id = OLD.id;
+          ELSIF (TG_OP = 'UPDATE') THEN
+            UPDATE #{PARTITIONED_TABLE_NAME}
+            SET author_id = NEW.author_id,
+              type = NEW.type,
+              entity_id = NEW.entity_id,
+              entity_type = NEW.entity_type,
+              details = NEW.details,
+              updated_at = NEW.updated_at,
+              ip_address = NEW.ip_address,
+              author_name = NEW.author_name,
+              entity_path = NEW.entity_path,
+              target_details = NEW.target_details,
+              created_at = NEW.created_at
+            WHERE #{PARTITIONED_TABLE_NAME}.id = NEW.id;
+          ELSIF (TG_OP = 'INSERT') THEN
+            INSERT INTO #{PARTITIONED_TABLE_NAME} (id,
+              author_id,
+              type,
+              entity_id,
+              entity_type,
+              details,
+              updated_at,
+              ip_address,
+              author_name,
+              entity_path,
+              target_details,
+              created_at)
+            VALUES (NEW.id,
+              NEW.author_id,
+              NEW.type,
+              NEW.entity_id,
+              NEW.entity_type,
+              NEW.details,
+              NEW.updated_at,
+              NEW.ip_address,
+              NEW.author_name,
+              NEW.entity_path,
+              NEW.target_details,
+              NEW.created_at);
+          END IF;
+          RETURN NULL;
+        SQL
+      end
+    end
+  end
+end

db/schema_migrations/20200724100421

+77601e653f7b4f2740db87a7b19b64bb73fffbe4ce59c0f68b0bb65599da0eb3
\ No newline at end of file

db/structure.sql

@@ -25,7 +25,6 @@ ELSIF (TG_OP = 'UPDATE') THEN
     entity_id = NEW.entity_id,
     entity_type = NEW.entity_type,
     details = NEW.details,
-    updated_at = NEW.updated_at,
     ip_address = NEW.ip_address,
     author_name = NEW.author_name,
     entity_path = NEW.entity_path,
@@ -39,7 +38,6 @@ ELSIF (TG_OP = 'INSERT') THEN
     entity_id,
     entity_type,
     details,
-    updated_at,
     ip_address,
     author_name,
     entity_path,
@@ -51,7 +49,6 @@ ELSIF (TG_OP = 'INSERT') THEN
     NEW.entity_id,
     NEW.entity_type,
     NEW.details,
-    NEW.updated_at,
     NEW.ip_address,
     NEW.author_name,
     NEW.entity_path,
@@ -72,7 +69,6 @@ CREATE TABLE public.audit_events_part_5fc467ac26 (
     entity_id integer NOT NULL,
     entity_type character varying NOT NULL,
     details text,
-    updated_at timestamp without time zone,
     ip_address inet,
     author_name text,
     entity_path text,
@@ -9469,7 +9465,6 @@ CREATE TABLE public.audit_events (
     entity_type character varying NOT NULL,
     details text,
     created_at timestamp without time zone,
-    updated_at timestamp without time zone,
     ip_address inet,
     author_name text,
     entity_path text,

spec/models/audit_event_partitioned_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe AuditEventPartitioned do
+  let(:source_table) { AuditEvent }
+  let(:partitioned_table) { described_class }
+
+  it 'has the same columns as the source table' do
+    expect(partitioned_table.column_names).to match_array(source_table.column_names)
+  end
+
+  it 'inserts the same record as the one in the source table', :aggregate_failures do
+    expect { create(:audit_event) }.to change { partitioned_table.count }.by(1)
+
+    event_from_source_table = source_table.connection.select_one(
+      "SELECT * FROM #{source_table.table_name} ORDER BY created_at desc LIMIT 1"
+    )
+    event_from_partitioned_table = partitioned_table.connection.select_one(
+      "SELECT * FROM #{partitioned_table.table_name} ORDER BY created_at desc LIMIT 1"
+    )
+
+    expect(event_from_partitioned_table).to eq(event_from_source_table)
+  end
+end