Add audit_events partitioning migration

This adds a migration to partition audit_events table and also adds a
model for it.

app/models/audit_event_partitioned.rb

+# frozen_string_literal: true
+
+# This model is not yet intended to be used.
+# It is in a transitioning phase while we are partitioning
+# the table on the database-side.
+# Please refer to https://gitlab.com/groups/gitlab-org/-/epics/3206
+# for details.
+class AuditEventPartitioned < ApplicationRecord
+  include PartitionedTable
+
+  self.table_name = 'audit_events_part_5fc467ac26'
+
+  partitioned_by :created_at, strategy: :monthly
+end

config/initializers/postgres_partitioning.rb

@@ -3,6 +3,8 @@
 # Make sure we have loaded partitioned models here
 # (even with eager loading disabled).
 
+Gitlab::Database::Partitioning::PartitionCreator.register(AuditEventPartitioned)
+
 begin
   Gitlab::Database::Partitioning::PartitionCreator.new.create_partitions
 rescue ActiveRecord::ActiveRecordError, PG::Error

db/migrate/20200716120000_partition_audit_events.rb

+# frozen_string_literal: true
+
+class PartitionAuditEvents < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+  include Gitlab::Database::PartitioningMigrationHelpers
+
+  # Set this constant to true if this migration requires downtime.
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    partition_table_by_date :audit_events, :created_at
+  end
+
+  def down
+    drop_partitioned_table_for :audit_events
+  end
+end

db/structure.sql

@@ -12,6 +12,78 @@ CREATE EXTENSION IF NOT EXISTS btree_gist WITH SCHEMA public;
 
 CREATE EXTENSION IF NOT EXISTS pg_trgm WITH SCHEMA public;
 
+CREATE FUNCTION public.table_sync_function_2be879775d() RETURNS trigger
+    LANGUAGE plpgsql
+    AS $$
+BEGIN
+IF (TG_OP = 'DELETE') THEN
+  DELETE FROM audit_events_part_5fc467ac26 where id = OLD.id;
+ELSIF (TG_OP = 'UPDATE') THEN
+  UPDATE audit_events_part_5fc467ac26
+  SET author_id = NEW.author_id,
+    type = NEW.type,
+    entity_id = NEW.entity_id,
+    entity_type = NEW.entity_type,
+    details = NEW.details,
+    updated_at = NEW.updated_at,
+    ip_address = NEW.ip_address,
+    author_name = NEW.author_name,
+    entity_path = NEW.entity_path,
+    target_details = NEW.target_details,
+    created_at = NEW.created_at
+  WHERE audit_events_part_5fc467ac26.id = NEW.id;
+ELSIF (TG_OP = 'INSERT') THEN
+  INSERT INTO audit_events_part_5fc467ac26 (id,
+    author_id,
+    type,
+    entity_id,
+    entity_type,
+    details,
+    updated_at,
+    ip_address,
+    author_name,
+    entity_path,
+    target_details,
+    created_at)
+  VALUES (NEW.id,
+    NEW.author_id,
+    NEW.type,
+    NEW.entity_id,
+    NEW.entity_type,
+    NEW.details,
+    NEW.updated_at,
+    NEW.ip_address,
+    NEW.author_name,
+    NEW.entity_path,
+    NEW.target_details,
+    NEW.created_at);
+END IF;
+RETURN NULL;
+
+END
+$$;
+
+COMMENT ON FUNCTION public.table_sync_function_2be879775d() IS 'Partitioning migration: table sync for audit_events table';
+
+CREATE TABLE public.audit_events_part_5fc467ac26 (
+    id bigint NOT NULL,
+    author_id integer NOT NULL,
+    type character varying NOT NULL,
+    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,
+    target_details text,
+    created_at timestamp without time zone NOT NULL,
+    CONSTRAINT check_492aaa021d CHECK ((char_length(entity_path) <= 5500)),
+    CONSTRAINT check_83ff8406e2 CHECK ((char_length(author_name) <= 255)),
+    CONSTRAINT check_d493ec90b5 CHECK ((char_length(target_details) <= 5500))
+)
+PARTITION BY RANGE (created_at);
+
 CREATE TABLE public.product_analytics_events_experimental (
     id bigint NOT NULL,
     project_id integer NOT NULL,
@@ -17442,6 +17514,9 @@ ALTER TABLE ONLY public.approvers
 ALTER TABLE ONLY public.ar_internal_metadata
     ADD CONSTRAINT ar_internal_metadata_pkey PRIMARY KEY (key);
 
+ALTER TABLE ONLY public.audit_events_part_5fc467ac26
+    ADD CONSTRAINT audit_events_part_5fc467ac26_pkey PRIMARY KEY (id, created_at);
+
 ALTER TABLE ONLY public.audit_events
     ADD CONSTRAINT audit_events_pkey PRIMARY KEY (id);
 
@@ -21053,6 +21128,8 @@ ALTER INDEX public.product_analytics_events_experimental_pkey ATTACH PARTITION g
 
 ALTER INDEX public.product_analytics_events_experimental_pkey ATTACH PARTITION gitlab_partitions_static.product_analytics_events_experimental_63_pkey;
 
+CREATE TRIGGER table_sync_trigger_ee39a25f9d AFTER INSERT OR DELETE OR UPDATE ON public.audit_events FOR EACH ROW EXECUTE PROCEDURE public.table_sync_function_2be879775d();
+
 ALTER TABLE ONLY public.chat_names
     ADD CONSTRAINT fk_00797a2bf9 FOREIGN KEY (service_id) REFERENCES public.services(id) ON DELETE CASCADE;
 
@@ -23993,6 +24070,7 @@ COPY "schema_migrations" (version) FROM STDIN;
 20200715135130
 20200715202659
 20200716044023
+20200716120000
 20200716120419
 20200716145156
 20200718040100

spec/db/schema_spec.rb

@@ -19,6 +19,7 @@ RSpec.describe 'Database schema' do
     approver_groups: %w[target_id],
     approvers: %w[target_id user_id],
     audit_events: %w[author_id entity_id],
+    audit_events_part_5fc467ac26: %w[author_id entity_id],
     award_emoji: %w[awardable_id user_id],
     aws_roles: %w[role_external_id],
     boards: %w[milestone_id],