Add primary key to preview_cards_statuses join table (includes deduplication migration) (#25243)

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Claire 2023-08-03 11:12:52 +02:00 committed by GitHub
parent a0fad5c8bb
commit 6b896b20cc
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5 changed files with 93 additions and 5 deletions

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@ -61,10 +61,14 @@ class FetchLinkCardService < BaseService
end
def attach_card
with_redis_lock("attach_card:#{@status.id}") do
return if @status.preview_cards.any?
@status.preview_cards << @card
Rails.cache.delete(@status)
Trends.links.register(@status)
end
end
def parse_urls
urls = if @status.local?

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@ -0,0 +1,39 @@
# frozen_string_literal: true
class AddUniqueIndexOnPreviewCardsStatuses < ActiveRecord::Migration[6.1]
disable_ddl_transaction!
def up
add_index :preview_cards_statuses, [:status_id, :preview_card_id], name: :preview_cards_statuses_pkey, algorithm: :concurrently, unique: true
rescue ActiveRecord::RecordNotUnique
deduplicate_and_reindex!
end
def down
remove_index :preview_cards_statuses, name: :preview_cards_statuses_pkey
end
private
def deduplicate_and_reindex!
deduplicate_preview_cards!
safety_assured { execute 'REINDEX INDEX preview_cards_statuses_pkey' }
rescue ActiveRecord::RecordNotUnique
retry
end
def deduplicate_preview_cards!
# Statuses should have only one preview card at most, even if that's not the database
# constraint we will end up with
duplicate_ids = select_all('SELECT status_id FROM preview_cards_statuses GROUP BY status_id HAVING count(*) > 1;').rows
duplicate_ids.each_slice(1000) do |ids|
# This one is tricky: since we don't have primary keys to keep only one record,
# use the physical `ctid`
safety_assured do
execute "DELETE FROM preview_cards_statuses p WHERE p.status_id IN (#{ids.join(', ')}) AND p.ctid NOT IN (SELECT q.ctid FROM preview_cards_statuses q WHERE q.status_id = p.status_id LIMIT 1)"
end
end
end
end

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@ -0,0 +1,20 @@
# frozen_string_literal: true
class AddPrimaryKeyToPreviewCardsStatusesJoinTable < ActiveRecord::Migration[6.1]
disable_ddl_transaction!
def up
safety_assured do
execute 'ALTER TABLE preview_cards_statuses ADD PRIMARY KEY USING INDEX preview_cards_statuses_pkey'
end
end
def down
safety_assured do
# I have found no way to demote the primary key to an index, instead, re-create the index
execute 'CREATE UNIQUE INDEX CONCURRENTLY preview_cards_statuses_pkey_tmp ON preview_cards_statuses (status_id, preview_card_id)'
execute 'ALTER TABLE preview_cards_statuses DROP CONSTRAINT preview_cards_statuses_pkey'
execute 'ALTER INDEX preview_cards_statuses_pkey_tmp RENAME TO preview_cards_statuses_pkey'
end
end
end

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@ -10,7 +10,7 @@
#
# It's strongly recommended that you check this file into your version control system.
ActiveRecord::Schema[7.0].define(version: 2023_07_24_160715) do
ActiveRecord::Schema[7.0].define(version: 2023_08_03_112520) do
# These are extensions that must be enabled in order to support this database
enable_extension "plpgsql"
@ -805,7 +805,7 @@ ActiveRecord::Schema[7.0].define(version: 2023_07_24_160715) do
t.index ["url"], name: "index_preview_cards_on_url", unique: true
end
create_table "preview_cards_statuses", id: false, force: :cascade do |t|
create_table "preview_cards_statuses", primary_key: ["status_id", "preview_card_id"], force: :cascade do |t|
t.bigint "preview_card_id", null: false
t.bigint "status_id", null: false
t.index ["status_id", "preview_card_id"], name: "index_preview_cards_statuses_on_status_id_and_preview_card_id"

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@ -63,6 +63,11 @@ namespace :tests do
puts 'Account domains not properly normalized'
exit(1)
end
unless Status.find(12).preview_cards.pluck(:url) == ['https://joinmastodon.org/']
puts 'Preview cards not deduplicated as expected'
exit(1)
end
end
desc 'Populate the database with test data for 2.4.3'
@ -238,6 +243,11 @@ namespace :tests do
(10, 2, '@admin hey!', NULL, 1, 3, now(), now()),
(11, 1, '@user hey!', 10, 1, 3, now(), now());
INSERT INTO "statuses"
(id, account_id, text, created_at, updated_at)
VALUES
(12, 1, 'check out https://joinmastodon.org/', now(), now());
-- mentions (from previous statuses)
INSERT INTO "mentions"
@ -326,6 +336,21 @@ namespace :tests do
(1, 6, 2, 'Follow', 2, now(), now()),
(2, 2, 1, 'Mention', 4, now(), now()),
(3, 1, 2, 'Mention', 5, now(), now());
-- preview cards
INSERT INTO "preview_cards"
(id, url, title, created_at, updated_at)
VALUES
(1, 'https://joinmastodon.org/', 'Mastodon - Decentralized social media', now(), now());
-- many-to-many association between preview cards and statuses
INSERT INTO "preview_cards_statuses"
(status_id, preview_card_id)
VALUES
(12, 1),
(12, 1);
SQL
end
end