perf: optimize migration 371 to run faster on large deployments (#20906)

closes https://github.com/coder/coder/issues/20899

This is in response to a migration in v2.27 that takes very long on
deployments with large `api_keys` tables.

NOTE: The optimization causes the _up_ migration to delete old data
(keys that expired more than 7 days ago). The _down_ migration won't
resurrect the deleted data.

coderd/database/migrations/000371_api_key_scopes_array_allow_list.up.sql

@@ -141,13 +141,19 @@ ALTER TYPE api_key_scope ADD VALUE IF NOT EXISTS 'workspace_proxy:read';
 ALTER TYPE api_key_scope ADD VALUE IF NOT EXISTS 'workspace_proxy:update';
 -- End enum extensions
 
+-- Purge old API keys to speed up the migration for large deployments.
+-- Note: that problem should be solved in coderd once PR 20863 is released:
+-- https://github.com/coder/coder/blob/main/coderd/database/dbpurge/dbpurge.go#L85
+DELETE FROM api_keys WHERE expires_at < NOW() - INTERVAL '7 days';
+
 -- Add new columns without defaults; backfill; then enforce NOT NULL
 ALTER TABLE api_keys ADD COLUMN scopes api_key_scope[];
 ALTER TABLE api_keys ADD COLUMN allow_list text[];
 
 -- Backfill existing rows for compatibility
-UPDATE api_keys SET scopes = ARRAY[scope::api_key_scope];
-UPDATE api_keys SET allow_list = ARRAY['*:*'];
+UPDATE api_keys SET
+    scopes = ARRAY[scope::api_key_scope],
+    allow_list = ARRAY['*:*'];
 
 -- Enforce NOT NULL
 ALTER TABLE api_keys ALTER COLUMN scopes SET NOT NULL;

coderd/database/migrations/testdata/fixtures/000371_add_api_key_and_oauth2_provider_app_token.up.sql

@@ -0,0 +1,57 @@
+-- Ensure api_keys and oauth2_provider_app_tokens have live data after
+-- migration 000371 deletes expired rows.
+INSERT INTO api_keys (
+	id,
+	hashed_secret,
+	user_id,
+	last_used,
+	expires_at,
+	created_at,
+	updated_at,
+	login_type,
+	lifetime_seconds,
+	ip_address,
+	token_name,
+	scopes,
+	allow_list
+)
+VALUES (
+	'fixture-api-key',
+	'\xaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa',
+	'30095c71-380b-457a-8995-97b8ee6e5307',
+	NOW() - INTERVAL '1 hour',
+	NOW() + INTERVAL '30 days',
+	NOW() - INTERVAL '1 day',
+	NOW() - INTERVAL '1 day',
+	'password',
+	86400,
+	'0.0.0.0',
+	'fixture-api-key',
+	ARRAY['workspace:read']::api_key_scope[],
+	ARRAY['*:*']
+)
+ON CONFLICT (id) DO NOTHING;
+
+INSERT INTO oauth2_provider_app_tokens (
+	id,
+	created_at,
+	expires_at,
+	hash_prefix,
+	refresh_hash,
+	app_secret_id,
+	api_key_id,
+	audience,
+	user_id
+)
+VALUES (
+	'9f92f3c9-811f-4f6f-9a1c-3f2eed1f9f15',
+	NOW() - INTERVAL '30 minutes',
+	NOW() + INTERVAL '30 days',
+	CAST('fixture-hash-prefix' AS bytea),
+	CAST('fixture-refresh-hash' AS bytea),
+	'b0eebc99-9c0b-4ef8-bb6d-6bb9bd380a11',
+	'fixture-api-key',
+	'https://coder.example.com',
+	'30095c71-380b-457a-8995-97b8ee6e5307'
+)
+ON CONFLICT (id) DO NOTHING;