2 files changed, 17 insertions, 2 deletions
diff --git a/packages/backend/src/GlobalModule.ts b/packages/backend/src/GlobalModule.ts
index 5544eeeddd..435bd8dd45 100644
--- a/packages/backend/src/GlobalModule.ts
+++ b/packages/backend/src/GlobalModule.ts
@@ -24,8 +24,13 @@ const $config: Provider = {
 const $db: Provider = {
 	provide: DI.db,
 	useFactory: async (config) => {
-		const db = createPostgresDataSource(config);
-		return await db.initialize();
+		try {
+			const db = createPostgresDataSource(config);
+			return await db.initialize();
+		} catch (e) {
+			console.log(e);
+			throw e;
+		}
 	},
 	inject: [DI.config],
 };
diff --git a/packages/backend/src/models/Note.ts b/packages/backend/src/models/Note.ts
index abaf615bcf..3dcbdb735b 100644
--- a/packages/backend/src/models/Note.ts
+++ b/packages/backend/src/models/Note.ts
@@ -10,6 +10,16 @@ import { MiUser } from './User.js';
 import { MiChannel } from './Channel.js';
 import type { MiDriveFile } from './DriveFile.js';
 
+// Note: When you create a new index for existing column of this table,
+// it might be better to index concurrently under isConcurrentIndexMigrationEnabled flag
+// by editing generated migration file since this table is very large,
+// and it will make a long lock to create index in most cases.
+// Please note that `CREATE INDEX CONCURRENTLY` is not supported in transaction,
+// so you need to set `transaction = false` in migration if isConcurrentIndexMigrationEnabled() is true.
+// Please refer 1745378064470-composite-note-index.js for example.
+// You should not use `@Index({ concurrent: true })` decorator because database initialization for test will fail
+// because it will always run CREATE INDEX in transaction based on decorators.
+// Not appending `{ concurrent: true }` to `@Index` will not cause any problem in production,
 @Index(['userId', 'id'])
 @Entity('note')
 export class MiNote {