fix: Add database indexes to the answer entity

src/achievements/achievements.seed.ts

@@ -1,5 +1,4 @@
 import { AchievementType, AchievementDifficulty } from './entities/achievement.entity';
-import { Logger } from '@nestjs/common';
 
 /**
  * Seed data for default achievements

src/assessment/entities/answer.entity.ts

@@ -1,10 +1,16 @@
-import { Column, Entity, ManyToOne, PrimaryGeneratedColumn, VersionColumn } from 'typeorm';
+import { Column, Entity, Index, ManyToOne, PrimaryGeneratedColumn, VersionColumn } from 'typeorm';
 import { AssessmentAttempt } from './assessment-attempt.entity';
 import { Question } from './question.entity';
 /**
  * Represents the answer entity.
  */
 @Entity()
+// Composite index for the common "answers of an attempt" lookup and
+// the "answer for a given question within an attempt" lookup. Because the
+// leading column is `attempt`, this also serves attempt-only filters, so a
+// separate single-column index on `attempt` would be redundant.
+@Index('IDX_answer_attempt_question', ['attempt', 'question'])
+@Index('IDX_answer_question', ['question'])
 export class Answer {
   @PrimaryGeneratedColumn('uuid')
   id: string;

src/auth/auth.controller.ts

@@ -20,7 +20,6 @@ import { RegisterDto } from './dto/register.dto';
 import { RefreshTokenDto } from './dto/refresh-token.dto';
 import { InjectRepository } from '@nestjs/typeorm';
 import { User } from '../users/entities/user.entity';
-import { Tenant } from '../tenancy/entities/tenant.entity';
 import { Repository } from 'typeorm';
 import * as bcrypt from 'bcrypt';
 import { JwtAuthGuard } from './guards/jwt-auth.guard';

src/migrations/1599999999999-BaselineSchema.ts

@@ -616,6 +616,10 @@ export class BaselineSchema1599999999999 implements MigrationInterface {
     "attemptId" uuid,
     "questionId" uuid
 )
+    `);
+    await queryRunner.query(`CREATE INDEX idx_answer_attempt_id ON public.answer USING btree ("attemptId")
+    `);
+    await queryRunner.query(`CREATE INDEX idx_answer_question_id ON public.answer USING btree ("questionId")
     `);
     await queryRunner.query(`CREATE TABLE public.archived_data (
     id uuid DEFAULT public.uuid_generate_v4() NOT NULL,

src/migrations/1756476695000-add-answer-indexes.ts

@@ -0,0 +1,29 @@
+import { MigrationInterface, QueryRunner } from 'typeorm';
+
+export class AddAnswerIndexes1756476695000 implements MigrationInterface {
+  name = 'AddAnswerIndexes1756476695000';
+
+  public async up(queryRunner: QueryRunner): Promise<void> {
+    // Foreign-key / lookup column indexes for the "answer" table.
+    await queryRunner.query(
+      'CREATE INDEX IF NOT EXISTS "IDX_answer_question_id" ON "answer" ("question_id")',
+    );
+    await queryRunner.query(
+      'CREATE INDEX IF NOT EXISTS "IDX_answer_submission_id" ON "answer" ("submission_id")',
+    );
+    await queryRunner.query(
+      'CREATE INDEX IF NOT EXISTS "IDX_answer_created_at" ON "answer" ("created_at")',
+    );
+    // Composite index for the common "answers for a submission, by question" lookup.
+    await queryRunner.query(
+      'CREATE INDEX IF NOT EXISTS "IDX_answer_submission_id_question_id" ON "answer" ("submission_id", "question_id")',
+    );
+  }
+
+  public async down(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query('DROP INDEX IF EXISTS "IDX_answer_submission_id_question_id"');
+    await queryRunner.query('DROP INDEX IF EXISTS "IDX_answer_created_at"');
+    await queryRunner.query('DROP INDEX IF EXISTS "IDX_answer_submission_id"');
+    await queryRunner.query('DROP INDEX IF EXISTS "IDX_answer_question_id"');
+  }
+}

src/payments/providers/payment-provider.service.ts

@@ -38,7 +38,7 @@ export class PaymentProviderService {
     userId: string,
     amount: number,
     currency: string,
-    metadata: Record<string, unknown> = {},
+    _metadata: Record<string, unknown> = {},
   ): Promise<ChargeResult> {
     // TODO: replace with real Stripe call:
     //   const intent = await stripe.paymentIntents.create({ amount: Math.round(amount * 100), currency, ... });
@@ -58,7 +58,7 @@ export class PaymentProviderService {
     userId: string,
     amount: number,
     currency: string,
-    metadata: Record<string, unknown> = {},
+    _metadata: Record<string, unknown> = {},
   ): Promise<CreditResult> {
     // TODO: replace with real Stripe call:
     //   const credit = await stripe.customers.createBalanceTransaction(customerId, { amount: -Math.round(amount * 100), currency });