Add database indexes to the message entity

src/messaging/message.entity.ts

@@ -5,6 +5,7 @@ import {
   CreateDateColumn,
   ManyToOne,
   JoinColumn,
+  Index,
 } from 'typeorm';
 import { User } from '../users/entities/user.entity'; // Assuming a User entity exists
 
@@ -14,15 +15,19 @@ export class Message {
   id: string;
 
   @Column({ type: 'uuid' })
+  @Index('IDX_messages_senderId')
   senderId: string;
 
   @Column({ type: 'uuid' })
+  @Index('IDX_messages_recipientId')
   recipientId: string;
 
   @Column({ type: 'text' })
   content: string;
 
   @CreateDateColumn({ type: 'timestamptz' })
+  @Index('IDX_messages_sender_recipient_createdAt')
+  @Index('IDX_messages_recipient_sender_createdAt')
   createdAt: Date;
 
   @Column({ type: 'timestamptz', nullable: true })

src/migrations/1804000000000-add-message-indexes.ts

@@ -0,0 +1,40 @@
+import { MigrationInterface, QueryRunner } from 'typeorm';
+
+/**
+ * Adds indexes to the `messages` table to cover the common query paths:
+ *
+ *  - "load conversation between two users"
+ *      → WHERE "senderId" = $1 AND "recipientId" = $2
+ *        or WHERE "recipientId" = $1 AND "senderId" = $2
+ *      → ORDER BY "createdAt"
+ *  - "lookup by sender" / "lookup by recipient"
+ *      → WHERE "senderId" = $1
+ *      → WHERE "recipientId" = $1
+ *
+ * The composite indexes on (senderId, recipientId, createdAt) and
+ * (recipientId, senderId, createdAt) allow the conversation query to use
+ * index-only scans and avoid a separate sort step.
+ */
+export class AddMessageIndexes1804000000000 implements MigrationInterface {
+  public async up(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query(
+      'CREATE INDEX IF NOT EXISTS "IDX_messages_senderId" ON "messages" ("senderId")',
+    );
+    await queryRunner.query(
+      'CREATE INDEX IF NOT EXISTS "IDX_messages_recipientId" ON "messages" ("recipientId")',
+    );
+    await queryRunner.query(
+      'CREATE INDEX IF NOT EXISTS "IDX_messages_sender_recipient_createdAt" ON "messages" ("senderId", "recipientId", "createdAt")',
+    );
+    await queryRunner.query(
+      'CREATE INDEX IF NOT EXISTS "IDX_messages_recipient_sender_createdAt" ON "messages" ("recipientId", "senderId", "createdAt")',
+    );
+  }
+
+  public async down(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query('DROP INDEX IF EXISTS "IDX_messages_recipient_sender_createdAt"');
+    await queryRunner.query('DROP INDEX IF EXISTS "IDX_messages_sender_recipient_createdAt"');
+    await queryRunner.query('DROP INDEX IF EXISTS "IDX_messages_recipientId"');
+    await queryRunner.query('DROP INDEX IF EXISTS "IDX_messages_senderId"');
+  }
+}