CRUD operations in NestJS - Performance & Optimization

Performance: CRUD operations

MEDIUM IMPACT

CRUD operations impact server response time and client rendering speed, affecting how quickly users see and interact with data changes.

Fetching and updating data in a NestJS API

NestJS

async updateUser(id: string, data: UpdateUserDto) {
  const result = await this.userRepository.update(id, data);
  if (result.affected === 0) throw new NotFoundException();
  return { id, ...data };
}

Direct update query reduces database calls and speeds up response.

📈 Performance GainReduces database queries from 2 to 1 for update, lowering server load.

Fetching and updating data in a NestJS API

NestJS

async updateUser(id: string, data: UpdateUserDto) {
  const user = await this.userRepository.findOneBy({ id });
  if (!user) throw new NotFoundException();
  Object.assign(user, data);
  await this.userRepository.save(user);
  return user;
}

Fetching full entity before update causes extra database query and delays response.

📉 Performance CostTriggers 2 database queries per update, increasing server response time.

Performance Comparison

Pattern	Database Queries	Server Response Time	Client Update Cost	Verdict
Fetch then update entity	2 queries	Higher latency	Moderate	[X] Bad
Direct update query	1 query	Lower latency	Moderate	[OK] Good

Rendering Pipeline

CRUD operations affect the server response time, which impacts when the browser receives data to render or update the UI. Slow CRUD delays data availability, causing slower interaction updates.

→Network

→JavaScript Execution

→Paint

⚠️ BottleneckNetwork latency and server processing time during CRUD calls

Core Web Vital Affected

INP

CRUD operations impact server response time and client rendering speed, affecting how quickly users see and interact with data changes.

Optimization Tips

1Avoid fetching full entities before updates to reduce database queries.

2Use direct update queries to lower server response time.

3Send minimal data to the client and update UI incrementally for faster interactions.

Performance Quiz - 3 Questions

Which CRUD pattern reduces server response time in NestJS?

A Using a direct update query without fetching the entity first

B Fetching the entity before updating it

C Sending the entire entity back after update

D Using multiple queries to confirm update

DevTools: Network

How to check: Open DevTools, go to Network tab, perform CRUD action, and observe request count and timing.

What to look for: Look for multiple requests for a single update or long server response times indicating inefficient CRUD.