Connecting and disconnecting (Concepts)

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PrismaClient connects and disconnects from your data source using the following two methods:

In most cases, you do not need to explicitly call these methods. PrismaClient automatically connects when you run your first query, creates a connection pool, and disconnects when the Node.js process ends.

See the connection management guide for information about managing connections for different deployment paradigms (long-running processes and serverless functions).

$connect()

It is not necessary to call $connect() thanks to the lazy connect behavior: The PrismaClient instance connects lazily when the first request is made to the API ($connect() is called for you under the hood).

Calling $connect() explicitly

If you need the first request to respond instantly and cannot wait for a lazy connection to be established, you can explicitly call prisma.$connect() to establish a connection to the data source:


const prisma = new PrismaClient()

// run inside `async` function
await prisma.$connect()

$disconnect()

When you call $disconnect() , Prisma Client:

Runs the beforeExit hook
Ends the Query Engine child process and closes all connections

In a long-running application such as a GraphQL API, which constantly serves requests, it does not make sense to $disconnect() after each request - it takes time to establish a connection, and doing so as part of each request will slow down your application.

To avoid too many connections in a long-running application, we recommend that you use a single instance of PrismaClient across your application.

Calling $disconnect() explicitly

One scenario where you should call $disconnect() explicitly is where a script:

Runs infrequently (for example, a scheduled job to send emails each night), which means it does not benefit from a long-running connection to the database and
Exists in the context of a long-running application, such as a background service. If the application never shuts down, Prisma Client never disconnects.

The following script creates a new instance of PrismaClient, performs a task, and then disconnects - which closes the connection pool:


import { PrismaClient } from '@prisma/client'

const prisma = new PrismaClient()
const emailService = new EmailService()

async function main() {
  const allUsers = await prisma.user.findMany()
  const emails = allUsers.map((x) => x.email)

  await emailService.send(emails, 'Hello!')
}

main()
  .then(async () => {
    await prisma.$disconnect()
  })
  .catch(async (e) => {
    console.error(e)
    await prisma.$disconnect()
    process.exit(1)
  })

If the above script runs multiple times in the context of a long-running application without calling $disconnect(), a new connection pool is created with each new instance of PrismaClient.

Exit hooks

From Prisma 5.0.0, the beforeExit hook only applies to the binary Query Engine.

The beforeExit hook runs when Prisma is triggered externally (e.g. via a SIGINT signal) to shut down, and allows you to run code before Prisma Client disconnects - for example, to issue queries as part of a graceful shutdown of a service:


const prisma = new PrismaClient()

prisma.$on('beforeExit', async () => {
  console.log('beforeExit hook')
  // PrismaClient still available
  await prisma.message.create({
    data: {
      message: 'Shutting down server',
    },
  })
})

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Connecting and disconnecting

$connect()

Calling $connect() explicitly

$disconnect()

Calling $disconnect() explicitly

Exit hooks

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