Pooling

Creating a connection pool

Pool class is used to create a connection pool. Constructor accepts connection string or PoolConfiguration interface

new Pool([config: String | PoolConfiguration]);

import { Pool } from 'postgrejs';

const dbpool = new Pool({
  host: 'postgres://localhost',
  min: 1,
  minIdle: 1,
  max: 10,
  maxQueue: 1000,
  idleTimeoutMillis: 30000,
  acquireMaxRetries: 0,
  acquireRetryWait: 2000,
  acquireTimeoutMillis: 0,
  validation: true
});
const qr = await dbpool.query('select * from my_table where id=1');
// Do whatever you need with pool
await dbpool.close(); // Disconnect all connections and shutdown pool

Obtaining a connection

The pool returns an idle Connection instance when you call pool.acquire() function. You must call connection.release() method when you done with the connection.

pool.acquire(): Promise<[Connection](#211-connection)>;

  const connection = await dbpool.acquire();
try {
    const qr = await connection.query('select * from my_table where id=1');
    // ... Do whatever you need with connection
} finally {
    await connection.release(); // Connection will go back to the pool
}

Pool class has pool.execute() and pool.query() methods which applies "obtain a connection", "execute the given query" and "release the connection" sequence. This is the comfortable and secure way if you don't execute your query in a transaction. So you don't need to take care of releasing the connection every time.

Shutting down the pool

To shut down a pool call pool.close() method. This will wait for active connections to get idle than will release all resources. If you define `terminateWait argument, the pool wait until the given period of time in ms, before force connections to close.

pool.close(terminateWait?: number): Promise<void>;