Nodejs + mysql2/promise 连接过多

Question

我正在使用 nodejs + mysql2 的项目中工作，有时我收到错误Too muchconnections。

我的连接：

import {createPool, Pool} from 'mysql2/promise';

export async function connect(): Promise < any > {
  const connection: Pool = await createPool({
    host: 'localhost',
    port: 3306,
    user: 'root',
    password: '',
    database: 'mendozarq',
    connectionLimit: 10
  });
  return connection;
}

控制器：

import { Response, Request } from 'express';
import { FieldPacket, Pool } from 'mysql2/promise';

import { connect } from './../../classes/database';
import { Personal } from './../../models/personal.interface';

export const getAllPersonal = async (req: Request, res: Response) => {
    try {
        const conn: Pool = await connect();

        const [personal]: [any[], FieldPacket[]] = await conn.query('SELECT * FROM personal ORDER BY creadoEn DESC');
        conn.end();

        return res.status(200).json(personal);

    } catch (error) {
        return res.status(400).json({
            error
        });
    }
}

所以，我的问题是我必须使用createConnection而不是createPool，或者我只需要创建我的 conn 的一个实例。

Answer 1

您应该只调用createPool一次，然后每次都从池中进行选择。

所以，它应该看起来像这样。创建一个存储池的常量。然后在函数中，如果池已经存在，则返回池而不调用createPool。如果它不存在，那么您将调用createPool并返回已创建的池。

import {createPool, Pool} from 'mysql2/promise';

const globalPool: Pool | undefined = undefined;

export async function connect(): Promise <Pool> {

  // If the pool was already created, return it instead of creating a new one.
  if(typeof globalPool !== 'undefined') {
    return globalPool;
  }

  // If we have gotten this far, the pool doesn't exist, so lets create one.
  globalPool = await createPool({
    host: 'localhost',
    port: 3306,
    user: 'root',
    password: '',
    database: 'mendozarq',
    connectionLimit: 10
  });
  return globalPool;
}