"Malformed communication packet" when using prepared statements

Hello,

I get the following MySQL error when I invoke .execute() with a prepared statement:

{
  type: "Error",
  message: "Malformed communication packet.",
  stack:
    "Error: Malformed communication packet.\n    at PromiseConnection.execute (/path/to/project/node_modules/mysql2/promise.js:111:22)\n    at UserRepository.<anonymous> (/path/to/project/src/lib/repository/UserRepository.ts:11:52)\n    at step (/path/to/project/src/lib/repository/UserRepository.ts:26:23)\n    at Object.next (/path/to/project/src/lib/repository/UserRepository.ts:7:53)\n    at /path/to/project/src/lib/repository/UserRepository.ts:8:71\n    at new Promise (<anonymous>)\n    at __awaiter (/path/to/project/src/lib/repository/UserRepository.ts:4:12)\n    at UserRepository.fetchUserById (/path/to/project/src/lib/repository/UserRepository.ts:51:16)",
  code: "ER_MALFORMED_PACKET",
  errno: 1835,
  sql: "SELECT * FROM `User` WHERE `userId` = ?",
  sqlState: "HY000",
  sqlMessage: "Malformed communication packet.",
}

My code looks like this:

import { Connection } from "mysql2/promise";
import { User } from "./model";

export class UserRepository {
    private mysqlConnection: Connection;

    constructor(mysqlConnection: Connection) {
        this.mysqlConnection = mysqlConnection;
    }

    async fetchUserById(userId: number): Promise<User> {
        const params = [userId];
        const [rows] = (await this.mysqlConnection.execute("SELECT * FROM `User` WHERE `userId` = ?"), params) as any;
        return rows[0];
    }
}

I’ve tried hard-coding the bound value, which produces the same result:

async fetchUserById(userId: number): Promise<User> {
    const params = [2];
    const [rows] = (await this.mysqlConnection.execute("SELECT * FROM `User` WHERE `userId` = ?"), params) as any;
    return rows[0];
}

I also tried removing the params array and hard-coding the value into the query, to eliminate the query itself as an issue. When I do this, the query executes properly and returns data.

async fetchUserById(userId: number): Promise<User> {
    const [rows] = (await this.mysqlConnection.execute("SELECT * FROM `User` WHERE `userId` = 2")) as any;
    return rows[0];
}

I am using MySQL 8:

bkotos@bkotos-pi:~$ mysql -V
mysql  Ver 8.0.27-0ubuntu0.21.04.1 for Linux on aarch64 ((Ubuntu))

Am I doing something wrong? Or is there maybe an issue with my MySQL setup? Any help is greatly appreciated!

[sidorares]

@bkotos hopefully this line can save some time debugging similar error in the future

[sidorares]

I suspect root cause is the same as described in https://github.com/sidorares/node-mysql2/issues/1239#issuecomment-718827355

I’m working on a fix in https://github.com/sidorares/node-mysql2/pull/1407