使用node.js批量删除mysql行

Question

var Sequelize= require('sequelize')
var sequelize = new Sequelize('db', 'user', 'password',
{pool: { maxConnections: 5, maxIdleTime: 30 }})
var table = sequelize.define('User', 
{ 
       trip_paramid: Sequelize.INTEGER
},

{timestamps:false})

table.sync({ force: false }).success(function()
{
  table.destroy('`id` >= 5685321').success(function() {
  console.log("deleted");
  })
  table.destroy('`id` >= 9600000').success(function() {
  console.log("deleted");
  })
  table.destroy('`id` >= 15600000').success(function() {
  console.log("deleted");
  })
  table.destroy('`id` >= 20000000').success(function() {
  console.log("deleted");
  })
  table.destroy('`id` >= 25000000').success(function() {
  console.log("deleted");
  })
  table.destroy('`id` >= 35600000').success(function() {
  console.log("deleted");
  })
})

I have used sequelize as an ORM here for bulk deletion of rows based on a condition. It is working. But now i am trying to do the same function without using sequelize. The problem is because i need to delete rows from an existing database. In this scenario using sequelize becomes a problem. i have tried bulk deletion without using sequelize it is also working but the whole process has become slow.

var mysql = require('mysql');              
var pool  = mysql.createPool({
connectionLimit : 10,
host            : 'host',
user            : 'user',
password        : 'password',
database        : 'db',
multipleStatements: true
 });


var id=57166;
var query='delete from users1 where id=';
bulkdelete();

function bulkdelete()
{
if(trip_paramid >=57166)
  {
   pool.query(query+ id+';'+query+(id+1)+';'+query+(id+1)+';'+query+(id+1)+';'+query+(id+1)+';', function(err, results) 
   {
    if (err) throw err;
    trip_paramid++;
        bulkdelete();
        console.log("deleted1");
    });
}
}

Can anyone suggest an idea to solve this issue. I need to speed up the process (many rows in less time without using any ORM)

Answer 1

Couple issues with your code that I can see.

First off, the concatenation of strings into the query the way you're doing it is extremely dangerous (prone to other folks hacking your stuff) and it's also slow by itself and a memory hog. You're allocating a new string for every time you do a + operation.

Second, databases excel in set operations and doing them quickly; why do it one-by-one if you're trying to get everything greater than 57166, just build the query like that.

delete from users where id >= 57166; .

If that needs to be an actual parameter, use the prepared statements as described in the mysql2 driver: https://github.com/sidorares/node-mysql2

Your query would then look something like:

delete from users where id >=?;

and you'd pass the min ID number as a parameter.