How does node mysql2/promise 's connection pool release connections?

connection pooling using mysql2/promise because the connection is not released, finally mysql will report a Can"t create more than max_prepared_stmt_count statements error, so how does it release the connection?
my code looks like this
1. Create a connection

const mysql = require("mysql2/promise")
 var connection =  mysql.createPool(mysqlConfig)
  global.connection = connection

2. Mount the link to ctx

app.use(async (ctx, next) => {

  ctx.mysqlConection = global.connection
  // console.log(global.connection, "99999999999")
  ctx.controller = controller
  ctx.service = service
  ctx.are = are
  ctx.iz = iz
  ctx.rules = rules.rules
  ctx.model = mongodb.mongoose.models;
  await next()
  ctx.mysqlConection.end()

})```

3. controller

findUv: async function (ctx) {
    let condition = ctx.request.body
    let sql = `SELECT count AS uv FROM gugudai_count ORDER BY id ASC LIMIT 1`
    console.log("******************2",ctx.mysqlConection.getConnection)
 
    const [rows, fields] = await ctx.mysqlConection.execute(sql)
    // let conne=await ctx.mysqlConection.getConnection;
    // console.log(conne)
    return { rows }
},

// For pool initialization, see above pool.getConnection(function(conn) { // Do something with the connection conn.query(/* ... */); // Don't forget to release the connection when finished! pool.releaseConnection(conn); })