netty: worker threads creating per connection not considering input 500

Expected behavior

create more worker threads and high performance

Actual behavior

created only 1 worker thread per connection giving low performance - most of txns timeout due to late response

Steps to reproduce

my application static connection (client-server) high volumes of transactions.

Minimal yet complete reproducer code (or URL to code)

  private EventLoopGroup bossGroup = new EpollEventLoopGroup(4, Executors.newCachedThreadPool());
   private EventLoopGroup  workerGroup = new EpollEventLoopGroup(500, Executors.newCachedThreadPool());

    // ===========================================================
    // 1. define a separate thread pool to execute handlers with
    //    slow business logic. e.g database operation
    // ===========================================================
     group = new DefaultEventExecutorGroup(500); //thread pool of 500
    try {
        ServerBootstrap bootstrap = new ServerBootstrap();
        bootstrap.group(bossGroup, workerGroup)
                //Linux Native Library classes
                .channel(EpollServerSocketChannel.class)
                .childHandler(new ChannelInitializer<SocketChannel>() {
                    @Override
                    public void initChannel(SocketChannel ch)
                            throws Exception {
                        ch.pipeline().addLast("decoder", new Decoder())
                                .addLast("encoder", new Encoder())
                                .addLast(group, new Handler());

                    }
                }).option(ChannelOption.ALLOCATOR, PooledByteBufAllocator.DEFAULT)
                .option(ChannelOption.SO_BACKLOG, 128)
                .childOption(ChannelOption.ALLOCATOR, PooledByteBufAllocator.DEFAULT)
                .childOption(ChannelOption.SO_SNDBUF, 1024 * 1024)
                .childOption(ChannelOption.SO_RCVBUF, 32 * 1024)
                .childOption(ChannelOption.TCP_NODELAY, true)
                .childOption(ChannelOption.SO_KEEPALIVE, true);

Netty version

4.1.50.Final

JVM version (e.g. java -version)

Open JdK11

OS version (e.g. uname -a)

linux