kotlinlang #ktor

/**
     * Creates a new {@code ScheduledThreadPoolExecutor} with the
     * given core pool size.
     *
     * @param corePoolSize the number of threads to keep in the pool, even
     *        if they are idle, unless {@code allowCoreThreadTimeOut} is set
     * @throws IllegalArgumentException if {@code corePoolSize < 0}
     */
    public ScheduledThreadPoolExecutor(int corePoolSize) {
        super(corePoolSize, Integer.MAX_VALUE, 0, NANOSECONDS,
              new DelayedWorkQueue());
    }

spand

09/13/2016, 8:35 AM

That has maximumPoolSize = Integer.MAX_VALUE

feng-zihao

09/13/2016, 8:37 AM

....... speechless.....

feng-zihao

09/13/2016, 8:37 AM

Check about Guava ? I remember that it has different implementations about these stuffs.

spand

09/13/2016, 8:45 AM

It doesnt look like they have anything useable

feng-zihao

09/13/2016, 8:48 AM

Maybe you can fork one. 🙂

spand

09/13/2016, 8:52 AM

My mistake. It is actually used in Ktor. Does ktor have any features to limit the amount of work it will accept ?

feng-zihao

09/13/2016, 8:57 AM

Maybe, they'll reject connection on a pre-handler. 🙂 If they implement in this way, connection out of limit will not be passed to thread pool.

spand

09/13/2016, 9:10 AM

Ah this is obviously a jetty setting. Will look into that

feng-zihao

09/13/2016, 9:13 AM

jetty ?! check about

jetty.xml

feng-zihao

09/13/2016, 9:16 AM

Jetty use QueuedThreadPool by default.

orangy

09/13/2016, 10:09 AM

@cy ^^ could you please clarify?

09/13/2016, 10:11 AM

ktor's pool and jetty's are irrelevant. Jetty's pool handles connections and initiates request handling, after that ktor's application call is starting on ktor's pool so jetty's thread is going to be released and jetty could accept more connections

09/13/2016, 10:13 AM

if you have too many requests then ktor's pool will be full while jetty will continue to accept connections and even can handle requests for example if you have some combined configuration with ktor and jetty handlers

spand

09/13/2016, 10:14 AM

It seems that by default both ktors and jettys pools are unbounded

feng-zihao

09/13/2016, 10:14 AM

Jetty's pool can be bounded.

feng-zihao

09/13/2016, 10:14 AM

But as to his description, it'll release once Ktor take control.

spand

09/13/2016, 10:15 AM

But given I would like to only process say 300 requests at a time how can I limit this ?

spand

09/13/2016, 10:16 AM

While I have not tested much of this it seems that in default configuration a server will accept any amount of work choking itself

09/13/2016, 10:18 AM

you can change thread pool factory in the config and provide bounded pool

09/13/2016, 10:18 AM

but it actually not going to help as if you have too high load the server will be unavailable anyway

09/13/2016, 10:19 AM

users will see infinite loading or connection reset errors

feng-zihao

09/13/2016, 10:19 AM

It's a little... wired.. as I think.

feng-zihao

09/13/2016, 10:19 AM

Whether user will see loading/connection reset is one problem.

spand

09/13/2016, 10:19 AM

In a synchronous setting I could just bound the task queue and number of threads for jetty.. but how does this interact with the asynchronous pipeline in ktor ?

feng-zihao

09/13/2016, 10:19 AM

And, wether the server will crash is another problem.

feng-zihao

09/13/2016, 10:20 AM

In our product, we'll always strictly limit the maximum thread pool size on each server.