How can I increase per host concurrency with HttpClient?

Ashish Datta

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Jun 5, 2018, 12:09:26 AM6/5/18

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My use case seems fairly typical but I can't seem to find a working example. I'm using Vert.x 3.5.0 with -instances=3

I have a Vert.x web server which services user requests and in doing so has to ping a 3rd party fraud service with their phone+email. I'm making these requests on a verticle through the EventBus but since all the requests are to the same domain and host it looks like I'll always only have a max of 3 (1 per verticle) connections open to the host. This class seems to be gone in master but it looks like https://gist.github.com/adatta02/2229da27d3d629981d3ba1be53bc8884#file-connectionmanager-java-L145 is what's limiting that. And seems independent of any HttpClientOptions being set like setMaxPoolSize()

So my question is how can I scale up the number of connections HttpClient (or WebClient) will make to a host short of boosting the number of verticles? Over half of the requests hitting the web server require a request to the 3rd party service so I'm trying to get to something like long lived ~25-30 HTTP connections to the service to boost my overall throughput since these verification requests have become a bottleneck in servicing traffic.

Thanks!

Julien Viet

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Jun 5, 2018, 3:09:29 AM6/5/18

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Hi,

we recommend to use several clients in this case.

there is no overhead for doing this (as a client is very lightweight and is basically a map of endpoint where each endpoint contains a pool of connections)

Julien

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Julien Viet

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Jun 5, 2018, 5:36:23 AM6/5/18

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Hi,

actually I'm not sure I understood well your question, because this event bus usage is confusing

can you rephrase it ?

the HttpClient currently uses up to N connection per host:port (for HTTP/1.1) as configured by maxPoolSize

if you deploy a verticle that configures this client M times, then you get N x M max connection.

Julien

On 5 Jun 2018, at 06:09, Ashish Datta <adat...@gmail.com> wrote:

Ashish Datta

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Jun 5, 2018, 11:41:33 AM6/5/18

to vert.x

Ah my fault, I actually inherited this codebase and didn't realize that the developers are actually creating a client per request. I think I'm hitting another issue which I'm not sure how to describe.

https://github.com/Setfive/vertx-slow-sessions/blob/http-concurrency/src/main/java/io/vertx/example/web/sessions/RequestVerticle.java

https://github.com/Setfive/vertx-slow-sessions/blob/http-concurrency/src/main/java/io/vertx/example/web/sessions/Server.java#L49

is basically what they're doing.

That project actually will reproduce this issue. Requests to the "fast" endpoint are fine:

ashish@loki:~$ curl http://localhost:8080/test-fast

But if I make several requests to http://app.s5srv.com/slow.php which times out and then make a request to the "fast" endpoint I seem to get a TimeoutException even thought I would assume the HttpClient instances aren't shared.

ashish@loki:~$ curl http://localhost:8080/test-slow

<html><body><h1>url
ashish@loki:~$ curl http://localhost:8080/test-fast

You'll notice the vertx process outputs:

ERROR
java.util.concurrent.TimeoutException: The timeout period of 1000ms has been exceeded while executing GET /slow.php?q=notslow&i=REQUESTED for host app.s5srv.com
    at io.vertx.core.http.impl.HttpClientRequestBase.timeout(HttpClientRequestBase.java:178)
    at io.vertx.core.http.impl.HttpClientRequestBase.handleTimeout(HttpClientRequestBase.java:163)
    at io.vertx.core.http.impl.HttpClientRequestBase.lambda$setTimeout$0(HttpClientRequestBase.java:121)
    at io.vertx.core.impl.VertxImpl$InternalTimerHandler.handle(VertxImpl.java:885)
    at io.vertx.core.impl.VertxImpl$InternalTimerHandler.handle(VertxImpl.java:844)
    at io.vertx.core.impl.ContextImpl.lambda$wrapTask$2(ContextImpl.java:339)
    at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:163)
    at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:404)
    at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:463)
    at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:886)
    at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
    at java.lang.Thread.run(Thread.java:745)
On fast got: ERROR