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#ldnclj
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2015-09-07
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pupeno07:09:15

Good morning.

pupeno09:09:49

I’m doing some performance testing of my Clojure app, and it seems the bare minimum will happily eat 350MB of RAM (Jetty with 6 threads, the minimum). As soon as I add Nashorn, it jumps to >512MB. Is this common or am I experience a problem here? Clojure/Java being memory hungry might have an effect on whether I use Heroku or not.

benedek12:09:32

u cant do ola jon. or can u? eh... :D

jamiei12:09:24

Or afternoon now..

tcrayford15:09:48

@pupeno: ime the jvm isn't super fast/happy until it has ~3gb of ram. Not surprised you have issues on Heroku

pupeno16:09:41

I just published what I think it’s the most comprehensive blog post in how to use New Relic with Clojure: https://carouselapps.com/2015/09/07/using-new-relic-with-clojure/

pupeno19:09:31

tcrayford: is that personal experience?

tcrayford19:09:45

I do actually work for Heroku as well though 😉

tcrayford19:09:17

certainly I've run java apps on Heroku at well under the 512mb limit though

pupeno19:09:01

For a few more experiments I think I’ll use big heroku instances for now for some experiments but then I’ll move to VPSs.

pupeno19:09:35

Probably just deploying with capistrano.

tcrayford19:09:47

I'd uh, recommend using bash or something over capistrano

tcrayford19:09:53

unless you know cap real well

tcrayford19:09:57

(it's kinda bad imo)

pupeno19:09:07

I do know capistrano as I use it already. Using bash would mean having to build a lot of plumbing that capistrano does for me.

tcrayford19:09:01

fair enough then simple_smile It depends how complex your deploys are. Yeller's deploy system doesn't keep around old deploy artifacts or anything like that, just shoves a file in a place and kills the existing process

pupeno19:09:43

Well, you also need to run it on all the servers, run migrations, etc.

pupeno19:09:13

I do like having the option to rollback, although I never used it in my life.

pupeno19:09:55

Also, are people just deploying uberjars that run standalone? No container like Tomcat? I’m new to the Java world so I don’t know if it’s a good idea to just run the uberjar.

tcrayford19:09:25

clojure standard is uberjar

tcrayford19:09:31

don't have leiningen on your production machines

tcrayford19:09:36

just embed jetty or whatever

pupeno19:09:54

Cool. That’s simple enough.

pupeno19:09:10

tcrayford: thanks for pointing it about 3GB of ram. I’m running with 1GB and I can’t go above 0.9 hits per second.

pupeno19:09:16

I mean, on average.

tcrayford19:09:34

yeah that's still very slow

tcrayford19:09:09

I'd expect the average clojure/jetty app to hit ~10k requests/s if it's completely unperformance tuned and not doing too much weirdness with the db

tcrayford19:09:24

maybe more like 70k-100k if it's still http and tuned somewhat

pupeno19:09:10

I’m going to try again with up to 20 virtual concurrent users.

pupeno19:09:40

But I do have Jetty limited to 10 threads, trying to stay within the RAM constraints.

pupeno19:09:58

Responses are fast though, 78ms.

pupeno19:09:46

It seems the JavaScript implementation, Nashorn, is very memory hungry.

tcrayford19:09:02

oh, you're hitting js on each request? that's likely the problem imo

pupeno19:09:30

tcrayford: this is what I’m testing.

pupeno19:09:55

I will think of ways to not execute JS when it’s not really needed, but first, I want to understand the performance of it.