Future termination

[Serzh Nechyporchuk]

Hello. I have a problems using code with futures. For example, if I run following code:

java -jar clojure-1.6.0.jar -e "(println 1)"

the process prints 1 and terminates.

But when I'm trying to run code with futures:

java -jar clojure-1.6.0.jar -e "(future 1)"

the process doesn't terminates.

This has real implication when I run some task using 

lein run -m some-ns/fun args

If code above uses futures then this process will not terminate. This is really frustrating.

[Andy Fingerhut]

Never is an awfully long time :-)  If you wait about 60 seconds, the command you gave calling (future 1) does terminate, at least on Mac OS X 10.8.5 where I tested it, and I have seen the same behavior on Linux and I think Windows.

This version terminates much more quickly:

java -jar clojure-1.6.0.jar -e "(future 1) (shutdown-agents)"

There is some discussion of this issue at the ClojureDocs page for the function 'future', including that this issue affects pmap and clojure.java.shell/sh, too, because are both implemented using futures:

    http://clojuredocs.org/clojure_core/clojure.core/future

It also includes a link to a Clojure ticket suggesting that this behavior change.  You can vote on it if you like (requires a Clojure JIRA account, which you can create by clicking on the "Log In" link near the top right of the page):

    http://dev.clojure.org/jira/browse/CLJ-124

Andy

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[Serzh Nechyporchuk]

On my Ubuntu 14.04 laptop process doesn't terminates at all. I was waiting about an hour.

Also this issue affects code which uses datomic.api, which, I think, uses futures too.

Середа, 30 липня 2014 р. 22:50:11 UTC+3 користувач Andy Fingerhut написав:

[Andy Fingerhut]

Serzh:

Could you give a few details about the software machine where you saw it not terminate, even after an hour?  I may try collecting some info like this to add to the Clojure ticket.  In particular, the outputs of the following commands.

java -version

uname -a

lsb_release -d

time java -jar clojure-1.6.0.jar -e "(future 1) (shutdown-agents)"
time java -jar clojure-1.6.0.jar -e "(future 1)"

For that last one, if it runs more than 2 minutes without terminating, you can kill it.  No need to wait for an hour.

I have tried Ubuntu 14.04 desktop 64-bit running in a VM on my Mac, and the last command above terminates in about 60 seconds, for several different JVM versions (mostly Oracle).  Yours is the first case I've heard of not terminating after about a minute, so wanted to try to reproduce that case.

I think it would be good if it took the same short time to terminate as if you call shutdown-agents, even without calling shutdown-agents.  I may also work on a patch for that ticket, after trying to summarize the long list of comments.

Thanks,
Andy

[Serzh Nechyporchuk]

Sorry for my delayed answer. I've tried examples with only futures that you give and they works really fine, all agent were closed.

 And I figured out that this problem arises only when I using datomic.api.

> java -version

java version "1.7.0_55"

OpenJDK Runtime Environment (IcedTea 2.4.7) (7u55-2.4.7-1ubuntu1)

OpenJDK 64-Bit Server VM (build 24.51-b03, mixed mode)

> lsb_release -a

No LSB modules are available.

Distributor ID: Ubuntu

Description:    Ubuntu 14.04 LTS

Release:        14.04

Codename:       trusty

> uname -a

Linux serzh-System-Product-Name 3.13.0-24-generic #47-Ubuntu SMP Fri May 2 23:30:00 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

> time java -cp `lein classpath` clojure.main  -e "(require 'datomic.api) (shutdown-agents)" 

java -cp `lein classpath` clojure.main -e   3,03s user 0,12s system 109% cpu 2,870 total

> time java -cp `lein classpath` clojure.main  -e "(require 'datomic.api)" 

# This doesn't released.

Четвер, 31 липня 2014 р. 17:21:50 UTC+3 користувач Andy Fingerhut написав:

-- 

Best regards,

Serhii Nechyporchuk

Четвер, 31 липня 2014 р. 17:21:50 UTC+3 користувач Andy Fingerhut написав: