EventEmitter memory leak on node v0.3.5, with possible fix about node-http-proxy

[indexzero]

We've been seeing this memory leak in production but hadn't been able to track it down yet.

We're running node 0.3.1 (for at least minimal https support), so that would explain where we don't see it.

Thanks for the heads up and I'll investigate and get back to you.

[thegreatape]

Interesting. I ran the same tests using node v0.3.1, with the same results - with the pool error handler in place, memory leaks occur. Without the error handler, it runs like champ under load. :-)

[indexzero]

Nice. Will try siege myself, I'd only been using ab up till now, but this looks wayyy better.

Thanks again.

[joelklabo]

I'm having the same issue on 0.3.7, did anyone solve this?

[indexzero]

All,

We will be dropping pool when we upgrade to 0.4.x in the next month or so because node.js > 0.3.6 does connection pooling for us.

In the meantime, let me know how the removal of the pool error handler works in prod. I don't think it's the cause and not handling it can cause uncaught exceptions under high load.

[davidmoshal]

Hi, what's the status of this bug?.

I'm getting this error, on node 0.4:

(node) warning: possible EventEmitter memory leak detected. 11 listeners added. Use emitter.setMaxListeners() to increase limit.
Trace:
at Pool. (events.js:101:17)
at Object.proxyRequest (/usr/local/lib/node/.npm/http-proxy/0.3.1/package/lib/node-http-proxy.js:185:7)
at Server. (/Users/davem/Petromatch/repository/eclipse/petromatch-java/node/faye-server.js:12:3)
at Server. (/usr/local/lib/node/.npm/faye/0.5.5/package/faye-node.js:1952:22)
at Server.emit (events.js:45:17)
at HTTPParser.onIncoming (http.js:1078:12)
at HTTPParser.onHeadersComplete (http.js:87:31)
at Socket.ondata (http.js:977:22)
at Socket._onReadable (net.js:654:27)
at IOWatcher.onReadable as callback

[davidmoshal]

oh, and node is definitely leaking.

[indexzero]

Working on a update for node 0.4.0. A lot of this has to do with the pool dependency which we can remove using the http.Agent API in 0.4.0

[davidmoshal]

thanks, rough eta?
node now at 760 Mb after 6 hours of very light dev testing (couple of connections)
ie: I wouldn't feel comfortable moving to production.

[davidmoshal]

ps: I also posted this on the node.js google group, and had some interesting replies:

https://groups.google.com/d/topic/nodejs/TbHMjwMdRRY/discussion

[davidmoshal]

note the following comment regarding the code I posted, which is based on the example in the node.js readme:

https://groups.google.com/d/msg/nodejs/TbHMjwMdRRY/eoDRenX0UCEJ

is it true that every request creates a new proxy which isn't garbage collected?

[indexzero]

It is true that every request creates a new proxy. It is false that it is not garbage collected.

[indexzero]

I replied to the thread here: https://groups.google.com/forum/#!msg/nodejs/TbHMjwMdRRY/eoDRenX0UCEJ

Will try to bang this out in the next week or so.

[davidmoshal]

I replaced this (which I found on your site):

var server = http.createServer (function (req, res) {

new httpProxy
.HttpProxy (req, res)
.proxyRequest (8080, 'localhost', req, res)

})

with:

var server = httpProxy.createServer (8080, 'localhost')

Functionality is the same, and the leak does seem to be less, but will know later today.

[davidmoshal]

Have you been following this:

https://groups.google.com/d/msg/nodejs/TbHMjwMdRRY/6YIi6ktiuOEJ

[davidmoshal]

I ran node-inspector on my code, with v8-profiling.
As far as I can tell, HttpProxy is not being GC'd

Every request increments HttpProxy, ClientRequest and ServerResponse counts.
These counts never decrease, even if the system is left alone for some time.

I have a screen shot of the profiler, though I don't see a way to attached files here, so email me if you want to see the screenshot: dmoshal at gmail dot com.

[indexzero]

I have fixed this issue in the v0.4.0 branch. Unfortunately, it is not stable due to a few bugs in the node.js http.Agent APIs that I am working to resolve.

We will push v0.4.0 when we can get these issues resolved in core; hopefully the aforementioned fixes will make it into 0.4.3

[davidmoshal]

Thanks, I'm using nginx for now (without websockets)

Dave

On Thu, Mar 10, 2011 at 7:49 PM, indexzero <
[email protected]>wrote:

I have fixed this issue in the v0.4.0 branch. Unfortunately, it is not
stable due to a few bugs in the node.js http.Agent APIs that I am working to
resolve.

We will push v0.4.0 when we can get these issues resolved in core;
hopefully the aforementioned fixes will make it into 0.4.3

#21 (comment)