Website built on: Rails 3.0.3 & Heroku
Installed: Exception Notifier & New Relic
I am rewriting this question since my previous attempt was unclear and subjective, hope this works better.
I have a website where users can perform calculations. Once in a while I get reports from the users through my (one way) communication media that "the website crashes and tells me I need to restart IE, but it still doesn't work" which is pretty much as specific information I have been retrieving.
I get no timestamps so I can not look for it in the logs (Heroku only allows 2000 lines of error logs), I get no exception notifications and I cannot make the error appear myself so I would like your help with the following:
What would make a website crash in the way that it would tell the user to restart the browser? I have never even heard of that! What should I look for in the logs, if I can get timestamps for the errors?
Assuming it is a JavaScript-problem (which seems likely). How could I trouble shoot this issue? What tools can I use? Firebug does not give me any errors.
Assuming it is a IE version thing. How can I test the application in a systematic manner? (without installing/reinstalling different versions). Is there any applications that can test an application for different browsers?
It seems to work for most users/combinations. Do you have an older version of IE installed and can produce this error? Site: www.countcalculate.com (try any calculation).
Probably related to a very intensive loop. For some reason IE thinks it's appropriate to block the UI thread while JavaScript is executing, so the whole thing will freeze up if your JavaScript breaks.
I can't reproduce the issue, so I'd suggest trying to get more detailed reports from your customers.
The problem was (appearantly) limited to IE8 & XP-users. That combination conflicted with a bug in jQuery 1.6.2 according to http://bugs.jquery.com/ticket/9981.
Downgrading to 1.6.1 solved the problem.
Related
Last week I was working through a chat app tutorial that guided me through using Redis for a turbo stream. But then I stumbled across DHH's demo of Rails 7 where he hooks up the broadcast simply using Rails out of the box.
Now, when I try to follow his approach, I get this error in the server output:
Error performing Turbo::Streams::ActionBroadcast (lots of numbers) Redis::CannotConnectError
I think the problem is that my turbo stream is configured to use Redis since I installed it last week. So what I'm hoping to be able to do is to revert to the turbo configuration that comes built in to Rails 7. I'd love to bypass Redis if possible, since this approach seems cleaner. Not to mention, with last week's chat app, I never managed to get Redis working after deploying to Heroku (but I did get it working in development).
I thought about uninstalling Redis, but I don't think that would change the turbo configuration anyway. And I'm worried leave me in a spot that's even trickier to fix.
Any insight is appreciated.
Edit: After a bit more research, Redis seems to come in the standard gemfile in Rails 7. I was able to clear this error by starting my Redis server. But DHH never does that in the demo video. Also, my views are still not updating live.
I have a weird issue that just started popping up for our customers. The portal they've been using for years has started freezing on some of the pages that the user navigates to. I tried restarting the IIS Server, the site within and the Application Pool under which the site is site is running. No difference.
In Chrome Dev Tools I can see that it is always one of these three calls that take time to complete:
When it happens, one of those three calls will report that the request is not finished, like this:
When eventually the call completes, I can see that the Content Download took 3.8 minutes. Not sure whether it is relevant or not, but it is always 3.8 minutes:
Did anyone else encounter a similar situation? Is there a suggestion on how to figure out what is happening all of a sudden that triggers these type of behaviours?
TIA,
Ed
Edit: The resource that fails to load after 3.8 minutes always generates a net::ERR_CONNECTION_RESET error:
Edit2: Thanks to all of you trying to help. A little update: I was able to isolate to problem to an issue with the server not serving some of the files. either *.css or *.js. The setting is that of two identical servers placed behind a load balancer. Apparently, the load balancer software was recently updated and right after that we started having these issues. I am working closely with the IT department of our client, trying to figure out what is the impact of the newer version that seems to have triggered all this drama.
I have a Rails 3 app that I am running on Heroku. The app is usually really fast but sometimes I'll get cases where the app seems to hang for upwards of 2 minutes before finally returning the requested page.
I have the New Relic addon installed and there doesn't seem to be anything sticking out at me. It seems to be kind of sporadic and doesn't seem to be connected to a particular controller/action.
How would you suggest I go about pinpointing the cause of this problem?
http://github.com/kyledecot/skateparks-web
Always check the logs. When it happens, immediately go check your logs. Pretty sure all SQL queries are logged and timed, and you might want to add logging and timing to some of your own service calls.
If you upgrade to the Pro level of New Relic, you can get detailed traces specifically of your slow transactions. Turn up your Transaction Trace threshold to a large number (1s is pretty big), and wait for traces to show up. You'll see a detailed breakdown of the performance of an individual request, including SQL queries.
(Full disclosure: I work for New Relic.)
I have noticed that after my Grails app has been deployed for about 2 weeks, performance degrades significantly, and I have to redeploy. I am using the Spring Security plugin and caching users. My first inclination is that it has something to do with this and the session cache size, but I'm not sure how to go about verifying this.
Does it sound like I'm on the right track? Has anyone else experienced this and narrowed down the problem? Any help would be great.
Thanks!
Never guess where to optimize, it's going to be wrong.
Get a heap dump and a profile it a little (VisualVM worked fine for me).
It might be a memory leak, like it happened to me. What is your environment - OS, webserver, Grails?
I would recommend getting YourKit (VisualVM has limited information) and use this to profile your application in production (if possible).
Alternatively you could create a performance test (with JMeter for example) and performance test the pieces of your application that you suspect is causing the performance degredation.
Monitoring memory,cpu,threads,gc and such while running some simple JMeter performance tests will definitely find the culprit. This way you can easily re-test your system over time and see if you have incorporated new "performance killing" bugs.
Performance testing tools/services:
JMeter
Grinder
Selenium (Can performance test with selenium grid, need hw though)
Browsermob (Commercial, which uses Selenium + Selenium-Grid)
NeoLoad by NeoTys (Commercial, trial version available)
HP Loadrunner (Commercial, The big fish on the market, trial version available)
I'd also look into installing the app-info plugin and turning on a bunch of the options (especially around hibernate) to see if things are getting out of control there. Could be something that's filling the hibernate session but never closing a transaction.
Another area to look at is if you're doing anything with the groovy template engine. That has a known memory leak, that's sort of unfixable if you're not caching the class/results. Recently fixed a problem around this on our app. If you're seeing any perm gen errors, this could be the case.
Try to install Javamelody plugin. In our case it helped to find problem with GC.
I am running a rails app on Dreamhost.
Today, a strange thing happened.
A page is almost loaded (it seems to be fully loaded but the status is not 'Done') and after that, the app didn't respond on any page.
I checked out the log and even the log was not complete.
How do I know it?
There are 3 missing images on the problem page and the log showed only 2 missing images and stopped there.
So I guess that something happened between the 2nd and the 3rd missing images.
I couldn't even start 'script/console production'.
After 14 minutes, it began to behave normally.
I asked the hosting company and they said that the process was killed due to over-use of memory.
Probably something was running heavily during the period.
The same thing happened one more time.
I had to kill the process to unlock the stucked app.
Passenger version is 2.2.4 and rails version is 2.3.2.
I am afraid that I can't give more specific info.
What do you guess cause such a problem?
Thanks.
Sam
As theIV stated, look at the last action called. Start this up locally and try to go through what was happening on the server to see if it's reproducable, or if you just get any sort of general hiccups. I've run Rails apps on Dreamhost for a while, and have not experienced this before, so I would guess that it's not Dreamhosts fault, but there is no 100% on that.
Good luck!
This sounds pretty app specific. I would start by looking at what action was last hit before the process started hoggin' and then work backwards from there to see if there are any calls that might be doing something you weren't expecting. Other than that, no clue. :(
Try using NewRelic RPM or TuneUp Lite to see what process is chunking most of your memory. You can run them locally but it would be better to test it on production.