I am wondering where this comes from : I have a 2 field form for a site that I am building and for some reason, the post request takes up to 13 seconds to complete, according to firebug... The script literally just sends an email in plain text with the user inputs and that's it, nothing complicated.
I am wondering where that delay could come from, any idea ?
Here is a link to a dev version : http://vps-sd.com/sd2012/
I tend not to click links to sites I don't trust, but it could be either
1) Network latency. Are you on a vpn? Where is the dev server hosted? You can use traceroute or something like that to follow the request from the command line.
If both the client and the server are on your dev box this should not be an issue.
2) For really long requests, I think it is more likely something in your dev server is screwed up. It could be the code, or it could be that the dev server is having some issues. Did you log onto the dev server and look at its load? Has some process gone haywire? Has it used all its memory? Did you add some simple benchmarking code to the application server?
You need to diagnose where exactly the slowdown is.
Related
I have done something silly and written a script for a website that does an ajax check every 2 seconds. In this case its using wordpress and its admin-ajax.php file every 2 seconds. This essentially burned up all the CPU power of the server, and made every site on the server run really slowly.
After a lot of detective work, i finally found the script and stopped it, so that it doesn't happen on new loads of that website. But looking at my apache log, i can see that it is still running in one browser somewhere.
Is there a way for me to stop that browser from requesting that ajax-call, or perhaps block it from my server? Or will I just have to wait until that browser is being refreshed or closed?
Try to use netstat or something similar through ssh to detect the IP and port of the unknown browser. Also you should try to reboot the server so it may will loose connection.
PS: It's pretty hard to give a clue or answer in the right direction without having any logs or evidence to ensure you answer to this question correctly.
Practical Challenge:
I have a LR script that runs against an app being mocked and do not have a logout button (yet).
The test runs fine With stable response time for about 10 minutes, but after that the response time peaks and the server goes into 99% memory usage and transactions start to fail.
I suspect this is due to the script does not terminate the vusers after each run anf it builds up a lot of running sessions against the server wich is not terminated. But I might be wrong.
Anyays I want to programatically close each run after it has competed the business process.
I have red somewhere that web_set_sockets_option ("SHUTDOWN_MODE", "ABRUPT") could be used for this, but I want to be sure that this function actually does what I want and what does 'ABRUPT' means?
Are there better ways of closing sessions? Clicking the close browser during recording does not result in anything being captured in the script.
It's a server issue on session aging. Your server admin for your website can adjust the timeout values where no activity has taken place on a given session. By default most places have this set at 30 minutes. Trim it to what you need rather than taking the default value on the server.
Also, you may have hit a leak situation if resources are constantly accumulated on the server side but never released.
Based on your question I assume you're using the WEB/HTML protocol. I agree that the core issue is that your app's sessions should expire more elegantly and probably sooner. But, in order to get beyond this while testing you can try this. It isn't a guarantee, but it has worked sometimes for me in the past when dealing with similar situations. Try changing your Run-time Settings for the script:
Run-time Settings > Browser > Browser Emulation
Make sure you have the box checked for "Simulate a new user on each iteration". You can also try playing with the other settings here, like clearing the cache each iteration. This could cause a new connection setting with the web page for each iteration depending on the server's session settings. Again, this isn't 100%, but it has worked for me from time to time.
try this:
web_set_sockets_option("CLOSE_KEEPALIVE_CONNECTIONS", "1");
I am using Meteor on Heroku (free tier) with MongoHQ. My app is very simple right now, it loads 3-4 entries from a Collection, but when I deploy it to Heroku, I am seeing ridiculous load times (1-2 minutes). The HTML is rendered immediately. When I deploy to Meteor.com's free server, load times are a lot lower but still about 15 seconds for 4 tiny pieces of data. I'm not seeing this whatsoever when I deploy locally, app pulls data from the DB right away.
It is worth noting that I don't think it's an "idling" issue for Heroku. Even if I already have one browser window with the app just opened, if I use a different browser and try again I still get 1-2 minute load times. Once the data is loaded, however, performance goes back to being great, I can read and write with no problems.
What am I missing? I'm not seeing any errors in the console, mongo shows several queries in the logs and shows that it is responding quickly with 4 documents, but apparently somewhere in the middle there's a traffic jam. Any help with this is greatly appreciated, if I can't get past this Meteor is useless for my needs right now.
UPDATE: I've been watching it closely in Firebug, and it looks like the performance is largely inconsistent. Sometimes a simple refresh will take 1 minute, sometimes it will take 10 seconds. But what I've noticed is that the times when its slow, it GETs the sockjs/info file, then right after that the sockjs POST is aborted (sometimes multiple times). When it runs fast, the POST and subsequent POSTs run smoothly
Slow:
GET http://pocleaderboard.herokuapp.com/sockjs/info 200 OK 22ms
POST http://pocleaderboard.herokuapp.com/sockjs/029/su0d77fb/xhr Aborted
GET http://pocleaderboard.herokuapp.com/sockjs/info 200 OK 27ms
POST http://pocleaderboard.herokuapp.com/sockjs/132/uljqusxd/xhr Aborted
GET http://pocleaderboard.herokuapp.com/sockjs/info 200 OK 28ms
POST http://pocleaderboard.herokuapp.com/sockjs/154/kcbr6a5p/xhr Aborted
Fast(er):
GET http://pocleaderboard.herokuapp.com/sockjs/info 200 OK 1.08s
POST http://pocleaderboard.herokuapp.com/sockjs/755/xiggb555/xhr 200 OK 1.02s
Meteor gets loaded that fast locally, because it doesn't depend on your internet connection and the files can just be read from your harddrive and don't need to be downloaded.
And once the data is loaded it's the same everywhere you host, because the client (you) perform all actions on your cached mongo database and then just wait for the server to say if the action was alright or not.
But for the Heroku loading times, I have no idea, Sorry!
UPDATE:
These are the long-pulls from SockJS that is used by Meteor.
Normally these pulls only get Aborted on a hot code push (when a file is added/changed/removed).
Either you or Heroku seem to write or change something in the directory.
Because then a hot code push may be initiated by Meteor.
Heroku may not support web-sockets, which means you're stuck with the slower polling approach. See this:
https://devcenter.heroku.com/articles/using-socket-io-with-node-js-on-heroku
Sometimes, perhaps once every few hundred AJAX requests and/or where AJAX requests are executing in quick succession, I've seen a request hang for up to several minutes before it completes. The weird thing is that the request completes successfully AND neither my machine or the server are really doing anything either (e.g. CPU and other resources are not spiking during the "hang").
I've noticed this issue with various web services too, so it isn't just my own website. It also isn't database related as it has happened on non-database sites. It also only seems to show up in non-localhost environments.
When I personally use AJAX, I am also using jQuery, so this might also be a jQuery issue. I also mostly use Firefox, so I don't know if this is just a Firefox issue or if it is an issue any browser could have. I've run into the issue on multiple computers in multiple locations.
If you have run into this issue before and "fixed" it, I would appreciate the solution you came up with.
Use a HTTP debugger like Firebug or Fiddler to track the AJAX requests to see how much time it takes (possible timeout issue due to server setting?) & what HTTP response status code it returns when it fails. Use the HTTP response status code to troubleshoot the issue.
I created two very simple Heroku apps to test out the service, but it's often taking several seconds to load the page when I first visit them:
Cropify - Basic Sinatra App (on github)
Textile2HTML - Even more basic Sinatra App (on github)
All I did was create a simple Sinatra app and deploy it. I haven't done anything to mess with or test the Heroku servers. What can I do to improve response time? It's very slow right now and I'm not sure where to start. The code for the projects are on github if that helps.
If your application is unused for a while it gets unloaded (from the server memory).
On the first hit it gets loaded and stays loaded until some time passes without anyone accessing it.
This is done to save server resources. If no one uses your app why keep resources busy and not let someone who really needs use them ?
If your app has a lot of continous traffic it will never be unloaded.
There is an official note about this.
You might also want to investigate the caching options you have on Heroku w/ Varnish and Memcached. These are persisted independent of the dynos.
For example, if you have an unchanging homepage, you can cache that for extended periods in Varnish by adding Cache-Control headers to the response. Then your users won't experience the load hit until they want to "do something" rather than when they arrive.
You should check out Tom Robinson's answer to "Scalability: How Does Heroku Work?" on Quora: http://www.quora.com/Scalability/How-does-Heroku-work
Heroku divides up server resources among many different customers/applications. Your app is allotted blocks of computing power. Heroku partitions based on resource demand. When you have a popular application that demands more power, you can pay for more 'dynos' (application containers) and then get a larger chunk of the pie in return.
In your case though, you are running a free app that few people--if any outside of you--are visiting/using. Therefore, Heroku cuts down on the resources you're getting by unloading your app--putting it in hibernation essentially--until there is a request made to your address. When that happens, and your app has been idling for a long time, it takes time to reload.
Add 1 extra dyno to keep your app from falling asleep, if that reload time is important.
I am having the same problem. I deployed a Rails 3 (1.9.2) app last night and it's slow. I know that 1.9.2/Rails 3 is in BETA on Heroku but the support ticket said it should be fine using some instructions they sent me.
I understand that the first request after a long time takes the longest. Makes sense. But simply loading pages that don't even connect to a DB taking 10 seconds sometimes is pretty bad.
Anyway, you might want to try what I'm going to do. That is profile my app and see how long it takes locally. If it's taking 400ms then something is wrong. But if I get 50ms locally and it still takes 10 seconds on Heroku then something is definitely wrong.
Obviously, caching helps but you only get 5MB for free and once again, with ONE person using the site, it shouldn't be that slow.
I had the same problem with every app I have put on via heroku's free account. Now there are options of adding dynos so that your app does not get offloaded while it is not being used for a while, you can also try using redis or memcached for caching. But I used a hacky solution for my small scale project, I basically built web scraper put it inside an infinite loop with sleep and tada the website actually had much better response times(I guess it was not getting offloaded because of the script).