I'm looking for tools to monitor/test performance in rails, and I'm not having much luck finding anything particularly effective. I've read the rails 'performance' guide, but I use RSpec instead of Rake:Test, so I'm not particularly keen to use the rake:test framework.
So, what do folks use for performance testing in rails apart from the rake:test benchmarker? Any suggestions appreciated
Performance benchmarking is one of those things that you'll get different opinions about depending on who you ask. One thing I hear over and over is that you shouldn't obsess over performance early on. I'm not sure where you're at with your application, but this could be something to consider. After developing a rather large application, I can honestly say I agree with them. It's better to use good practice when developing and wait to do performance tuning at a later time. Best practices include things like indexing database columns.
For performance monitoring of live Rails applications, New Relic is one of the best tools out there*. The free plan is a little limited as it only provides 30 minutes of historical data, but the information it collects is priceless. Some of the cloud hosts like Heroku and Engine Yard are offering free bronze plan upgrades, which stores a week of data. Once you have information about your application, you can make educated decisions about where to focus your time.
* My opinion
When your app needs some performance testing, the default TestUnit based performance benchmarking tests are a great start. However, you shouldn't stop there, and should consider using a variety of tools based on the nature of your application.
For example, analyzing production logs using a tool like the request-log-analyzer is a great way to identify the real performance bottlenecks. Bullet is another great tool you can run in your development environment to identify performance inefficiencies in your database calls. For low level benchmarking, rails also gives you the benchmark helper methods in models, controllers and views. This can be handy if you are focusing on tuning some specific part of your application.
It is also worth noting that rspec is not the best tool for benchmarking performance (to date). In my opinion, trying to assert things like it should_take_less_than 50 is stretching the idea of performance testing and trying to force it into the concept of BDD. Performance is less often about absolute expectations and more about identifying the slowest parts of your app and making them faster.
There are many online resources on the topic. I've found these railscasts to be a great starting point:
http://railscasts.com/episodes/368-miniprofiler (free)
http://railscasts.com/episodes/411-performance-testing (pro, requires subscription)
Related
I'm dealing with a rails application which is growing too big. It takes long time to start and lots of memory. We are having performance issues. Tests are very slow. Managing the codebase, debugging and introducing new futures becoming harder everyday. We are thinking to split the application into smaller components (Rails engines or different Rails apps) where all components will share a single database.
Considering such scenario we will need to share the models, maybe some libs, tests, and some gems, etc... It doesn't sound right for me!
Is there any pattern can be applied?
There are some great suggestions here about to to split up a Rails code base however I think that before you apply any of then you need to stop and seriously consider how you got into this position. All of these solutions introduce new complexities and challenges. They might be worthwhile trade offs but only if you make sure they also solve a problem you have today.
Take each of the pain points you listed (startup time is slow, memory use if high, performance is poor, rest performance is poor, development speed is slow) and run a "5 whys" exercise on them. Why are these things happening. Why did the app get into this state.
Most importantly before you commit to any plan for splitting up a large app consider if the app should be large in the first place. If your app is more complex than your product demands then switching to an equally complex cluster of services is not an improvement.
More concretely I would recommend against shared database access between apps/services/whatever. A shared database has a shared schema which becomes fragile. It also leads to tightly coupled services which lack the separation of concerns you need to see any improvement in your pace of development. Just as splitting one massive class into several tightly coupled files does not improve it nor does splitting one app into coupled services.
If you must maintain a large app you need to isolate separate concerns. In order to do so you need to break the dependencies between them. Based on the efforts I have seen to repair Rails monoliths you'll have better success creating clean interface within your existing app an then splitting out components than if you split the app apart and then hope the resulting pieces can be improved independently.
Yes, there are several ways to do it:
Micro services Erin Swenson-Healey has a nice post for rails.
Hexagonal Architecture GoRuCo 2012 Hexagonal Rails by Matt Wynne and Refactoring with Hexagonal Rails
Rails Engines Approach. Dealing with Rails Application Complexity - A Report from MWRC
Use other framework more suitable for high complexity and more PORO oriented. http://lotusrb.org/
Also see Ruby Midwest 2011 - Keynote: Architecture the Lost Years by Robert Martin
Read "Practical Object Oriented Design in Ruby" by Sandi Metz. Also, watch every presentation and talk by her on the internet. Youtube is a great place to start. She's a great speaker. Rails is written in Ruby and Ruby is an object oriented language which brings with it massive benefits. But grokking the object oriented part takes a little work. Sandi will get you there.
Usually, accessing a database tends to be the most costly operation in terms of time.
However, since Ruby is among the slowest executing languages (with rails representing an abstraction built on top of an already existing abstraction), do rails apps tend to perform slower than (or as slowly as) most queries to the db?
This is a really subjective question, but in short, yes, of course it can become more of a bottleneck than the DB, depending on your core business concerns. If, say, the only reason you have a database is to require a login, and therefore only make one call to the users table, but your website is all about image processing and you do lots of computationally expensive stuff, then ruby will be more of a concern to you than the database.
The age old idea that you should pick the right tool for the job will never fail to be true.
I don't have much experience on this topic, as I don't do Rails development any more. However, Aaron "tenderlove" Patterson gave a talk "ZOMG WHY IS THIS CODE SO SLOW?" (slideshare, confreaks video), where he talked about ActiveRecord previously being slow because the Ruby implementation used to be sub-optimal.
Yes.
A stupid but true example will be...
def index
#thing = Thing.find_by_something_not_needed params[:something_not_needed]
unless something_happens do
sleep
end
end
def something_happens; nil; end
Now imagine you were doing some complex logic - such as image processing, or maybe an extraneous stab at the travelling salesman problem with substantial data - that could be modeled by the death loop I have in my silly example. Other factors may be external web requests that just dont go well.
Rails is already the slowest framework among the rest of the 'active' Ruby frameworks (Camping, Sinatra, Merb, Padrino, Ramaze).
I found a recent 'unscientific' benchmark: http://pastie.org/2294509 (benchmark source padrino framework's github repository) that provides some results.
The slowness may not manifestate itself that much in production (It probably shouldnt be the cause of a bottleneck), but you will surely experience it while developing applications: Extremely slow boot times, slow rake tasks, very slow test suites, high memory footprint.
This is a compromise. Rails is feature rich and has been around for a long time with a large, active community.
Unfortunately the situation may not improve as with every new Rails version the framework grows larger, with additional layers of abstraction that affect speed. This is pure speculation on my side, but judging by the user base, we won't see any drastic changes to Rails itself to alleviate these problems. The last game changing version 3 has brought a lot of long sought improvements, but they were more of improvements to the modularity of the framework, rather than improvements to performance.
This question is like asking "Can a Porsche be slowed down to a slower speed than a Pinto?".
You should judge your performance in average millisecond response times. For example, if a page in your app takes on average 100ms to sun, then in theory, you can get 10 request per second. If you investigate and determine that 100ms is because 60ms is being spent parsing some string...a string that can be reduced or even ignored, then the problem really isn't Ruby or Rails is it?
Ruby/Rails is fast enough for most web applications. I think you are trying to convince yourself to use something other than Rails. If you don't want to use Rails, that is fine. But don't abandon Rails because it COULD be slowed down by bad programming. This is true of any language.
Instead, embrace Rails (or Sinatra or Padrino or Django) and have fun. Worry about performance when performance is an issue.
I have some (I think) really great ideas for an online strategy game similar to Travian. There's some content that I haven't yet figured out and some other challenges that I don't know of yet.
This is quite a big project and perhaps too heavy for one person that isn't a skilled web developer (yet). I'd still like to give it a shot, but I'm having trouble choosing a platform. The world "scales" has been thrown around a lot lately and I've seen Ruby on Rails being bashed because it doesn't scale well, so I've come here to get some answers.
I like Ruby on Rails, both Ruby and Rails. I'm certainly no expert at it but I love working with it. I have also worked with Python + Django before and also with PHP (which I am not fond of.)
Ideally the game would have, let's say, 7000 players per server, presumably a lot of data to be processed per second. Would RoR still be a viable platform?
I'm sorry if this question is vague, I guess I'm looking for a "RoR is fine, go at it!" kind of answer. Anything you might want to add is fine.
Thanks!
So if I were you, I would be looking into non-blocking servers like node.js, just because they are MUCH more suited to keeping many connections open for long periods of time, which is what games need to do, compared to traditional web servers.
That being said
There are 3 main things to worry about when you are scaling a web app; memory, execution speed, and io (hd and network) in that order.
For memory, things are much better then they used to be. Phusion Passenger uses copy on write to fork its workers, so the rails environment will get shared among all the workers on a given slice, which is pretty significant. There have also been huge improvements to the way ruby manages memory compared to "the dark times", if you are using 1.8.7 then you want to be using the patches that make up Ruby Enterprise Edition (the difference is like night and day). 1.9.x was pretty much a total rewrite of the runtime, so if you are using that the memory issues ruby had have already been addressed.
For execution speed, 1.8.7 is typically "fast enough" (at least after tuning garbage collection settings). 1.9.2 is actually around the same speed as python, which puts it on the faster side of interpreted languages. How important this point is completely depends on the nature of your application.
Last point is IO, which isn't really a concern of rails, but more your persistence strategy. Rubyists tend to love new things, so you will find first class support for things like redis and mongodb, with loads of people talking about using them and their wins/gotchas. I would look into mongo if I were you and see if the durability trade-offs are acceptable.
I was in java/.net before going to rails, and at the end of the day you are going to pay more for infrastructure, but the amount will be completely dwarfed by what you save in development time.
build it in Rails, host it on Heroku.com - job done. Almost infinite scaling that you don't have to worry about how it works (it just does) and it hosts a lot of highly trafficked Facebook apps so can more than handle it.
I think Ruby on Rails is a good choice for what you need. Actually, we recently created a platform for an online gaming tournament, where players and their gaming bots were playing a logic game.
We used Ruby on Rails and Sidekiq on the backend, ReactJS and WebSocket on the frontend. And it worked well for a quite massive number of players. Here is the tutorial based on what we learnt while building it: How to Write a Game Engine Using Ruby on Rails
As you said yourself, you already have the answer and you are only looking for encouraging words:). I am not RoR expert myself, but I don't think scalability is still such a great issue on this platform. I would advice you to do an architecture spike (XP terminology). Write a test with 7000 clients and method which would perform similar operations to what you intend to create. For example you might load files, render views or even just wait... The point is to test only the thing you are worried about. Good luck!
This is a bit of an impossible question to answer because in order to know whether rails is suitable for what you want to do we would need to a lot more about what you are trying to do. The best advice I can give in the absence of information is for you to check out the railslab scaling videos in order to work it out for yourself.
I made some searches on Google, and I read some posts, articles and benchmarks about Ruby on Rails being slow and I am planning to build one website that will have a good amount of users inserting data and there will be some applications to process this data (maybe in Ruby, you can help me choosing the language).
What is the real performance of Ruby on Rails with large traffic ?
Thank you !
You are asking a lot of questions, so I'll just try to answer you're first one. It is true that ruby, as a language, is slower compared to some others. This means that rails may not perform as well as some other frameworks. However, most websites will not receive the sort of traffic that poses a problem. The productivity gained by using rails most definitely outweighs the potential performance issues you may have later.
Dynamic web pages are slower than static, in general. Scale and performance are more about good design and caching than language choice.
I'm a big fan of ruby on rails, and it seems to incorporate many of the 'greatest hits' of web application programming techniques. Convention over configuration in particular is a big win to my mind.
However I also have the feeling that some of the convenience I am getting is coming at the expense of technical debt that will need to be repaid down the road. It's not that I think ROR is quick and dirty, as I think it incorporates a lot of best practices and good default options in many cases. However, it seems to me that just doesn't cover some things yet (in particular there is little direct support for security in the framework, and plugins that I have seen are variable in quality).
I'm not looking for religious opinions or flamewars here, but I'd be interested to know the community's opinion on what areas Rails needs to improve on, and/or things that users of Rails need to watch out for on their own because the framework won't hold their hand and guide them to do the right thing.
Regardless of framework the programmer needs to know what she's doing. I'd say that it's much easier to build a secure web application using something as mature, well designed and widely adapted as Ruby on Rails than going without the framework support.
Take care with plugins and find out how they work (know what you do, again).
I love Rails too, but its important for us to understand the shortcomings of the framework that we use. Though it might be a broad topic addressing these issues wont hurt anyone.
Aside from security issues, one other big issue is DEPLOYMENT on Shared Hosts. PHP thrives in shared hosting environments but Rails is still lagging behind.
Of course most professional Rails developers know that their apps need fine-tuned servers for production and they will obviously deploy on Rails-Specific hosts.
In order for Rails to continue success the core team should address this issue, especially with Rails 3.0 (Merb +Rails) coming..
An example of this is simple: I have a bluehost account, and i noticed the Rails icon in my cpanel. I talked to the bluehost support and they said its more or less a dummy icon, and that it doesn't function properly.
Having said that any professional who wanted to deploy a Rails App would not use bluehost. , but it does hurt Rails, when hosts say that they support it and then users run into problems which their support know nothing about..
The article you refer to defines technical debt as
[the] eventual consequences of
slapdash software architecture and
hasty software development
With rails, any development that is not test driven incurs technical debt. But that is the case with any platform.
At an architectural level Rails provides some deployment challenges. A busy site must scale with lots of hardware or use intelligent caching strategies.
My advice to anyone adapting Rails would be to:
use TDD for all your development
verify the quality off any plugin
you use by reading its tests. If
they are not clear and complete,
avoid the plugin
read "Rails
Recipes" and "Advanced Rails
Recipes" (Advanced Rails Recipes has
a good recipe for adding
authentication in a RESTful way)
be prepared to pay for hardware to scale your site (hardware is cheaper than development time)
From my experience, by far the biggest tolls you end up paying with RoR are:
Pretty big default stack (not counting plugins you might be using)
Updating models tends to be a pain in the ass, at least in production servers.
Updating Rails or Ruby themselves is a bit more complicated than it should, but this differs depending on your server setup.
As ewalshe mentioned, deployment is sometimes a drag, and further down the road, should you require it, scaling gets a bit iffy, as it does with most development frameworks.
That being said, I'm an avid user of RoR for some projects, and with the actual state of hardware, even though you do end up paying some tech debt to using it, it's almost negligible. And one can hope these issues will be reviewed eventually and solved.
With any level of abstraction there is a bit of a toll you pay - genericized methods aren't quite as fast as those specific to something built just for your purpose. Fortunately though, it's all right there for you to change. Don't like the query plans that come out of the dynamic find methods? write your own, good to go.
Someone above put it well - hardware is cheaper than developers. I'd add "at a sufficiently low amount of hardware"
I'm reading Deploying Rails Applications and recommend it highly to answer your concerns.
The book is full of suggestions to make life easier, taking a deployment-aware approach to your Rails development from scratch, rather than leaving it to later.
I don't think the choice of RoR implies a technical debt but just reading the first few chapters alerted me to practices I should be following, particularly on shared hosts, such as freezing the core rails gems so you can't be disrupted by upgrades on the host.
The 30-page chapter on Shared Hosts includes memory quote tips such as using multiple accounts (if possible) with one Rails app per account. It also warns about popular libraries such as RMagick possibly pushing your memory size to the point where your processes are killed (such as a 100MB limit, which it suggests some hosts periodically apply).