I am currently working with a Banking firm, we have a requirement to develop a fairly complex but Rich UI application. We are using EXTJS 4.2 and Spring MVC.
The first release of the app went into Production about a month back.
Now while modelling the new phase, we have come across a major hurdle. The application load up time is fairly high at this point of time. This is happening because the application has followed a single Page web 2.0 model and multiple JS files which when minified -> all-classes.js is 3 MB.
Now there is a lot of work to be done going ahead in order to build additional functionality.
Since all code is getting loaded at once during startup it would take a lot of time for this.
I figured out a design but I am not sure if that would help.. If we divide our application into multiple pages each have a different --> all-classes.js , will it help improve the performance ?
I need some advice on this.
You can refer to this links which I found : http://docs.sencha.com/extjs/4.2.0/#!/guide/command_app_multi
http://www.sencha.com/forum/showthread.php?130449-Large-Single-Page-Architecture-in-ExtJS-4.0/page2
Well, there are a number of answers to this, the best of which is "it depends".
Splitting into multiple pages is obviously going to produce some performance improvements. After all, you'll (presumably) have smaller files to initially load, fewer controllers to instantiate, etc.
The question is how much? I'm not sure I can answer that very well, without knowing more about the app and how it's structured.
I do know this, however. I have an app whose all-classes.js is around 2 MB. While there is obviously the initial hit loading it, subsequent visits use a cached version of it. And even the initial load of the 2MB file is pretty fast on most decent connections.
Related
i am working on a medium sized gwt app it uses MVP and activities/places, gin/guice. in the last month i am more and more disgusted by the many boiler plate classes/ much boiler plate code - writing a place that simply (de)serializes some parameters is a pain. Setting up activity mapper and managers is also only a matter of correct copying and pasting.
now i again stumbled across gwtp and read some wiki pages. I think with it i could delete many classes on client side.
but is it a good idea to migrate a project to gwtp at this state? does anybody has experience with such an migration? could activities/places/boiler plate coexist with gwtp stuff?
Depending on the size of your app, it may require a lot of work. If you're not used to GWTP, I don't suggest to do that yourself until you're used to do it.
I've personnally done it on several projects, small, medium to large size and it can be done, but it needs that you understand the workflow perfectly.
It can also live together with some existing code, we did that on a large scale project that had a lot of legacy code.
But I'm afraid that if you're not already a experienced user of GWTP, this will be a hard change to make by yourself.
UPDATE : I also found ncache which seems useful and also came to know that stackoverflow uses redis for caching. I also have come across memcached and seems one of the better alternatives.
I have found this but I needed to know what are the ways in which I can cache some of my LINQ queries and use them efficiently. I found Output cache in asp.net mvc are there other ways to do caching?
I am kind of a newbie and never done caching before so I would appreciate if anyone can point me in the right direction here? Mainly I want answer to when would be caching necessary and how to go about doing caching in asp.net mvc ?
In my experience application level caching is rarely the correct approach to fixing performance issues and it nearly always causes more problems than it solves.
Before you embark on any caching you should first:
(i) profile your application and the queries it makes to see if you can address them directly (e.g. query patterns that are too wide (fetching columns that aren't displayed) or too deep (e.g. fetching more rows than you display), too frequent (lazy loading might be causing more round trips than you need), too expensive (poor table design might mean more joins than you need), or the tables themselves might not be indexed correctly;
(ii) take a holistic look at your web site and the user experience to see how you can improve the perceived performance (e.g. set proper browser-level cache cache headers on static content). Using AJAX might and a paged grid view like jQGrid might eliminate many database accesses while a user is paging through records because the rest of the page content is not changing.
After you've exhausted fixing the real problem you may then then be ready to consider caching.
But before you do, make a simple calculation: how much does an upgraded server cost vs the development and testing time you will spend implementing caching and tracking down odd stale-cache issues? Sometimes it's cheaper just to upgrade...
A job came in to me that's built with CodeCharge - had a look at it and seems to be a pretty basic point-and-click site builder tool. Has anyone got any in-depth experience with it? My first reaction is one of horror and to just rebuild the code in Rails or PHP but I thought I'd ask the question first, maybe i'm missing something...
I'm currently evaluating it for use in quickly producing a back-office environment, and it seems a very comfortable way of getting an interface up and running quickly.
Once the code is generated it is simple, but easily modified for any special needs you have.
In short it is a very good tool (though it would seem that Iron Speed Designer is much better though much more expensive) for what it does - fast prototyping and almost no coding approach to developing a web application. In my opinion, not much different than a Ruby On Rails application in terms of functionality, and, I can generate the code in any language I want.
You have to realize, it is all about speed - some quality is thrown in, but it is a very generic of quality - this is NOT a custom application, mind you, the resulting code you get here might not be pretty but it is a few level higher than your average script kiddie code.
I'm seriously considering this tool for creating back-office applications for sites I develop - a fast and easy solution instead of mucking around in tables of data and useless and repetitive SQL code.
Codecharge is a powerful tool that I have used for over 10 years to build very large content management systems, CRMs and many other management type tools.
Its far from simple once you get into it, and honestly when you use a tool like Codecharge to cleanly generate your user interfaces, you end up with a healthier application that can last many many years.
For instance, I have three clients that have been running Codecharge created portals for over 10 years and they always comment how bug free they have been.
There is a learning curve to learning CodeCharge but it will also teach you what entire applications should have in place and it will please the executives every time because they can get functionality within hours or days rather than weeks or never.
Development teams will often not like it though, because they would rather hand code everything or use the latest and greatest approach to development.
I'm at a point in my freelance career where I've developed several web applications for small to medium sized businesses that support things such as project management, booking/reservations, and email management.
I like the work but find that eventually my applications get to a point where the overhear for maintenance is very high. I look back at code I wrote 6 months ago and find I have to spend a while just relearning how I originally coded it before I can make a fix or feature additions. I do try to practice using frameworks (I've used Zend Framework before, and am considering Django for my next project)
What techniques or strategies do you use to plan out an application that is capable of handling a lot of users without breaking and still keeping the code clean enough to maintain easily?
If anyone has any books or articles they could recommend, that would be greatly appreciated as well.
Although there are certainly good articles on that topic, none of them is a substitute of real-world experience.
Maintainability is nothing you can plan straight ahead, except on very small projects. It is something you need to take care of during the whole project. In fact, creating loads of classes and infrastructure code in advance can produce code which is even harder to understand than naive spaghetti code.
So my advise is to clean up your existing projects, by continuously refactoring them. Look at the parts which were a pain to change, and strive for simpler solutions that are easier to understand and to adjust. If the code is even too bad for that, consider rewriting it from scratch.
Don't start new projects and expect them to succeed, just because your read some more articles or used a new framework. Instead, identify the failures of your existing projects and fix their specific problems. Whenever you need to change your code, ask yourself how to restructure it to support similar changes in the future. This is what you need to do anyway, because there will be similar changes in the future.
By doing those refactorings you'll stumble across various specific questions you can ask and read articles about. That way you'll learn more than by just asking general questions and reading general articles about maintenance and frameworks.
Start cleaning up your code today. Don't defer it to your future projects.
(The same is true for documentation. Everyone's first docs were very bad. After several months they turn out to be too verbose and filled with unimportant stuff. So complement the documentation with solutions to the problems you really had, because chances are good that next year you'll be confronted with a similar problem. Those experiences will improve your writing style more than any "how to write good" style guide.)
I'd honestly recommend looking at Martin Fowlers Patterns of Enterprise Application Architecture. It discusses a lot of ways to make your application more organized and maintainable. In addition, I would recommend using unit testing to give you better comprehension of your code. Kent Beck's book on Test Driven Development is a great resource for learning how to address change to your code through unit tests.
To improve the maintainability you could:
If you are the sole developer then adopt a coding style and stick to it. That will give you confidence later when navigating through your own code about things you could have possibly done and the things that you absolutely wouldn't. Being confident where to look and what to look for and what not to look for will save you a lot of time.
Always take time to bring documentation up to date. Include the task into development plan; include that time into the plan as part any of change or new feature.
Keep documentation balanced: some high level diagrams, meaningful comments. Best comments tell that cannot be read from the code itself. Like business reasons or "whys" behind certain chunks of code.
Include into the plan the effort to keep code structure, folder names, namespaces, object, variable and routine names up to date and reflective of what they actually do. This will go a long way in improving maintainability. Always call a spade "spade". Avoid large chunks of code, structure it by means available within your language of choice, give chunks meaningful names.
Low coupling and high coherency. Make sure you up to date with techniques of achieving these: design by contract, dependency injection, aspects, design patterns etc.
From task management point of view you should estimate more time and charge higher rate for non-continuous pieces of work. Do not hesitate to make customer aware that you need extra time to do small non-continuous changes spread over time as opposed to bigger continuous projects and ongoing maintenance since the administration and analysis overhead is greater (you need to manage and analyse each change including impact on the existing system separately). One benefit your customer is going to get is greater life expectancy of the system. The other is accurate documentation that will preserve their option to seek someone else's help should they decide to do so. Both protect customer investment and are strong selling points.
Use source control if you don't do that already
Keep a detailed log of everything done for the customer plus any important communication (a simple computer or paper based CMS). Refresh your memory before each assignment.
Keep a log of issues left open, ideas, suggestions per customer; again refresh your memory before beginning an assignment.
Plan ahead how the post-implementation support is going to be conducted, discuss with the customer. Make your systems are easy to maintain. Plan for parameterisation, monitoring tools, in-build sanity checks. Sell post-implementation support to customer as part of the initial contract.
Expand by hiring, even if you need someone just to provide that post-implementation support, do the admin bits.
Recommended reading:
"Code Complete" by Steve Mcconnell
Anything on design patterns are included into the list of recommended reading.
The most important advice I can give having helped grow an old web application into an extremely high available, high demand web application is to encapsulate everything. - in particular
Use good MVC principles and frameworks to separate your view layer from your business logic and data model.
Use a robust persistance layer to not couple your business logic to your data model
Plan for statelessness and asynchronous behaviour.
Here is an excellent article on how eBay tackles these problems
http://www.infoq.com/articles/ebay-scalability-best-practices
Use a framework / MVC system. The more organised and centralized your code is the better.
Try using Memcache. PHP has a built in extension for it, it takes about ten minutes to set up and another twenty to put in your application. You can cache whatever you want to it - I cache all my database records in it - for every application. It does wanders.
I would recommend using a source control system such as Subversion if you aren't already.
You should consider maybe using SharePoint. It's an environment that is already designed to do all you have mentioned, and has many other features you maybe haven't thought about (but maybe you will need in the future :-) )
Here's some information from the official site.
There are 2 different SharePoint environments you can use: Windows Sharepoint Services (WSS) or Microsoft Office Sharepoint Server (MOSS). WSS is free and ships with Windows Server 2003, while MOSS isn't free, but has much more features and covers almost all you enterprise's needs.
At what level of complexity is it mandatory to switch to an existing framework for web development?
What measurement of complexity is practical for web development? Code length? Feature list? Database Size?
If you work on several different sites then by using a common framework across all of them you can spend time working on the code rather than trying to remember what is located where and why.
I'd always use a framework of some sort, even if it's your own, as the uniformity will help you structure your project. Unless it's a one page static HTML project.
There is no mandatory limit however.
I don't think there is a level of complexity that necessitates a framework. For me whenever I am writing a dynamic site I immediately consider a framework, and if it will save me time, I use it(it almost always does, and I almost always do).
Consider that the question may be faulty. Many of the most complex websites don't use any popular, preexisting, framework. Google has their own web server and their own custom way of doing things, as does Amazon, and probably lots of other sites.
If a framework makes your task easier, or provides added value, go for it. However, when you get that framework you are tied to a new dependancy. I'm starting to essentially recreate a Joel on Software post, so I will redirect you here for more on adding unneeded dependencies to your code:
http://www.joelonsoftware.com/articles/fog0000000007.html
All factors matter. You should measure how much time you can save using 3rd party framework and compare it to the risks of using other's code
Never "mandatory." Some problems are not well solved by any framework. It would be suggestible to switch to a framework when most of the code you are implementing has already be implemented by the framework in question in a way that suits your particular application. This saves you time, energy, and will most likely be more stable than the fresh code you would have written.
This is really two questions, you realize. :-) The answer to the first one is that it's never mandatory, but honestly, parsing HTML request parameters directly is pretty horrible right from the start. I don't want to do it even once, so I tend to go toward a framework relatively early on.
As far as what measurement is practical, well, what are you worried about? All of the descriptions that you list have value. Database size matters primarily for scaling, in my opinion (you can write a very simple app if you have a very simple schema, even if there are hundreds of thousands of rows in the database). The feature list will probably determine the number and complexity of UI pages, which will in turn help to dictate the code length.
There are frameworks that are there for getting moving very quickly with a simple blog, django or RoR all the way to enterprise full-stack applications Zope. Not to be tied to just the buzz world, you also have ASP.Net and J2EE, etc.
All frameworks and libraries are tools at your disposal. Determine which ones will make your life easier for your given project and use them.
I would say the reverse is true. At some point, your project gets so expansive, that you actually get slowed down by the shortcomings of the framework. For sufficiently large projects you may, in fact, be better off developing your own framework, to meet your own needs. I have seen many times where people were held back in the decisions they could make, or the work they could produce, because they were trying to do something that the framework didn't anticipate. And doing these things that the framework doesn't anticipate can be very troublesome. The nice thing about making your own framework, is that it can evolve with your project, to be a help to you system, instead of a hindrance.
So, to conclude, small projects should be use existing frameworks. Large projects should contain their own framework.