Common reasons for poor web performance

Inappropriate use of caching... does that logic need to be cached or is its invocation infrequent enough that maybe a plain old CGI is exactly how it should be implemented?

The technology and ways of implementation keeps on changing even as i write this Idea. Lets take a case: earlier we had problems of long loading time of images in the page, but not we use CSS sprites. But the implementation does not necessarily change with the incoming, advanced and better technology. It involves some effort in re-engineering of the web application. No company will like to go for this, unless the are ready to shell out some money.

However the new projects which are developed at this point of time, do use updated technologies (if the developers and architects are well updated with the trends.). We generally tend to measure the performance with a similar application hosted as a competitor site. It really does matter, how are we using the technology. The technology has the solution to speed up the web performance, but the key is to have well informed developers to implement it.

Most of the time I have seen the problem mainly lies with poor Db design, basic things like indexing not proper, even queries to fetch record is also poor. If the Db design and the queries are improved then one of the basic reson for poor performance is resolved. Small sites are not much effected with this but sites dealing wirh millions of records will surely have the benefit.

Excessive round-tripping to the database

Too many features spoils the application. One first needs to identify the business goal and what are the features it required. Simplicity is the key. Your taret customers should not be puzzled and they should get all information at ease. Giving them the best user experience in terms of colors, navigation, accesibility and information are the keys of success. An attractive site does not sell well but a site where the selling process is easier and secured.

Tight coupling of architectural pieces that have independent scaling and/or stability requirements...

Nailing up resources i.e. does each child thread/process require its own database connection?

Development shortcuts that are quick-n-dirty that also happen to introduce slow-n-dirty runtime characteristics

Insufficient use of caching or pre-generation of components that are static or have a low change rate

the absence of foresight on how the architecture will smoothly scale with four or ten or a hundred times the use and sure enough, someone will blame the language or a framework

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• JVM Tunning - GC, load average
• Database Tunning - Based on the load and data, tunning must be done.
• Excess log printing (hibernate in debug mode kill the performance)
• Content delivery optimizations for large traffic across the geographical locations (Expiry headers, web clustering
• WRONG HTML DESIGN - Too much nested tables, images without size
• Unused javascripts, large javascripts on the top which is not used until the user actions...

Using certain features makes the developers life easier. But they are the main bottleneck when it comes to performance. In a performance sensitive application these features must be diabled.

E.g. In ASP.NET using Viewstate helps the programmer a lot. But it consumes a lot of bandwith that will degrade the performance of the system.