I'm not a "die hard" coder and I need some advice.
I'm developing a website where users may search for a store or a brand.
I've created a class called Search and Store.
There are two ways search is executed: "jQuery Live Search" and "normal search".
Live search is triggered for each character entered above 2 characters. So if you enter 5 characters, a search is performed 3 times. If the store you are looking for is in the dropdown list, you can click the store and the store page will be loaded.
The other search is when you click the search button after entering 3 or more characters.
Every time a search is performed, the following code is executed
$search = new Search();
$result = $search->search($_GET);
Each time a store page is loaded a $store = new Store() is executed.
My question is this:
Let's assume I get a very successful website and I have aroun 100 users per hour. Each user searches at least 3 times and looks at least 5 stores.
That means between 300 and 900 search objects are created every hour and 500 store objects.
Is it bad or good to create so many new objects?
I've read a bit about Singleton, but many advices against this.
How should I do this to achieve best performance? Any specific design pattern I should use?
I don't think that creating the classes will become a bottleneck for your site. Look at an MVC Framework like Zend Framework, and examine how many instances of classes are generated for every call. The overhead of creating an instance of a class is almost nothing, the search will put heat on your db(assuming you are using a db like mysql).
I suggest using a timer for your jQuery Live search to do the search after the user stopped entering more characters. Like refreshing everytime the timer when a character has been entered and when the timer fires you can actually search.
I think one of the bigger problems will be your database. If you have many reading requests a good caching layer like memcache may take a good heap of load from you DB.
Optimizing your db for searches should be a good measure to hold performance high. There are many tweaks and best practices to follow to get the most out of the db you are using.
As a comment of prodigitalson suggested diving into full text search with Lucene could even be more efficient than tuning the db.
If Lucene is bit overhead for you, you may want to look at the Zend_Search_Lucene component, which does the same job and is written in php.
Don't overcomplicate your design by guessing at performance bottlenecks. Number of objects created would rarely be an issue.
If you need to optimize at a later point, a memcached layer could help you.
Creating an high number of objects shouldn't be a performance problem in your application even if you have to pay a bit of attention to the dimensions of these objects.
Don't complicate too much your design, but i think that singleton pattern isn't a complication and it isn't difficult to implement.
So if the same object instance can be reused more times upon different search from the same user (or even by different users, if it is possible inside your application logic), then don't be afraid of using singleton. It saves your memory and preserves you from doing errors related of having multiple instance of objects that performs the same task, eventually sharing resources.