I am storing some history information on my website for future retrieval of the users. So when they visit certain pages it will record the page that they visited, the time, and then store it under their user id for future additions/retrievals.
So my original plan was to store all of the data in an array, and then serialize/unserialize it on each retrieval and then store it back in a TEXT field in the database. The problem is: I don't know how efficient or inefficient this will get with large arrays of data if the user builds up a history of (e.g.) 10k pages.
EDIT: So I want to know what is the most efficient way to do this? I was also considering just inserting a new row in the database for each and every history, but then this would make a large database for selecting things from.
The question is what is faster/efficient, massive amount of rows in database or massive serialized array? Any other better solutions are obviously welcome. I will eventually be switching to Python, but for now this has to be done in PHP.
There is no benefit to storing the data as serialized arrays. Retrieving a big blob of data, de-serializing, modifying it and re-serializing to update is slow - and worse, will get slower the larger the piece of data (exactly what you're worried about).
Databases are specifically designed to handle large numbers of rows, so use them. You have no extra cost per insert as the data grows, unlike your proposed method, and you're still storing the same amount of data, so let the database do what it does best, and keep your code simple.
Storing the data as an array also makes any sort of querying and aggregation near impossible. If the purpose of the system is to (for example) see how many visits a particular page got, you would have to de-serialize every record, find all the matching pages, etc. If you have the data as a series of rows with user and page, it's a trivial SQL count query.
If, one day, you find that you have so many rows (10,000 is not a lot of rows) that you're starting to see performance issues, find ways to optimize it, perhaps through aggregation and de-normalization.
you can check for session variable and store all data of one session and can dump it together into database.
You can do Indexing at db level to save time.
Last and the most effective thing you can do is to do operation/manipulation on data and store it in separate table.And always select data from manuplated table.You can achieve this using cron job or some schedular.