Is this a good optimization method?

naxalyte

Hello all,
I have a website that allows a user to review items, and store these reviews in a database. My main page shows the latest 5 reviews to have been added to the db.

I am wondering if it is more useful to store the latest 5 reviews twice, once in the database and once in a text file, so that when a user logs on to the main page, the information can be retrieved directly from the text file instead of querying the database.

I guess what I really want to say is, is it a good idea to use a text file as a cache to bypass querying the db?

Any thoughts on concurrency issues?

NogDog

My guess is that the savings - if any - are not likely to be worth the trouble. If the database is very large (and I'm not sure what would qualify as that), the query is complex and/or returns a lot of data, and/or you expect a high volume of traffic, then you may want to consider some sort of caching mechanism.

But the first thing to do is get some empirical measurements of the current implementation's performance, and then do some analysis as to whether it is acceptable. If not, then you may first just need to check the database design and implementation (table engine types, indexing, structure), the SQL being used, and how efficiently the PHP code is using the database (e.g. not making multiple database connection/close calls in one page).

richie

I have something similar on one of my websites. Basically, the index page displays the last few entries. Since new entries don't occur very often, the result is often the same over the course of a day or so.

Hence, I have a static file that gets written to every 6 hours by a cronjob. The main page is then displayed by reading the html in the static file. This makes the page display very fast, and prevents thousands of unneccessary database calls.

But, like nogdog said, if your db query is not complicated, you may not need a caching system. In that case, make sure you add to your db query LIMIT 5.