Question

I’ve been using Dreamweaver to develop PHP and MySQL based websites, but as it tends to overdo simple things I normally write my own queries and PHP to handle the results.

After doing a more complex page, I can have up to 5 SELECTs and as many UPDATEs, maybe more in loops etc.

Persistent connections are not being used, and I only connect to the database once per script.

What I want to know is, given that I only connect to MySQL once, does the amount / complexity of queries have much impact with regards to MySQL connections, and do I ever need to explictly call mysql_close() in my scripts?

Also at what point should I start using mysql_free_result() (or should I be using it anyway?)

A psuedo-example of the type of thing I’m concerned about:

connect to database;

aSelect;

do {
    anUpdate;
} while(select has rows);

anotherSelect;

anotherSelect;

anUpdate;

do {
    aSelect;
    anUpdate;
} while (anotherSelect has rows);

anotherUpdate;

aVeryBigSelect;

//end of file
//no mysql_free_result() or mysql_close() calls, should there be?

Answer 1

If the scripts are running for a very short time, like to deliver a web page, it’s alright not to call mysql_close and mysql_free_result, since PHP will close the connection and free the memory automatically at the end of your web page execution.

On the other hand, if you’ll write a long running batch script, doing thousands of query, it may be a good idea to call mysql_free_result.