I'm building a web app that uses lots of requests to my database. Every thing was working perfectly smooth until a half an hour ago when the requests weren't returning... I checked the PHP file directly and it displays the following:
<br />
<b>Warning</b>: mysql_connect() [<a href='function.mysql-connect'>function.mysql-connect</a>]: Too many connections in <b>/home/sanity/public_html/dev/forest/js/database.php</b> on line <b>7</b><br />
Unable to connect to MySQL
So I figured let's check phpMyAdmin, but it's not showing me ANYTHING except for a big red box that says:
SQL query: Edit Edit
SET CHARACTER SET 'utf8';
MySQL said: Documentation
#1045 - Access denied for user 'root'@'localhost' (using password: NO)
Between the last time it worked and now I haven't changed any configurations or code.. How do I begin to fix this?
Could this be caused by the fact my PHP files don't close the connection after using it? If so should I be closing the connection after every query? I figured the connection would close automatically when the user leaves the web site.
EDIT: The requests are sending through now and phpMyAdmin is back up, but how do I prepare this site for heavier traffic?
When I started my job, one of my first tasks was to continue working on what one of the directors had started coding. In his code, I saw this monstrosity:
function getTicket($id) {
mysql_connect("localhost","username","password");
mysql_select_db("database");
$sql = mysql_query("select * from tickets where id = ".intval($id));
return mysql_fetch_assoc($sql);
}
In other words, he was creating a whole new database connection every single time he wanted something from the database, and never closing any of them (instead letting them be closed at the end of the script automatically)
This was fine for basic testing, but as soon as I started writing more advanced stuff (before I'd discovered this piece of code) things majorly screwed up with the same "too many connections" error as you.
The solution was simple: restart the server to clear all pending connections, and fix the code to only connnect once per script execution.
This is what you should do. There should only ever be one call to mysql_connect (or indeed any database library's connect function) in your script (and I don't mean in a function that gets called several times!)
You should also check the database's configuration, just in case someone accidentally set the maximum connections too low, but generally this shouldn't be a problem if you manage your connections properly.
Though the mysql_* functions are deprecated (use a modern driver like PDO for instance), you should take a look at the mysql_close($con) function.
Here is the doc.
EDIT
If you are not using mysql_pconnect function, then your connection should be closed at the end of the execution of your script.
Apparently, one reason for such error is shared hostings. If you are using a shared hosting, generally speaking, the maximum connections to the server allowed by the hosting is not the greatest.
If you can change the max_connections system variable then try to change it to a greater number:
max_connections = 200