How to fix: mysql_connect(): Too many connections - mysql

Question

I am getting the following error:
mysql_connect(): Too many connections
It has completely shut down my site, which has been running seamlessly for several years.
Note: I have shared hosting with GoDaddy.
How do I fix this?
ALSO: is there a way to close all connections and restart when on a shared hosting plan?

Answer 1

This is a Technical Response
You will get this "too many connections" error upon connecting to MySQL when the MySQL server has reached its software configurable artificial limit of maximum concurrent client connections.
So, the proper way to fix this is:
Directly connect to the MySQL server, and perform the query: SET GLOBAL max_connections = 1024; to change the connection limit at runtime (no downtime).
Make your change permanent, and edit the /etc/my.cnf (or similar) and add the line max_connections = 1024 line within the [mysqld] section; then restart if you couldn't do the live change.
The chosen limit of 1024 was pure subjective; use whatever limit you want to. You can also inspect your current limit via query SHOW VARIABLES LIKE "max_connections";. Keep in mind, that these limits are there for good use, in order to prevent unnecessary overload of your backend database. So always choose wise limits.
However, for those steps you are required to have direct access to your database MySQL server.
As you said, you are using GoDaddy (I do not know them that much), you are left out with the option to contact your service provider (i.e. GoDaddy). However, they will see this in their logs anyway, also.
Possible Root Causes
This of course means, that too many clients are attempting to connect to the MySQL server at the same time - as of the per configuration specified artificial software limit.

Answer 2

Most probably, you have been a subject of a DDoS attack.
People on this forum complain on exactly same thing with exactly same provider.
The answer is this:
VB told me it was a DOS attack - here is their message:
This is not an 'exploit'. This is a DoS attack (Denial of Service). Unfortunately there is nothing we can do about this. DoS attacks can only be fought at the server or router level, and this is the responsibility of your host. Instead of doing this they have decided to take the easy way out and suspend your account.
If you cannot get them to take this seriously, then you should look for another host. Sorry for the bad news.
A possible workaround can be this: if your connection fails with mysql_connect(): Too many connections, you don't quit, but instead sleep() for half a second and try to connect again, and exit only when 10 attempts fail.
It's not a solution, it's a workaround.
This of course will delay your page loading, but it's better than an ugly too many connections message.
You also can come with a some kind of a method which tells bots and browsers apart.
Like, set a salted SHA1 cookie, redirect to the same page and then check that cookie and connect to MySQL only if the user agent had passed the test.

Answer 3

Another thing that can cause this error is if the Database has run out of space. I recently had this occur, and the issue wasn't connections, it was Disk space. Hope this helps someone else!

Answer 4

Do you close your connection when you're done with them? Are you using some type of connection pooling? Sounds like you're opening connections and not closing them.
EDIT: Already answered by Quassnoi. In the case it is a DDoS, and you're using shared hosting, you may be left with just contacting your host and working it out with them. Unfortunately this is a risk when you don't have control of your whole system.

Answer 5

Consider using mysql_pconnect(). Your host may have adding some sort of throttling for connections. Like a maximum of 100 per 20 minutes or something weird.

Answer 6

First, check your database connections:
show variables like 'max_connections';
to check all variables
show variables;
Connect your MySQL server and update the connection size:
SET GLOBAL max_connections = 1001;