MySQL Manual
A Problems and Common Errors
- A.2 Common Errors When Using MySQL
- A.2.1
Access deniedError - A.2.2
MySQL server has gone awayError - A.2.3
Can't connect to [local] MySQL serverError - A.2.4
Client does not support authentication protocolerror - A.2.5
Host '...' is blockedError - A.2.6
Too many connectionsError - A.2.7
Some non-transactional changed tables couldn't be rolled backError - A.2.8
Out of memoryError - A.2.9
Packet too largeError - A.2.10 Communication Errors / Aborted Connection
- A.2.11
The table is fullError - A.2.12
Can't create/write to fileError - A.2.13
Commands out of syncError in Client - A.2.14
Ignoring userError - A.2.15
Table 'xxx' doesn't existError - A.2.16
Can't initialize character set xxxerror - A.2.17 File Not Found
- A.2.1
A.2.6 Too many connections Error
If you get the error Too many connections when you try to connect
to MySQL, this means that there is already max_connections
clients connected to the mysqld server.
If you need more connections than the default (100), then you should restart
mysqld with a bigger value for the max_connections variable.
Note that mysqld actually allows (max_connections+1)
clients to connect. The last connection is reserved for a user with the
SUPER privilege. By not giving this privilege to normal
users (they shouldn't need this), an administrator with this privilege
can log in and use SHOW PROCESSLIST to find out what could be
wrong. See section 4.5.7.6 SHOW PROCESSLIST.
The maximum number of connects MySQL is depending on how good the thread library is on a given platform. Linux or Solaris should be able to support 500-1000 simultaneous connections, depending on how much RAM you have and what your clients are doing.
