[problem record] 03 connect to MySQL database prompt: 1040 too many connections

1、 The error information is as follows ：

Connect MySQL Database prompt ：1040 Too many connections：

2、 reason ：

Due to the number of database connections , The maximum number of connections to the database has been exceeded .
PS： Because these database connections , be in sleep state , But it has not been cleared away .

View reasons ：

1） Log in to the database

logon server , Enter the command ：

mysql -uroot -p

Enter the database login password , Login successful .

2） View database process status

show status like  'Threads%';

treads_cached ： Number of threads in the buffer pool .
Threads_connected： Current connection （ Running and sleeping ） Number of threads in .
Threads_created ： The number of threads that have created connections .
Threads_running： Currently running （ No sleep ） Number of threads in .

A total of ：152 individual .

3） View the maximum number of database connections

show variables like '%max_connection%';

maximum connection ：151 individual , Less than the current total number of connections 152, So the tip ：Too many connections.

4） View clear Sleep Connection time

show variables like 'wait_timeout';

The clearance interval is ：28800 second （8 Hours ）, After connection 8 Hours clear .

3、 resolvent ：

The solution priority is as follows 1、2、3 The order of ：

1） Troubleshoot code problems

See where there are too many connections , It may be caused by code, such as scheduled tasks .

2） Increase the maximum number of connections

set GLOBAL max_connections=1000; 

such as , Change it to 1000 Number of connections ：

3） Reduce and clear Sleep Connection time

set GLOBAL wait_timeout=14400; 

Change to 4 Hours or shorter intervals .