Increase the maximum number of MySQL connections

1. Errors occurred

Too many connections

2. reason

One reason is MySQL In profile max_connections It's too small . Another reason , That is, the number of visits to the server is too high ,MySQL Server can't resist .

3. First determine the of the current machine mysql Is the maximum number of connections

show variables like '%max_connections%';

4. Set the maximum number of connections

4.1. Temporary settings are valid

set GLOBAL max_connections=1024;

Then go and check , See if it works

show variables like '%max_connections%';

Pay attention , This way of setting , once mysql After restart , In this way mysql Directly set variables will fail . 

4.2. Permanent settings are valid

 modify mysql The configuration file my.cnf, stay [mysqld] Section max_connections value .

max_connections=1024

 

 

After saving the configuration file , restart mysql that will do .

5. Enter server , View the number of accesses through the port

netstat -an | grep 3306 | grep ESTABLISHED | wc -l

 6. You can also view the specific number of connections

show processlist;

Reference resources ：MySQL: ERROR 1040: Too many connections - Simple books

Mysql The number of connections , Maximum concurrency setting - Zhou Botong's wheat field - Blog Garden