Applicable to:
- Plesk for Linux
Symptoms
-
Plesk and websites are not accessible or working slow due to high CPU load by MySQL or MariaDB processes observed with
top -c
command. -
Slow long running MySQL queries are shown with the following command and under Tools & Settings > Database Process List:
# plesk db "SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST ORDER BY TIME ASC \G;" | grep TIME:
TIME: 455
TIME: 300 -
On CloudLinux, dbtop utility shows a user as restricted:
restricted 196/237/203 10761/11833/32292 0/2362/2936 R/c:cpu/30
Cause
Slow MySQL queries generate high CPU usage on the server.
Resolution
-
Log in to Plesk server via SSH
-
Identify the slowest queries:
# plesk db "SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST ORDER BY TIME ASC \G;"
Id: 4047
User: johndoe
Host: localhost
db: ExampleDB
Command: Query
Time: 300
State: Sending data -
Kill the slow queries by their ID from step 2:
# plesk db "kill 4047"
-
Identify the subscription associated with the database from the previous step:
# plesk db "select d.name from domains as d, data_bases as db where db.dom_id=d.id and db.name like '%ExampleDB%';"
+----------------------------+
| name |
+----------------------------+
| example.com |
+----------------------------+ -
Temporarily suspend the subscription the associated subscription to decrease CPU load.
-
Contact website developers to review slow SQL queries and fix the issue.
Additional information
Troubleshooting slow performance of the MySQL on Plesk server
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