Question
Mysql issue: Warning: mysqli_real_connect(): Error while reading greeting packet
Hi guys, I hope you can help me. I’m launching a web site and I’m having issues with my droplet. I use 5$ droplet to run a wordpress site which uses mysql. At some points (not always) there is an error:
Warning: mysqli_real_connect(): Error while reading greeting packet. PID=862598 in /var/www/html/wp-includes/wp-db.php on line 1653
Here is the line 1653:
mysqli_real_connect( $this->dbh, $host, $this->dbuser, $this->dbpassword, null, $port, $socket, $client_flags );
Mysql version: mysql Ver 8.0.22-0ubuntu0.20.04.3 for Linux on x86_64 ((Ubuntu))
I checked the error.log, but I can not find anything meaningful: https://pastebin.com/QxLRi54p
Please advise me how to fix the issue
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Hi there @jasminap,
There was a similar question regarding the same issue that you are seeing in your logs here:
https://www.digitalocean.com/community/questions/help-mysql-keeps-crashing-error-establishing-a-database-connection
Answer:
This crash is most likely due to your system running out of memory. I’d suggest that you add a swap file to give yourself a bit more of a buffer. Check out this tutorial:
How To Add Swap on Ubuntu 18.04
What you can also do is to use the MySQLTuner script.
The MySQLTuner is a script written in Perl and allows you to quickly test your MySQL configuration and it gives you suggestions for adjustments to increase performance and stability.
According to the official GitHub page, it supports 300 indicators for MySQL/MariaDB/Percona Server in this last version.
To run the script you could do the following:
The script would run multiple checks against your MySQL instance, all checks done by MySQLTuner are documented here.
Also as stated in the official documentation, it is still extremely important for you to fully understand each change you make to a MySQL database server. If you don’t understand portions of the script’s output, or if you don’t understand the recommendations, you should consult a knowledgeable DBA or system administrator that you trust.
As a good practice make sure to always test your changes on staging environments before implementing them on your production database.
On the same note, if you want to have worry-free MySQL hosting and focus on your application, I would recommend trying out the DigitalOcean Managed Databases:
https://www.digitalocean.com/products/managed-databases-mysql/
Source: https://www.digitalocean.com/community/questions/how-to-tweak-mysql-mariadb-configuration-for-increased-performance-and-stability
Regards, Bobby