Problem solve with this code..

sudo start mysql

have a nice day !
embunhati

Run the following after you start seeing that, and look at the output:

free -m

My bet is it looks something like this:

             total       used       free     shared    buffers     cached
Mem:          512       512        0         256        256       0
-/+ buffers/cache:       256       0
Swap:            0          0          0

If Mem and buffers/cache both show 0 free, you’re overutilizing the server, and need to move to at least a 1GB server.

You might want to verify that you’ve properly blocked requests to xmlrpc.php. You can do that with the following command:

curl -XPOST http://YOUR_DOMAIN/xmlrpc.php

if you see this, you have not blocked requests to xmlrpc.php:

<?xml version="1.0" encoding="UTF-8"?>
<methodResponse>
  <fault>
    <value>
      <struct>
        <member>
          <name>faultCode</name>
          <value><int>-32700</int></value>
        </member>
        <member>
          <name>faultString</name>
          <value><string>parse error. not well formed</string></value>
        </member>
      </struct>
    </value>
  </fault>
</methodResponse>

Hello all,

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:

• SSH to your Droplet
• Download the script:

wget http://mysqltuner.pl/ -O mysqltuner.pl

• Then execute it:

perl mysqltuner.pl

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

Hope that this helps!
Regards,
Alex