Question

MySQL keeps crashing - Error establishing a database connection

My wordpress blog has been working for over a year and all of a sudden it stopped working. This morning I posted the following question on Stack Overflow

http://stackoverflow.com/questions/35799917/wordpress-site-down-mysql-crashing

I first decided to bump my memory from 512 to 1GB on the droplet. With no responses I started doing some digging. I found this solution which looked exactly like my problem so I tried setting up a swap file

http://www.webtrafficexchange.com/comment/reply/156

Still not having any luck here and this is the latest from my logs. Anyone have any clue is to what is happening to me?

160304 14:05:29 [Warning] Using unique option prefix myisam-recover instead of myisam-recover-options is deprecated and will be removed in a future release. Please use the full name instead. 160304 14:05:29 [Note] Plugin ‘FEDERATED’ is disabled. 160304 14:05:29 InnoDB: The InnoDB memory heap is disabled 160304 14:05:29 InnoDB: Mutexes and rw_locks use GCC atomic builtins 160304 14:05:29 InnoDB: Compressed tables use zlib 1.2.8 160304 14:05:29 InnoDB: Using Linux native AIO 160304 14:05:29 InnoDB: Initializing buffer pool, size = 64.0M InnoDB: mmap(68681728 bytes) failed; errno 12 160304 14:05:29 InnoDB: Completed initialization of buffer pool 160304 14:05:29 InnoDB: Fatal error: cannot allocate memory for the buffer pool 160304 14:05:29 [ERROR] Plugin ‘InnoDB’ init function returned error. 160304 14:05:29 [ERROR] Plugin ‘InnoDB’ registration as a STORAGE ENGINE failed. 160304 14:05:29 [ERROR] Unknown/unsupported storage engine: InnoDB 160304 14:05:29 [ERROR] Aborting

160304 14:05:30 [Note] /usr/sbin/mysqld: Shutdown complete

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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

same problem I’ve done everything but not solved. but Finally, I solved the problem try this https://www.digitalocean.com/community/tutorials/how-to-add-swap-space-on-ubuntu-16-04