Question

"Error establishing a database connection" on a new WordPress site?

Posted September 4, 2013 43.3k views
Hey. I created a new 512MB droplet, and used the 1-click wordpress install. I added a few plugins, and created just one page. This is a brand new site, and currently has no other content. The website was running fine a few days back, however, when I tried to load it today, I got the message: "error establishing a database connection" I rebooted the droplet through SSH, and the website started working again. A few articles in the DO community point out that this may be due to MySQL crashing because its falling short of memory. So I checked my Google Analytics account to see if there has been a sudden surge of activity on my website, and the only activity was 5 or so visitors a couple of days back. MySQL memory shortage seems like a plausible explanation, but I have difficulty believing that a 512 MB droplet is not enough to run a completely empty wordpress website and serve 5 users. I have a few questions: 1. Is 512 MB really too low to just host a blank site? Should the DB fail with 5 visitors? 2. If not, then what other factors could cause the DB to stop working? 3. How can I check the logs/ or find out for sure what the problem was? 4. Is there any way to keep a track of the droplet's memory usage? Additional information: I installed the following plugins on my WP site: - Better WP Security - Google Analytics for WordPress - WordPress SEO - Microkid's Related Posts - Disqus Comment System - Contact Form 7 - All in one Favicon I also installed a couple of other plugins, but they were deactivated. Also, the "Better WP Security" plugin is configured to create a backup of the WP DB every few days. Please help me out with this. I'd like to prevent my site from failing again.
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shishir
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shishir
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3 comments
  • sasho2210 September 6, 2014
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    If you have 512MB ram - add 1024MB swap file.

    In tutorial above swap is 256MB. Create 1024MB file like this:
    dd if=/dev/zero of=/swapfile bs=1M count=1000

  • scottrod May 24, 2015
    Reply Report

    This seems like a common issue. I’ve contacted DO support sever times. First I was told it was due to noisy neighbors, then I was told it might be something wrong on my end. I guess—plugins. My 1gb ram droplet typically uses 5%-10% CPU, then randomly, every 1-4 days, my server gets hit with 80%-100% CPU spike. This is when I receive the database connection error.

    My site has low traffic. I use WP Super Cache to only dump cache once per day. I am also using serverpilot.io to manage my WP install. I’ve followed their suggested settings. https://serverpilot.io/community/articles/how-to-install-wp-super-cache.html

    The cache dumping time does not match the CPU spike time.

    It also seems swap is enabled.

    Running sudo swapon -s
    returns the following:
    “`Filename Type Size Used Priority
    /swapfile file 524284 0 -1

    
Any ideas?
  • o0Synn0o December 18, 2015
    Reply Report

    Go here: http://www.thegeekstuff.com/2010/08/how-to-add-swap-space/

    Their WP image has no swap so memory gets used up 100% and causes mysql to crash. I wonder if it’s the same for their other images.

    DigitalOcean #nochill

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38 answers
kamaln7 October 17, 2013
@Dave: Is MySQL running? sudo service mysql status

Was it working fine previously?
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dahunsilanre November 16, 2013
Hi Everyone, please I need help:

When i try to access myipaddress/phpmyadmin i get the following error:

phpMyAdmin - Error
The mysqli extension is missing. Please check your PHP configuration. Documentation

I just recently moved 2 sites to the digital ocean droplet (2GB, 40GB Ubuntu droplet) and the frontend of the site is showing error connecting to database.

Please help, very urgent.
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eric September 4, 2013
We are having the same issue and are thinking about WPEngine to solve these headaches. One suggestion was to use nginix on DO as well.
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idenkov September 5, 2013
It can be result of high load and MySQl crash. I use script to check couple of services every 5 minute if they are running, and start/restart them if they don't. You can use "monit" I think there is tutorial here how to install it.
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  • beitisetiawan November 23, 2014

    Can you give me/us the example script of it? The script to control and check couple of services every 5 minute if they are running, and start/restart the system.

    Thanks

    Reply Report
studio September 5, 2013
512 droplet is definitely enough to host a wordpress website. Mine is on a 512 droplet, never experienced any issues. I'd suspect the problem might be related to one of the plugins leaking memory.
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shishir September 5, 2013
@Goran: Possibly. Is there any way to check if this is the case, and which plugin could be the culprit?
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studio September 5, 2013
First I'd check any plugins doing backups. Schedule a backup from the plugin and check if that's the issue. Sometimes backup plugins can use a lot of memory.
Next I'd disable the plugins one by one and test the website performance. If you find a certain plugin to be the one causing the issues, disable it and seek alternative if you must have its functionality.
If you'd like to get a deeper insight I'd install New Relic to check what's consuming memory.
By the way, which php5 modules are you running? Which apache2 modules do you have installed? I'm asking because I don't know which ones are installed using the 1-click install and you may have some modules that are unnecessary.
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studio September 5, 2013
See here: http://wordpress.org/support/topic/plugin-better-wp-security-uses-up-a-lot-of-memory

also make sure you have swap and if not do it https://www.digitalocean.com/community/articles/how-to-add-swap-on-ubuntu-12-04
How To Add Swap on Ubuntu 12.04
by Etel Sverdlov
Linux swaps allow a system to harness more memory than was originally physically available. Here's how to set up a linux swap file on Ubuntu 12.04
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kamaln7 September 5, 2013
Apache uses a lot of memory by default, especially if you have a lot of plugins/themes installed. This wouldn't leave a lot of memory for MySQL and would cause it to crash.

Try adding some swap to your droplet:

https://www.digitalocean.com/community/articles/how-to-add-swap-on-ubuntu-12-04
How To Add Swap on Ubuntu 12.04
by Etel Sverdlov
Linux swaps allow a system to harness more memory than was originally physically available. Here's how to set up a linux swap file on Ubuntu 12.04
Reply Report
shishir September 5, 2013
@Goran: Thanks for the suggestions. I ended up creating a larger droplet, mainly because I'm certain that I will install more plugins on my site, and some more software on my server.

@Goran, @Kamal: I had an extensive chat with DO support today. They told me that DO VPS no longer support swap. The article is outdated, and is going to be removed.
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