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

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.