MySQL Workbench 6.3 (Mac) hangs on simple queries

Question

I am using MySQL Workbench 6.3.7 build 1199 CE (64 bits) on a Mac with OS X Yosemite 10.10.5. I am connecting to an Amazon RDS MySQL instance.

When I enter a simple

Answer 1

In my case, the IP address changed where mySQL was served. Flushing the DNS fixed it for me:

sudo dscacheutil -flushcache;
sudo killall -HUP mDNSResponder; 
say cache flushed