/etc/hosts and the thousand-characters-long line

This is a self-note in the case I encounter another strange behaviour like this. We were experiencing a strange problem with MySQL and DNS. I was trying to do this:

$ mysql -h server.mysql
Unknown MySQL server host 'server.mysql' (-1)

but both dig and a normal ping (which in turns uses libc and nsswitch to do the name resolving) were working:

$ dig +short server.mysql
192.168.10.1

$ ping server.mysql
PING server.mysql (192.168.10.1) 56(84) bytes of data.
64 bytes from server.mysql (192.168.10.1): icmp_req=1 ttl=64 time=0.399 ms


and obviously connecting using the MySQL client and the IP address worked. So, what was happening? The smarter amongst you maybe already know the problem: a very very large line in /etc/hosts was driving the mysql client crazy (but not ping). Removing the “files” database fron the hosts entry in /etc/nsswitch.conf showed where the problem lied, and fixing the bad-ass line fixed the problem