It's a long shot (and not really Perl related), but localhost is defined in /etc/hosts with a line like this: 

127.0.0.1       localhost

[download]
I'm wondering if that file was updated recently on your system, perhaps removing that definition. On my client's machine, it looks like that file hasn't been changed in a while (like, not since I set it up almost five years ago). 
-rw-r--r-- 1 root root 187 Feb  4  2018 /etc/hosts

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Alex / talexb / Toronto

Thanks PJ. We owe you so much. Groklaw -- RIP -- 2003 to 2013.

In reply to Re^2: DBI mysql connection broke suddenly by talexb
in thread DBI mysql connection broke suddenly by jimr451

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