15 October 2010

Might come in handy again

The table amgp_release associates UPC codes (amgp_upc) with album IDs (amgp_a_id). You'd think that this would be a one-to-one relationship, but apparently multiple IDs can share the same UPC code. Question: What are the UPCs that are associated with multiple IDs? Query:

select count(*), amgp_upc
from (select distinct amgp_upc, amgp_a_id from amg.amgp_release) tbl
group by amgp_upc
having count(*) > 1

13 October 2010

'N Sync

At this shop, a developer uses a Windows laptop to shell into a virtualized machine running Linux where the source code is compiled into a web application. Most of us use Eclipse as a development studio. I had set up my Eclipse to edit my working copy of the code base directly on the virtual machine, mounting it as an SMB network drive. But over time, I found that some serious latencies would occur sporadically--Eclipse would take several minutes to open a short file of JavaScript, that sort of hassle. So, after some cajoling from colleague Jared, I followed his lead and moved my setup so that my working copy is on my laptop's hard drive. So now, instead of an edit-build-test-think cycle, I have an edit-rsync-build-test-think cycle, but the edit step is much faster.

But I was faced with a new annoyance. Every rsync or ssh to the VM required me to type my password. (The other way with SMB, I just left a shell window open already logged in to the VM.)

(Hunh. I suppose I could have set up rsync to pull from the VM rather than push from the laptop. Never thought of that.)

Anyway, the team's wiki links to a helpful crib on how to make RSA keys to perform an automatic login with ssh, but my first efforts failed. Colleague Harold provided the missing piece. He checked /var/log/auth.log on the VM and found an error message that indicated the file permissions on my home directory were too open. We did a chmod 755 on my home directory, and I was in!