[[!comment format=mdwn
 username="joey"
 subject="""comment 1"""
 date="2017-09-29T16:47:18Z"
 content="""
The only way I can see to improve this would be to keep track of which
keys already have a thread working on them, and avoid a second thread
working on the same key.

I've started this in the avoid-dup-threads branch.

Getting key information to commandAction would be quite the plumbing job;
there are something like 50 call sites.

More difficult, the key is not known yet when commandAction is called in a
lot of cases, and looking up the key redundantly will slow down all
git-annex scanning. Seems that nontrivial changes would be needed to every
command.
"""]]
