Wednesday, 22 May 2019

Re: mlocate - what is it good for?

Hi Brian,

I personally use 'locate' all the time, and rarely use 'find' if 'locate' is available.

The major problem I have with find is that it's slow. Even restricting the search space to a specific directory (as opposed to searching everything under "/") can be slow. For example, searching my home directory takes a while, due to the large number of Python virtual envs that I have.

Sometimes searching a specific directory simply does not work with find due to the presence of symlinks. You have to wait for find to complete (which might take a while), realize that maybe symlinks are involved (which is not obvious) and re-run find with -L, hoping it will work.

Searching from the root directory "/" with find is not just slow, but also clobbers the terminal with "Permission Denied" or "Operation Not Permitted" errors. You must remember to use 2>/dev/null (hoping that won't hide any useful errors).

With locate instead you can search the entire filesystem and get your results in a few milliseconds, without thinking about edge cases.

Also, if you want to always exclude certain filesystems or directories, with find you have to play with -prune or -xdev or similar, and repeat the same arguments every time. With locate, you can just edit one configuration file once and you're done. In my locate configuration I exclude things like my LXC/LXD containers: I never want results involving those.

Those are the reasons why I wish locate was enabled everywhere, not just Ubuntu :-)

Hope this helps!

On Wed, May 22, 2019, 20:00 Brian Murray <> wrote:
The Ubuntu Foundations team was recently looking at an issue with
mlocate[1] and the effect it has on all users of Ubuntu. While that
specific issue is fixable there are also issues[2,3] with keeping
PRUNEFS and PRUNEPATHS current in updatedb.conf. So we ended up
questioning the usefulness of installing mlocate by default on systems
at all. We believe that find is an adequate replacement for mlocate but
want to hear from you about use cases where it may not be. I'll start
with a personal example:

"I don't remember (because I need to know so infrequently) where the
meta-release file is cached on disk by update-manager and use locate to
find it. The find command itself is inadequate because the cached file
exists in both /home and /var."


Brian Murray

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