Re: solving(?) the updatedb problem w/ the kernel cache

From: Ray Lee
Date: Fri Jul 27 2007 - 12:42:41 EST


On 7/27/07, Douglas J Hunley <doug@xxxxxxxxxxxxxxxxx> wrote:
> I've been following lkml for a little while (not understanding it all, but
> following nonetheless <g>) and I've noticed that in a lot of the talks about
> schedulers, elevators, and performance, the issue of running updatedb and its
> effects on the kernel's fs cache seems to recur. I've also yet to see anyone
> present a solution that others think is worth pursuing. I'm curious why we're
> trying to solve the problem, when we can simply avoid the problem to begin
> with by making use of inotify and introducing a new user-space
> daemon, 'located'.

inotify doesn't scale for lots of directories. I have about 18,000
directories under ~ on my laptop, and that's with a few source trees
that I use infrequently tarballed up.

But yes, if we had a full filesystem events notifier, then we could
just toss updatedb aside and have the benefit of a live index into the
system. It's been suggested before, at least by me. Other projects
want this as well, such as an on-demand virus scanner, or a live
backup to another site, or beagle/tracker who would like to index
documents on the fly. beagled already uses inotify, I think, but as it
takes over my system (in a bad way) whenever I tried to run it, I had
no choice but to remove it.

Perhaps it was choking on the 18k subdirectories, dunno.

Ray
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