[Yum-devel] makecache process

[Michael Stenner]

On Fri, Nov 04, 2005 at 04:41:46PM -0500, seth vidal wrote:
> We would also need to add a more informative message to yum to let the
> user know what's going on if the yum lockfile is engaged while the
> metadata is being read in for the regular run.

I'm not familiar with the locking and metadata subsystems, so forgive
me if this is naive or incorrect.  When you only hit locking conflicts
when yum is being run interactively twice, then fine.  If you have to
hit the 4 am update job, then fine again.  If we're talking about
something that runs every few hours, it pays to think carefully about
it as collisions will get annoying.  If the metadata rebuild only
takes a few (5-20) seconds, then no biggie.  I suspect that's the
case, so fine one more time.

All that said, if you decide it's worthwhile, you might consider doing
the following:

  a) on metadata update, build the metadata separately (no lock)
     without removing the "real" metadata
  b) lock the real metadata
  c) swap in the new metadata
  d) unlock

This could result in significant disk usage, which is annoying.  Also,
the new metadata should be in the same directory soas to be
filesystem-efficient (no cross-filesystem moves).

					-Michael
-- 
  Michael D. Stenner                            mstenner at ece.arizona.edu
  ECE Department and Optical Sciences Center                520-626-1619
  University of Arizona                                         ECE 524G