Red Hat Bugzilla – Bug 451047
yum update sorts files by size for downloading
Last modified: 2014-01-21 18:03:02 EST
Description of problem:
More of an "enhancement"...
"yum update" appears to sort files for download by size, smallest first.
Not sure if this is a deliberate sort, or just coinicdence. But sorting so the
largest is download first conveys more user information and improves *perceived
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. yum update
2. reply y to prompt asking if it's OK to download xxx MB
files are downloaded, smallest first
Actually I *expected* no particular order.
But, since the order appears to be deliberately smallest first, I'd like to
suggest it be largest first:
- While waiting/watching a user would always know the next file is the same size
or SMALLER than the one just downloaded
- The *Perception* would be that the process is speeding up instead of slowing
See initial thread on fedora forum:
My understanding from people who have taken psychology is that people split
into "first impression lasts" and "later impression eventually wins" ... and
that the former is _much_ more common. So it's much more likely that the
perception of largest first would be that it's slower.
Also the point of downloading smallest first, from a purely technical point of
view, is that at any time you can break out of the download and you'll have the
largest set of _complete_ packages that you can install.
Point 1: So provide an option to control the sort option, default to "most people".
Point 2: Not much of an argument. If a package has dependencies, what's in place
to make sure the dependency is downloaded before beginning the next package?
Also, since downloading/installing a whole set of updates was checked for
dependency issues, you can't reliably just "break out" any time and install what
Sorting files by size does not guarantee that any package is complete. What if a
common dependency IS the largest file? Worst case: The smallest file has a
dependency on the largest file. So you can't install that package until the last
file is obtained. So much for "break out any time".
Actually, the idea of simply sorting by size is a waste of resources... it
really doesn't provide any useful benefit. It looks neat and tidy, but other
If you really want to support a "break out any time" theory better, take
dependencies into account so files and their dependencies are downloaded
together, then the next set, and so on.