A grumpy editor's calendar search [LWN.net]

A grumpy editor's calendar search

Posted Mar 9, 2004 21:59 UTC (Tue) by coriordan (guest, #7544)
Parent article: A grumpy editor's calendar search

'dist-upgrade' shouldn't be used by people running Debian unstable, you should be using just 'upgrade'. 'dist-upgrade' is for upgrading between versions of debian (2.2 -> 3.0), but unstable doesn't have versions.

Anyway, our editor should be using emacs, 'M-x calender' 'M-x diary' etc. :)

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A grumpy editor's calendar search

Posted Mar 10, 2004 4:37 UTC (Wed) by socket (guest, #43) [Link]

So I don't post comments that much anymore, but this needs to be responded to: the parent post is simply wrong. There are many cases where you need to use 'apt-get dist-upgrade' instead of just 'apt-get upgrade'. The difference between the two isn't only relevant in a major version upgrade, especially if you're running unstable which has a lot of packages changing all the time. Here's the difference, as described in the apt-get manual page:

upgrade:

upgrade is used to install the newest versions of all packages currently installed on the system from the sources enumerated in /etc/apt/sources.list. Packages currently installed with new versions available are retrieved and upgraded; under no circumstances are currently installed packages removed, or packages not already installed retrieved and installed. New versions of currently installed packages that cannot be upgraded without changing the install status of another package will be left at their current version. An update must be performed first so that apt-get knows that new versions of packages are available.

dist-upgrade:

dist-upgrade, in addition to performing the function of upgrade, also intelligently handles changing dependencies with new versions of packages; apt-get has a "smart" conflict resolution system, and it will attempt to upgrade the most important packages at the expense of less important ones if necessary. The /etc/apt/sources.list file contains a list of locations from which to retrieve desired package files.

In short, it's sometimes important to do a dist-upgrade on debian testing or unstable, otherwise packages won't install because they depend on something which conflict with something you've got installed. A dist-upgrade will remove a package if doing so resolves a conflict and allows a new package to be installed.

In fact, dist-upgrade is always supposed to keep your system consistent, even if the packages themselves are otherwise broken.

That said, I can't say I have a whole lot of respect for Debian after the whole All Documentation Must Be Free Including RFCs fiasco. Free documentation is apparently more important than open standards, I suppose. Whatever.

A grumpy editor's calendar search

Posted Mar 10, 2004 6:09 UTC (Wed) by coriordan (guest, #7544) [Link]

> the parent post is simply wrong

Nope.

'dist-upgrade' is better than 'upgrade' for complex upgrades because it attempts to be "smart" and it is more aggressive - though this means it should be monitored. Our editor used 'dist-upgrade' for a routine upgrade, and he didn't monitor it, and he got stung.

I commented that he should have been using 'upgrade'. I'm right.

I also gave a one line description of the difference between 'dist-upgrade' and 'upgrade'. If your post is just a very long-winded claim that my one line does not constitute complete documentation, you'll get no further argument from me.

A grumpy editor's calendar search

Posted Mar 10, 2004 13:22 UTC (Wed) by rise (guest, #5045) [Link]

Your original comment looks to me to be either highly misleading to users unfamiliar with apt or outright wrong. Both the Debian FAQ and the APT HOWTO recommend dist-upgrade in places specifically because of its ability to handle dependencies correctly. The author's direct mistake was simply that he missed noticing a removal and that's logically independent of your claim about dist-upgrade's suitability. I can see how you might jump to the conclusion that dist-upgrade is for version upgrades only from the more extensive documentation that accompanies doing something that complex with it, but a closer reading might be order.

The "very long-winded" potshot you took seems a little over the line as well. The user who responded to you quotes the canonical descriptions of the functions and then explains why dist-upgrade is sometimes unnecessary. He tried to justify his position and provide evidence to let others decide for themselves while you've wallowed in proof by assertion. Could you please offer even one shred of evidence instead of the straw-man argument about "complete documentation" and your naked statement that you're right?

Recklessly directing Debian users to avoid using the tool that properly supervised does the best job of keeping a system up to date and consistent is a disservice to the community.

A grumpy editor's calendar search

Posted Mar 10, 2004 15:42 UTC (Wed) by coriordan (guest, #7544) [Link]

Our editor lost ical when he used 'dist-upgrade' for an unmonitored routine upgrade. Routine upgrades should not delete your favourite applications. He should have used 'upgrade' for such an upgrade.

That is why I'm right.

There is one detail that is up for debate though, and that's my claim that 'dist-upgrade' is for version upgrades. 'dist-upgrade' is for unusual circumstances. Version upgrades are the best example I know of, and are the only example I have encountered in the last 3 years. If you'd like to list all the possible circumstances where 'dist-upgrade' can be useful, I probably won't dispute you (although apt-get is not the topic of this forum).

(small thing: both tools "handle dependencies correctly". If one doesn't: please file a bug report.)

A grumpy editor's calendar search

Posted Mar 10, 2004 20:37 UTC (Wed) by socket (guest, #43) [Link]

We're talking about slightly different senses of the word 'upgrade', I think.

When I was running Debian testing, I'd use 'apt-get upgrade' most of the time, until I had a situation where nothing more would get installed despite new packages being available unless I used 'apt-get dist-upgrade'. On one occasion, I think python had to be ripped out and replaced with python#.# packages and a whole raft of other packages depended on the old python instead of python#.#. Lots of things needed to be deleted, and many of the same had no newer version to provide a smooth transition to python#.#. The new python packages conflicted with the old ones. Thus, a normal 'upgrade' would say, "Ah. I'll spare your system -- better to upgrade nothing than to remove anything." Perhaps a wise choice, for many.

This makes sense for people running the stable branch of debian. But if you're running testing or unstable, things are going to change a lot, and users want to continue to get new packages, they will have to accept some amount of bridge-burning in the form of removing old packages responsible for a conflict. The newer packages of Python conflicted with the existing one specifically to encourage users to move with the times.

I think there was also some confusion in what I meant by 'handling dependencies correctly' -- in one sense, it just makes sure that Depends: requirements are satisfied, no other conditions necessary. In another sense, (the one I meant,) it means that Depends: requirements are satisfied, and that you don't get into a state where you can no longer upgrade your system to newly available packages on account of the importance of keeping old ones around. For developers, the latter is a pretty important dependency.

I'd be surprised if I ever made it more than a week with Debian Testing without the normal 'apt-get upgrade' process simply refusing to install new packages. I'd also argue that 'dist-upgrade' is for both unusual circumstances, and running a suitably modern system.

We're both right, I think. You're right, for people running Stable.

But the issue of which sense of the word 'upgrade' we mean is really at the core of this. I'd argue that most people consider a system upgrade (in the generic, non-debian sense) to be something that modernizes the system. A user running testing or unstable and only using 'apt-get upgrade' will eventually be making no changes to their system at all, and that doesn't constitute much of an upgrade.

apt-get dist-upgrade can seriously damage your health

Posted Mar 10, 2004 21:58 UTC (Wed) by robster (subscriber, #4849) [Link]

Of course APT will kindly tell you what it is holding back because of conflicts/new packages required when doing a plain upgrade. Often the best approach is to do an upgrade and then manually go through the kept back packages and install them, allowing you to get any new packages that are needed to upgrade existing ones and maybe prevent yourself from removing packages you do want.

This is one example of why apt-get dist-upgrade is dangerous, and is in fact not recommended for distribution migrations anymore except for advanced users . (Please see the woody release notes for more details on this).

Cheers,

Rob

A grumpy editor's calendar search

Posted Mar 11, 2004 8:11 UTC (Thu) by lacostej (guest, #2760) [Link]

A usefull use of dist-upgrade is when you modify your package selection.

E.g. I have two machines, one desktop and a laptop that I keep in sync.
I move the data (/home) over using a rsync script. I update the packages as follow:
on the primary machine:

apt-get upgrade every now and then

When about to apply changes onto laptop.

dpkg --get-selections > /home/dpkg-get-selections-master.txt

on the mirror (laptop)

apt-get update
scp desktop:/home/dkpg-get-selections-master.txt /home/
dkpg --set-selections < /home/dpkg-get-selections-master.txt
apt-get dist-upgrade

apt-get upgrade doesn't work in that case, based on my experience.

A problem of apt-get dist-upgrade is that it also pulls the "Suggested" packages.

Some pointers:
http://lists.debian.org/debian-user/2003/debian-user-200311/msg00024.html
http://www.debian.org/doc/manuals/quick-reference/ch-package.en.html#s-record
(this one should probably be updated)

A grumpy editor's calendar search

Posted Mar 18, 2004 11:16 UTC (Thu) by sholden (guest, #7881) [Link]

If you has said "'dist-upgrade' shouldn't be used for an unmonitored routine upgrade" then, yes, you may have been right. But you didn't, you said:

"'dist-upgrade' shouldn't be used by people running Debian unstable"

Which is completely false. If dist-upgrade is not used by people running unstable they will reach a point at which their system does not upgrade when they tell it to.

"'dist-upgrade' should be used with care when 'upgrade' doesn't perform as expected" sounds reasonable. But again, that isn't what you said. You gave no qualifier and simply stated dist-upgrade should not be used by unstable users.

right or wrong

Posted Mar 11, 2004 23:17 UTC (Thu) by giraffedata (subscriber, #1954) [Link]

>> the parent post is simply wrong
>Nope.
>I commented that he should have been using 'upgrade'. I'm right.

But that was a minor part of the subject post. The thrust of it was,

>'dist-upgrade' shouldn't be used by people running Debian
>unstable... 'dist-upgrade' is for upgrading between versions of debian
>(2.2 -> 3.0), but unstable doesn't have versions.

Do you stand by that? As a general rule, and not limited to our editor's recent sorrow, should dist-upgrade not be used by people running Debian unstable? Is it for upgrading between versions?

I'm not attacking; I really want to know.

right or wrong

Posted Mar 12, 2004 0:06 UTC (Fri) by coriordan (guest, #7544) [Link]

dist-upgrade will do you no harm (AFAIK) *if* you monitor it each time you use it. If you don't monitor it, you may end up having to write an insightful article about alternative software packages.

If you use 'upgrade', you won't have to write the article. If 'upgrade' is not going to upgrade a certain pacakge, it will tell you. You can then 'apt-get install' that package if you want to, and you'll be told that to install package "x", package "y" has to be removed - or whatever the problem is.

Back in my day (all of 3 years ago), when upgrading from a stable version to another stable version, or for upgrading from stable -> testing, it was recommended that you use 'dist-upgrade'. robster above says that 'dist-upgrade' is not even recommended for this anymore. (the release notes for Woody-3.0 still recommend 'dist-upgrade' for version upgrades. Maybe robster is talking about the release notes for the upcoming 3.1?)

The main thrust of my post was meant to be my advice to Our Editor. I'm glad no one disputed that he should be using Emacs - that is a little harder to prove ;-)

A grumpy editor's calendar search

Posted Mar 14, 2004 20:16 UTC (Sun) by jschrod (subscriber, #1646) [Link]

Please reread the article: Our editor wrote that he "learned to scrutinize every dist-upgrade carefully before turning it loose, but he missed the one that deleted ical from his system".

Anyhow, if that means good articles like the current one, I won't feel too sorry for him. :-) :-)

Joachim

5 days later...

Posted Mar 15, 2004 1:36 UTC (Mon) by coriordan (guest, #7544) [Link]

Our editor learned to be careful while using a hammer to kill a fly. I pointed out that there is a fly swatter within arms reach :-)