Re: Streaming Package Installation for dpkg/APT
Hi,
Guillem and Lars, thank you very much for your detailed replies. They
are really informative and encouraging.
>From your replies what I learned was that, the idea is quite complex
and instead of streaming, we can think of other ways of speeding up
the installation process, which has taken my idea to a new direction.
As you have pointed out, I will also look into the possibilities of
using self-contained batches and debdeltas with apt/dpkg in the
speeding up process.
But still, the streaming idea also looks interesting to me. I will
study apt/dpkg functionality and streaming technologies in more detail
and try to come up with a suggestion on it. What I feel is, we can use
a tree like structure to resolve the dependencies and use it in the
streaming process in some way to achieve our goal. I am not sure if
it's doable or not. But I would like to develop the idea on top of
this. I will let you know if I could come up with something
interesting.
I really appreciate your help.
Thank you.
On 1/6/11, Lars Wirzenius <liw@liw.fi> wrote:
> On ke, 2011-01-05 at 07:01 +0100, Guillem Jover wrote:
>> Something which I guess would speed up the installation process could
>> be to just make apt download the packages in self-contained batches,
>> which can be unpacked/configured independently. This would also not
>> really need any change in dpkg AFAICS. This way the installation
>> process could start sooner than having to wait for the whole thing to
>> get downloaded. It does not remove the need to store those batched
>> packages on disk, but still.
>
> I can't look up the URLs for this, but when I worked for Canonical we
> discussed something like this at one UDS, and there should be blueprints
> and wiki pages on the Ubuntu sites for this. Some searching should turn
> them up.
>
> From memory, what we came up with was basically what Guillem hints at:
>
> * apt will order its downloads in "installation order"
> * whenever apt has a self-contained batch, it will feed them to dpkg
> * while dpkg runs, apt will continue to download things in the
> background
>
> Further, we discussed the possibility of doing some of the dpkg
> installation phases in parallel, even while waiting for the rest of a
> batch to be downloaded: for example, unpacking might be possible already
> at that time. This is more error prone and more complicated, though.
>
> Related to these discussions we also discussed the possibility of
> speeding up downloads by using debdeltas. debdelta seems to work quite
> well, and it might be a good idea for Debian to adopt it officially.
>
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--
Regards,
Ishan Jayawardena.
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