[Rpm-maint] [PATCH 4/5] Extend header size to 64MB due to file signatures

[Lubos Kardos]

It is just a thought. Rpm transaction can be divided in two phases.
In the first phase in the beginning of transaction rpm loads all file infos to
perform transactions checks and then releases them. In the second phase rpm
reloads single file infos to install single packages in row. The memory peak
happens in the first phase when all file infos are loaded. These file infos
contain also file signatures but in the first phase they needn't to contain
them because the signature checking is performed only in the second phase.

So if the file signatures blow up the file infos so much so we need to increase
maximum header size then maybe it would be nice not to load file signatures
into file infos during the first phase of transaction when the rpm memory peak
happens.

Lubos

----- Original Message -----
> From: "Florian Festi" <ffesti at redhat.com>
> To: "Stefan Berger" <stefanb at us.ibm.com>
> Cc: rpm-maint at lists.rpm.org
> Sent: Friday, April 29, 2016 10:27:39 AM
> Subject: Re: [Rpm-maint] [PATCH 4/5] Extend header size to 64MB due to file signatures
> 
> On 04/27/2016 09:47 PM, Stefan Berger wrote:
> > "Rpm-maint" <rpm-maint-bounces at lists.rpm.org> wrote on 04/27/2016
> > 05:50:54 AM:
> > 
> > 
> >>
> >> Well changing header size limit needs a bit more thought. The main
> >> problem is that packages with bigger header will look broken on older
> >> rpm versions and the usual way of dealing with this (adding rpmlib()
> >> Requires) won't work it needs reading the header.
> > 
> > These huge headers are only occurring in a few very large packages and
> > only if one applies the per-file signatures. So most users probably
> > won't notice.
> > 
> >>
> >> Also I wonder if we should increase the header size even more, to get
> >> rid of this topic for a longer time. I thought about 256MB which gives a
> >> 4 times increase over the 16MB. I am kinda tempted to go even further.
> >> Otoh the limit is there for a reason. And having rpm chew through one GB
> >> of broken data doesn't sound like a pleasant experience.
> > 
> > Anything >=16 MB works with signed files for all packages in Fedora 23.
> > Let me know if you want me to resubmit the patch with a higher limit.
> 
> Yes, please. 256MB is probably the way to go. Let's hope we don't reach
> that any time soon.
> 
> Florian
> 
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