[pulseaudio-discuss] RFC: Database formats on upgrade - auto-convert and save or just auto-convert

[Colin Guthrie]

'Twas brillig, and Xavier Bestel at 05/09/11 12:47 did gyre and gimble:
> On Sun, 2011-09-04 at 17:59 +0200, Maarten Bosmans wrote:
>>> What do you think the best route forward here is?
>>>
>>>  1. Convert on the fly only.
>>>  2. Convert on the fly and write to disk.
>>>
>>> Vote now!
>>
>> 2.
>>
>> I'm not too worried about preserving stored values either way
>> actually. It's just user preferences, moreover, they are implicit
>> preferences, only resulting from volume change or moving of a stream.
>> In my opinion that's not so valuable as to make significant effort to
>> protect it in some rather uncommon scenarios. (downgrading to pulse
>> using previous db format or severe bug in db handling code)
> 
> Not good. There's a not-so-uncommon scenario which is the NFS-mounted
> $HOME shared between desktops with differing versions (for instance,
> where I work we have a mix of RHEL4, RHEL5 & RHEL6).
> 
> To correctly handle that situation, db formats should of course be
> backward & forward compatible, but if it's not possible at least not
> write to disk the new format if possible.

This scenario is not a problem.

We specifically do not save one database for all machines you log in on
as all machines are typically different - e.g. different h/w and thus
remembering the settings for these in a single database is generally
pointless.

We use the dbus machine-id (as UUID that is generated by dbus at every
install) to name our databases, thus the one you use on $HOSTA will be
different to $HOSTB. Just look in the ~/.pulse/ folder and you'll see
what I mean. When $HOSTA upgrades, we will update *it's* host-specific
database but not any of the others.

The same is true even if you mutli-boot different OS's using the same
/home (something which is generally going to be problematic in many
applications, but it won't stop people doing it occasionally!).

So I don't think your fears in this case are realised.

Col


-- 

Colin Guthrie
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http://colin.guthr.ie/

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