[gentoo-amd64] Re: About to install on a 64 bit system. Advice wanted.

[Duncan]

Dale posted on Wed, 08 Dec 2010 23:21:53 -0600 as excerpted:

> Alex Schuster wrote:

>> If you are running databases like mysql, you need to export the
>> databases and import them later. This is because they are in binary
>> format, and the datatypes are different in x86 and amd64 world.

> I don't have anything that I generated anyway.  I have something
> installed that KDE pulled in if I recall correctly.  I'll let KDE start
> off fresh tho.
>
> This does bring me to another thought tho.  Would I be able to copy my
> /home directory over from a x86 system?  I'm thinking I would but want
> to make sure.

In general, the same /home should be fine, 32-bit or 64-bit.

However, kde4 uses a database for akonadi.  With older versions (thru 4.3 
at least), it was mysql by default.  Newer versions (from 4.5) use sqlite 
by default, tho there can be a bit of an issue trying to upgrade as the 
ebuild tries to default to sqlite, but the user config is still set to 
mysql.  If mysql is still on the system, it'll use it since that's what 
was (automatically) configured in user settings, but if it's cleaned off 
as a now unneeded dependency, akonadi would of course fail, until the 
user's configure is (manually) updated.  Of course, new-installs or new-
users wouldn't have the issue as they'd not have that bit of existing 
config.  I don't recall for sure whether it was 4.4 or 4.5 that switched, 
thus the gap above, but the sqlite dependency is FAR easier to deal with, 
now that they've worked thru the threading issues or whatever it was that 
was blocking its use earlier.

I wasn't aware of a 32/64 mysql database incompatibility, but assuming 
Alex is correct, you might experience issues with that mysql/akonadi 
dependency, if you're still using an older kde or if you migrate the same 
home (with the mysql config) over.  But as long as you either don't use 
akonadi (with 4.4/4.5 it's used for the address book but not for kmail 
itself; I don't know about kopete/etc as I don't do IRC/IM), or already 
have it configured for the sqlite backend, and aren't using mysql for 
anything else, you should be fine.

And even in the event that you're still using the mysql backend, at worst, 
akonadi only caches the data before its written to traditional text files, 
so any loss of data should be only what didn't get written back to the 
permanent storage. tho of course it might not be working for a bit as you 
get the config squared away.

Basically, then, as from what I recall you're following newer kde, 4.5.x, 
and not waiting for full Gentoo stabilization, I'd ensure that you're 
using the sqlite backend, not mysql, before you copy your home dir over, 
and then you should be fine.

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman