Running multiple instances of DigiKam?

[Peter Albrecht]

Hi list,

I just accidently started a second instance of digiKam,
while the first one was still running.

Could this lead to problems? Since two programms use the
same database file at the same time?

If so, I think digiKam should show a short warning:
"Warning! Another instance of DigiKam is already running."

(I still use digiKam 3.5.0. No time for update yet).

Should I file a bug about this at bko? Couldn't find one there.

Regards,
        Peter
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[Daniel Bauer-2]

Am 01.08.2014 11:46, schrieb Peter Albrecht:

> Hi list,
>
> I just accidently started a second instance of digiKam,
> while the first one was still running.
>
> Could this lead to problems? Since two programms use the
> same database file at the same time?
>
> If so, I think digiKam should show a short warning:
> "Warning! Another instance of DigiKam is already running."
>
> (I still use digiKam 3.5.0. No time for update yet).
>
> Should I file a bug about this at bko? Couldn't find one there.
>
> Regards,
> Peter

What happens is that digikam gets incredibly slow. But it works. There
are situations that I like to have two instances, one on each screen,
for easy comparing for example. But a lot of changes (moving files etc.)
make it really VERY slow...

Sometimes digikam doesn't shut down when I close the window, and when I
reopen it clicking the desktop icon, I realize how slow it is, check the
processes and see that there are more digikam processes, which I then
kill...

I do not often log out or reboot, but sometimes it happens that after
reboot two or even three digikams open, although I have closed all
windows before shutting down...

I think this is a known bug (?).

regards

Daniel

--
Daniel Bauer photographer Basel Barcelona
professional photography: http://www.daniel-bauer.com
google+: https://plus.google.com/109534388657020287386
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[Gilles Caulier-4]

First digiKam instance will open in R.W the database. The second one in R only.

If you try to process change in DB through 2nd instance, it will try
to write in DB until a time out, and will fail.

It's not recommend to play with 2 instance in the same time. To
compare images, use LT. I play also with WDHQ dual flat screens here
like this...

https://www.flickr.com/photos/digikam/14801149154/

Gilles Caulier

2014-08-01 11:57 GMT+02:00 Daniel Bauer <[hidden email]>:

>
>
> Am 01.08.2014 11:46, schrieb Peter Albrecht:
>
>> Hi list,
>>
>> I just accidently started a second instance of digiKam,
>> while the first one was still running.
>>
>> Could this lead to problems? Since two programms use the
>> same database file at the same time?
>>
>> If so, I think digiKam should show a short warning:
>> "Warning! Another instance of DigiKam is already running."
>>
>> (I still use digiKam 3.5.0. No time for update yet).
>>
>> Should I file a bug about this at bko? Couldn't find one there.
>>
>> Regards,
>>         Peter
>
>
> What happens is that digikam gets incredibly slow. But it works. There are
> situations that I like to have two instances, one on each screen, for easy
> comparing for example. But a lot of changes (moving files etc.) make it
> really VERY slow...
>
> Sometimes digikam doesn't shut down when I close the window, and when I
> reopen it clicking the desktop icon, I realize how slow it is, check the
> processes and see that there are more digikam processes, which I then
> kill...
>
> I do not often log out or reboot, but sometimes it happens that after reboot
> two or even three digikams open, although I have closed all windows before
> shutting down...
>
> I think this is a known bug (?).
>
> regards
>
> Daniel
>
> --
> Daniel Bauer photographer Basel Barcelona
> professional photography: http://www.daniel-bauer.com
> google+: https://plus.google.com/109534388657020287386
>
> _______________________________________________
> Digikam-users mailing list
> [hidden email]
> https://mail.kde.org/mailman/listinfo/digikam-users

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[Marcel Wiesweg]

> I just accidently started a second instance of digiKam,
> while the first one was still running.
>
> Could this lead to problems? Since two programms use the
> same database file at the same time?
>
> If so, I think digiKam should show a short warning:
> "Warning! Another instance of DigiKam is already running."
>
> (I still use digiKam 3.5.0. No time for update yet).
>
> Should I file a bug about this at bko? Couldn't find one there.

It should be safe to run multiple instances. SQlite uses file locking to
protect its database, it is fully supported to access a db file concurrently.
Read access from multiple instances will be fast.
Write access is already slow from a single instance, will be even slower from
multiple instances. Enabling Write-ahead-logging may solve a lot of these
problems (but there is not much experience with that from our side, and never
dare to backup your db file if there's a -shm or -wal file still around)

Marcel
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[Peter Albrecht]

Hi,

thanks all for your feedback!

So there is no potential problem, thanks to proper database
locking. Good to know.

Regards,
        Peter

On 02.08.2014 19:49, Marcel Wiesweg wrote:

>
>> I just accidently started a second instance of digiKam,
>> while the first one was still running.
>>
>> Could this lead to problems? Since two programms use the
>> same database file at the same time?
>>
>> If so, I think digiKam should show a short warning:
>> "Warning! Another instance of DigiKam is already running."
>>
>> (I still use digiKam 3.5.0. No time for update yet).
>>
>> Should I file a bug about this at bko? Couldn't find one there.
>
> It should be safe to run multiple instances. SQlite uses file locking to
> protect its database, it is fully supported to access a db file concurrently.
> Read access from multiple instances will be fast.
> Write access is already slow from a single instance, will be even slower from
> multiple instances. Enabling Write-ahead-logging may solve a lot of these
> problems (but there is not much experience with that from our side, and never
> dare to backup your db file if there's a -shm or -wal file still around)
>
> Marcel
> _______________________________________________
> Digikam-users mailing list
> [hidden email]
> https://mail.kde.org/mailman/listinfo/digikam-users
>

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