How to get rid of bad data in the hub?

[Fritz Meissner]

Hi,
I booted up my computer and started up Chandler as usual this morning. When I came back to the computer, there was a long list of blank notes/tasks with only a few of my own ones scattered amongst them. When I say blank, they had dates, but no title and no body text. Then it crashed, and wanted to shut down. During the backup on shutdown, there was a further error message that it could not complete backup.

I then went to my laptop, backed up the .chex and .tgz backup files to a USB drive for safety,  and tried starting Chandler. It started without error, then synced and during syncing the blank tasks started appearing, so I assume that my Hub data is now corrupt. I'm not sure if the bad data started on the desktop machine this morning and then was propogated to the hub when it synced, or if the corruption has happened in the Hub and is now spreading to all my machines.

As I see it now, I need to wipe the hub data, then start up Chandler one of my machines with a known good .chex and then repopulate the hub data from that - what I don't want is for the bad data on the hub to corrupt my local data. In Chandler I can only see options for cleaning out the local data, and I don't see anything in the hub for resetting the account (only for closing it). Is there a graceful way of doing this ?

Of course, the next question is what caused this - I use three machines synchronised via the hub (desktop with XP, desktop with Ubuntu 9.04 and netbook with Ubuntu 9.04 netbook remix) and have not previously had any data loss problems. As a suggestion, I think that when Chandler should rename the old .chex file (at least for one generation of files), rather than overwriting it - the present system is ineffective because when Chandler encounters data corruption, the first thing it does is close down, backing up the bad data and wiping out the old data (which was hopefully still good).

Fritz

_______________________________________________
[hidden email] mailing list
unsubscribe here: http://lists.osafoundation.org/mailman/listinfo/chandler-users
Chandler wiki: http://chandlerproject.org/wikihome

[Graham Perrin]

Fritz Meissner wrote:

what I don't want is for the bad data on the hub to corrupt my local data.

Avoidance can be tricky, mostly because restoration from backup.chex is followed by sync with the Hub, and if the Hub is wrong you may lose what you restored.

I should probably point you to:

1. <https://bugzilla.osafoundation.org/show_bug.cgi?id=12636#c0> concerning the undesirable sync with Hub

2. <http://n2.nabble.com/-tp2184993p2210390.html> concerning the steps that I took in a comparable situation.

Hope that helps,
Graham

[Fritz Meissner]

Thanks for the warnings - sometimes bad news is also a help! This is clearly going to be more complicated than I had thought, but at least you have mapped out a possible route.

I'm seriously wondering about just closing my hub account and then opening a new one and synchronising from my most up-to-date (uncorrupted) client. It sounds like less work than what you did.

Did you ever figure out if your data loss occurred on the hub, or did it start on the client and then become copied to the hub ? If the hub is unstable, then that is quite a serious issue.

Fritz

2009/9/21 Graham Perrin <[hidden email]>

Fritz Meissner wrote:
>
> what I don't want is for the bad data on the hub to corrupt my local data.
>

Avoidance can be tricky, mostly because restoration from backup.chex
Chandler Desktop is followed by sync with the Hub, and if the Hub is wrong
you may lose what you restored.

I should probably point you to:

1. <https://bugzilla.osafoundation.org/show_bug.cgi?id=12636#c0> concerning
the undesirable sync with Hub

2. <http://n2.nabble.com/-tp2184993p2210390.html> concerning the steps that
I took in a comparable situation.

Hope that helps,
Graham

--
View this message in context: http://n2.nabble.com/How-to-get-rid-of-bad-data-in-the-hub-tp3686102p3687735.html
Sent from the Chandler users mailing list archive at Nabble.com.
_______________________________________________
[hidden email] mailing list
unsubscribe here: http://lists.osafoundation.org/mailman/listinfo/chandler-users
Chandler wiki: http://chandlerproject.org/wikihome

_______________________________________________
[hidden email] mailing list
unsubscribe here: http://lists.osafoundation.org/mailman/listinfo/chandler-users
Chandler wiki: http://chandlerproject.org/wikihome

[Graham Perrin]

Fritz Meissner wrote:

Did you ever figure out if your data loss occurred on the hub, or did it start on the client and then become copied to the hub ?

In my case, the origin of loss was as mentioned in <http://n2.nabble.com/-tp2184993p2184993.html> point 1.

Regards
Graham

[Fritz Meissner]

2009/9/21 Graham Perrin <[hidden email]>

Fritz Meissner wrote:
>
> what I don't want is for the bad data on the hub to corrupt my local data.
>

Avoidance can be tricky, mostly because restoration from backup.chex
Chandler Desktop is followed by sync with the Hub, and if the Hub is wrong
you may lose what you restored.

I should probably point you to:

1. <https://bugzilla.osafoundation.org/show_bug.cgi?id=12636#c0> concerning
the undesirable sync with Hub

2. <http://n2.nabble.com/-tp2184993p2210390.html> concerning the steps that
I took in a comparable situation.

Hope that helps,
Graham

For the record, I managed to recover the situation as follows :

1. Copied an uncorrupted backup.chex file off one of my other computers (fortunately the most recent one was not on the machine where I first discovered the problem - that backup file was corrupt).
2. Logged in to the hub and looked for the corrupted data, which turned out to be all in one collection. I started deleting the bad notes one by one, but eventually found that some of them couldn't be deleted. I then deleted the whole collection from the hub.
3. Then opened up my Chandler client holding the ctrl key to get the options menu, selected option 6 to clear my data and reload, and reloaded from the copy of the good backup.chex file.
4. To recreate the deleted collection on the hub, I had to unpublish and then republish that one collection from my client.

Everything seems good now.

I must comment that the present system where the backup is overwritten every time you shut down is very dangerous because a shutdown after data corruption wipes out your good backup. I'm considering using a script to start Chandler which would first make a copy of the backup.chex file so that I would always be able to roll back one generation in the event of getting bad data.

Regards,

Fritz

_______________________________________________
[hidden email] mailing list
unsubscribe here: http://lists.osafoundation.org/mailman/listinfo/chandler-users
Chandler wiki: http://chandlerproject.org/wikihome