[Kobo] Is there a way to disable database writes?

Lucas Malor · 07-27-2014, 01:29 PM

To be completely safe, I would disable any writes to the device database by Calibre, like it acts when the firmware is a newer, and so not yet supported, version. Is there an option or any other way to do this?

PeterT · 07-27-2014, 01:46 PM

I believe the only writes are done when calibre updates series info and collections on the device.

Frankly, IMHO, there is just a great deal of unwarranted paranoia regarding calibre and the Kobo database.

Lucas Malor · 07-27-2014, 02:23 PM

Maybe, but I I get a db corruption after deleting books using Calibre. It could be a coincidence, but I want to be sure about it. I think that if the device stores a false fw version, Calibre will disable the database support. Where Calibre gets this information?

PeterT · 07-27-2014, 07:27 PM

Unfortunately, you are SOL. While YES, the driver does check the DB version, if it is an unsupported one and you have elected NOT to bypass the safety check, it will disable eBook deletion.

(And yes, I was wrong; eBook deletions DO update the database).

davidfor · 07-27-2014, 09:01 PM

The KoboTouch driver will updated the database at the following times:

- During the initial sync to while checking shelves and series info (only if options are set)
- Deleting a book
- Resending a book if the file size changed

If you are using the KoboTouchExtendedDriver, there is one other place as well, but it will rarely happen.

The first two can be stopped through the driver options. Or changing the metadata management to manual. The other two can't be stopped in the driver.

If you want to prevent any updates to the database, the only way to do this is to disable the driver and connect to the device as a folder. This will find the books on the device by scanning the directories. But, you won't be able to do the shelf or series management.

I have seen reports that deleting a book caused a database corruption, but not for a while. I would be interested in seeing a debug log when it happened to try and work out what is happening.

PeterT · 07-28-2014, 12:38 AM

David; just wondering about the Kobo Utilities plugin (and thought it might fit in here).

I know that when it goes to do a backup, it also does a validity check first. However, if you attach it multiple times a day, the validity check is only done the first time.

Any thought to either provide a means in Kobo Utility to do a validity check automatically on connect OR to add that as an option to the main driver itself? If added to the driver itself I could see that being an added "safety" measure, and would ensure that the database was shown to be intact BEFORE the driver made any changes to it.

davidfor · 07-28-2014, 02:42 AM

Peter: Not a bad idea. I have thought of adding a an option to backup on every connect. That is probably overkill, but I'm sure someone would want it. An automatic database check could be handy. If it gets added to the utilities, it won't get run until after the two jobs for the driver. But it could be run as the first of the other jobs.

Adding it to the driver might be a good idea. The question becomes which of the two jobs and what to do if it finds errors.

Lucas Malor · 07-28-2014, 07:09 AM

Quote:

Originally Posted by davidfor

I have seen reports that deleting a book caused a database corruption, but not for a while. I would be interested in seeing a debug log when it happened to try and work out what is happening.

Finger crossed, next time it will happen I'll take it. How to get a log with Calibre? Do you need also a dmesg from Kobo?

PS: I noticed that after a delete, "New" informations are not updated. For "New" informations I mean the tile that it's added when 1 or more books are added to the device. If there's only a new book, clicking on the tile will open the book, otherwise Library will be opened. The covers of the new books are displayed in the tile.
If some books are deleted by Calibre, and there was a "New" tile with some of deleted books, their covers are not removed from the tile. On the contrary an empty image is displayed. Tile is not dismissed even if all the books listed by the tile are removed.
I suppose Kobo reads some other information about deleted books that Calibre does not write in the database. Anyway I don't know if this is somewhat related to corruption.

davidfor · 07-28-2014, 07:41 AM

Quote:

Originally Posted by Lucas Malor

Finger crossed, next time it will happen I'll take it. How to get a log with Calibre? Do you need also a dmesg from Kobo?

Unfortunately, you have to run calibre in debug mode to get a log. To do this, either right click on the preferences button and select "Restart in debug mode" or run calibre with the command "calibre-debug -g".

Quote:

PS: I noticed that after a delete, "New" informations are not updated. For "New" informations I mean the tile that it's added when 1 or more books are added to the device. If there's only a new book, clicking on the tile will open the book, otherwise Library will be opened. The covers of the new books are displayed in the tile.
If some books are deleted by Calibre, and there was a "New" tile with some of deleted books, their covers are not removed from the tile. On the contrary an empty image is displayed. Tile is not dismissed even if all the books listed by the tile are removed.
I suppose Kobo reads some other information about deleted books that Calibre does not write in the database. Anyway I don't know if this is somewhat related to corruption.

The information for the tiles is in a table in the database. For the new books tile, the list of books to show are stored in a way that is not easy to check or change.

Lucas Malor · 07-28-2014, 09:31 AM

Quote:

Originally Posted by davidfor

The information for the tiles is in a table in the database. For the new books tile, the list of books to show are stored in a way that is not easy to check or change.

What is the table? Is there some BLOB field?

PeterT · 07-28-2014, 09:46 AM

I find this to be quite amusing.... Someone concerned about calibre writring to the Kobo database is now interested in how to remove entries from the table used to populate the matrix entry for new books

Lucas Malor · 07-28-2014, 05:26 PM

There's a possibility that the problem is caused by nickel itself. Since db data are not as it expects, it could do something wrong and do a transaction without close it. I do not bet on it, but you never know.

davidfor · 07-28-2014, 09:20 PM

Quote:

Originally Posted by Lucas Malor

What is the table? Is there some BLOB field?

Yes, it is a BLOB with what I assume is serialized data in it. I can see some info in them, but not enough to easily decode it. Or have a real desire to do so.

Quote:

Originally Posted by Lucas Malor

There's a possibility that the problem is caused by nickel itself. Since db data are not as it expects, it could do something wrong and do a transaction without close it. I do not bet on it, but you never know.

I am pretty sure the driver is deleting everything correctly. If something is missed, it would be very bad if nickel killed the database because of it.

But, when do you see the corruption? If it is while the delete is done, then it isn't likely to be nickel. If it is the next connection, that might be different.

Lucas Malor · 07-29-2014, 06:38 AM

At reboot. Not all books are detected, and covers are not displayed.

davidfor · 07-29-2014, 07:19 AM

So, calibre is not reporting an error but when you disconnect the device shows signs of a corrupt database. Have you checked at the next connection and see that it is corrupted? Have you tried checking the database after the delete from calibre?

I had to check back. You posted a database backup mechanism a while ago. Are you still using that? Is there any chance it might be getting in the way?

07-27-2014, 01:29 PM	#1
Lucas Malor Pain in the arse Posts: 758 Karma: 77856 Join Date: Apr 2013 Device: Kobo Aura One, Kindle 4	[Kobo] Is there a way to disable database writes? To be completely safe, I would disable any writes to the device database by Calibre, like it acts when the firmware is a newer, and so not yet supported, version. Is there an option or any other way to do this?

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07-27-2014, 01:46 PM	#2
PeterT Grand Sorcerer Posts: 13,511 Karma: 78910202 Join Date: Nov 2007 Location: Toronto Device: Libra H2O, Libra Colour	I believe the only writes are done when calibre updates series info and collections on the device. Frankly, IMHO, there is just a great deal of unwarranted paranoia regarding calibre and the Kobo database.

07-27-2014, 02:23 PM	#3
Lucas Malor Pain in the arse Posts: 758 Karma: 77856 Join Date: Apr 2013 Device: Kobo Aura One, Kindle 4	Maybe, but I I get a db corruption after deleting books using Calibre. It could be a coincidence, but I want to be sure about it. I think that if the device stores a false fw version, Calibre will disable the database support. Where Calibre gets this information?

07-27-2014, 07:27 PM	#4
PeterT Grand Sorcerer Posts: 13,511 Karma: 78910202 Join Date: Nov 2007 Location: Toronto Device: Libra H2O, Libra Colour	Unfortunately, you are SOL. While YES, the driver does check the DB version, if it is an unsupported one and you have elected NOT to bypass the safety check, it will disable eBook deletion. (And yes, I was wrong; eBook deletions DO update the database).

07-27-2014, 09:01 PM	#5
davidfor Grand Sorcerer Posts: 24,905 Karma: 47303824 Join Date: Jul 2011 Location: Sydney, Australia Device: Kobo:Touch,Glo, AuraH2O, GloHD,AuraONE, ClaraHD, Libra H2O; tolinoepos	The KoboTouch driver will updated the database at the following times: - During the initial sync to while checking shelves and series info (only if options are set) - Deleting a book - Resending a book if the file size changed If you are using the KoboTouchExtendedDriver, there is one other place as well, but it will rarely happen. The first two can be stopped through the driver options. Or changing the metadata management to manual. The other two can't be stopped in the driver. If you want to prevent any updates to the database, the only way to do this is to disable the driver and connect to the device as a folder. This will find the books on the device by scanning the directories. But, you won't be able to do the shelf or series management. I have seen reports that deleting a book caused a database corruption, but not for a while. I would be interested in seeing a debug log when it happened to try and work out what is happening.

07-28-2014, 12:38 AM	#6
PeterT Grand Sorcerer Posts: 13,511 Karma: 78910202 Join Date: Nov 2007 Location: Toronto Device: Libra H2O, Libra Colour	David; just wondering about the Kobo Utilities plugin (and thought it might fit in here). I know that when it goes to do a backup, it also does a validity check first. However, if you attach it multiple times a day, the validity check is only done the first time. Any thought to either provide a means in Kobo Utility to do a validity check automatically on connect OR to add that as an option to the main driver itself? If added to the driver itself I could see that being an added "safety" measure, and would ensure that the database was shown to be intact BEFORE the driver made any changes to it.

07-28-2014, 02:42 AM	#7
davidfor Grand Sorcerer Posts: 24,905 Karma: 47303824 Join Date: Jul 2011 Location: Sydney, Australia Device: Kobo:Touch,Glo, AuraH2O, GloHD,AuraONE, ClaraHD, Libra H2O; tolinoepos	Peter: Not a bad idea. I have thought of adding a an option to backup on every connect. That is probably overkill, but I'm sure someone would want it. An automatic database check could be handy. If it gets added to the utilities, it won't get run until after the two jobs for the driver. But it could be run as the first of the other jobs. Adding it to the driver might be a good idea. The question becomes which of the two jobs and what to do if it finds errors.

07-28-2014, 09:46 AM	#11
PeterT Grand Sorcerer Posts: 13,511 Karma: 78910202 Join Date: Nov 2007 Location: Toronto Device: Libra H2O, Libra Colour	I find this to be quite amusing.... Someone concerned about calibre writring to the Kobo database is now interested in how to remove entries from the table used to populate the matrix entry for new books

07-28-2014, 05:26 PM	#12
Lucas Malor Pain in the arse Posts: 758 Karma: 77856 Join Date: Apr 2013 Device: Kobo Aura One, Kindle 4	There's a possibility that the problem is caused by nickel itself. Since db data are not as it expects, it could do something wrong and do a transaction without close it. I do not bet on it, but you never know.

07-29-2014, 06:38 AM	#14
Lucas Malor Pain in the arse Posts: 758 Karma: 77856 Join Date: Apr 2013 Device: Kobo Aura One, Kindle 4	At reboot. Not all books are detected, and covers are not displayed.

07-29-2014, 07:19 AM	#15
davidfor Grand Sorcerer Posts: 24,905 Karma: 47303824 Join Date: Jul 2011 Location: Sydney, Australia Device: Kobo:Touch,Glo, AuraH2O, GloHD,AuraONE, ClaraHD, Libra H2O; tolinoepos	So, calibre is not reporting an error but when you disconnect the device shows signs of a corrupt database. Have you checked at the next connection and see that it is corrupted? Have you tried checking the database after the delete from calibre? I had to check back. You posted a database backup mechanism a while ago. Are you still using that? Is there any chance it might be getting in the way?

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