Internal Calibre Book ID displayed in Custom Column

[kovidgoyal]

UUID's are used to match books between library and device.

@chaley: If you are worried about the non-atomic part, you can change the code to generate a new uuid and only set the old uuid for the moved record after deletion of the exisiting record completes.

[chaley]

Originally Posted by kovidgoyal

@chaley: If you are worried about the non-atomic part, you can change the code to generate a new uuid and only set the old uuid for the moved record after deletion of the exisiting record completes.

I am not worried enough about it to get into that level of change. Book matching (and content server fetching by UUID) will work acceptably as long as the UUID is unique within a library. If the same UUID exists in two libraries then it is possible to have books on the device get new metadata on connect, but this is already made possible by title/author matching.

One possible problem: as far as I can tell nothing checks that the UUID is in fact unique in a given library. There isn't a constraint on the table and set_uuid seems not to check. I think that the only way this "hole" could be exploited is via DB recovery, which unconditionally sets the UUID to the one in the metadata.inf. Perhaps recovery should check, and if the UUID is already there create a new one. I will look at it.