On the file metadata_db_prefs_backup.json

Horus68 · 06-03-2020, 04:30 AM

Os the file "metadata_db_prefs_backup.json".
Is it really needed in the root folder of your library?
I do have some libraries with that file and others without it, i don't know why I can see it is updated sometimes, maybe when I change some preferences.

I've read an old post on library restore saying that:
"If there is no metadata_db_prefs_backup.json file then custom column definitions might be wrong and none of the library-specific preferences will be restored."

And also this note "the file metadata_db_prefs_backup.json contains all the plugboards, custom columns, saved searches, virtual libraries, etc. and is backed up when calibre quits-- basically, anything that IS stored per-library."

So is it required and why isn't it on all libraries I have?
I don't need to have it deleted, just super-curious!

Note: My goal is to share my empty library with all my library-specific preferences (custom columns and so on) so some fellows of mine can start a new empty library with some settings already done.

I was able to create a new empty library from my master library (with feature: Create library / Copy structure) and got an empty master without the file "metadata_db_prefs_backup.json"
I created a copy from that folder and created a library from it and the library settings are there.
It was done in a 32 bit windows machine, didn't test it on a 64 bit machine!

kovidgoyal · 06-03-2020, 04:34 AM

IIRC that file is written every time you quit calibre with that library open.

Horus68 · 06-03-2020, 05:10 AM

Quote:

Originally Posted by kovidgoyal

IIRC that file is written every time you quit calibre with that library open.

Confirmed!

06-03-2020, 04:30 AM	#1
Horus68 Zealot Posts: 143 Karma: 76596 Join Date: Feb 2015 Location: Portugal Device: Kobo Aura HD	On the file metadata_db_prefs_backup.json Os the file "metadata_db_prefs_backup.json". Is it really needed in the root folder of your library? I do have some libraries with that file and others without it, i don't know why I can see it is updated sometimes, maybe when I change some preferences. I've read an old post on library restore saying that: "If there is no metadata_db_prefs_backup.json file then custom column definitions might be wrong and none of the library-specific preferences will be restored." And also this note "the file metadata_db_prefs_backup.json contains all the plugboards, custom columns, saved searches, virtual libraries, etc. and is backed up when calibre quits-- basically, anything that IS stored per-library." So is it required and why isn't it on all libraries I have? I don't need to have it deleted, just super-curious! Note: My goal is to share my empty library with all my library-specific preferences (custom columns and so on) so some fellows of mine can start a new empty library with some settings already done. I was able to create a new empty library from my master library (with feature: Create library / Copy structure) and got an empty master without the file "metadata_db_prefs_backup.json" I created a copy from that folder and created a library from it and the library settings are there. It was done in a 32 bit windows machine, didn't test it on a 64 bit machine! Last edited by Horus68; 06-03-2020 at 04:33 AM.

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06-03-2020, 04:34 AM	#2
kovidgoyal creator of calibre Posts: 45,604 Karma: 28548974 Join Date: Oct 2006 Location: Mumbai, India Device: Various	IIRC that file is written every time you quit calibre with that library open.

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