Calibre Sync for Android & iOS

[PeterT]

Originally Posted by jbusnengo

If I were to temporarily go back to Calibre 8, would it work with a Calibre 9 database, or would I have to rebuild it?

Onve a schema upgrade has been done on an upgrade, calibre will not reverse it. ie Once the isbn column has been removed the only way to get it back is to either restore your backed up database (you DO take backups, right) or reinstall calibre at the old version and create a brand new library and reload all content into it.

[JSWolf]

Originally Posted by PeterT

Onve a schema upgrade has been done on an upgrade, calibre will not reverse it. ie Once the isbn column has been removed the only way to get it back is to either restore your backed up database (you DO take backups, right) or reinstall calibre at the old version and create a brand new library and reload all content into it.

I would think you could use an older version of calibre and rebuild the database. Am I wrong here?

[PeterT]

@jswolf why don't you try it. Install calibre portable 8.x, make a small library. Upgrade portable to 9.x and the downgrade to 8.x and rebuild.



Sent from my Pixel 9a using Tapatalk

[dizzy274]

Originally Posted by PeterT

@jswolf why don't you try it. Install calibre portable 8.x, make a small library. Upgrade portable to 9.x and the downgrade to 8.x and rebuild.

I did this and so far everything is fine. I did it on my actual Calibre Library and didn't use portable.

Best Regards.

Ian.

[Mike356]

I was able to downgrade my library as well. In more detail:

1. I deinstalled Calibre
2. I downloaded and installed https://download.calibre-ebook.com/8.16.2/
3. I started Calibre
4. The Calibre 8 could load the database of Calibre 9. But the missing columns in the database were still missing
5. I rebuild the database.

Now the missing columns are there again and calibre sync is working again.

[KhenemetHeru]

Originally Posted by kovidgoyal

It will be because the isbn, lccn and flags columns have been deleted from the calibre books table in calibre 9 (they were never used for anything and just tkae up unneccessary disk space). The developer of Calibre Sync should update his SQL query to exclude those columns.

Seeing as there's no such thing in this day and age as "taking up unnecessary disk space" since available disk space is essentially vast and nearly limitless even on today's phones and tablets, it was "unnecessary" to remove those three columns and the problems it causes should be enough reason to revert it (a trivial change for a non-trivial inconvenience), especially since it seems the dev for Calibre Sync has gone missing.

[theducks]

Originally Posted by KhenemetHeru

Seeing as there's no such thing in this day and age as "taking up unnecessary disk space" since available disk space is essentially vast and nearly limitless even on today's phones and tablets, it was "unnecessary" to remove those three columns and the problems it causes should be enough reason to revert it (a trivial change for a non-trivial inconvenience), especially since it seems the dev for Calibre Sync has gone missing.

NOT everyone runs on (or can afford) the latest and greatest hardware.
Nor do they want to add more e-waste to the environment than is necessary.
My Laptops are pushing 20+
My K4 is well over 10
My Aura2 is 6ish
My L2 is 4
I have the Knowledge and tools, so I have updated the RAM and HD Disks + some are now SSD. But I would guess that 50% of the folk who run Calibre can't do or afford any of those.

[GeniusJ]

Originally Posted by theducks

NOT everyone runs on (or can afford) the latest and greatest hardware.
Nor do they want to add more e-waste to the environment than is necessary.
My Laptops are pushing 20+
My K4 is well over 10
My Aura2 is 6ish
My L2 is 4
I have the Knowledge and tools, so I have updated the RAM and HD Disks + some are now SSD. But I would guess that 50% of the folk who run Calibre can't do or afford any of those.

Maybe I'm not following the logic of your response, but I don't see how 3 columns in a database table would require a hardware upgrade to run the software.

[theducks]

Originally Posted by GeniusJ

Maybe I'm not following the logic of your response, but I don't see how 3 columns in a database table would require a hardware upgrade to run the software.

It was about keeping up with OS and hardware requirements and that causing lots of older WORKING hardware be retired (binned) to use newer apps.

eg I have a small Dell GX60 (32 bit Celeron) I used to use in my workshop to Remote Desktop connection into my i7 desktop in my home office. Perfect as it was basically a super Monitor (I could transfer files and sound). I did not need crunch or much RAM. No Longer. MS does not offer a W10 compatible client that runs on 32bit (Intel in this case). Neither did the last Ubuntu 32bit.

So basically stuck running really old XP/Ubuntu standalone (no real usage model) or scrap.
Why? So the saturated PC market can sell New systems and not have older stuff repurposed until it drop naturally.

[KhenemetHeru]

Originally Posted by theducks

NOT everyone runs on (or can afford) the latest and greatest hardware.

...and I doubt anyone's database is large enough to matter. For example, I have around 9500 books in mine right now, and my db file is 14.3MB; before the update that screwed up the database, I had 8993 books, and my database was... 14.3MB. 3 empty categories take up no space, or a negligible amount.

I regularly download files on the order of 50GB or more, on my cellphone. Unless people are running old nokia or motorola flip phones (or as you point out, Windows XP machines - which can't even run Calibre 9, btw), I seriously doubt that putting the categories back will overtax even the most meagre of storage. OTOH, if Calibre Sync never gets an update, which is a highly likely scenario, putting them back will help a lot of people out of a jam that didn't need to be created in the first place.

[JSWolf]

Originally Posted by KhenemetHeru

...and I doubt anyone's database is large enough to matter. For example, I have around 9500 books in mine right now, and my db file is 14.3MB; before the update that screwed up the database, I had 8993 books, and my database was... 14.3MB. 3 empty categories take up no space, or a negligible amount.

I regularly download files on the order of 50GB or more, on my cellphone. Unless people are running old nokia or motorola flip phones (or as you point out, Windows XP machines - which can't even run Calibre 9, btw), I seriously doubt that putting the categories back will overtax even the most meagre of storage. OTOH, if Calibre Sync never gets an update, which is a highly likely scenario, putting them back will help a lot of people out of a jam that didn't need to be created in the first place.

Don't blame calibre for Calibre Sync's problem. No external program should be writing to the database. That's the fault of Calibre Sync.

[theducks]

I don't believe the UPDATE was all to blame for the screw up.
Something else may have been happening at that time.

Almost 10% of Calibre USAGE (see the official stats page) is now 9.x. I believe if YOUR issue was common, these pages would have more than a couple of posts.

BTW What OS. Linux distro versions have been known to tamper without extensive testing. Only use the official Calibre download command line

[Wiggo]

Originally Posted by JSWolf

Don't blame calibre for Calibre Sync's problem. No external program should be writing to the database. That's the fault of Calibre Sync.

You're talking about things you don't understand again. CalibreSync doesn't write anything to the database.

Originally Posted by theducks

I don't believe the UPDATE was all to blame for the screw up.
Something else may have been happening at that time.

Almost 10% of Calibre USAGE (see the official stats page) is now 9.x. I believe if YOUR issue was common, these pages would have more than a couple of posts.

BTW What OS. Linux distro versions have been known to tamper without extensive testing. Only use the official Calibre download command line

Believe what you want, the update is to blame for the screw up

[slm]

This isn't complicated: Calibre Sync reads the Calibre Database assuming it contains three columns that are no longer there in version 9 of Calibre. This causes Calibre Sync to fail to be able to sync.

If Calibre Sync were being actively maintained, the fix would be quick and easy, but the author does not seem to be reachable.

Likely only a small percentage of Calibre user use Calibre Sync and those who do have probably discovered the problem.

[Glsparks2]

I use a filesync program to periodically mirror my Calibre library on my PC to the internal memory of my Android phone. I use Calibre Sync to browse the books on my phone and open them with Moon+ Reader.
My workaround is to modify a COPY of the metadata.db as described earlier and transfer that to the internal memory of my phone. Calibre Sync works then. I have a Powershell script to do the mods. I used the Copilot feature to <help> draft the script. You have to know where System.Data.SQLite.dll is. I use a windows 11 machine.