Stopping Device Jobs/scanning of device help/suggestion/complaint

[ranmas]

OK, I am looking for a way to keep Calibre from scanning devices every time they are plugged in. Calibre has no need to know what books are on the device if we are not going to be removing anything from it. There is even less reason for it to be reading the metadata from every book, especially when you have deselected metadata from being read in the options. The speed at which Calibre does this is also horrendous.

What makes this even worse is you can not stop Calibre from scanning a device that is plugged in, nor can you stop the job once it has started. I can not begin to even describe how poor this behavior is, and there are more than a few reasons why this is a very dumb thing to do.

A couple of examples quickly would be that when android devices 'sleep' they can disconnect from the computer crashing calibre and forcing you to start over from scratch. If your just looking to transfer a couple books over it can be a very long wait if you have many books on your device.

Making it faster to just open the folders for each individual book you want to transfer and manually coping them over. For instance it takes over 4 and a half minutes for calibre to scan my phone alone, and my tablet has even more books on it, and less than 10 seconds to copy a folder over via windows explorer.

If Calibre does 'want' to know what is on the device then it should be keeping a record of what was on the device the last time it was accessed so it can cut down on what it needs to scan, or ask to update its catalog.

[davidfor]

Originally Posted by ranmas

If Calibre does 'want' to know what is on the device then it should be keeping a record of what was on the device the last time it was accessed so it can cut down on what it needs to scan, or ask to update its catalog.

Well, I'll disagree with that. Even if it is simply because there might have been books added or removed directly on the device that can be matched. For most of us, automatically doing this is a good thing.

But, if you want to prevent calibre from automatically handling a device when it is plugged in, try the Unplugged plugin.

[PeterT]

Additionally once that scan has been completed configure calibre as to what directories to scan in future on that device (assuming that this is an Android device connecting via MTP)

Sent from my Nexus 7 using Tapatalk

[jackie_w]

... or, alternatively, tell calibre to ignore your device (Prefs - Ignored devices) and spend a tiny amount on the Calibre Companion app for Android and transfer your books wirelessly.

[ranmas]

Thank you for your suggestions. I had not heard of the unplugged plugin before, nor had I thought about the companion app. I'll check them out and see what they can do.

I still say there should be a way to configure Calibre to either run the scan manually or automatically

[AnotherCat]

I ran into this issue recently when introducing another MTP device after not having any problems with a couple of other devices. I hadn't spent any time troubleshooting this as the added device was for occasional use only but this thread (and there have been others before it) prompted me to have a quick look. The situation was:

Existing devices:
Android 7, thousands of books on 32GB microSD, USB-3 - no problem
Android 8, thousands of books on 64GB microSD, USB-C - no problem

Added device:
Android 7, 2 only books on 128GB microSD, USB-3 - took 3 or more minutes to scan every time it was connected with Calibre.

In all cases the books were in one folder in card's root with subfolders under that for each primary Calibre Tag (the books had only one such tag each), Calibre was given only that folder and its subfolders to scan. All else, such as the Save Template and Automatic Metadata Management (I think that is also the default??) was equal.

What I have found with the problematic device is that with it connected and the lengthy scan finished, then doing a manual metadata cache update (Calibre menu "Device>Update cached metadata on device") the problem has now gone away for future connection instances.

This seems to have survived system reboots with the added device now scanned quickly. If the problem with the added device was typical of the issues others have then there are some clues here relating to where the cause may lie (and hence my lengthy explanation ).

[AnotherCat]

Subsequent to the above, the problem returned immediately. I have a had a bit of time today to look into this some more. Precis of issue was one MTP device connected each time without lengthy rescanning but the other rescanned for 3 to 4 minutes every time it was connected.

What I found was that Calibre's mtp_devices.json file appeared incomplete and from an uninformed look at it, it seems maybe the swapping of a card in the problematical device caused that as it had two incomplete references to cards associated with that device.

I renamed the existing mtp_devices.json file to mtp_devices.json.bak, started Calibre, then connected (configuring their folders to be scanned) the devices in turn so that the .json file rebuilt.

The rebuilt mtp_devices.json looks sensible and contains about 6 times the information as the old; both devices now behave correctly when connected, hopefully forever .

So if one has this long rescanning problem, despite configuring the folders to be scanned, perhaps the first action is to delete the mtp_devices.json file and rebuild it as I have described.

[AnotherCat]

After appearing to work OK for a while, 24 hours later all is back to bad again as between Calibre and the problem device. The device does not have such problems with other MTP scanning Windows applications, nor indeed any other comm's issues. My other devices work fine with Calibre.

As I only put the couple of books I am currently reading on this phone in case I don't have my tablet with me when a reading opportunity arises, and it is easy enough to just copy them on with Windows File Explorer, I will not invest any more time on the issue.