Send metadata to device Slow on 2nd Kindle Voyage?

[kovidgoyal]

The thumbnails as separate files are uploaded in /system/thumbnails see the upload_kindle_thumbnail() function in kindle/driver.py

[kovidgoyal]

Though I have to say that even writing a couple of hundred MB over a USB connection should not take more than a few seconds. For example, even the ancient USB 2 standard supports data transfer at ~30 MB/s https://en.wikipedia.org/wiki/USB#USB_2.0

[Phssthpok]

Originally Posted by kovidgoyal

There definitely haven't been any (intentional) changes to sending thumbnails in the last month.

What is the breakup of the data in thumbnails vs user metadata? user_metatata I am willing to get rid of on a per device basis.

Thumbnails can be fixed in one of several ways:

1) Stop storing them in metadata.calibre and instead use a subdirectory named calibre-thumbnails or similar. That way update jobs dont have to resend all thumbnails on every update.

2) Make it a per device driver thing. For instance e-ink kindles have calibre send thumbnails as separate files already. the driver could be changed to use those and not store thumbnails in metadata.calibre

I'm having similar issues, mainly because I now have a 32G Kindle and keep my entire library on it. I keep books as EPUBs in Calibre and autoconvert when I upload them to the Kindle, so each book is processed separately:

1) convert to AZW3 -- about 5 mins average
2) upload -- 1 or 2 seconds
3) update metadata -- typically 3 mins

It's much faster if I convert manually and then upload, because the uploads are treated as a single job -- even when there are hundreds of books involved, the upload takes a few minutes, and this spawns a single "update metadata" job that takes about 10 mins or so.

I've no idea how the upload system works, but it would be nice if when I select several books to upload, it batched the uploads into a single job after conversion the way I do if I do it manually. Or deferred the metadata update until all the pending uploads have completed and then processed all the updates at once. Is anything like this possible?