Keep updated vs Background export

[dbitouze]

Hello, I read https://retorque.re/zotero-better-bibtex/exporting/auto/index.html but I don't understand the point of “Background export” in the export screen if “Keep updated” is not enabled (I noticed that enabling “Keep updated” activates but makes inaccessible “Background export”).

Could you please clarify this for me?

Thank you.

[retorquere]

Background export is the friendly name for exports happening on a separate thread. You can think of threads as separate programs running within a program.

Normal translators, and BBT in foreground mode, do their work in the same thread as zotero which means that for the duration of any export, zotero freezes entirely because the foreground thread is busy exporting and until that is done, it can't process mouse clicks, keyboard strokes, or update the UI. This is fine if you do small exports, and if you do simple work in the export; these exports are over before you notice any of this happening.

But BBTs export is complex, meaning it takes more time than most other translators, and BBT users also tend to export fairly big chunks of their library. With auto export, zotero would freeze on pretty much any change you made if you had a big library set up for auto export. This is the reason foreground auto exports are not allowed.

Background exports do the minimum amount of work required on the foreground thread and then hand it off to the background thread where it doesn't bother zotero. The reason foreground exports are still available:

• it needs to be there anyway because drag and drop only works on the foreground
• it is technically still sort of experimental. Zotero does not in any way facilitate background exports and I have had to mock parts of zotero to make it happen. I also had to do runtime code modification to Zotero and call a bunch of zotero-private apis to make it possible. Over the years this has become pretty battle-hardened, and I do nightly testing to find regressions, but it is inherently brittle, and zotero can change something at any time that will break background exports until I find a workaround. If that happens, foreground export still works, because it stays within the supported framework of zotero. Breakage hasn't happened in a long while, but it's a good insurance policy
• the setup and teardown of a background export incurs some overhead, and if you're exporting a single item, foreground may technically be faster. For a single item you're unlikely to notice however, and BBT does extensive caching for background exports.

[retorquere]

Bet you weren't expecting an essay 😄

[dbitouze]

Such an essay wasn't expected but is very welcome: many thanks! 😄

But I'm still not sure I understand everything:

• What would do BBT with “Background export” checked and “Keep updated” unchecked?
• I systematically advise “Keep updated” to be checked: do you agree?

[retorquere]

* What would do BBT with “Background export” checked and “Keep updated” unchecked?

It would do a one-time export using the background thread

* I systematically advise “Keep updated” to be checked: do you agree?

That is what I would advice, and which is the default

[retorquere]

Oh sorry - I thought you asked whether background should be on. Automatic export should not be the default use, I don't want people to create automatic exports by accident, so I deliberately uncheck the checkbox after each use.

[dbitouze]

OK for the one-time export. But, AFAICS, “Keep updated” isn't checked by default: