So long as it doesn't turn into a performance sink, I don't mind.

Will experiment to check how it affects performance. If it is fine then I will submit a PR.

reftex-parse-all should be put into a customizable hook to make it optional or for replacing it with something better.

An example for a better solution would be to watch input files or compare their modification dates with those from the last scan.

See: https://emacs.stackexchange.com/questions/73745/company-reftex-slow-when-searching-for-labels

Hi @TobiasZawada. Sorry to hear that #12 caused a performance sink for the OP in Emacs-StackExchange. I would be happy to collaborate on a PR to fix this new issue.

should be put into a customizable hook

This should be possible and fairly straight-forward to implement. As per here, there are two high-level functions for parsing either the current file or the (multifile) document. I could imagine this being part of the hook in our case and perhaps we could even remove the line containing (reftex-access-scan-info) since it is essentially being called twice.

An example for a better solution would be to watch input files or compare their modification dates with those from the last scan.

But before that, I would like to check if the performance sinks are mitigated by using the options specified here: https://www.gnu.org/software/auctex/manual/reftex/Optimizations.html? The descriptions of these options sound somewhat in the direction of your suggestion.

It would also be great if the OP could share a MWE to reproduce the performance sink here.

Hi @TobiasZawada. I created a PR (#13) to address the reported issue. Let me know if this and the aforementioned optimizations help with the performance sink.

The easiest work-around for me is to perform rescan on save. In this way, we don't need to change company-reftex at all, so there won't be any performance issue.

@zhenhua-wang indeed that seems like the best solution. Could you share a snippet of the hook you use for this?

@zhenhua-wang indeed that seems like the best solution. Could you share a snippet of the hook you use for this?

I didn't use hook for this. I simply rebind C-x C-s in reftex-mode-map to

 (defun zw/latex-rescan-on-save ()
    (interactive)
    (reftex-reset-mode)
    (save-buffer))

If you want, you can add-advice around the function save-buffer to achieve similar thing. I just don't want to perform mode checking every time I run save-buffer.