Slow rendering of the files list

[Anks]

I have over 1000 different files in my deft directory.

Over time, deft has started to feel very slow while filtering: there is a noticeable delay with every key press while filtering files.

My first assumption was that incremental search might be slow, but a little profiling revealed that most of the time is spent in these lines of the deft-buffer-setup function:

      (if deft-current-files
          (progn
            (mapc 'deft-file-widget deft-current-files))
        (widget-insert (deft-no-files-message))))

I'm not sure if it's something wrong with my local emacs configuration: I'm running emacs-mac with font composition enabled via mac-auto-operator-composition-mode. I haven't noticed a slowdown in any other modes though.

For now, I have locally edited this function to show the first 10 files from deft-current-files. This fixes the problem for me – typing / filtering feels realtime again, without any perceived delay.

I just wanted to report this. If anyone else has noticed a similar problem, I can provide a PR which will let you customise the total number of files displayed in deft.

[jrblevin]

Thanks for reporting this. I can confirm a similar result when profiling, although I only have about 300 notes at the moment.

I think rather than limiting the number of lines rendered (which would prevent being able to scroll down and see more), to solve the underlying issue a better approach would be a slight redesign where the widget and summary line for each file is created once and stored for re-use. I can't tackle that at the moment, but if anyone wants to take a shot at that I'll certainly accept at a PR.

[Anks]

Small update: for my personal use, I ended up defining a advice function like this which limits the display to 30 files:

  ;; Overwrite `deft-current-files` for the `deft-buffer-setup` and limit it to 30 entries
  (defun anks-deft-limiting-fn (orig-fun &rest args)
    (let
        ((deft-current-files (-take 30 deft-current-files)))
      (apply orig-fun args)))

  (advice-add 'deft-buffer-setup :around #'anks-deft-limiting-fn)

This gives me snappy search, and 30 results are 'good enough'.

This is probably not the best solution, but works for me.

Note: the -take function is from dash.el

[joech4n]

Update: Nvm, user error. :)

@Anks I'm seeing this error with your snippet after adding to dotspacemacs/user-config, any idea why?

(Spacemacs) Error in dotspacemacs/user-config: Wrong type argument: symbolp, (defalias (quote anks-deft-limit\
ing-fn) (function (lambda (orig-fun &rest args) (let ((deft-current-files (-take 30 deft-current-files))) (ap\
ply orig-fun args)))))

[Henry-T]

@joech4n why added into a (defalias (quote ...)) block?
I just added directly under user-config, it works quite well

[jrblevin]

I added built-in support for limiting the number of files shown via `deft-file-limit'. See the updated README and the docstring for details.

[Anks]

@jrblevin Thank you!