Re: [patch suggestion] Mitigating the poor Emacs performance on huge org files: Do not use overlays for PROPERTY and LOGBOOK drawers

[Karl Voit]

Hi,

* Karl Voit <address@hidden> wrote:
> Hi Ihor,
>
> * Ihor Radchenko <address@hidden> wrote:
>>
>> So far, I came up with the following partial solution searching and
>> showing hidden text.
>>
>> (defun org-find-text-property-region (pos prop)
>> (define-advice isearch-search-string (:after (&rest _) put-overlay)
>> (defun org-restore-invisibility-specs (&rest _)
>> (add-hook 'post-command-hook #'org-restore-invisibility-specs)
>> (defun org-flag-region (from to flag spec)
>> (defun org-unfontify-region (beg end &optional _maybe_loudly)
>
> After a couple of hours working with these patches, my feedback is
> very positive. Besides some visual glitches when creating a new
> heading with org-expiry-insinuate activated (which automatically
> adds :CREATED: properties), I could not detect any side-effect so
> far (will keep testing).
>
> The visual glitch looks like that:
>
>:PROPERTIES:X:CREATED:  [2020-05-04 Mon 18>54]
> X
>
> ... with "X" being my character that symbolizes collapsed content.
> The way it looked without the patch was a simple collapsed property
> drawer.

Here some hard numbers to demonstrate the impact:

my-org-agenda: from 11-16s down to 10 -> not much of a difference

helm-org-contacts-refresh-cache: 29-59s down to 2½ -> HUGE

Emacs boot time: 50-65s down to 10 -> HUGE

Navigating the cursor in large Org files -> HUGE subjective impact

>>> Anyway, the real fix should come from Emacs itself. There are ways to
>>> make overlays faster. These ways have already been discussed on the
>>> Emacs devel mailing list, but no one implemented them. It is a bit sad
>>> that we have to find workarounds for that.
>>
>> I guess that it is a very old story starting from the times when XEmacs
>> was a thing [1]. I recently heard about binary tree implementation of
>> overlays (there should be a branch in emacs git repo) [2], but there was
>> no update on that branch for a while. So, I do not have much hope on
>> Emacs implementing efficient overlay access in the near future. (And I
>> have problems with huge org files already).
>
> I can not express how this also reflects my personal situation.
>
>> [1] 
>> https://www.reddit.com/r/planetemacs/comments/e9lgwn/history_of_lucid_emacs_fsf_emacs_schism/
>> [2] https://lists.gnu.org/archive/html/emacs-devel/2019-12/msg00323.html
>
> [3] https://karl-voit.at/2020/05/03/current-org-files
>

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