Bug 136069 - FILEOPEN DOCX: Slow file opening DOCX if document contains certain number of formula's
Summary: FILEOPEN DOCX: Slow file opening DOCX if document contains certain number of ...
Alias: None
Product: LibreOffice
Classification: Unclassified
Component: Writer (show other bugs)
(earliest affected)
3.5.0 release
Hardware: All All
: medium normal
Assignee: Not Assigned
Keywords: perf
Depends on:
Blocks: DOCX-Opening
  Show dependency treegraph
Reported: 2020-08-24 09:32 UTC by Telesto
Modified: 2021-09-15 03:38 UTC (History)
3 users (show)

See Also:
Crash report or crash signature:

Example file ODT (168.92 KB, application/vnd.oasis.opendocument.text)
2020-08-24 09:32 UTC, Telesto
Example file DOCX exported with 7.1 (7.64 KB, application/vnd.openxmlformats-officedocument.wordprocessingml.document)
2020-08-24 09:32 UTC, Telesto

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Description Telesto 2020-08-24 09:32:02 UTC
FILEOPEN DOCX: Slow file opening DOCX if document contains certain number of formula's 

Steps to Reproduce:
1. Open the attached file
2. Save as DOCX
3. File reload

Actual Results:
7 seconds

Expected Results:
Nearly instant as the ODT

Reproducible: Always

User Profile Reset: No

Additional Info:
Version: (x64)
Build ID: 8700bace8c0714d853f5df6918ab9c8bb3d81f77
CPU threads: 4; OS: Windows 6.3 Build 9600; UI render: Skia/Raster; VCL: win
Locale: nl-NL (nl_NL); UI: en-US
Calc: CL
Comment 1 Telesto 2020-08-24 09:32:21 UTC
Created attachment 164628 [details]
Example file ODT
Comment 2 Telesto 2020-08-24 09:32:37 UTC
Created attachment 164629 [details]
Example file DOCX exported with 7.1
Comment 3 Telesto 2020-08-24 09:35:12 UTC
Also found in
Build ID: 3215f89-f603614-ab984f2-7348103-1225a5b
Comment 4 Telesto 2020-08-24 09:47:06 UTC
You might be interested in this one. LibreOffice doesn't include thumbnails of the formula's inside the DOCX. Which must be rendered every time on file open. Causing a massive slowdown.

Word itself does include thumbails based on file size
Comment 5 Telesto 2020-08-24 11:42:39 UTC
Any clue why LibreOffice isn't exporting 'thumbnails' of formula's inside the DOCX?
Comment 6 Justin L 2020-08-24 12:08:36 UTC
no - I don't know anything about images or shapes.
Comment 7 Xisco Faulí 2021-02-15 18:20:52 UTC
Hi Telesto,
Could you please try to reproduce it with a master build from
http://dev-builds.libreoffice.org/daily/master/ ?
You can install it alongside the standard version.
I have set the bug's status to 'NEEDINFO'. Please change it back to
'UNCONFIRMED' if the bug is still present in the master build
Comment 8 QA Administrators 2021-08-15 03:46:40 UTC Comment hidden (obsolete)
Comment 9 QA Administrators 2021-09-15 03:38:41 UTC
Dear Telesto,

Please read this message in its entirety before proceeding.

Your bug report is being closed as INSUFFICIENTDATA due to inactivity and
a lack of information which is needed in order to accurately
reproduce and confirm the problem. We encourage you to retest
your bug against the latest release. If the issue is still
present in the latest stable release, we need the following
information (please ignore any that you've already provided):

a) Provide details of your system including your operating
   system and the latest version of LibreOffice that you have
   confirmed the bug to be present

b) Provide easy to reproduce steps – the simpler the better

c) Provide any test case(s) which will help us confirm the problem

d) Provide screenshots of the problem if you think it might help

e) Read all comments and provide any requested information

Once all of this is done, please set the bug back to UNCONFIRMED
and we will attempt to reproduce the issue. Please do not:

a) respond via email 

b) update the version field in the bug or any of the other details
   on the top section of our bug tracker

Warm Regards,
QA Team