Last modified: 2014-05-17 17:38:31 UTC

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Bug 35895 - DjVu thumbs failing (fuzzy black image; 2144×3282px)
DjVu thumbs failing (fuzzy black image; 2144×3282px)
Product: Wikimedia
Classification: Unclassified
Media storage (Other open bugs)
All All
: Low normal with 1 vote (vote)
: ---
Assigned To: Nobody - You can work on this!
Depends on:
Blocks: Wikisource
  Show dependency treegraph
Reported: 2012-04-11 20:49 UTC by Nemo
Modified: 2014-05-17 17:38 UTC (History)
5 users (show)

See Also:
Web browser: ---
Mobile Platform: ---
Assignee Huggle Beta Tester: ---


Description Nemo 2012-04-11 20:49:35 UTC
Usual problem, filing as a new bug for further investigation.

The linked DjVu had been replaced with some adjusted pages. Not all the thumbs have been purged and images don't always correspond to the actual DjVu content and to the text. In the linked URL you should see "restrained enthusiasm catch [...]" but sometimes you're shown the image of /342 with a Joel Chandler Harris picture etc.

The result seems to be the same everywhere in Europe at least if you have the same resolution: ok for me because my browser gets a 400px thumb, but if I wget a 600px I get the wrong one.

Correct 400px:
Wrong 600px by Doug:
Wrong 600px here:
Correct 601px here:
Comment 1 Amgine 2012-06-09 01:04:45 UTC
Is this a dupe of #31680 ?
Comment 2 Bawolff (Brian Wolff) 2012-06-11 19:55:10 UTC
(In reply to comment #1)
> Is this a dupe of #31680 ?

Seems kind of unlikely because if none of the images on the europe squids were getting purged like in bug 31680, I feel there would be a lot more anger (so same symptom different cause). This appears to be a more one-time incident.

I would guess (this is just a guess, I haven't even looked at said images or looked into this at all), was that a (HTCP) packet just happened to be lost somewhere which resulted in a stale cache entry not being purged. After all, HTCP does send udp packets, and there's nothing checking they actually get through, so if a packet gets dropped it just dissapears. (OTOH if this happens often perhaps there's some issue that comes up when mediawiki has to purge large number of thumbnails [since djvu files have 100's of pages, so a purge might be thousands of images]). But to re-iterate that's all idle speculation.

Is the image still bad if one does ?action=purge on the image description page?
Comment 4 Bawolff (Brian Wolff) 2014-05-17 17:38:31 UTC
This works for me. Page 340 at 600px displays the correct page even when loading from esams. Re-open if you're still having issues

(In reply to Andre Klapper from comment #3)
> djvu?action=purge didn't help (yet).
>Summary: DjVu thumbs failing → DjVu thumbs failing (fuzzy black image; 2144×3282px)

The black fuzzy image on page 1 is the cover of the book. That's supposed to be like that.

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