[pmwiki-users] thumblist, jpg.jpg.lock

ABClf languefrancaise at gmail.com
Wed Apr 27 16:51:19 CDT 2016

Thank you very much for your great explanation Petko.

> About your problem, I suspect the AutoPurge has progressively deleted some
> of the oldest thumbnails, but users were served the cached HTML pages with
> links to now deleted thumbnails.

That was something I thought that might have happened. Yet is was not
possible to track it, first because I didn't give attention to
autopurge until I made use of fastcache. And there is no Thumblist
hidden activity log I am aware of.
How does Thumblist know how many thumbnails have been created and
which ones to delete (I store files per page) ?

> Setting  $ThumbList['AutoPurgeDelay'] = 0; should prevent this from now on,
> but you may need to once revisit all your pages with the Admin account, or
> maybe simply clear the existing FastCache cache, and let it rebuild itself
> once again.

I have recently deleted a big bunch of cached files and I confirm it
looks like the regenerated files are fine, concerning thumbnails,
although I have not checked all ; browsed samples were fine.

> Now, I haven't used or reviewed FastCache, but it must not cache a page when
> the thumbnail is not yet created. Thumblist issues a NoCache() call to
> notify about this: I hope FastCache respects it.

As for this paragraph, I dont know ; I suspect fastcache saves
uncached page as soon as a visitor browse that page, but I dont know
if it does take care of any delaying request.
As a remark, if I'm not mistaken, I guess I have at least one cached
page saved with createthumbnail action :
which has a thumbnail coming from :

(and 58707 folder has :

> P.S. This should be rare: If a thumbnail lock exists, but not the thumbnail,
> this may mean that the person who edited the page, after saving it, moved
> away from it, before the thumbnails were generated (appeared in the page).
> Or, s/he used a text browser, and the browser never requested the thumbnail.
> Or, used an ad-blocker that thought that the thumbnail was an advertisement
> and stopped the browser from requesting it. Or, the server process crashed
> and didn't send the thumbnail, and the editor moved away. In any of these
> cases, the next visitor on that page should generate the missing thumbnails.
> There may be other reasons I haven't thought of, but probably less common.

Are robots (Google and others) text browsers ?
Every time I edit page, it's name is reported in Home page and I'm
quite sure the newly edited pages are often quickly visited (it
happens the edited pages are cached before I have finished writing a
quote in another, which shoud be agregated by pagelist.)

Last word, I remark that, in my first example,
Listing directory after ?action=regen :


there is only 1 thumbnail created for 2 pictures, because one of them
is smaller than the expected thumbnail (just to mention).


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