TOPIC: Jocache problem with multipage Category Blog items

Jocache problem with multipage Category Blog items 05 Nov 2017 14:00 #2062

Hi,

I have a collection of about 80 articles on my website, which have been tagged by any of about 20 tags. I provided (hidden) Category Blog menu items filtered by a single tag for each of these tags. I have set Joomla to show 5 articles per page, so for most tags multiple pages are needed to show all articles.

Since Joomla 3.8.0 there is an issue, that when selecting a higher page, sometimes actually the first page is returned. The URL might show something like "?start=10", but the page navigator says page 1 and articles shown are the first 5 articles.

This is what I have found so far:
  • Turning of jotcache immediately resolves the issue.
  • The issue occurs with Joomla 3.8 and all recent versions of jotcache (5.3.2, 6.0.2, 6.1.1)
  • The issue only occurs on Category Blog items filtered by a tag.
  • There are no errors shown with Joomla error_reporting=development.
  • Setting the plugin to verbose logging does not provide an error. The logging is the same for a correct page and an incorrect page.
  • The issue appears to occur only when using crawler(ext) to populate an empty page cache, or when cron recaching has run. When populating an empty cache manually (by visiting pages in the frontend) the issue does not occur.
  • Excluding URL's with a query from caching does not help.

This issue is vaguely similar to Joomla core issue 18138, (github.com/joomla/joomla-cms/issues/18138), which was due to the filter.tag value being taken from the session state, instead of the url since J3.8.0. Could there be something similar going on with the page number in combination with the crawlers and recaching?

Version information:
Joomla 3.8.1 + PR 18248
Jotcache 6.1.1
Template Purity III 1.2.0
PHP 7.1.10
Apache 2.4.6
Centos 7.4
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Jocache problem with multipage Category Blog items 15 Nov 2017 00:19 #2068

Is nobody able to confirm or NOT confirm this issue?

In between I upgraded this website to Joomla 3.8.2. I tried to debug this a bit further. Joomla 3.8.2 does not seem to bring any change.

After updating to 3.8.2 I cleared the cache. First I populated the cache using crawler_ext from the website backend. Many pages showing the wrong articles as before.

Then I cleared jotcache again and populated it using the frontend. Initially, no errors as before. After manually populating the cache, I ran a recache from the backend and via the cron script. No errors, unlike before.

After leaving the website alone for some days, the problem is back. The jotcache page cache has been recached via the cron script multiple times now and the joomla caching of individual items has timed out. Now, when I select any of the tag filtered Catagory Blog pages (first page) and then select any of the higher pages, every first one of these is wrong, the next are all correct.

Any ideas?
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