Panel disappears on menu rebuild - page rendering, panels just...not [#1113614]

I have a custom panel layout that works 99.9% of the time. However, sometimes (when editing views, mainly) when the menu router rebuilds itself, panels on the site (usually the homepage, but it depends on what is being viewed at that instant) will fail to render. The page template will render - our menus show up, so I know panel-pane.tpl is being loaded - but the panel-set itself is blank. Worse, this result ends up cached and stays that way for hours.

If I log in and edit the panel, and view "Contents" it appears *empty*. If I click onto another tab, and then back to "Contents", the panels are full again. I don't even have to save at this point and everything starts to render properly again on my homepage (for logged-in users - I do have to save to clear the cache for anon).

Various caching has helped, but not removed, the problem. I've made sure that panels isn't falling into legacy mode, it's specified properly in my theme.info file...

Anybody seen this behaviour before? Any tips, tricks, or ideas?

Comment	File	Size	Author
#6	diff_registry-1113614-6.txt	32.94 KB	osopolar

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Comments

Comment #1

jfolwarski CreditAttribution: jfolwarski commented 19 April 2011 at 15:29

Version:

6.x-3.8

» 6.x-3.9

I ran into this same issue. All of a sudden the node types that used panels just showed a blank screen and messages where being logged saying the layout wasn't being loaded. Then when I went to the panel page editor and changed tabs it fixed the issue. The time the messages started to get logged coincides with a cron run so the menu rebuild is a decent thought to the reason behind it. I also bumped the issue to latest release version since that's what we're using.

edit: we are using custom layouts

Comment #2

Renee S CreditAttribution: Renee S commented 29 April 2011 at 06:38

As are we.

Further to: running cron or doing a few other things causes a rebuild of the theme registry, and that is when the behaviour happens. Drupal is unsetting my default theme! Because I have it specified in settings.php also, however, the site still mostly works, but panels needs what's specified in the theme.info file to get the path to the custom layouts. Oddly it doesn't happen every time, but I think it has something to do with how it caches and when the cache gets rebuilt; if the page is hit by a visitor at the wrong time, it rebuilds without that layout information.

Comment #3

Renee S CreditAttribution: Renee S commented 10 May 2011 at 22:27

Status:

Active

» Fixed

This is a clash of Drupal's well-documented "theme getting unset" problem #305653: Themes disabled during update, in conjunction with the above. Turning off Update fixes it during crons... for now... I'm marking this as "fixed" because it's not really Panels' fault :)

Comment #4

anoopjohn CreditAttribution: anoopjohn commented 11 May 2011 at 00:57

Status:

Fixed

» Active

I have a similar symptom but I am not doing any menu_rebuilds or view_saves. I don't have update status module enabled as well. The problem occurs and then clears itself without me doing anything. I have memcache on the server. Going through 305653 mentioned above I came across the following threads.

http://drupal.org/node/305653
http://drupal.org/node/147000
http://drupal.org/node/632080
http://drupal.org/node/1113614

Still not quite sure as to what exactly is the direction I should take with this issue though.

Comment #5

anoopjohn CreditAttribution: anoopjohn commented 11 May 2011 at 13:30

I run memcache on the server. I see that when I restart memcache the issue is resolved.

Comment #6

osopolar

German

🇩🇪 GER 🌐

CreditAttribution: osopolar commented 14 September 2011 at 18:13

File	Size
diff_registry-1113614-6.txt	32.94 KB

I have the same symptoms: the panel content disappears (randomly) from time to time, while the menu content is still present.

There is a big issue #979912: Panels cache getting stuck, getting white screen on my homepage panel., but I guess it's a bit different because people gets white screens (wsod) there, while in this issue only the panel content disapears.

How we deal with the problem currently:

We set up a script on our webserver which checks every 3 minutes if the panel content is on page (just by looking for an panel css id), if not, the script dumps the database, runs two dimes drush cc all and call the frontpage again, to built it for the cache. This is working well and in 2 weeks the error appeared 3 times and got "cured" successfully. Clearing the theme registry solves the problem for authenticated users but I use normal or aggressive caching so I need a cache clear all.

Now I have a dump with the missing panels, which I can use for more research purposes on my stage server. BTW: I experienced the problem on the live an on the stage server.

I followed the instructions from dsnopek in #104 from the mentioned issue and created a diff between the good and the bad registry (see attachment).

Comment #7

Renee S CreditAttribution: Renee S commented 14 September 2011 at 18:33

ospolar, have you tried turning off the Updates module? (Not terribly good practice but if you have a dev site it can go there.)

Comment #8

osopolar

German

🇩🇪 GER 🌐

CreditAttribution: osopolar commented 14 September 2011 at 22:42

Yes, update-status-module is off (good practice for a dev/stage/live environment), but it didn't solve the problem, I still have empty content for panel pages. This solved your problem?