Posted by alberto56 on August 20, 2013 at 4:09pm
Hi all,
I have a Drupal site which uses a dedicated Varnish server. Most pages are set to be accessed by Varnish every 30 minutes. Still, because of the sheer number of pages, Varnish is hitting Drupal quite a lot (which is why I'm putting this in the high-performance group).
Once in a while (can be once a week), on the production server, Drupal does not load certain template (tpl.php) files, instead leaving a blank space in the markup where their output should be.
On a test server, by continuously clearing the cache and polling Drupal a lot more often, we managed to be able to reproduce it about once an hour.
I'm wondering if anyone has any idea what might be causing this and where to begin debugging it.
Cheers,
Albert.
Comments
Debug on the cache side of the problem
It is likely that this is due to a cache issue where an item is returned from cache but without content. You might want to debug around the caching for the blocks. Are you using memcache? Are you using panels? We have run into this with panels + memcache on a site and I remember that it was a caching issue. There was an issue on Drupal.org around this in the Panels issue queue.
Work around would be to clear the cache for the item and recreate the content for the block / pane if the cache returned is an empty string.
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@zyxware thanks for your
@zyxware thanks for your response. I will check what you suggested, which seems quite logical. I am not using either memcache or panels.
The idea of checking for empty strings in valid cache items is a good one, it will help me with debugging.
Thanks again,
Albert.