Drupal Embedded Gallery 2 and Caching
Gallery 2 embedded in Drupal can make a good combination. When you combine two of the best open source software packages together you end up with a versatile gallery/CMS combination.
As your site grows you may however experience some issues with server load and start to look at caching to reduce server load. Both Gallery 2 and Drupal can be configured from their respective admin interfaces to achieve this.
Gallery 2 claims around a 90% increase in performance with Full Acceleration and a 10%-25% performance increase with Partial Acceleration. There is of course a tradeoff with some of the dynamic data not updating until the cache expires.
While Drupal does not define the expected increase in performance there are indications that the performance boost can be significant.
The cache lifetime can be configured in both applications.
I have a Drupal embedded Gallery 2 site that I am running that is currently experiencing a growth stage with a monthly increase in traffic. Until the server can be upgraded I decided to activate the Drupal caching mechanism (I was already doing Full Acceleration for Guest users within Gallery). After turning on caching and setting a reasonable cache time of 3 hours things were going fine until I had some more images to upload to gallery.
I successfully uploaded the images without any problems. Gave them names, descriptions and applied watermarks. Everything appeared to be normal until the next day when I went to view the images as the guest user. To my surprise the images were not there. If I logged back in I could see the images. If I viewed the stand-alone version of Gallery it was working correctly and I could see the new images.
After disabling the Drupal cache everything is back to normal.
So, at this stage without further investigation I have come to the conclusion that the Drupal caching is not currently compatible with Gallery 2 caching. Or perhaps, I was just unlucky that it didn't work for me?
In either case I won't consider using caching on both applications in an embedded environment until I can investigate further.