Access Control Change
When an ac-change is made that affects the whole site, e.g. adding a
group, the whole site is added to the persistent cache crawler queue.
This means that the backend server will be busy crawling the site.
The ac-change will be replicated to the frontends immediately when
the change is made and thus before the crawling is finished. All
caches are preserved on the frontends until the prefetch is
done. This means that no load change should be observed on the
frontends until the prefetch data arrives.
When the prefetch crawler transaction arrives to the frontends they
will be quite busy unpacking and installing the new cache data.
If the crawling takes more time than 30 min the transaction will be
closed and replicated to the frontends. A new transaction will be
created and the crawling will continue for another 30 min. This will
be repeated until the maximum crawl time is reached.
If this happens it is possible that a template is replicated before
its corresponding prefetch cache data. All files that depends on this
template will be invalidated and there cache emptied. Those files
will be generated on demand and added to the cache.
