Archives and comment pages can be a little tricky when deciding how a cache should behave, but the Faster Cache has you covered.
Cache Back Pages of Archives?
By default, when handling archives or the index page, the Faster Cache will cache only the first page of a paged collection. For example, if your 2010 archive includes 28 pages of posts from 2010, the Faster Cache will leave 27 pages uncached. The rationale behind this is that a change to just page 1 of those 28 pages may actually change the content of all 28. For example, when adding a new post, the previously oldest post displayed on page 1 may be pushed to page 2, the oldest of page 2 pushed to page 3, and so on. If you have quite a few posts, this can create significant housekeeping overhead when a post gets updated, as potentially hundreds or even thousands of pages may need to be expired. However, by caching only page 1, we also give up the performance benefits of caching for all those hundreds or even thousands of pages. As a compromise, you can set the Faster Cache to go ahead and cache all those extra pages but not to update them again until the next scheduled check for expired files. This means the extra archive pages will not be updated automatically in response to the types of events that would otherwise cause an update, such as publishing a new post — they’ll just expire as usual when they get too old. This means that there may be occasions when a post falls off the first page of a set of archives but has not yet appeared on the second page, because the second page is still cached. Similarly, if your archives display comment counts for posts, those counts may get out of sync when a new comment is left on a post that is listed on other than the front page of an archive. By default, the Faster Cache opts for delivering the most up to date content, but the trade-off can be made to cache more pages by enabling the option below.
- Yes — Cache Back Pages of Archives, Potentially Leaving a Mismatch When Page 1 Changes
- No — Cache Only the First Page of Archives, Leaving Back Pages to Be Generated On-the-Fly
Cache Back Pages of Comments?
Something different — but similarly tricky — occurs with comment pages. WordPress handles numbering of comment pages in a way that is exactly opposite its numbering of archive pages. Unlike posts in an archive, once a comment is pushed to a numbered page, that comment will always stay on that numbered page, provided you do not alter your setting for how many top-level comments should be displayed per page. Likewise, if you number your comments with a plugin like Greg’s Threaded Comment Numbering, that number will also remain the same. However, the content of the highest-numbered comment page will still change when a comment is pushed off the main post due to the arrival of new comments. Because comment pages therefore behave slightly differently, you can specify separately whether you would like to cache back pages of comments.
- Yes — Cache Back Pages of Comments, Potentially Leaving Mismatches
- No — Cache Only the First Page of Comments, Leaving Back Pages to Be Generated On-the-Fly
As a precaution, in its default configuration the Faster Cache doesn’t cache attachments. However, if you are certain you will only ever be delivering attachments in the context of an ordinary web page handled by an ordinary theme file (for example, a web page displaying an image attachment) and never directly (for example, delivering a raw movie file), and you would prefer to go ahead and cache them, you can enable this below.
- Yes — Cache Attachments
- No — Do Not Cache Attachments