After mentioning this plugin on my host's support forum as an alternative to other caching plugins. This is how I described it:
"I use DB Cache Reloaded. It has quite a different approach compared to other caching plugins, placing itself between WP and MySQL and storing in the filesystem, for a short period (5 min default), answers to database queries."
However, the sysadmin (the one who manages the whole server farm) replied thus:
This will destroy your blog's performance at any kind of high traffic level. The filesystem is the slowest resource PHP can address.
For lots of reasons I trust his advices as I know he really knows his stuff, and if he says on his system filesystem access is way slower than direct MySQL-access, this is certainly true.
However, his advice is based on my description of how DB Cache Reloaded works, which I'm not quite sure is a precise description at that. So, I'd like to know whether what I described is accurate.
I mean, when a DB Cache Reloaded-enabled WordPress blog renders a page, does DB Cache Reloaded read the cached queries from the cache folder, by direct file operations (open/read/close, open/read/close, open/read/close...), one set of file operations for each query? Or does it use some other mechanism that doesn't involve multiple such filesystem accesses?
I'd love to continue using DB Cache Reloaded in this host, but for that I need to know a little more about its inner working to ask my sysadmin whether it's efficient or not in his system. If he still says it isn't, I'll have to unfortunately switch to a more traditional full-page caching solution. :(