I'm quite happy with WP Super Cache, which I use in half-on mode* (since I also have Bad Behavior and that's how they play nicely together). However, I'm also seeing a slew of very regular PHP warnings showing up on the server log in series of four or five, and I'll be darned if I understood where that comes from...
First, I'll just plop one example of such five warnings in a row, which I think are related to garbage clean up:
[17-Aug-2009 19:30:07] PHP Warning: fopen(/path/to/wp-content/cache/meta/20054525174a89e7ff628775.91622553.tmp) [<a href='function.fopen'>function.fopen</a>]: failed to open stream: Permission denied in /path/to/wp-content/plugins/wp-super-cache/wp-cache-phase2.php on line 573 [17-Aug-2009 19:30:07] PHP Warning: fputs(): supplied argument is not a valid stream resource in /path/to/wp-content/plugins/wp-super-cache/wp-cache-phase2.php on line 574 [17-Aug-2009 19:30:07] PHP Warning: fclose(): supplied argument is not a valid stream resource in /path/to/wp-content/plugins/wp-super-cache/wp-cache-phase2.php on line 575 [17-Aug-2009 19:30:07] PHP Warning: unlink(/path/to/wp-content/cache/meta/wp-cache-d41d8cd98f00b204e9800998ecf8427e.meta) [<a href='function.unlink'>function.unlink</a>]: No such file or directory in /path/to/wp-content/plugins/wp-super-cache/wp-cache-phase2.php on line 578 [17-Aug-2009 19:30:07] PHP Warning: rename(/path/to/wp-content/cache/meta/20054525174a89e7ff628775.91622553.tmp,/path/to/wp-content/cache/meta/wp-cache-d41d8cd98f00b204e9800998ecf8427e.meta) [<a href='function.rename'>function.rename</a>]: No such file or directory in /path/to/wp-content/plugins/wp-super-cache/wp-cache-phase2.php on line 579
I've deliberately changed the path, but left the meta cache filenames as-is, just to give more detail where I think it matters.
I'm stumped: as it is a mere warning I'm not too much concerned, but given that they show up like clockwork every 15 minutes, it obviously looks like a garbage collection routine that runs into an issue.
Oddly enough, the deletion of meta and normal cache files seems to work well, as the number of files isn't worrisome whatsoever. Obviously this is a file perms related thing, but since the files can be created and (somehow, perhaps at a later stage) be deleted, I'm stumped.
So here are the key questions I have:
- What's going on here? And:
- Should I worry? Only if so:
- What should I do to remedy this?
Please accept the anticipated tributes, jubilations and gratitude in general toward the kind insightful soul who can deliver me from my ignorant misery here. ;-)
*Added later: it's running half-on and with mobile support active. The other options in the (first) WP Super Cache Status section are inactive.