With an object cache backend, transients will be stored in that object backend <b>and will not get written to the options table</b>. So the “not writing to the wp_options table” part is expected.
Throw something like this in your WP root then hit it up:
<?php
include( 'wp-load.php' );
set_transient( 'foo', 'bar' );
var_dump( get_transient( 'foo' ) );
Next, comment out the set_transient() line to test the permanence of the transient. If that doesn’t work, let me know:
- What version of APC?
- What version of the backend?
- What version of WordPress?
- Single server situation?
Thread Starter
meeble
(@meeble)
Hi Mark,
Thanks for your quick response. The first time I ran the page, I got this response:
string(3) “bar”
After commenting out the set_transient line, I get this:
bool(false)
Here’s the info you asked for:
APC version: 3.1.13
PHP version: 5.3.3
Backend version: 2.0.4
WP version: 3.5 RC2 (this is a new dev site)
Single server? yes
Thanks again!
Thread Starter
meeble
(@meeble)
Hi Mark,
Any ideas about how to fix this?
Thanks,
Devin
Thread Starter
meeble
(@meeble)
Mark,
Update: I migrated my site over to a new server with PHP 5.4.10 and now transients are working fine with APC object cache enabled. I also switched from mod_fcgid to php-fpm – not sure if that could have anything to do with it.
Thanks,
Devin
Hi Devin,
I did the transient test too but added one more step…
On a WP 3.5 Multisite with APC Object Cache Backend 2.0.6 running on VPS with Debian Squeeze, Nginx 1.3.3, PHP-FPM 5.3.20 and APC 3.1.9
Both times, the request showed me
string(3) "bar"
But then I removed wp-content/object-cache.php, refreshed a third time and got:
bool(false)
And moving the object-cache.php back into place, the old bar value is echoed again…
Not completely sure what it means, but the result does worry me a bit 🙁
Similarly, clearing the APC immediately after the first two requests, results in bool(false) on third request… The transient did not make it into the database.
Hi all –
Does anyone have a solution yet?
Same problem on a customers server:
set- and get-(site)-transient runs fine without APC Object Cache Backend (default db storage) – As soon as I copy object-cache.php to wp-content: no cache hits anymore.
set_site_transient always returns TRUE
i can’t see my transients in apc.php (User Cache Entries)
- 5.3.2-1ubuntu4.18
- APC 3.1.3p1
- WP 3.5.1
- APC Backend 2.0.6
Without object-cache.php, Marks test case returns String(3)”bar”, with object-cache.php it returns bool(false).
br from Salzburg,
– Johannes
Hi Johannes, my only solution has been to disable the APC Object Cache Backend plugin… As Mark (the developer) said:
With an object cache backend, transients will be stored in that object backend and will not get written to the options table. So the “not writing to the wp_options table” part is expected.
Too bad because the plugin did noticeably improve site speed. But then, it also caused a huge amount of cache fragmentation which worried me a bit. Plus these weird effects where options seemed to not get saved while they actually where and vise-versa, which is hard to explain to clients.
Ah well… Stability before speed, hey?
