Support » Plugin: WP Super Cache » WP Super Cache control screen blank but still running

  • Went to the WP Super Cache settings screen to “clear cache” today to check a unrelated error, the screen was blank, last time I went (a few weeks ago) it was fine. We never have been able to run Super Cache (only legacy) since we use the original permalinks structure.

    The only item on the screen is the usual Permlink Structure Error at the top.

    Checking the source being served it looks like the cache is being presented.

    <!-- Dynamic page generated in 1.276 seconds. -->
    <!-- Live page served on 2010-12-06 17:15:51 -->
    <!-- Compression = gzip -->

    Is at the end of the page.

    “Ismyblogworking” shows that WP super Cache is active.

    Thoughts from anyone before I break something? (I was going to turn off the plugin and turn it back on, but at least now it appears to be working even if I can not control it.)

    By the way I have not changed to a custom url or permalink structure So we can use “super cache” because we have over 4000 posts over 4 years, I have always feared the change would mess up what we have. Links and search engines. We have been running WPSC for well over a year.

Viewing 6 replies - 1 through 6 (of 6 total)
  • Plugin Author Donncha O Caoimh


    There’s no problem changing your permalink structure. WordPress will redirect from the ?p=xxxx url to the friendlier custom url.

    Is there anything in your PHP error log?

    Thanks for the advise on the permalink structure, we have been running sites since WP1.2 change sometimes worries me. We should have made the change on the install of WP Super Cache, only 20,000 page views a month then, now we are over 100K. By the way your utility saved us, we had a day with 40,000 pageviews, without it we would have been down. (we are a free community news site and had a sexting teacher story)

    The log has some errors only one this month related to wp-super-cache;
    [06-Dec-2010 06:33:47] PHP Fatal error: Call to undefined function get_option() in /big/dom/xlondonderrynh/www/wp-content/plugins/wp-super-cache/ossdl-cdn.php on line 6

    Bad Behavior is showing the following error, we run SK2;
    [06-Dec-2010 10:09:36] PHP Warning: Cannot modify header information - headers already sent by (output started at /big/dom/xlondonderrynh/www/wp-content/plugins/SK2/sk2_second_chance.php:2) in /big/dom/xlondonderrynh/www/wp-content/plugins/bad-behavior/bad-behavior/ on line 8

    Then an hourly error I need to go find out why that is;
    [07-Dec-2010 12:36:55] PHP Fatal error: Out of memory (allocated 49283072) (tried to allocate 5536049 bytes) in /big/dom/xlondonderrynh/www/wp-includes/wp-db.php on line 785

    Thank you for your personal help, very kind of you and it is appreciated very much!

    Plugin Author Donncha O Caoimh


    Woah, that’s a lot of pageviews! I don’t know how that get_option() error happens as it’s loaded by wp-cache.php. Do you have WP Super Cache in mu-plugins or plugins?

    You should probably only run SK2 or Bad Behavior, not both. You could also try Cookies for Comments instead. It’s a simpler plugin but works perfectly on cached pages.

    Memory error can be fixed by allocating more memory. Look up “WP_MEMORY_LIMIT” to change that.

    We ran Bad Behavior because I thought it was needed for WP Super Cache. Used SK2 forever, and know it’s not supported anymore, just trusted it for so long hate to let it go. I will test shutting it off and also check out cookies for comments.

    By the way that’s the first time I looked at the error log in years, guess I should keep a better eye on that.

    Not running MU, the files are in wp-super-cache in the plugins folder. I must have just done an update recently (automatic) since the file dates are 11/26, could it be that screen has been blank since then? (version

    I have a backup ( but not sure if that was the version I was running prior. Before auto updates, I would do a mini backup before changing a plugin.

    Should I fall back or will I have database issues?

    I will go get smart on memory, the site has gotten bloated I should clean it up too. As soon as I can see the WP Super Cache Screen I will convert the permalinks too so we can start running Super Cache in the full mode.

    Plugin Author Donncha O Caoimh


    Do you get a lot of the get_option() errors? Can you correlate that error with a request from your access_log? It would help to know what request is causing the problem.

    You could try using That doesn’t have the CDN support and a number of bugfixes but it runs very well.

    You might find that increasing the memory limit will fix the get_option problem.

    That was the only get_option() error the entire month.

    I found this entry at exactly the same time as that PHP error in the access logs;
    [06/Dec/2010:06:33:47 -0500] "GET /wp-content/plugins/wp-super-cache/ossdl-cdn.php HTTP/1.1" 500 5 "-" "Mozilla/5.0 (compatible; Googlebot/2.1; +"

    Installed still have the blank WP-Super-Cache screen. I did not deactivate and start it again, this is a busy time of day for the site.

    We are on a shared server and can not increase our memory, so I am looking for ways to trim the things we are running on the site.

Viewing 6 replies - 1 through 6 (of 6 total)
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