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W3 Total Cache
Heavy APC fragmentation (9 posts)

  1. Mark Rowatt Anderson
    Member
    Posted 2 years ago #

    I've been using W3TC without problem on a site for a while now. I recently added APC caching for database and object caches. The site still works OK, but the APC cache quickly gets very fragmented (e.g. typically 100% fragmentation after a day or so), even though there is plenty of free memory (server has ~1Gb free, and I've never seen the cache with more than 50% memory used).

    I've read lots of pieces on APC and tried everything suggested (e.g. set TTL's to 0, set apc.stat=0, exclude things like timthumb, only one segment and increased segment size) and increased the TTL's in W3TC to 7200, but none of it seems to make any difference.

    APC reports that the only things in the user cache are W3TC objects (4000 or so after the cache has been running for a while) and the system cache has a few hundred files.

    Some more detail is on a post I made on Stack Exchange.

    I'm confused as to why I should be seeing such heavy fragmentation even though there is plenty of free cache memory. Since W3TC is the main user of APC on this server, I was wondering if there might be some configuration to W3TC that can help to resolve this?

    Any pointers would be appreciated.

    http://wordpress.org/extend/plugins/w3-total-cache/

  2. Frederick Townes
    Member
    Plugin Author

    Posted 2 years ago #

    That experience is not unexpected on some sites. I will be working on the caching logic in the next release to improve APC performance.

  3. Mark Rowatt Anderson
    Member
    Posted 2 years ago #

    Thanks Frederick I look forward to the update. Some further testing on my end suggests:-

    • the main culprit is the object cache
    • fragmentation from object cache is made much worse (or more quickly worse) by also having DB cache on
    • DB cache on its own doesn't (so far) seem to lead do much fragmentation

    Would you recommend disabling object caching in the meantime?

  4. Frederick Townes
    Member
    Plugin Author

    Posted 2 years ago #

    Yes definitely.

  5. two7s_clash
    Member
    Posted 2 years ago #

    Any update on this one? Workarounds? Use the development version?

  6. veerbahadur
    Member
    Posted 2 years ago #

    Development version of??

  7. two7s_clash
    Member
    Posted 2 years ago #

    Development version of the plugin, of course.

  8. Frederick Townes
    Member
    Plugin Author

    Posted 2 years ago #

    Look for the next release. Consider increasing the TTL of your objects.

  9. rebellajones
    Member
    Posted 1 year ago #

    You should try the other one. http://blustandard.com/newsletter.php

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