Stale in-request cache after wp_cache_flush()

  • palsch

    (@palsch)


    1 week, 3 days ago

    Hi SiteGround Optimizer team,

    I’m a WordPress plugin developer (neo-wp.com) and found an issue in the Memcached object-cache drop-in generated by SiteGround Optimizer 7.8.0: wp_cache_flush() does not fully invalidate cached data, causing stale WordPress metadata to be returned within the same request.

    File: templates/memcached.tpl

    • Line 47: wp_cache_flush() delegates to $wp_object_cache->flush().
    • Line 223: WP_Object_Cache::flush() flushes the Memcached instances but does not clear the local $this->cache array.
    • Line 239: WP_Object_Cache::get() preferentially returns values from that local array.

    Consequently, wp_cache_flush() can continue returning stale values during the same request.

    This causes failures after direct database updates: WordPress reads stale metadata, attempts to write the already-correct database value, and update_post_meta() returns false because zero rows were changed.

    Please clear the local cache inside flush() as well, so wp_cache_flush() fully invalidates cached values.

    Best regards,
    Paul Schwind

    The page I need help with: [log in to see the link]

Viewing 2 replies - 1 through 2 (of 2 total)
  • Plugin Support Ivaylo Stoyanov

    (@ivaylostoyanov)

    1 week, 3 days ago

    Hello @palsch,

    Thank you for your feedback and observations.

    I have reported this behaviour to our WordPress developers and will update this topic once we have more information.

    In the meantime, your patience is greatly appreciated.

    Best regards,

    Ivaylo Stoyanov

    Plugin Support Ivaylo Stoyanov

    (@ivaylostoyanov)

    1 week, 2 days ago

    Hello @palsch,

    Once again, we would like to thank you for your feedback.

    Our WordPress developers have reviewed the reported behaviour and they have been able to replicate it.

    While we cannot provide you with an ETA, I would like to assure you that this issue will be addressed in the future releases of our Speed Optimizer plugin.

    Best regards,

    Ivaylo Stoyanov

Viewing 2 replies - 1 through 2 (of 2 total)

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