Slow queries causing errors 500

  • Resolved Kevin_LT

    (@kevin_lt)


    10 years, 8 months ago

    Hi,

    I have been experiencing 500 errors for a while now on my website and it looks like these errors are coming from slow queries that use all the hosting resources and make the website crash.

    I have used P3 Plugin Profiler to make sure this didn’t come from plugins I installed but couldn’t find anything obvious. I also tried deactivating all plugins but still got the errors.

    Below in an example of slow query (this one took 174 seconds!):

    SELECT wp_posts.ID FROM wp_posts INNER JOIN wp_term_relationships ON (wp_posts.ID = wp_term_relationships.object_id) INNER JOIN wp_term_relationships AS tt1 ON (wp_posts.ID = tt1.object_id) INNER JOIN wp_term_relationships AS tt2 ON (wp_posts.ID = tt2.object_id) INNER JOIN wp_term_relationships AS tt3 ON (wp_posts.ID = tt3.object_id) INNER JOIN wp_term_relationships AS tt4 ON (wp_posts.ID = tt4.object_id) INNER JOIN wp_term_relationships AS tt5 ON (wp_posts.ID = tt5.object_id) INNER JOIN wp_postmeta ON (wp_posts.ID = wp_postmeta.post_id) WHERE 1=1 AND wp_posts.ID NOT IN (1584) AND ( wp_term_relationships.term_taxonomy_id IN (4) OR tt1.term_taxonomy_id IN (31) OR tt2.term_taxonomy_id IN (35) OR tt3.term_taxonomy_id IN (48) OR tt4.term_taxonomy_id IN (6,48,49,50,51) OR tt5.term_taxonomy_id IN (39) ) AND wp_posts.post_type = ‘tour’ AND (wp_posts.post_status = ‘publish’) AND (wp_postmeta.meta_key = ‘_thumbnail_id’ ) GROUP BY wp_posts.ID ORDER BY wp_posts.post_date DESC LIMIT 0, 4;

    I’m starting to suspect this is coming from my theme (Midway by Themex). Could that be possible? And, if so, any idea on how to fix it?

    Thanks in advance for your help!

Viewing 3 replies - 1 through 3 (of 3 total)

  • Can you replicate the problem using the default Twenty Fourteen theme?

    Thread Starter Kevin_LT

    (@kevin_lt)

    Thanks for your reply.

    I didn’t try. Is there a safe way to switch back to the default theme without breaking stuff? ?? The theme I have now has a lot of custom things (like custom post type) so just want to make sure I won’t lose anything.

    Thanks!

    Thread Starter Kevin_LT

    (@kevin_lt)

    Update on this: apparently the slow queries were not caused by the template but by the WordPress related posts feature it was using. Thanks for Themex (who created the Midway template) for spotting the issue.

    I deactivated it and now the site seems fine (fingers crossed).

Viewing 3 replies - 1 through 3 (of 3 total)
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