Database slowdown after update to 3.4.1

2 Views

I own a wordpress installation, and Updated to 3.4.1.

After the upgrade, I got a very strange slowdown to my wordpress.

Read More

After all, I used the 

define('SAVEQUERIES', true);

in my wp-config.php with combined with the following code in my theme footer.php 

global $wpdb;
echo "<pre>";
print_r($wpdb->queries);
echo "</pre>";

and I found that while I don’t have many queries (49 queries I got), there are

  • 4 Quiries took more than 9”
  • 3 Quiries took more than 8”
  • 4 Quiries took more than 7”
  • 4 Quiries took more than 6”
  • 8 Quiries took more than 5”
  • 1 Quiry took more than 4”

Here I will show you some of the queries: 

/* Execution time 7.0095062E-5 */
SELECT t.*, tt.* FROM wp_terms AS t INNER JOIN wp_term_taxonomy AS tt ON t.term_id = tt.term_id WHERE tt.taxonomy IN ('category') AND tt.count > 0 ORDER BY t.name ASC

/* Execution time 5.3167343E-5 */
SELECT post_id, meta_key, meta_value FROM wp_postmeta WHERE post_id IN (77375,77379,77381)

/* Execution time 9.2029572E-5 */
SELECT wp_posts.* FROM wp_posts WHERE ID IN (77381,77379,77375)

In most of the queries there query is simple, with no complexity, and I cannot imagine why that queries are so slow.

The WordPress database contains in about 60.000 records and running on percona.

Any idea for that issue and how maybe can I fix it ?

Post Views: 2

Related posts

Leave a Reply

2 comments

  1. If you’ve got 60,000 records, try cleaning post/page revisions; these really accumulate and cause excessively long queries. I’ve seen database sizes drop 90% with huge increases in performance.

    Run the query below in phpmyadmin or from the command line and then optimize:

    DELETE a,b,c
FROM wp_posts a
LEFT JOIN wp_term_relationships b ON (a.ID = b.object_id)
LEFT JOIN wp_postmeta c ON (a.ID = c.post_id)
WHERE a.post_type = 'revision'

    Talk to your web host, too. Maybe MySQL or your CPU is being throttled down.