Title: Scalability issues Last modified: January 22, 2019 --- # Scalability issues * Resolved [ctrlaltdelete](https://wordpress.org/support/users/ctrlaltdelete/) * (@ctrlaltdelete) * [7 years, 4 months ago](https://wordpress.org/support/topic/scalability-issues/) * On a site with 10,000+ posts and new ones being posted daily. How can we stop ` DELETE FROM wp_postmeta WHERE meta_key LIKE '_rpbt_related_posts%';` from running so many times? I understand relevant related posts are important but if it clears the cache all the time MySQL is going to cripple the entire website. * We need control over when this runs. ideally once a week would be acceptable. - This topic was modified 7 years, 4 months ago by [ctrlaltdelete](https://wordpress.org/support/users/ctrlaltdelete/). Viewing 9 replies - 1 through 9 (of 9 total) * Plugin Author [keesiemeijer](https://wordpress.org/support/users/keesiemeijer/) * (@keesiemeijer) * [7 years, 4 months ago](https://wordpress.org/support/topic/scalability-issues/#post-11117489) * Hi ctrlaltdelete * Have you tried disabling flushing? [https://keesiemeijer.wordpress.com/related-posts-by-taxonomy/cache/#disable-flushing](https://keesiemeijer.wordpress.com/related-posts-by-taxonomy/cache/#disable-flushing) * Try it with this in your (child) theme’s functions.php * ``` add_filter( 'related_posts_by_taxonomy_cache_args', 'rpbt_disable_cache_flush' ); function rpbt_disable_cache_flush( $args ) { // Disable automatic flushing from actions $args['flush_manually'] = true; // bool. // Disable automatic flushing after a time limit $args['expiration'] = 0; // time in seconds (0 == no expiration). return $args; } add_action( 'wp_loaded', 'rpbt_flush_cache', 11 ); function rpbt_flush_cache() { // Get the transient to manually flush the cache $flush_cache = get_transient( 'rpbt_related_posts_flush_cache_manually' ); if ( ! $flush_cache ) { // Transient doesn't exist // Flush cache km_rpbt_flush_cache(); // Set transient to expire in 7 days set_transient( 'rpbt_related_posts_flush_cache_manually', 1, DAY_IN_SECONDS * 7 ); } } ``` * Thread Starter [ctrlaltdelete](https://wordpress.org/support/users/ctrlaltdelete/) * (@ctrlaltdelete) * [7 years, 4 months ago](https://wordpress.org/support/topic/scalability-issues/#post-11117656) * Perfect thanks i’ll implement it! * Plugin Author [keesiemeijer](https://wordpress.org/support/users/keesiemeijer/) * (@keesiemeijer) * [7 years, 4 months ago](https://wordpress.org/support/topic/scalability-issues/#post-11117777) * There are also other query optimization options to take into consideration for larger sites. * See: [https://keesiemeijer.wordpress.com/related-posts-by-taxonomy/query-optimization/](https://keesiemeijer.wordpress.com/related-posts-by-taxonomy/query-optimization/) * Thread Starter [ctrlaltdelete](https://wordpress.org/support/users/ctrlaltdelete/) * (@ctrlaltdelete) * [7 years, 4 months ago](https://wordpress.org/support/topic/scalability-issues/#post-11118048) * Hello thanks for the info. I added: `add_filter( 'related_posts_by_taxonomy_id_query',' __return_true' );` Everything seems to work so i’ll use it. * I have these queries that aren’t very fast, does the above filter helps with that or it’s something else? * ``` # Query_time: 0.426876 Lock_time: 0.000090 Rows_sent: 0 Rows_examined: 0 SET timestamp=1548164968; INSERT INTO 'wp_postmeta' ('post_id', 'meta_key', 'meta_value') VALUES (134484, '_rpbt_related_posts:6375249561307eaaeef25731acbb4f17', 'a:2:{s:3:\"ids\";a:8:{i:134931;s:1:\"3\";i:134479;s:1:\"3\";i:123545;s:1:\"3\";i:137687;s:1:\"2\";i:137220;s:1:\"2\";i:137179;s:1:\"2\";i:136913;s:1:\"2\";i:136687;s:1:\"2\";}s:4:\"args\";a:3:{s:7:\"post_id\";i:134484;s:10:\"taxonomies\";a:2:{i:0;s:5:\"genre\";i:1;s:9:\"publisher\";}s:13:\"related_terms\";a:3:{i:0;i:4;i:1;i:55;i:2;i:27;}}}'); ``` - This reply was modified 7 years, 4 months ago by [ctrlaltdelete](https://wordpress.org/support/users/ctrlaltdelete/). * Plugin Author [keesiemeijer](https://wordpress.org/support/users/keesiemeijer/) * (@keesiemeijer) * [7 years, 4 months ago](https://wordpress.org/support/topic/scalability-issues/#post-11118102) * That’s the query for update_post_meta() [https://developer.wordpress.org/reference/functions/update_post_meta/](https://developer.wordpress.org/reference/functions/update_post_meta/) * I don’t know why this would take longer than normal. The value is not that big: `' a:2:{s:3:\"ids\";a:8:{i:134931;s:1:\"3\";i:134479;s:1:\"3\";i:123545;s:1:\"3\"; i:137687;s:1:\"2\";i:137220;s:1:\"2\";i:137179;s:1:\"2\";i:136913;s:1:\"2\";i: 136687;s:1:\"2\";}s:4:\"args\";a:3:{s:7:\"post_id\";i:134484;s:10:\"taxonomies\"; a:2:{i:0;s:5:\"genre\";i:1;s:9:\"publisher\";}s:13:\"related_terms\";a:3:{i:0; i:4;i:1;i:55;i:2;i:27;}}}` * Is this query consistently slow? * Plugin Author [keesiemeijer](https://wordpress.org/support/users/keesiemeijer/) * (@keesiemeijer) * [7 years, 4 months ago](https://wordpress.org/support/topic/scalability-issues/#post-11118120) * Oh, and the id query does speed up the cache but does not influence the update_post_meta() query. * Thread Starter [ctrlaltdelete](https://wordpress.org/support/users/ctrlaltdelete/) * (@ctrlaltdelete) * [7 years, 4 months ago](https://wordpress.org/support/topic/scalability-issues/#post-11118216) * It is above 0.1 secs about 200 times a day. I guess my SQL is just too slow to INSERT. It’s probably also overloaded. I think i need a bigger server, just look at queries before i throw $ at it. * Plugin Author [keesiemeijer](https://wordpress.org/support/users/keesiemeijer/) * (@keesiemeijer) * [7 years, 4 months ago](https://wordpress.org/support/topic/scalability-issues/#post-11118304) * Good point. Related posts database queries are always going to be expensive the larger the site. There comes a point where you should look for different options if it all slows down. Like a bigger server, elastic search, related posts from a service (like jetpack) or cache. * Thread Starter [ctrlaltdelete](https://wordpress.org/support/users/ctrlaltdelete/) * (@ctrlaltdelete) * [7 years, 4 months ago](https://wordpress.org/support/topic/scalability-issues/#post-11121211) * hmm now i’m thinking on getting a cheap VPS to offload search with elastic search. Thanks for the suggestion. Not sure if i’ll manage cos seems very complicated. * The other monster queries are from “beautiful taxonomy filters”..i have no idea how big sites do it. Certainly not with that plugin. Viewing 9 replies - 1 through 9 (of 9 total) The topic ‘Scalability issues’ is closed to new replies. * ![](https://ps.w.org/related-posts-by-taxonomy/assets/icon.svg?rev=1115231) * [Related Posts by Taxonomy](https://wordpress.org/plugins/related-posts-by-taxonomy/) * [Frequently Asked Questions](https://wordpress.org/plugins/related-posts-by-taxonomy/#faq) * [Support Threads](https://wordpress.org/support/plugin/related-posts-by-taxonomy/) * [Active Topics](https://wordpress.org/support/plugin/related-posts-by-taxonomy/active/) * [Unresolved Topics](https://wordpress.org/support/plugin/related-posts-by-taxonomy/unresolved/) * [Reviews](https://wordpress.org/support/plugin/related-posts-by-taxonomy/reviews/) * 9 replies * 2 participants * Last reply from: [ctrlaltdelete](https://wordpress.org/support/users/ctrlaltdelete/) * Last activity: [7 years, 4 months ago](https://wordpress.org/support/topic/scalability-issues/#post-11121211) * Status: resolved