There is no doubt, our WordPress site is heavy loaded, but why it crashed, and why we couldn't restart it on Cloudways only rollback it?
I see hungreds of similar lines before the crash like:
[Tue Apr 13 15:12:25.882171 2021] [proxy_fcgi:error] [pid 6670:tid 139911898322688] [client 89.135.146.241:13425] AH01079: failed to make connection to backend: httpd-UDS, referer: https://www.palferi.hu/hanganyagok/2006-2007/2007-01-02/
And after the crash, 4 similar line like:
[Wed Apr 14 10:34:50.809931 2021] [proxy_fcgi:error] [pid 1200:tid 140238550603520] [client 138.197.189.13:52981] AH01071: Got error 'PHP message: WordPress adatb\xc3\xa1zis hiba Table 'hudxsgwarf.wpar_posts' doesn't exist a lek\xc3\xa9rdez\xc3\xa9sben SELECT wpar_posts.* FROM wpar_posts LEFT JOIN wpar_term_relationships ON (wpar_posts.ID = wpar_term_relationships.object_id) WHERE 1=1 AND ( \n wpar_term_relationships.term_taxonomy_id IN (1,86)\n) AND wpar_posts.post_type IN ('post', 'hanganyagok', 'csoportok', 'programok', 'teljess-gre-hangolva') AND (wpar_posts.post_status = 'publish') GROUP BY wpar_posts.ID ORDER BY wpar_posts.post_date DESC k\xc3\xa9sz\xc3\xadtette require('wp-blog-header.php'), wp, WP->main, WP->query_posts, WP_Query->query, WP_Query->get_posts, do_action_ref_array, WP_Hook->do_action, WP_Hook->apply_filters, WPSEO_Sitemaps->redirect, WPSEO_Sitemaps->get_sitemap_from_cache, WPSEO_Sitemaps->refresh_sitemap_cache, WPSEO_Sitemaps->build_sitemap, WPSEO_Sitemaps->build_root_map, WPSEO_Taxonomy_Sitemap_Provider->get_index_links, WP_Query->__construct, WP_Query->query, WP_Query->get_posts\n', referer: https://www.palferi.hu/sitemap_index.xml
Do you have any idea what were happen? Cloudways claim, CPU power was short to serve the requests. I do not know.