After upgrading to Flarum 1.1, my forum has slowed down a lot. I noticed that it was due to the Tags extension. When I disable Tags (obviously I can't do this on prod) the forum runs very fast. Evidently some change in the Tags extension messed up the performance.
Right after the upgrade the CPU and RAM load soared on the server:
Flarum core 1.1.0
PHP version: 7.4.1-dh30
MySQL version: 5.5.5-10.5.11-MariaDB
Loaded extensions: Core, date, libxml, openssl, pcre, sqlite3, zlib, bcmath, bz2, calendar, ctype, curl, dom, hash, fileinfo, filter, ftp, gd, gettext, SPL, iconv, session, intl, json, ldap, mbstring, standard, odbc, PDO, mysqlnd, PDO_ODBC, pdo_pgsql, pdo_sqlite, pgsql, Phar, posix, Reflection, imap, shmop, SimpleXML, snmp, soap, sockets, pdo_mysql, exif, sysvmsg, tokenizer, xml, xmlreader, xmlrpc, xmlwriter, xsl, zip, mysqli, apcu, dba, imagick, mailparse, memcached, redis, yaml, Zend OPcache
+-----------------------------------+------------+--------+
| Flarum Extensions | | |
+-----------------------------------+------------+--------+
| ID | Version | Commit |
+-----------------------------------+------------+--------+
| flarum-flags | v1.1.0 | |
| flarum-approval | v1.1.0 | |
| flarum-tags | v1.1.0 | |
| flarum-subscriptions | v1.1.0 | |
| v17development-support | v2.3.2 | |
| flarum-suspend | v1.1.0 | |
| fof-follow-tags | 1.0.1 | |
| aberit-communities | dev-master | |
| fof-user-directory | dev-master | |
| flarum-markdown | v1.1.0 | |
| fof-pages | 1.0.1 | |
| fof-best-answer | 1.1.5 | |
| fof-masquerade | 1.0.0 | |
| fof-oauth | 1.1.0 | |
| rob006-lang-polish | v0.5.10 | |
| aberit-gamification | dev-master | |
| fof-nightmode | 1.0.0 | |
| flarumite-simple-discussion-views | 1.0.3 | |
| fof-byobu | 1.0.1 | |
| fof-ignore-users | 1.0.0 | |
| ianm-follow-users | 1.0.3 | |
| askvortsov-moderator-warnings | v0.6.1 | |
| fof-analytics | 1.0.0 | |
| blomstra-cache-assets | 0.5 | |
| the-turk-diff | 1.1.1 | |
| fof-sitemap | 1.0.2 | |
| fof-polls | 1.0.3 | |
| askvortsov-pwa | v3.0.5 | |
| aberit-follow-communities | dev-master | |
| flarum-bbcode | v1.1.0 | |
| fof-user-bio | 1.0.0 | |
| flarum-mentions | v1.1.0 | |
| v17development-seo | v1.8.0 | |
| clarkwinkelmann-author-change | 1.0.1 | |
| askvortsov-rich-text | v2.1.0 | |
| flarum-statistics | v1.1.0 | |
| fof-formatting | 1.0.1 | |
| flarum-lock | v1.1.0 | |
| fof-upload | 1.0.5 | |
| fof-spamblock | 1.0.1 | |
| fof-socialprofile | 1.1.0 | |
| aberit-forum | dev-master | |
| fof-merge-discussions | 1.0.0 | |
| aberit-moderation-tools | dev-master | |
| flarum-pusher | v1.1.0 | |
| flarum-akismet | v1.1.0 | |
| fof-terms | 1.1.1 | |
| aberit-ads | dev-master | |
| flarum-emoji | v1.1.0 | |
| sycho-move-posts | v0.1.5 | |
+-----------------------------------+------------+--------+
Base URL: https://forum.android.com.pl/
Installation path: *****************
Queue driver: redis
Mail driver: smtp
Debug mode: off
I have 2506 secondary tags on my forum.