Hi, I have a Windows server that has been running MariaDB 10.1 successfully for over a year. The server remains mostly idle for long times with some read access, but occasionally there are transactions that add data (about 500k rows per commit). There can be up to 10 such transactions (one per database) at the same time and during those times the server is under quite some load (the code processing the data resides on the same server as the database). We're using an 8 core AMD Ryzen, 32 GB RAM and a Samsung SSD. Like I said, this worked fine with MariaDB 10.1 all the time. We're currently in the process of setting up a new server (specs similar to the ones above) and because MariaDB 10.3 has been released recently, I was curious and installed it. The database now constantly shuts down because of "[FATAL] InnoDB: Semaphore wait has lasted > 600 seconds. We intentionally crash the server because it appears to be hung." whenever there is one of the load situations described above. If I install MariaDB 10.1 on the new server, it runs as fine as the old one. The crashes also happen when I start with a clean database (no data migrated from 10.1 databases). I'm not a huge MariaDB config pro, as it's only a tool to store the data, it just needs to run with reasonable performance and has always worked until now. As far as I know and can judge from comments in the file, the my.ini in use is (mostly?) based on my-innodb-heavy-4G.cnf, but coworkers might have made modifications. I've attached the contents below. I don't know how I can debug this issue further. Windows event viewer contains several log warnings with the text "InnoDB: A long semaphore wait:" but no further information why this wait happens. I couldn't find any other error logs. I guess it is some configuration error (I read about MariaDB switching from XtraDB to InnoDB, so I guess that the issue might be related). Migrating to 10.3 is not an absolute must, but it would be nice to be able to fix the problem. Any help would be greatly appreciated and if you need more information, I'll gladly try to provide it. Thanks, Tom. my.ini: [mysqld] max_connections = 100 max_allowed_packet = 16M binlog_cache_size = 1M max_heap_table_size = 64M read_buffer_size = 2M read_rnd_buffer_size = 16M sort_buffer_size = 8M join_buffer_size = 8M thread_cache_size = 10 query_cache_size = 64M query_cache_limit = 2M thread_stack = 240K tmp_table_size = 64M slow_query_log expire_logs_days = 14 log-bin = mysql-bin character-set-server=utf8 collation-server=utf8_general_ci #*** MyISAM Specific options key_buffer_size = 32M bulk_insert_buffer_size = 64M myisam_sort_buffer_size = 128M myisam_max_sort_file_size = 10G myisam_repair_threads = 1 myisam_recover # *** INNODB Specific options *** #innodb_fatal_semaphore_wait_threshold = 6000 #tried that, didn't help #innodb_adaptive_hash_index = 0 #tried that (suggested in some stack overflow post, didn't help) innodb_buffer_pool_size = 2G innodb_data_file_path = ibdata1:10M:autoextend innodb_write_io_threads = 8 innodb_read_io_threads = 8 innodb_thread_concurrency = 16 innodb_log_buffer_size = 8M innodb_log_file_size = 256M innodb_log_files_in_group = 3 innodb_max_dirty_pages_pct = 10 innodb_io_capacity = 2000 innodb_lock_wait_timeout = 120 [mysql] no-auto-rehash [myisamchk] key_buffer_size = 512M sort_buffer_size = 512M read_buffer = 8M write_buffer = 8M [mysqld_safe] open-files-limit = 8192