A Counter Said MariaDB Wrote Its Redo Log Every 5.6 ms. It Wrote It Once a Second.
Somewhere in your monitoring there is a panel built on a status counter you picked because of its name. Maybe the query came from a dashboard written for another database, or for another fork of the same one. Have you ever sampled that counter by hand, next to one you already understand, to check that the two move the way you think? I picked Innodb_os_log_written for a measurement because its name says exactly what I wanted: bytes of redo log written. On MySQL 8.4 it agreed with the crash results. On MariaDB 11.8 it said the redo log left the process every 5.6 ms. A crash test on the same server, earlier that day, had lost 9,123 acknowledged commits, which only happens if the log sits in memory for most of a second. I had measured both numbers myself, and they could not both be true. ...