Marko Mäkelä added a comment - 2020-11-04 07:36 mleich , the stated 10.5 revision does not include the fix of MDEV-24101 . Without that fix, I confirm that ./mysql-test-run.pl --mysqld=--innodb_random_read_ahead=ON innodb.create-index will hang on bootstrap. I changed this report to cover innodb_flush_sync=OFF only, because innodb_random_read_ahead=ON was already covered by MDEV-24101 . I confirm the hang with innodb_flush_sync=0 with the latest 10.5. During the early development of MDEV-23855 , I did test the performance with innodb_flush_sync=OFF , and it did work back then. This must have been broken later. Curiously, for the following invocation, the parameter appears to be ignored for some reason: ./mtr --mysqld=--skip-innodb-flush-sync innodb.create-index This might be the reason why I failed to catch this regression later. I think that a proper fix is to let the page cleaner thread handle the checkpoint flushing also in the innodb_flush_sync=OFF case, and limit the write rate to innodb_io_capacity_max pages per second. With the default innodb_flush_sync=ON setting, we would attempt to write out up to innodb_io_capacity_max pages that were modified before the target checkpoint LSN, and then perform a checkpoint, and keep looping until the target has been met. With this bug fixed, innodb_flush_sync=OFF would do the same, except that we may pause between the batches so that the rate of innodb_io_capacity_max pages per second will not be exceeded.