Marko Mäkelä added a comment - 2018-05-30 19:33 The same issue appears to exist in MySQL since version 5.7.8 , where some code was refactored. Either the function AIO::print_segment_info()  or its caller should display m_n_reserved .

Marko Mäkelä added a comment - 2021-04-26 12:29 It looks like this got broken further in MDEV-16264 (10.5.0). We now have totally useless output in os_aio_print() , which I will remove: diff --git a/storage/innobase/os/os0file.cc b/storage/innobase/os/os0file.cc index fc3da454d2d..48d7c69319f 100644 --- a/storage/innobase/os/os0file.cc +++ b/storage/innobase/os/os0file.cc @@ -4160,10 +4160,6 @@ os_aio_print(FILE* file) time_t current_time; double time_elapsed; - fputs("Pending normal aio reads:", file); - - - putc('\n', file); current_time = time(NULL); time_elapsed = 0.001 + difftime(current_time, os_last_printout); As part of MDEV-16264 , other output (along with class AIO ) was already removed in MariaDB Server 10.5.0. Because there have not been any further votes or comments for this issue, I think that it is fine to remove the code. Asynchronous reads are only used by read-ahead. Asynchronous writes are being used for data file pages, and it could hurt performance to accurately track the number of pending operations, which is not interesting anyway. I suspect that the output had originally been added in order to be able to diagnose some hangs. I do not remember any I/O hangs lately.

Marko Mäkelä added a comment - 2021-04-26 12:48 Most of the statistics were already removed in MariaDB 10.5.0. 10.5.10 will remove the string "Pending normal aio reads" that was not followed by any numbers.