linux

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.

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.

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.