Bug #110404 Update docs for using large_pages

• Submitted: 17 Mar 2023 0:17
• Modified: 28 Mar 2023 21:06
• Reporter: Mark Callaghan
• Status: Closed
• Category: MySQL Server: Documentation
• Severity: S3 (Non-critical)
• Version: 8.0
• OS: Linux
• CPU Architecture: Any

[17 Mar 2023 0:17] Mark Callaghan

Description:
I think the docs here should be updated:
https://dev.mysql.com/doc/refman/8.0/en/large-page-support.html

Older versions of MySQL (certainly 5.7.40 and 5.6.51) used shm (shmat, shmget) for the InnoDB buffer pool memory allocations with large_pages=on and if that failed it used mmap. But modern MySQL (certainly 8.0.32) always uses mmap. Therefore, I don't need to worry about editing these files but the docs still mention them.

/proc/sys/vm/hugetlb_shm_group
/proc/sys/kernel/shmmax
/proc/sys/kernel/shmall

I explained this here: 
http://smalldatum.blogspot.com/2023/03/huge-pages-with-postgres-innodb-better.html

How to repeat:
Read the docs, set large_pages=on in my.cnf, edit /proc/sysctl.conf, sudo sysctl -p, start mysqld

Suggested fix:
Update the docs

[17 Mar 2023 6:53] MySQL Verification Team

Hello Mark,

Thank you for the report and feedback!

Thanks,
Umesh

[28 Mar 2023 21:06] Jon Stephens

Fixed in mysqldoc rev 75238-75239.

Closed.