Re: PostgreSQL14.2 can not start because of huge_page_size is equal to 1048576

Found this:

https://www.postgresql.org/docs/current/kernel-resources.html#LINUX-HUGE-PAGES <https://www.postgresql.org/docs/current/kernel-resources.html#LINUX-HUGE-PAGES>

See section: 19.4.5. Linux Huge Pages

"The default behavior for huge pages in PostgreSQL is to use them when possible, with the system's default huge page size, and to fall back to normal pages on failure. To enforce the use of huge pages, you can set huge_pages <https://www.postgresql.org/docs/current/runtime-config-resource.html#GUC-HUGE-PAGES> to on in postgresql.conf. Note that with this setting PostgreSQL will fail to start if not enough huge pages are available.”

> On May 9, 2022, at 8:56 AM, 类延良 <msdnchina(at)163(dot)com> wrote:
>
> My rhel 7.9 enabled 1GB hugepagesize,and in this rhel7.9,there is a postgresql 14.2 (from compile installation).
> [root(at)localhost ~]# cat /proc/meminfo |grep -i hugep
> AnonHugePages: 8192 kB
> HugePages_Total: 0
> HugePages_Free: 0
> HugePages_Rsvd: 0
> HugePages_Surp: 0
> Hugepagesize: 1048576 kB
> [root(at)localhost ~]# hugeadm --pool-list
> Size Minimum Current Maximum Default
> 1073741824 0 0 0 *
> [root(at)localhost ~]#
>
>
>
> after I change pg parameter huge_page_size to 1048576， I can not start PostgreSQL 14.2 . the following is the error,
> [pg142(at)localhost data]$ grep huge postgresql.conf
> #huge_pages = try # on, off, or try
> huge_page_size = 1048576 # zero for system default
> [pg142(at)localhost data]$ pg_ctl start
> waiting for server to start....2022-05-09 04:36:58.220 GMT [1719] LOG: invalid value for parameter "huge_page_size": 1048576
> 2022-05-09 04:36:58.220 GMT [1719] DETAIL: huge_page_size must be 0 on this platform.
> 2022-05-09 12:36:58.220 CST [1719] FATAL: configuration file "/home/pg142/data/postgresql.conf" contains errors
> stopped waiting
> pg_ctl: could not start server
> Examine the log output.
> [pg142(at)localhost data]$
>
> I want to know why ？
>
>
>