Hello.
At Fri, 3 Sep 2021 06:28:58 +0000, "Shinoda, Noriyoshi (PN Japan FSIP)"
<noriyoshi.shin...@hpe.com> wrote in
> Fujii-san, Julien-san
>
> Thank you very much for your comment.
> I followed your comment and changed the elog function to ereport function and
> also changed the log level. The output message is the same as in the case of
> non-HugePages memory acquisition failure.I did not simplify the error
> messages as it would have complicated the response to the preprocessor.
>
> > I agree that the message should be promoted to a higher level. But I
> > think we should also make that information available at the SQL level,
> > as the log files may be truncated / rotated before you need the info,
> > and it can be troublesome to find the information at the OS level, if
> > you're lucky enough to have OS access.
>
> In the attached patch, I have added an Internal GUC 'using_huge_pages' to
> know that it is using HugePages. This parameter will be True only if the
> instance is using HugePages.
IF you are thinking to show that in GUC, you might want to look into
the nearby thread [1], especially about the behavior when invoking
postgres -C using_huge_pages. (Even though the word "using" in the
name may suggest that the server is running, but I don't think it is
neat that the variable shows "no" by the command but shows "yes" while
the same server is running.)
I have some comment about the patch.
- if (huge_pages == HUGE_PAGES_TRY && ptr == MAP_FAILED)
- elog(DEBUG1, "mmap(%zu) with MAP_HUGETLB failed, huge
pages disabled: %m",
- allocsize);
+ if (ptr != MAP_FAILED)
+ using_huge_pages = true;
+ else if (huge_pages == HUGE_PAGES_TRY)
+ ereport(LOG,
+ (errmsg("could not map anonymous shared
memory: %m"),
+ (mmap_errno == ENOMEM) ?
+ errhint("This error usually means that
PostgreSQL's request "
If we set huge_pages to try and postgres falled back to regular pages,
it emits a large message relative to its importance. The user specifed
that "I'd like to use huge pages, but it's ok if not available.", so I
think the message should be far smaller. Maybe just raising the
DEBUG1 message to LOG along with moving to ereport might be
sufficient.
- elog(DEBUG1, "CreateFileMapping(%zu) with
SEC_LARGE_PAGES failed, "
- "huge pages disabled",
- size);
+ ereport(LOG,
+ (errmsg("could not create
shared memory segment: error code %lu", GetLastError()),
+ errdetail("Failed system call
was CreateFileMapping(size=%zu, name=%s).",
+ size,
szShareMem)));
It doesn't seem to be a regular user-facing message. Isn't it
sufficient just to raise the log level to LOG?
[1]
https://www.postgresql.org/message-id/20210903.141206.103927759882272221.horikyota.ntt%40gmail.com
