database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-06-26 12:21:12 +03:00
Code Activity

Introduce num_os_semaphores GUC.

Browse Source 
The documentation for System V IPC parameters provides complicated
formulas to determine the appropriate values for SEMMNI and SEMMNS.
Furthermore, these formulas have often been wrong because folks
forget to update them (e.g., when adding a new auxiliary process).

This commit introduces a new runtime-computed GUC named
num_os_semaphores that reports the number of semaphores needed for
the configured number of allowed connections, worker processes,
etc.  This new GUC allows us to simplify the formulas in the
documentation, and it should help prevent future inaccuracies.
Like the other runtime-computed GUCs, users can view it with
"postgres -C" before starting the server, which is useful for
preconfiguring the necessary operating system resources.

Reviewed-by: Tom Lane, Sami Imseih, Andres Freund, Robert Haas
Discussion: https://postgr.es/m/20240517164452.GA1914161%40nathanxps13
This commit is contained in:
Nathan Bossart
2024-07-26 15:28:55 -05:00
parent 8a53539bd6
commit 0dcaea5690
4 changed files with 54 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
src/backend/utils/misc/guc_tables.c
View File

@ -591,6 +591,7 @@ static int segment_size;
static int shared_memory_size_mb;
static int shared_memory_size_in_huge_pages;
static int wal_block_size;
static int num_os_semaphores;
static bool data_checksums;
static bool integer_datetimes;
@ -2283,6 +2284,17 @@ struct config_int ConfigureNamesInt[] =
NULL, NULL, NULL
},
{
{"num_os_semaphores", PGC_INTERNAL, PRESET_OPTIONS,
gettext_noop("Shows the number of semaphores required for the server."),
NULL,
GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE | GUC_RUNTIME_COMPUTED
},
&num_os_semaphores,
0, 0, INT_MAX,
NULL, NULL, NULL
},
{
{"commit_timestamp_buffers", PGC_POSTMASTER, RESOURCES_MEM,
gettext_noop("Sets the size of the dedicated buffer pool used for the commit timestamp cache."),