Re: Enhancing Memory Context Statistics Reporting - Mailing list pgsql-hackers

This issue occurs on my M1 Mac, but I couldn’t reproduce it on Ubuntu,
so it might be environment-dependent.

Looking at the logs, Assert() is failing:

   2025-10-07 08:48:26.766 JST [local] psql [23626] WARNING:  01000:
server process 23646 is processing previous request
   2025-10-07 08:48:26.766 JST [local] psql [23626] LOCATION: 
pg_get_process_memory_contexts, mcxtfuncs.c:476
   TRAP: failed Assert("victim->magic == FREE_PAGE_SPAN_LEADER_MAGIC"),
File: "freepage.c", Line: 1379, PID: 23626
   0   postgres                            0x000000010357fdf4
ExceptionalCondition + 216
   1   postgres                            0x00000001035cbe18
FreePageManagerGetInternal + 684
   2   postgres                            0x00000001035cbb18
FreePageManagerGet + 40
   3   postgres                            0x00000001035c84cc
dsa_allocate_extended + 788
   4   postgres                            0x0000000103453af0
pg_get_process_memory_contexts + 992
   5   postgres                            0x0000000103007e94
ExecMakeFunctionResultSet + 616
   6   postgres                            0x00000001030506b8
ExecProjectSRF + 304
   7   postgres                            0x0000000103050434
ExecProjectSet + 268
   8   postgres                            0x0000000103003270
ExecProcNodeFirst + 92
   9   postgres                            0x0000000102ffa398
ExecProcNode + 60
   10  postgres                            0x0000000102ff5050 ExecutePlan
+ 244
   11  postgres                            0x0000000102ff4ee0
standard_ExecutorRun + 456
   12  postgres                            0x0000000102ff4d08 ExecutorRun
+ 84
   13  postgres                            0x0000000103341c84
PortalRunSelect + 296
   14  postgres                            0x0000000103341694 PortalRun +
656
   15  postgres                            0x000000010333c4bc
exec_simple_query + 1388
   16  postgres                            0x000000010333b5d0
PostgresMain + 3252
   17  postgres                            0x0000000103332750
BackendInitialize + 0
   18  postgres                            0x0000000103209e48
postmaster_child_launch + 456
   19  postgres                            0x00000001032118c8
BackendStartup + 304
   20  postgres                            0x000000010320f72c ServerLoop
+ 372
   21  postgres                            0x000000010320e1e4
PostmasterMain + 6448
   22  postgres                            0x0000000103094b0c main + 924
   23  dyld                                0x0000000199dc2b98 start +
6076


Could you please check if you can reproduce this crash on your
environment?

As discussed earlier, I believe we decided to remove stats_timestamp,
but it seems it’s still mentioned here.

> + * Update timestamp and signal all the waiting client backends after
> copying
> + * all the statistics.
> + */
> +static void
> +end_memorycontext_reporting(MemoryStatsDSHashEntry *entry,
> MemoryContext oldcontext, HTAB *context_id_lookup)

Should “Update timestamp” in this comment also be removed for
consistency?

The column order differs slightly from pg_backend_memory_contexts.
If there’s no strong reason for the difference, perhaps aligning the
order might improve consistency: