Introduce pg_shmem_allocations_numa view

Introduce new pg_shmem_alloctions_numa view with information about how
shared memory is distributed across NUMA nodes. For each shared memory
segment, the view returns one row for each NUMA node backing it, with
the total amount of memory allocated from that node.

The view may be relatively expensive, especially when executed for the
first time in a backend, as it has to touch all memory pages to get
reliable information about the NUMA node. This may also force allocation
of the shared memory.

Unlike pg_shmem_allocations, the view does not show anonymous shared
memory allocations. It also does not show memory allocated using the
dynamic shared memory infrastructure.

Author: Jakub Wartak <jakub.wartak@enterprisedb.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Tomas Vondra <tomas@vondra.me>
Discussion: https://postgr.es/m/CAKZiRmxh6KWo0aqRqvmcoaX2jUxZYb4kGp3N%3Dq1w%2BDiH-696Xw%40mail.gmail.com

src/test/regress/expected/numa.out

@@ -0,0 +1,13 @@
+SELECT NOT(pg_numa_available()) AS skip_test \gset
+\if :skip_test
+SELECT COUNT(*) = 0 AS ok FROM pg_shmem_allocations_numa;
+\quit
+\endif
+-- switch to superuser
+\c -
+SELECT COUNT(*) >= 0 AS ok FROM pg_shmem_allocations_numa;
+ ok 
+----
+ t
+(1 row)
+

src/test/regress/expected/numa_1.out

@@ -0,0 +1,5 @@
+SELECT NOT(pg_numa_available()) AS skip_test \gset
+\if :skip_test
+SELECT COUNT(*) = 0 AS ok FROM pg_shmem_allocations_numa;
+ERROR:  libnuma initialization failed or NUMA is not supported on this platform
+\quit

src/test/regress/expected/privileges.out

@@ -3219,8 +3219,8 @@ REVOKE MAINTAIN ON lock_table FROM regress_locktable_user;
 -- clean up
 DROP TABLE lock_table;
 DROP USER regress_locktable_user;
--- test to check privileges of system views pg_shmem_allocations and
--- pg_backend_memory_contexts.
+-- test to check privileges of system views pg_shmem_allocations,
+-- pg_shmem_allocations_numa and pg_backend_memory_contexts.
 -- switch to superuser
 \c -
 CREATE ROLE regress_readallstats;
@@ -3242,6 +3242,12 @@ SELECT has_table_privilege('regress_readallstats','pg_shmem_allocations','SELECT
  f
 (1 row)
 
+SELECT has_table_privilege('regress_readallstats','pg_shmem_allocations_numa','SELECT'); -- no
+ has_table_privilege 
+---------------------
+ f
+(1 row)
+
 GRANT pg_read_all_stats TO regress_readallstats;
 SELECT has_table_privilege('regress_readallstats','pg_aios','SELECT'); -- yes
  has_table_privilege 
@@ -3261,6 +3267,12 @@ SELECT has_table_privilege('regress_readallstats','pg_shmem_allocations','SELECT
  t
 (1 row)
 
+SELECT has_table_privilege('regress_readallstats','pg_shmem_allocations_numa','SELECT'); -- yes
+ has_table_privilege 
+---------------------
+ t
+(1 row)
+
 -- run query to ensure that functions within views can be executed
 SET ROLE regress_readallstats;
 SELECT COUNT(*) >= 0 AS ok FROM pg_aios;

src/test/regress/expected/rules.out

@@ -1757,6 +1757,10 @@ pg_shmem_allocations| SELECT name,
     size,
     allocated_size
    FROM pg_get_shmem_allocations() pg_get_shmem_allocations(name, off, size, allocated_size);
+pg_shmem_allocations_numa| SELECT name,
+    numa_node,
+    size
+   FROM pg_get_shmem_allocations_numa() pg_get_shmem_allocations_numa(name, numa_node, size);
 pg_stat_activity| SELECT s.datid,
     d.datname,
     s.pid,

src/test/regress/parallel_schedule

@@ -119,7 +119,7 @@ test: plancache limit plpgsql copy2 temp domain rangefuncs prepare conversion tr
 # The stats test resets stats, so nothing else needing stats access can be in
 # this group.
 # ----------
-test: partition_join partition_prune reloptions hash_part indexing partition_aggregate partition_info tuplesort explain compression memoize stats predicate
+test: partition_join partition_prune reloptions hash_part indexing partition_aggregate partition_info tuplesort explain compression memoize stats predicate numa
 
 # event_trigger depends on create_am and cannot run concurrently with
 # any test that runs DDL

src/test/regress/sql/numa.sql

@@ -0,0 +1,10 @@
+SELECT NOT(pg_numa_available()) AS skip_test \gset
+\if :skip_test
+SELECT COUNT(*) = 0 AS ok FROM pg_shmem_allocations_numa;
+\quit
+\endif
+
+-- switch to superuser
+\c -
+
+SELECT COUNT(*) >= 0 AS ok FROM pg_shmem_allocations_numa;

src/test/regress/sql/privileges.sql

@@ -1947,8 +1947,8 @@ REVOKE MAINTAIN ON lock_table FROM regress_locktable_user;
 DROP TABLE lock_table;
 DROP USER regress_locktable_user;
 
--- test to check privileges of system views pg_shmem_allocations and
--- pg_backend_memory_contexts.
+-- test to check privileges of system views pg_shmem_allocations,
+-- pg_shmem_allocations_numa and pg_backend_memory_contexts.
 
 -- switch to superuser
 \c -
@@ -1958,12 +1958,14 @@ CREATE ROLE regress_readallstats;
 SELECT has_table_privilege('regress_readallstats','pg_aios','SELECT'); -- no
 SELECT has_table_privilege('regress_readallstats','pg_backend_memory_contexts','SELECT'); -- no
 SELECT has_table_privilege('regress_readallstats','pg_shmem_allocations','SELECT'); -- no
+SELECT has_table_privilege('regress_readallstats','pg_shmem_allocations_numa','SELECT'); -- no
 
 GRANT pg_read_all_stats TO regress_readallstats;
 
 SELECT has_table_privilege('regress_readallstats','pg_aios','SELECT'); -- yes
 SELECT has_table_privilege('regress_readallstats','pg_backend_memory_contexts','SELECT'); -- yes
 SELECT has_table_privilege('regress_readallstats','pg_shmem_allocations','SELECT'); -- yes
+SELECT has_table_privilege('regress_readallstats','pg_shmem_allocations_numa','SELECT'); -- yes
 
 -- run query to ensure that functions within views can be executed
 SET ROLE regress_readallstats;