From f66d63613d8db0974c79a83a67184efa1dddfd93 Mon Sep 17 00:00:00 2001 From: Florents Tselai Date: Wed, 4 Jun 2025 21:02:01 +0300 Subject: [PATCH v4] Add pg_dsm_registry_allocations system view --- doc/src/sgml/system-views.sgml | 68 +++++++++++++++++++ src/backend/catalog/system_views.sql | 8 +++ src/backend/storage/ipc/dsm_registry.c | 34 ++++++++++ src/include/catalog/pg_proc.dat | 6 ++ .../expected/test_dsm_registry.out | 6 ++ .../sql/test_dsm_registry.sql | 2 + src/test/regress/expected/rules.out | 3 + 7 files changed, 127 insertions(+) diff --git a/doc/src/sgml/system-views.sgml b/doc/src/sgml/system-views.sgml index b58c52ea50f..e41a7b5745f 100644 --- a/doc/src/sgml/system-views.sgml +++ b/doc/src/sgml/system-views.sgml @@ -186,6 +186,11 @@ NUMA node mappings for shared memory allocations + + pg_dsm_registry_allocations + DSM segment allocations registered via the DSM registry + + pg_stats planner statistics @@ -4146,6 +4151,69 @@ SELECT * FROM pg_locks pl LEFT JOIN pg_prepared_xacts ppx + + <structname>pg_dsm_registry_allocations</structname> + + + pg_dsm_registry_allocations + + + + The pg_dsm_registry_allocations view shows current + allocations registered in the dynamic shared memory (DSM) registry. This + includes all DSM segments that have been allocated and tracked by + PostgreSQL during the server's operation. + + + + This view is useful for monitoring DSM usage by extensions or internal + components using dynamic shared memory segments. + + + + <structname>pg_dsm_registry_allocations</structname> Columns + + + + + Column Type + + + Description + + + + + + + + name text + + + The name of the DSM allocation as registered in the DSM registry. + + + + + + size int8 + + + The size of the allocated dynamic shared memory segment in bytes. + + + + +
+ + + By default, access to the pg_dsm_registry_allocations + view is restricted to superusers or roles granted the + pg_read_all_stats role due to the sensitive nature + of dynamic shared memory usage information. + + + <structname>pg_stats</structname> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 08f780a2e63..64e62732f18 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -666,6 +666,14 @@ GRANT SELECT ON pg_shmem_allocations_numa TO pg_read_all_stats; REVOKE EXECUTE ON FUNCTION pg_get_shmem_allocations_numa() FROM PUBLIC; GRANT EXECUTE ON FUNCTION pg_get_shmem_allocations_numa() TO pg_read_all_stats; +CREATE VIEW pg_dsm_registry_allocations AS +SELECT * FROM pg_get_dsm_registry_allocations(); + +REVOKE ALL ON pg_dsm_registry_allocations FROM PUBLIC; +GRANT SELECT ON pg_dsm_registry_allocations TO pg_read_all_stats; +REVOKE EXECUTE ON FUNCTION pg_get_dsm_registry_allocations() FROM PUBLIC; +GRANT EXECUTE ON FUNCTION pg_get_dsm_registry_allocations() TO pg_read_all_stats; + CREATE VIEW pg_backend_memory_contexts AS SELECT * FROM pg_get_backend_memory_contexts(); diff --git a/src/backend/storage/ipc/dsm_registry.c b/src/backend/storage/ipc/dsm_registry.c index 1d4fd31ffed..0650c70e173 100644 --- a/src/backend/storage/ipc/dsm_registry.c +++ b/src/backend/storage/ipc/dsm_registry.c @@ -26,10 +26,12 @@ #include "postgres.h" +#include "funcapi.h" #include "lib/dshash.h" #include "storage/dsm_registry.h" #include "storage/lwlock.h" #include "storage/shmem.h" +#include "utils/builtins.h" #include "utils/memutils.h" typedef struct DSMRegistryCtxStruct @@ -198,3 +200,35 @@ GetNamedDSMSegment(const char *name, size_t size, return ret; } + +Datum +pg_get_dsm_registry_allocations(PG_FUNCTION_ARGS) +{ + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + DSMRegistryEntry *entry; + dshash_seq_status status; + + InitMaterializedSRF(fcinfo, MAT_SRF_USE_EXPECTED_DESC); + + /* Ensure DSM registry initialized */ + init_dsm_registry(); + + /* Use non-exclusive access to avoid blocking other backends */ + dshash_seq_init(&status, dsm_registry_table, false); + + while ((entry = dshash_seq_next(&status)) != NULL) + { + Datum values[2]; + bool nulls[2] = {false, false}; + + values[0] = CStringGetTextDatum(entry->name); + values[1] = Int64GetDatum(entry->size); + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, + values, nulls); + } + + dshash_seq_term(&status); + + return (Datum) 0; +} diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index d3d28a263fa..bef92be8250 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -8541,6 +8541,12 @@ proallargtypes => '{text,int8,int8,int8}', proargmodes => '{o,o,o,o}', proargnames => '{name,off,size,allocated_size}', prosrc => 'pg_get_shmem_allocations' }, +{ oid => '6062', descr => 'dsm registry allocations', + proname => 'pg_get_dsm_registry_allocations', prorows => '50', proretset => 't', + provolatile => 'v', prorettype => 'record', proargtypes => '', + proallargtypes => '{text,int8}', proargmodes => '{o,o}', + proargnames => '{name,size}', + prosrc => 'pg_get_dsm_registry_allocations' }, { oid => '4099', descr => 'Is NUMA support available?', proname => 'pg_numa_available', provolatile => 's', prorettype => 'bool', diff --git a/src/test/modules/test_dsm_registry/expected/test_dsm_registry.out b/src/test/modules/test_dsm_registry/expected/test_dsm_registry.out index 8ffbd343a05..3c279378b5b 100644 --- a/src/test/modules/test_dsm_registry/expected/test_dsm_registry.out +++ b/src/test/modules/test_dsm_registry/expected/test_dsm_registry.out @@ -12,3 +12,9 @@ SELECT get_val_in_shmem(); 1236 (1 row) +SELECT size > 0 FROM pg_dsm_registry_allocations WHERE name = 'test_dsm_registry'; + ?column? +---------- + t +(1 row) + diff --git a/src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql b/src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql index b3351be0a16..d27ee2e6a1a 100644 --- a/src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql +++ b/src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql @@ -2,3 +2,5 @@ CREATE EXTENSION test_dsm_registry; SELECT set_val_in_shmem(1236); \c SELECT get_val_in_shmem(); + +SELECT size > 0 FROM pg_dsm_registry_allocations WHERE name = 'test_dsm_registry'; diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 6cf828ca8d0..893c5b2b933 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1340,6 +1340,9 @@ pg_cursors| SELECT name, is_scrollable, creation_time FROM pg_cursor() c(name, statement, is_holdable, is_binary, is_scrollable, creation_time); +pg_dsm_registry_allocations| SELECT name, + size + FROM pg_get_dsm_registry_allocations() pg_get_dsm_registry_allocations(name, size); pg_file_settings| SELECT sourcefile, sourceline, seqno, -- 2.49.0