10 files changed, 170 insertions, 0 deletions
diff --git a/src/test/modules/Makefile b/src/test/modules/Makefile
index 5d33fa6a9a8..f656032589d 100644
--- a/src/test/modules/Makefile
+++ b/src/test/modules/Makefile
@@ -18,6 +18,7 @@ SUBDIRS = \
 		  test_custom_rmgrs \
 		  test_ddl_deparse \
 		  test_dsa \
+		  test_dsm_registry \
 		  test_extensions \
 		  test_ginpostinglist \
 		  test_integerset \
diff --git a/src/test/modules/meson.build b/src/test/modules/meson.build
index 00ff1d77d19..2c3b8d73bce 100644
--- a/src/test/modules/meson.build
+++ b/src/test/modules/meson.build
@@ -15,6 +15,7 @@ subdir('test_copy_callbacks')
 subdir('test_custom_rmgrs')
 subdir('test_ddl_deparse')
 subdir('test_dsa')
+subdir('test_dsm_registry')
 subdir('test_extensions')
 subdir('test_ginpostinglist')
 subdir('test_integerset')
diff --git a/src/test/modules/test_dsm_registry/.gitignore b/src/test/modules/test_dsm_registry/.gitignore
new file mode 100644
index 00000000000..5dcb3ff9723
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/.gitignore
@@ -0,0 +1,4 @@
+# Generated subdirectories
+/log/
+/results/
+/tmp_check/
diff --git a/src/test/modules/test_dsm_registry/Makefile b/src/test/modules/test_dsm_registry/Makefile
new file mode 100644
index 00000000000..b13e99a354f
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/Makefile
@@ -0,0 +1,23 @@
+# src/test/modules/test_dsm_registry/Makefile
+
+MODULE_big = test_dsm_registry
+OBJS = \
+	$(WIN32RES) \
+	test_dsm_registry.o
+PGFILEDESC = "test_dsm_registry - test code for the DSM registry"
+
+EXTENSION = test_dsm_registry
+DATA = test_dsm_registry--1.0.sql
+
+REGRESS = test_dsm_registry
+
+ifdef USE_PGXS
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+subdir = src/test/modules/test_dsm_registry
+top_builddir = ../../../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif
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
new file mode 100644
index 00000000000..8ffbd343a05
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/expected/test_dsm_registry.out
@@ -0,0 +1,14 @@
+CREATE EXTENSION test_dsm_registry;
+SELECT set_val_in_shmem(1236);
+ set_val_in_shmem 
+------------------
+ 
+(1 row)
+
+\c
+SELECT get_val_in_shmem();
+ get_val_in_shmem 
+------------------
+             1236
+(1 row)
+
diff --git a/src/test/modules/test_dsm_registry/meson.build b/src/test/modules/test_dsm_registry/meson.build
new file mode 100644
index 00000000000..a4045fea37e
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/meson.build
@@ -0,0 +1,33 @@
+# Copyright (c) 2024, PostgreSQL Global Development Group
+
+test_dsm_registry_sources = files(
+  'test_dsm_registry.c',
+)
+
+if host_system == 'windows'
+  test_dsm_registry_sources += rc_lib_gen.process(win32ver_rc, extra_args: [
+    '--NAME', 'test_dsm_registry',
+    '--FILEDESC', 'test_dsm_registry - test code for the DSM registry',])
+endif
+
+test_dsm_registry = shared_module('test_dsm_registry',
+  test_dsm_registry_sources,
+  kwargs: pg_test_mod_args,
+)
+test_install_libs += test_dsm_registry
+
+test_install_data += files(
+  'test_dsm_registry.control',
+  'test_dsm_registry--1.0.sql',
+)
+
+tests += {
+  'name': 'test_dsm_registry',
+  'sd': meson.current_source_dir(),
+  'bd': meson.current_build_dir(),
+  'regress': {
+    'sql': [
+      'test_dsm_registry',
+    ],
+  },
+}
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
new file mode 100644
index 00000000000..b3351be0a16
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql
@@ -0,0 +1,4 @@
+CREATE EXTENSION test_dsm_registry;
+SELECT set_val_in_shmem(1236);
+\c
+SELECT get_val_in_shmem();
diff --git a/src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql b/src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql
new file mode 100644
index 00000000000..8c55b0919b1
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql
@@ -0,0 +1,10 @@
+/* src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql */
+
+-- complain if script is sourced in psql, rather than via CREATE EXTENSION
+\echo Use "CREATE EXTENSION test_dsm_registry" to load this file. \quit
+
+CREATE FUNCTION set_val_in_shmem(val INT) RETURNS VOID
+	AS 'MODULE_PATHNAME' LANGUAGE C;
+
+CREATE FUNCTION get_val_in_shmem() RETURNS INT
+	AS 'MODULE_PATHNAME' LANGUAGE C;
diff --git a/src/test/modules/test_dsm_registry/test_dsm_registry.c b/src/test/modules/test_dsm_registry/test_dsm_registry.c
new file mode 100644
index 00000000000..96eaa850bfa
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/test_dsm_registry.c
@@ -0,0 +1,76 @@
+/*--------------------------------------------------------------------------
+ *
+ * test_dsm_registry.c
+ *	  Test the dynamic shared memory registry.
+ *
+ * Copyright (c) 2024, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *		src/test/modules/test_dsm_registry/test_dsm_registry.c
+ *
+ * -------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "fmgr.h"
+#include "storage/dsm_registry.h"
+#include "storage/lwlock.h"
+
+PG_MODULE_MAGIC;
+
+typedef struct TestDSMRegistryStruct
+{
+	int			val;
+	LWLock		lck;
+} TestDSMRegistryStruct;
+
+static TestDSMRegistryStruct *tdr_state;
+
+static void
+tdr_init_shmem(void *ptr)
+{
+	TestDSMRegistryStruct *state = (TestDSMRegistryStruct *) ptr;
+
+	LWLockInitialize(&state->lck, LWLockNewTrancheId());
+	state->val = 0;
+}
+
+static void
+tdr_attach_shmem(void)
+{
+	bool		found;
+
+	tdr_state = GetNamedDSMSegment("test_dsm_registry",
+								   sizeof(TestDSMRegistryStruct),
+								   tdr_init_shmem,
+								   &found);
+	LWLockRegisterTranche(tdr_state->lck.tranche, "test_dsm_registry");
+}
+
+PG_FUNCTION_INFO_V1(set_val_in_shmem);
+Datum
+set_val_in_shmem(PG_FUNCTION_ARGS)
+{
+	tdr_attach_shmem();
+
+	LWLockAcquire(&tdr_state->lck, LW_EXCLUSIVE);
+	tdr_state->val = PG_GETARG_UINT32(0);
+	LWLockRelease(&tdr_state->lck);
+
+	PG_RETURN_VOID();
+}
+
+PG_FUNCTION_INFO_V1(get_val_in_shmem);
+Datum
+get_val_in_shmem(PG_FUNCTION_ARGS)
+{
+	int			ret;
+
+	tdr_attach_shmem();
+
+	LWLockAcquire(&tdr_state->lck, LW_SHARED);
+	ret = tdr_state->val;
+	LWLockRelease(&tdr_state->lck);
+
+	PG_RETURN_UINT32(ret);
+}
diff --git a/src/test/modules/test_dsm_registry/test_dsm_registry.control b/src/test/modules/test_dsm_registry/test_dsm_registry.control
new file mode 100644
index 00000000000..813f099889b
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/test_dsm_registry.control
@@ -0,0 +1,4 @@
+comment = 'Test code for the DSM registry'
+default_version = '1.0'
+module_pathname = '$libdir/test_dsm_registry'
+relocatable = true