Add helper UDFs to inspect object dependencies (#5293)

- citus_get_all_dependencies_for_object: emulate what Citus
                                         would qualify as
					 dependency when adding
					 a new node
- citus_get_dependencies_for_object: emulate what Citus would qualify
				     as dependency when creating an
				     object

Example use:
```SQL
-- find all the depedencies of table test
SELECT
	pg_identify_object(t.classid, t.objid, t.objsubid)
FROM
	(SELECT * FROM pg_get_object_address('table', '{test}', '{}')) as addr
JOIN LATERAL
	citus_get_all_dependencies_for_object(addr.classid, addr.objid, addr.objsubid) as t(classid oid, objid oid, objsubid int)
ON TRUE
	ORDER BY 1;
```

src/backend/distributed/metadata/dependency.c

@@ -207,6 +207,31 @@ GetDependenciesForObject(const ObjectAddress *target)
 }
 
 
+/*
+ * GetAllDependenciesForObject returns a list of all the ObjectAddresses to be
+ * created in order before the target object could safely be created on a
+ * worker. As a caller, you probably need GetDependenciesForObject() which
+ * eliminates already distributed objects from the returned list.
+ *
+ * Some of the object might already be created on a worker. It should be created
+ * in an idempotent way.
+ */
+List *
+GetAllDependenciesForObject(const ObjectAddress *target)
+{
+	ObjectAddressCollector collector = { 0 };
+	InitObjectAddressCollector(&collector);
+
+	RecurseObjectDependencies(*target,
+							  &ExpandCitusSupportedTypes,
+							  &FollowAllSupportedDependencies,
+							  &ApplyAddToDependencyList,
+							  &collector);
+
+	return collector.dependencyList;
+}
+
+
 /*
  * OrderObjectAddressListInDependencyOrder given a list of ObjectAddresses return a new
  * list of the same ObjectAddresses ordered on dependency order where dependencies

src/backend/distributed/test/dependency.c

@@ -0,0 +1,113 @@
+/*-------------------------------------------------------------------------
+ *
+ * test/src/dependency.c
+ *
+ * This file contains functions to exercise dependency resolution for objects.
+ *
+ * Copyright (c) Citus Data, Inc.
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+#include "c.h"
+#include "fmgr.h"
+
+#include "distributed/listutils.h"
+#include "distributed/metadata/dependency.h"
+#include "distributed/metadata_cache.h"
+#include "distributed/tuplestore.h"
+
+
+PG_FUNCTION_INFO_V1(citus_get_all_dependencies_for_object);
+PG_FUNCTION_INFO_V1(citus_get_dependencies_for_object);
+
+
+/*
+ * citus_get_all_dependencies_for_object(classid oid, objid oid, objsubid int)
+ *
+ * citus_get_all_dependencies_for_object gets an object and returns all of its
+ * dependencies irrespective of whether the dependencies are already distributed
+ * or not.
+ *
+ * This is to emulate what Citus would qualify as dependency when adding a new
+ * node.
+ */
+Datum
+citus_get_all_dependencies_for_object(PG_FUNCTION_ARGS)
+{
+	CheckCitusVersion(ERROR);
+
+	Oid classid = PG_GETARG_OID(0);
+	Oid objid = PG_GETARG_OID(1);
+	int32 objsubid = PG_GETARG_INT32(2);
+
+	TupleDesc tupleDescriptor = NULL;
+	Tuplestorestate *tupleStore = SetupTuplestore(fcinfo, &tupleDescriptor);
+
+	ObjectAddress address = { 0 };
+	ObjectAddressSubSet(address, classid, objid, objsubid);
+
+	List *dependencies = GetAllDependenciesForObject(&address);
+	ObjectAddress *dependency = NULL;
+	foreach_ptr(dependency, dependencies)
+	{
+		Datum values[3];
+		bool isNulls[3];
+
+		memset(values, 0, sizeof(values));
+		memset(isNulls, 0, sizeof(isNulls));
+
+		values[0] = ObjectIdGetDatum(dependency->classId);
+		values[1] = ObjectIdGetDatum(dependency->objectId);
+		values[2] = Int32GetDatum(dependency->objectSubId);
+
+		tuplestore_putvalues(tupleStore, tupleDescriptor, values, isNulls);
+	}
+
+	PG_RETURN_VOID();
+}
+
+
+/*
+ * citus_get_dependencies_for_object(classid oid, objid oid, objsubid int)
+ *
+ * citus_get_dependencies_for_object gets an object and returns all of its
+ * dependencies that are not already distributed.
+ *
+ * This is to emulate what Citus would qualify as dependency when creating
+ * a new object.
+ */
+Datum
+citus_get_dependencies_for_object(PG_FUNCTION_ARGS)
+{
+	CheckCitusVersion(ERROR);
+
+	Oid classid = PG_GETARG_OID(0);
+	Oid objid = PG_GETARG_OID(1);
+	int32 objsubid = PG_GETARG_INT32(2);
+
+	TupleDesc tupleDescriptor = NULL;
+	Tuplestorestate *tupleStore = SetupTuplestore(fcinfo, &tupleDescriptor);
+
+	ObjectAddress address = { 0 };
+	ObjectAddressSubSet(address, classid, objid, objsubid);
+
+	List *dependencies = GetDependenciesForObject(&address);
+	ObjectAddress *dependency = NULL;
+	foreach_ptr(dependency, dependencies)
+	{
+		Datum values[3];
+		bool isNulls[3];
+
+		memset(values, 0, sizeof(values));
+		memset(isNulls, 0, sizeof(isNulls));
+
+		values[0] = ObjectIdGetDatum(dependency->classId);
+		values[1] = ObjectIdGetDatum(dependency->objectId);
+		values[2] = Int32GetDatum(dependency->objectSubId);
+
+		tuplestore_putvalues(tupleStore, tupleDescriptor, values, isNulls);
+	}
+
+	PG_RETURN_VOID();
+}

src/include/distributed/metadata/dependency.h

@@ -19,6 +19,7 @@
 
 extern List * GetUniqueDependenciesList(List *objectAddressesList);
 extern List * GetDependenciesForObject(const ObjectAddress *target);
+extern List * GetAllDependenciesForObject(const ObjectAddress *target);
 extern List * OrderObjectAddressListInDependencyOrder(List *objectAddressList);
 extern bool SupportedDependencyByCitus(const ObjectAddress *address);
 extern List * GetPgDependTuplesForDependingObjects(Oid targetObjectClassId,

src/test/regress/expected/object_propagation_debug.out

@@ -0,0 +1,102 @@
+CREATE SCHEMA "object prop";
+SET search_path TO "object prop";
+CREATE OR REPLACE FUNCTION citus_get_all_dependencies_for_object(classid oid, objid oid, objsubid int)
+    RETURNS SETOF RECORD
+    LANGUAGE C STRICT
+    AS 'citus', $$citus_get_all_dependencies_for_object$$;
+COMMENT ON FUNCTION citus_get_all_dependencies_for_object(classid oid, objid oid, objsubid int)
+IS 'emulate what Citus would qualify as dependency when adding a new node';
+CREATE OR REPLACE FUNCTION citus_get_dependencies_for_object(classid oid, objid oid, objsubid int)
+    RETURNS SETOF RECORD
+    LANGUAGE C STRICT
+    AS 'citus', $$citus_get_dependencies_for_object$$;
+COMMENT ON FUNCTION citus_get_dependencies_for_object(classid oid, objid oid, objsubid int)
+IS 'emulate what Citus would qualify as dependency when creating the object';
+create type t1 as (a int);
+create table test(a int, b t1);
+SELECT create_distributed_table('test', 'a');
+ create_distributed_table
+---------------------------------------------------------------------
+
+(1 row)
+
+CREATE VIEW v1 AS SELECT * FROM test;
+-- find all the dependencies of table test
+SELECT
+	pg_identify_object(t.classid, t.objid, t.objsubid)
+FROM
+	(SELECT * FROM pg_get_object_address('table', '{test}', '{}')) as addr
+JOIN LATERAL
+	citus_get_all_dependencies_for_object(addr.classid, addr.objid, addr.objsubid) as t(classid oid, objid oid, objsubid int)
+ON TRUE
+	ORDER BY 1;
+                      pg_identify_object
+---------------------------------------------------------------------
+ ("composite type","""object prop""",t1,"""object prop"".t1")
+ (schema,,"""object prop""","""object prop""")
+ (type,"""object prop""",t1,"""object prop"".t1")
+(3 rows)
+
+-- find all the dependencies of view v1
+SELECT
+	pg_identify_object(t.classid, t.objid, t.objsubid)
+FROM
+	(SELECT * FROM pg_get_object_address('view', '{v1}', '{}')) as addr
+JOIN LATERAL
+	citus_get_all_dependencies_for_object(addr.classid, addr.objid, addr.objsubid) as t(classid oid, objid oid, objsubid int)
+ON TRUE
+	ORDER BY 1;
+                      pg_identify_object
+---------------------------------------------------------------------
+ ("composite type","""object prop""",t1,"""object prop"".t1")
+ (schema,,"""object prop""","""object prop""")
+ (type,"""object prop""",t1,"""object prop"".t1")
+(3 rows)
+
+-- find all the dependencies of type t1
+SELECT
+	pg_identify_object(t.classid, t.objid, t.objsubid)
+FROM
+	(SELECT * FROM pg_get_object_address('type', '{t1}', '{}')) as addr
+JOIN LATERAL
+	citus_get_all_dependencies_for_object(addr.classid, addr.objid, addr.objsubid) as t(classid oid, objid oid, objsubid int)
+ON TRUE
+	ORDER BY 1;
+                      pg_identify_object
+---------------------------------------------------------------------
+ ("composite type","""object prop""",t1,"""object prop"".t1")
+ (schema,,"""object prop""","""object prop""")
+(2 rows)
+
+-- find non-distributed dependencies of table test
+SELECT
+	pg_identify_object(t.classid, t.objid, t.objsubid)
+FROM
+	(SELECT * FROM pg_get_object_address('table', '{test}', '{}')) as addr
+JOIN LATERAL
+	citus_get_dependencies_for_object(addr.classid, addr.objid, addr.objsubid) as t(classid oid, objid oid, objsubid int)
+ON TRUE
+	ORDER BY 1;
+ pg_identify_object
+---------------------------------------------------------------------
+(0 rows)
+
+-- find non-distributed dependencies of the local table test2
+CREATE SCHEMA objectprop2;
+create table objectprop2.test2(a int, b t1);
+SET search_path TO objectprop2;
+SELECT
+	pg_identify_object(t.classid, t.objid, t.objsubid)
+FROM
+	(SELECT * FROM pg_get_object_address('table', '{test2}', '{}')) as addr
+JOIN LATERAL
+	"object prop".citus_get_dependencies_for_object(addr.classid, addr.objid, addr.objsubid) as t(classid oid, objid oid, objsubid int)
+ON TRUE
+	ORDER BY 1;
+        pg_identify_object
+---------------------------------------------------------------------
+ (schema,,objectprop2,objectprop2)
+(1 row)
+
+SET client_min_messages TO ERROR;
+DROP SCHEMA  "object prop", objectprop2 CASCADE;

src/test/regress/multi_schedule

@@ -98,6 +98,8 @@ test: binary_protocol
 test: alter_table_set_access_method
 test: alter_distributed_table
 test: issue_5248
+test: object_propagation_debug
+
 
 # ---------
 # test that no tests leaked intermediate results. This should always be last

src/test/regress/sql/object_propagation_debug.sql

@@ -0,0 +1,77 @@
+CREATE SCHEMA "object prop";
+SET search_path TO "object prop";
+
+CREATE OR REPLACE FUNCTION citus_get_all_dependencies_for_object(classid oid, objid oid, objsubid int)
+    RETURNS SETOF RECORD
+    LANGUAGE C STRICT
+    AS 'citus', $$citus_get_all_dependencies_for_object$$;
+COMMENT ON FUNCTION citus_get_all_dependencies_for_object(classid oid, objid oid, objsubid int)
+IS 'emulate what Citus would qualify as dependency when adding a new node';
+
+CREATE OR REPLACE FUNCTION citus_get_dependencies_for_object(classid oid, objid oid, objsubid int)
+    RETURNS SETOF RECORD
+    LANGUAGE C STRICT
+    AS 'citus', $$citus_get_dependencies_for_object$$;
+COMMENT ON FUNCTION citus_get_dependencies_for_object(classid oid, objid oid, objsubid int)
+IS 'emulate what Citus would qualify as dependency when creating the object';
+
+create type t1 as (a int);
+create table test(a int, b t1);
+SELECT create_distributed_table('test', 'a');
+CREATE VIEW v1 AS SELECT * FROM test;
+
+-- find all the dependencies of table test
+SELECT
+	pg_identify_object(t.classid, t.objid, t.objsubid)
+FROM
+	(SELECT * FROM pg_get_object_address('table', '{test}', '{}')) as addr
+JOIN LATERAL
+	citus_get_all_dependencies_for_object(addr.classid, addr.objid, addr.objsubid) as t(classid oid, objid oid, objsubid int)
+ON TRUE
+	ORDER BY 1;
+
+-- find all the dependencies of view v1
+SELECT
+	pg_identify_object(t.classid, t.objid, t.objsubid)
+FROM
+	(SELECT * FROM pg_get_object_address('view', '{v1}', '{}')) as addr
+JOIN LATERAL
+	citus_get_all_dependencies_for_object(addr.classid, addr.objid, addr.objsubid) as t(classid oid, objid oid, objsubid int)
+ON TRUE
+	ORDER BY 1;
+
+-- find all the dependencies of type t1
+SELECT
+	pg_identify_object(t.classid, t.objid, t.objsubid)
+FROM
+	(SELECT * FROM pg_get_object_address('type', '{t1}', '{}')) as addr
+JOIN LATERAL
+	citus_get_all_dependencies_for_object(addr.classid, addr.objid, addr.objsubid) as t(classid oid, objid oid, objsubid int)
+ON TRUE
+	ORDER BY 1;
+
+-- find non-distributed dependencies of table test
+SELECT
+	pg_identify_object(t.classid, t.objid, t.objsubid)
+FROM
+	(SELECT * FROM pg_get_object_address('table', '{test}', '{}')) as addr
+JOIN LATERAL
+	citus_get_dependencies_for_object(addr.classid, addr.objid, addr.objsubid) as t(classid oid, objid oid, objsubid int)
+ON TRUE
+	ORDER BY 1;
+
+-- find non-distributed dependencies of the local table test2
+CREATE SCHEMA objectprop2;
+create table objectprop2.test2(a int, b t1);
+SET search_path TO objectprop2;
+SELECT
+	pg_identify_object(t.classid, t.objid, t.objsubid)
+FROM
+	(SELECT * FROM pg_get_object_address('table', '{test2}', '{}')) as addr
+JOIN LATERAL
+	"object prop".citus_get_dependencies_for_object(addr.classid, addr.objid, addr.objsubid) as t(classid oid, objid oid, objsubid int)
+ON TRUE
+	ORDER BY 1;
+
+SET client_min_messages TO ERROR;
+DROP SCHEMA  "object prop", objectprop2 CASCADE;