Add SQL-callable pg_get_object_address

This allows access to get_object_address from SQL, which is useful to
obtain OID addressing information from data equivalent to that emitted
by the parser.  This is necessary infrastructure of a project to let
replication systems propagate object dropping events to remote servers,
where the schema might be different than the server originating the
DROP.

This patch also adds support for OBJECT_DEFAULT to get_object_address;
that is, it is now possible to refer to a column's default value.

Catalog version bumped due to the new function.

Reviewed by Stephen Frost, Heikki Linnakangas, Robert Haas, Andres
Freund, Abhijit Menon-Sen, Adam Brightwell.

src/backend/commands/event_trigger.c

@@ -1055,6 +1055,7 @@ EventTriggerSupportsObjectType(ObjectType obtype)
 		case OBJECT_COLUMN:
 		case OBJECT_COLLATION:
 		case OBJECT_CONVERSION:
+		case OBJECT_DEFAULT:
 		case OBJECT_DOMAIN:
 		case OBJECT_DOMCONSTRAINT:
 		case OBJECT_EXTENSION:

src/backend/parser/parse_type.c

@@ -705,13 +705,11 @@ pts_error_callback(void *arg)
 /*
  * Given a string that is supposed to be a SQL-compatible type declaration,
  * such as "int4" or "integer" or "character varying(32)", parse
- * the string and convert it to a type OID and type modifier.
- * If missing_ok is true, InvalidOid is returned rather than raising an error
- * when the type name is not found.
+ * the string and return the result as a TypeName.
+ * If the string cannot be parsed as a type, an error is raised.
  */
-void
-parseTypeString(const char *str, Oid *typeid_p, int32 *typmod_p,
-				bool missing_ok)
+TypeName *
+typeStringToTypeName(const char *str)
 {
 	StringInfoData buf;
 	List	   *raw_parsetree_list;
@@ -720,7 +718,6 @@ parseTypeString(const char *str, Oid *typeid_p, int32 *typmod_p,
 	TypeCast   *typecast;
 	TypeName   *typeName;
 	ErrorContextCallback ptserrcontext;
-	Type		tup;
 
 	/* make sure we give useful error for empty input */
 	if (strspn(str, " \t\n\r\f") == strlen(str))
@@ -779,6 +776,7 @@ parseTypeString(const char *str, Oid *typeid_p, int32 *typmod_p,
 		typecast->arg == NULL ||
 		!IsA(typecast->arg, A_Const))
 		goto fail;
+
 	typeName = typecast->typeName;
 	if (typeName == NULL ||
 		!IsA(typeName, TypeName))
@@ -786,6 +784,31 @@ parseTypeString(const char *str, Oid *typeid_p, int32 *typmod_p,
 	if (typeName->setof)
 		goto fail;
 
+	pfree(buf.data);
+
+	return typeName;
+
+fail:
+	ereport(ERROR,
+			(errcode(ERRCODE_SYNTAX_ERROR),
+			 errmsg("invalid type name \"%s\"", str)));
+}
+
+/*
+ * Given a string that is supposed to be a SQL-compatible type declaration,
+ * such as "int4" or "integer" or "character varying(32)", parse
+ * the string and convert it to a type OID and type modifier.
+ * If missing_ok is true, InvalidOid is returned rather than raising an error
+ * when the type name is not found.
+ */
+void
+parseTypeString(const char *str, Oid *typeid_p, int32 *typmod_p, bool missing_ok)
+{
+	TypeName   *typeName;
+	Type		tup;
+
+	typeName = typeStringToTypeName(str);
+
 	tup = LookupTypeName(NULL, typeName, typmod_p, missing_ok);
 	if (tup == NULL)
 	{
@@ -808,13 +831,4 @@ parseTypeString(const char *str, Oid *typeid_p, int32 *typmod_p,
 		*typeid_p = HeapTupleGetOid(tup);
 		ReleaseSysCache(tup);
 	}
-
-	pfree(buf.data);
-
-	return;
-
-fail:
-	ereport(ERROR,
-			(errcode(ERRCODE_SYNTAX_ERROR),
-			 errmsg("invalid type name \"%s\"", str)));
 }

src/include/catalog/catversion.h

@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	201412232
+#define CATALOG_VERSION_NO	201412233
 
 #endif

src/include/catalog/objectaddress.h

@@ -55,6 +55,7 @@ extern HeapTuple get_catalog_object_by_oid(Relation catalog,
 extern char *getObjectDescription(const ObjectAddress *object);
 extern char *getObjectDescriptionOids(Oid classid, Oid objid);
 
+extern int read_objtype_from_string(const char *objtype);
 extern char *getObjectTypeDescription(const ObjectAddress *object);
 extern char *getObjectIdentity(const ObjectAddress *address);
 

src/include/catalog/pg_proc.h

@@ -3036,6 +3036,9 @@ DESCR("get identification of SQL object");
 DATA(insert OID = 3839 (  pg_identify_object		PGNSP PGUID 12 1 0 0 0 f f f f t f s 3 0 2249 "26 26 23" "{26,26,23,25,25,25,25}" "{i,i,i,o,o,o,o}" "{classid,objid,subobjid,type,schema,name,identity}" _null_ pg_identify_object _null_ _null_ _null_ ));
 DESCR("get machine-parseable identification of SQL object");
 
+DATA(insert OID = 3954 (  pg_get_object_address    PGNSP PGUID 12 1 0 0 0 f f f f t f s 3 0 2249 "25 1009 1009" "{25,1009,1009,26,26,23}" "{i,i,i,o,o,o}" "{type,name,args,classid,objid,subobjid}" _null_ pg_get_object_address _null_ _null_ _null_ ));
+DESCR("get OID-based object address from name/args arrays");
+
 DATA(insert OID = 2079 (  pg_table_is_visible		PGNSP PGUID 12 10 0 0 0 f f f f t f s 1 0 16 "26" _null_ _null_ _null_ _null_ pg_table_is_visible _null_ _null_ _null_ ));
 DESCR("is table visible in search path?");
 DATA(insert OID = 2080 (  pg_type_is_visible		PGNSP PGUID 12 10 0 0 0 f f f f t f s 1 0 16 "26" _null_ _null_ _null_ _null_ pg_type_is_visible _null_ _null_ _null_ ));

src/include/nodes/parsenodes.h

@@ -1185,6 +1185,7 @@ typedef enum ObjectType
 	OBJECT_COLLATION,
 	OBJECT_CONVERSION,
 	OBJECT_DATABASE,
+	OBJECT_DEFAULT,
 	OBJECT_DOMAIN,
 	OBJECT_DOMCONSTRAINT,
 	OBJECT_EVENT_TRIGGER,

src/include/parser/parse_type.h

@@ -47,6 +47,7 @@ extern Datum stringTypeDatum(Type tp, char *string, int32 atttypmod);
 
 extern Oid	typeidTypeRelid(Oid type_id);
 
+extern TypeName *typeStringToTypeName(const char *str);
 extern void parseTypeString(const char *str, Oid *typeid_p, int32 *typmod_p, bool missing_ok);
 
 #define ISCOMPLEX(typeid) (typeidTypeRelid(typeid) != InvalidOid)

src/include/utils/builtins.h

@@ -1201,6 +1201,9 @@ extern Datum pg_last_committed_xact(PG_FUNCTION_ARGS);
 extern Datum pg_describe_object(PG_FUNCTION_ARGS);
 extern Datum pg_identify_object(PG_FUNCTION_ARGS);
 
+/* catalog/objectaddress.c */
+extern Datum pg_get_object_address(PG_FUNCTION_ARGS);
+
 /* commands/constraint.c */
 extern Datum unique_key_recheck(PG_FUNCTION_ARGS);
 

src/test/regress/parallel_schedule

@@ -83,7 +83,7 @@ test: select_into select_distinct select_distinct_on select_implicit select_havi
 # ----------
 # Another group of parallel tests
 # ----------
-test: brin gin gist spgist privileges security_label collate matview lock replica_identity rowsecurity
+test: brin gin gist spgist privileges security_label collate matview lock replica_identity rowsecurity object_address
 
 # ----------
 # Another group of parallel tests

src/test/regress/serial_schedule

@@ -106,6 +106,7 @@ test: matview
 test: lock
 test: replica_identity
 test: rowsecurity
+test: object_address
 test: alter_generic
 test: misc
 test: psql

src/test/regress/sql/object_address.sql

+--
+-- Test for pg_get_object_address
+--
+
+-- Clean up in case a prior regression run failed
+SET client_min_messages TO 'warning';
+
+DROP ROLE IF EXISTS regtest_addr_user;
+
+CREATE USER regtest_addr_user;
+
+-- Test generic object addressing/identification functions
+CREATE SCHEMA addr_nsp;
+SET search_path TO 'addr_nsp';
+CREATE FOREIGN DATA WRAPPER addr_fdw;
+CREATE SERVER addr_fserv FOREIGN DATA WRAPPER addr_fdw;
+CREATE TEXT SEARCH DICTIONARY addr_ts_dict (template=simple);
+CREATE TEXT SEARCH CONFIGURATION addr_ts_conf (copy=english);
+CREATE TEXT SEARCH TEMPLATE addr_ts_temp (lexize=dsimple_lexize);
+CREATE TEXT SEARCH PARSER addr_ts_prs
+    (start = prsd_start, gettoken = prsd_nexttoken, end = prsd_end, lextypes = prsd_lextype);
+CREATE TABLE addr_nsp.gentable (
+	a serial primary key CONSTRAINT a_chk CHECK (a > 0),
+	b text DEFAULT 'hello');
+CREATE VIEW addr_nsp.genview AS SELECT * from addr_nsp.gentable;
+CREATE MATERIALIZED VIEW addr_nsp.genmatview AS SELECT * FROM addr_nsp.gentable;
+CREATE TYPE addr_nsp.gencomptype AS (a int);
+CREATE TYPE addr_nsp.genenum AS ENUM ('one', 'two');
+CREATE FOREIGN TABLE addr_nsp.genftable (a int) SERVER addr_fserv;
+CREATE AGGREGATE addr_nsp.genaggr(int4) (sfunc = int4pl, stype = int4);
+CREATE DOMAIN addr_nsp.gendomain AS int4 CONSTRAINT domconstr CHECK (value > 0);
+CREATE FUNCTION addr_nsp.trig() RETURNS TRIGGER LANGUAGE plpgsql AS $$ BEGIN END; $$;
+CREATE TRIGGER t BEFORE INSERT ON addr_nsp.gentable FOR EACH ROW EXECUTE PROCEDURE addr_nsp.trig();
+CREATE POLICY genpol ON addr_nsp.gentable;
+
+CREATE FUNCTION addr_nsp.etrig() RETURNS EVENT_TRIGGER LANGUAGE plpgsql AS $$ BEGIN END; $$;
+CREATE EVENT TRIGGER evttrig ON ddl_command_end EXECUTE PROCEDURE addr_nsp.etrig();
+
+-- test some error cases
+SELECT pg_get_object_address('stone', '{}', '{}');
+SELECT pg_get_object_address('table', '{}', '{}');
+SELECT pg_get_object_address('table', '{NULL}', '{}');
+
+-- unrecognized object types
+DO $$
+DECLARE
+	objtype text;
+BEGIN
+	FOR objtype IN VALUES ('toast table'), ('index column'), ('sequence column'),
+		('toast table column'), ('view column'), ('materialized view column'),
+		('operator of access method'), ('function of access method'),
+		('user mapping')
+	LOOP
+		BEGIN
+			PERFORM pg_get_object_address(objtype, '{one}', '{}');
+		EXCEPTION WHEN invalid_parameter_value THEN
+			RAISE WARNING 'error for %: %', objtype, sqlerrm;
+		END;
+	END LOOP;
+END;
+$$;
+
+DO $$
+DECLARE
+	objtype text;
+	names	text[];
+	args	text[];
+BEGIN
+	FOR objtype IN VALUES
+		('table'), ('index'), ('sequence'), ('view'),
+		('materialized view'), ('foreign table'),
+		('table column'), ('foreign table column'),
+		('aggregate'), ('function'), ('type'), ('cast'),
+		('collation'),
+		('table constraint'), ('domain constraint'), ('conversion'), ('default value'),
+		('operator'), ('operator class'), ('operator family'), ('rule'), ('trigger'),
+		('text search parser'), ('text search dictionary'),
+		('text search template'), ('text search configuration'),
+		('policy')
+	LOOP
+		FOR names IN VALUES ('{eins}'), ('{addr_nsp, zwei}'), ('{eins, zwei, drei}')
+		LOOP
+			FOR args IN VALUES ('{}'), ('{integer}')
+			LOOP
+				BEGIN
+					PERFORM pg_get_object_address(objtype, names, args);
+				EXCEPTION WHEN OTHERS THEN
+						RAISE WARNING 'error for %,%,%: %', objtype, names, args, sqlerrm;
+				END;
+			END LOOP;
+		END LOOP;
+	END LOOP;
+END;
+$$;
+
+-- these object types cannot be qualified names
+SELECT pg_get_object_address('language', '{one}', '{}');
+SELECT pg_get_object_address('language', '{one,two}', '{}');
+SELECT pg_get_object_address('large object', '{123}', '{}');
+SELECT pg_get_object_address('large object', '{123,456}', '{}');
+SELECT pg_get_object_address('large object', '{blargh}', '{}');
+SELECT pg_get_object_address('schema', '{one}', '{}');
+SELECT pg_get_object_address('schema', '{one,two}', '{}');
+SELECT pg_get_object_address('role', '{one}', '{}');
+SELECT pg_get_object_address('role', '{one,two}', '{}');
+SELECT pg_get_object_address('database', '{one}', '{}');
+SELECT pg_get_object_address('database', '{one,two}', '{}');
+SELECT pg_get_object_address('tablespace', '{one}', '{}');
+SELECT pg_get_object_address('tablespace', '{one,two}', '{}');
+SELECT pg_get_object_address('foreign-data wrapper', '{one}', '{}');
+SELECT pg_get_object_address('foreign-data wrapper', '{one,two}', '{}');
+SELECT pg_get_object_address('server', '{one}', '{}');
+SELECT pg_get_object_address('server', '{one,two}', '{}');
+SELECT pg_get_object_address('extension', '{one}', '{}');
+SELECT pg_get_object_address('extension', '{one,two}', '{}');
+SELECT pg_get_object_address('event trigger', '{one}', '{}');
+SELECT pg_get_object_address('event trigger', '{one,two}', '{}');
+
+-- test successful cases
+WITH objects (type, name, args) AS (VALUES
+				('table', '{addr_nsp, gentable}'::text[], '{}'::text[]),
+				('index', '{addr_nsp, gentable_pkey}', '{}'),
+				('sequence', '{addr_nsp, gentable_a_seq}', '{}'),
+				-- toast table
+				('view', '{addr_nsp, genview}', '{}'),
+				('materialized view', '{addr_nsp, genmatview}', '{}'),
+				('foreign table', '{addr_nsp, genftable}', '{}'),
+				('table column', '{addr_nsp, gentable, b}', '{}'),
+				('foreign table column', '{addr_nsp, genftable, a}', '{}'),
+				('aggregate', '{addr_nsp, genaggr}', '{int4}'),
+				('function', '{pg_catalog, pg_identify_object}', '{pg_catalog.oid, pg_catalog.oid, int4}'),
+				('type', '{pg_catalog._int4}', '{}'),
+				('type', '{addr_nsp.gendomain}', '{}'),
+				('type', '{addr_nsp.gencomptype}', '{}'),
+				('type', '{addr_nsp.genenum}', '{}'),
+				('cast', '{int8}', '{int4}'),
+				('collation', '{default}', '{}'),
+				('table constraint', '{addr_nsp, gentable, a_chk}', '{}'),
+				('domain constraint', '{addr_nsp, gendomain, domconstr}', '{}'),
+				('conversion', '{pg_catalog, ascii_to_mic}', '{}'),
+				('default value', '{addr_nsp, gentable, b}', '{}'),
+				('language', '{plpgsql}', '{}'),
+				-- large object
+				('operator', '{+}', '{int4, int4}'),
+				('operator class', '{int4_ops}', '{btree}'),
+				('operator family', '{integer_ops}', '{btree}'),
+				-- operator of access method
+				-- function of access method
+				('rule', '{addr_nsp, genview, _RETURN}', '{}'),
+				('trigger', '{addr_nsp, gentable, t}', '{}'),
+				('schema', '{addr_nsp}', '{}'),
+				('text search parser', '{addr_ts_prs}', '{}'),
+				('text search dictionary', '{addr_ts_dict}', '{}'),
+				('text search template', '{addr_ts_temp}', '{}'),
+				('text search configuration', '{addr_ts_conf}', '{}'),
+				('role', '{regtest_addr_user}', '{}'),
+				-- database
+				-- tablespace
+				('foreign-data wrapper', '{addr_fdw}', '{}'),
+				('server', '{addr_fserv}', '{}'),
+				-- user mapping
+				-- extension
+				('event trigger', '{evttrig}', '{}'),
+				('policy', '{addr_nsp, gentable, genpol}', '{}')
+        )
+SELECT (pg_identify_object(classid, objid, subobjid)).*
+  FROM objects, pg_get_object_address(type, name, args)
+ORDER BY classid, objid;
+
+---
+--- Cleanup resources
+---
+DROP FOREIGN DATA WRAPPER addr_fdw CASCADE;
+
+DROP SCHEMA addr_nsp CASCADE;
+
+DROP USER regtest_addr_user;