Routine usage information schema tables

Several information schema views track dependencies between
functions/procedures and objects used by them.  These had not been
implemented so far because PostgreSQL doesn't track objects used in a
function body.  However, formally, these also show dependencies used
in parameter default expressions, which PostgreSQL does support and
track.  So for the sake of completeness, we might as well add these.
If dependency tracking for function bodies is ever implemented, these
views will automatically work correctly.

Reviewed-by: Erik Rijkers <er@xs4all.nl>
Discussion: https://www.postgresql.org/message-id/flat/ac80fc74-e387-8950-9a31-2560778fc1e3%40enterprisedb.com

2 files changed, 62 insertions, 0 deletions

diff --git a/src/test/regress/expected/create_function_3.out b/src/test/regress/expected/create_function_3.out
index ce508ae1dcc..f25a407fddc 100644
--- a/src/test/regress/expected/create_function_3.out
+++ b/src/test/regress/expected/create_function_3.out
@@ -284,6 +284,44 @@ SELECT routine_name, ordinal_position, parameter_name, parameter_default
 (7 rows)
 
 DROP FUNCTION functest_IS_1(int, int, text), functest_IS_2(int), functest_IS_3(int);
+-- routine usage views
+CREATE FUNCTION functest_IS_4a() RETURNS int LANGUAGE SQL AS 'SELECT 1';
+CREATE FUNCTION functest_IS_4b(x int DEFAULT functest_IS_4a()) RETURNS int LANGUAGE SQL AS 'SELECT x';
+CREATE SEQUENCE functest1;
+CREATE FUNCTION functest_IS_5(x int DEFAULT nextval('functest1'))
+    RETURNS int
+    LANGUAGE SQL
+    AS 'SELECT x';
+SELECT r0.routine_name, r1.routine_name
+  FROM information_schema.routine_routine_usage rru
+       JOIN information_schema.routines r0 ON r0.specific_name = rru.specific_name
+       JOIN information_schema.routines r1 ON r1.specific_name = rru.routine_name;
+  routine_name  |  routine_name  
+----------------+----------------
+ functest_is_4b | functest_is_4a
+(1 row)
+
+SELECT routine_name, sequence_name FROM information_schema.routine_sequence_usage;
+ routine_name  | sequence_name 
+---------------+---------------
+ functest_is_5 | functest1
+(1 row)
+
+-- currently empty
+SELECT routine_name, table_name, column_name FROM information_schema.routine_column_usage;
+ routine_name | table_name | column_name 
+--------------+------------+-------------
+(0 rows)
+
+SELECT routine_name, table_name FROM information_schema.routine_table_usage;
+ routine_name | table_name 
+--------------+------------
+(0 rows)
+
+DROP FUNCTION functest_IS_4a CASCADE;
+NOTICE:  drop cascades to function functest_is_4b(integer)
+DROP SEQUENCE functest1 CASCADE;
+NOTICE:  drop cascades to function functest_is_5(integer)
 -- overload
 CREATE FUNCTION functest_B_2(bigint) RETURNS bool LANGUAGE 'sql'
        IMMUTABLE AS 'SELECT $1 > 0';
diff --git a/src/test/regress/sql/create_function_3.sql b/src/test/regress/sql/create_function_3.sql
index bd108a918fb..549b34b4b2a 100644
--- a/src/test/regress/sql/create_function_3.sql
+++ b/src/test/regress/sql/create_function_3.sql
@@ -177,6 +177,30 @@ SELECT routine_name, ordinal_position, parameter_name, parameter_default
 
 DROP FUNCTION functest_IS_1(int, int, text), functest_IS_2(int), functest_IS_3(int);
 
+-- routine usage views
+
+CREATE FUNCTION functest_IS_4a() RETURNS int LANGUAGE SQL AS 'SELECT 1';
+CREATE FUNCTION functest_IS_4b(x int DEFAULT functest_IS_4a()) RETURNS int LANGUAGE SQL AS 'SELECT x';
+
+CREATE SEQUENCE functest1;
+CREATE FUNCTION functest_IS_5(x int DEFAULT nextval('functest1'))
+    RETURNS int
+    LANGUAGE SQL
+    AS 'SELECT x';
+
+SELECT r0.routine_name, r1.routine_name
+  FROM information_schema.routine_routine_usage rru
+       JOIN information_schema.routines r0 ON r0.specific_name = rru.specific_name
+       JOIN information_schema.routines r1 ON r1.specific_name = rru.routine_name;
+SELECT routine_name, sequence_name FROM information_schema.routine_sequence_usage;
+-- currently empty
+SELECT routine_name, table_name, column_name FROM information_schema.routine_column_usage;
+SELECT routine_name, table_name FROM information_schema.routine_table_usage;
+
+DROP FUNCTION functest_IS_4a CASCADE;
+DROP SEQUENCE functest1 CASCADE;
+
+
 -- overload
 CREATE FUNCTION functest_B_2(bigint) RETURNS bool LANGUAGE 'sql'
        IMMUTABLE AS 'SELECT $1 > 0';