Create the catalog infrastructure for foreign-data-wrapper handlers.

Add a fdwhandler column to pg_foreign_data_wrapper, plus HANDLER options
in the CREATE FOREIGN DATA WRAPPER and ALTER FOREIGN DATA WRAPPER commands,
plus pg_dump support for same.  Also invent a new pseudotype fdw_handler
with properties similar to language_handler.

This is split out of the "FDW API" patch for ease of review; it's all stuff
we will certainly need, regardless of any other details of the FDW API.
FDW handler functions will not actually get called yet.

In passing, fix some omissions and infelicities in foreigncmds.c.

Shigeru Hanada, Jan Urbanski, Heikki Linnakangas

2 files changed, 98 insertions, 92 deletions

diff --git a/src/test/regress/expected/foreign_data.out b/src/test/regress/expected/foreign_data.out
index d6c650be14d..780098c2373 100644
--- a/src/test/regress/expected/foreign_data.out
+++ b/src/test/regress/expected/foreign_data.out
@@ -16,11 +16,11 @@ CREATE ROLE unprivileged_role;
 CREATE FOREIGN DATA WRAPPER dummy;
 CREATE FOREIGN DATA WRAPPER postgresql VALIDATOR postgresql_fdw_validator;
 -- At this point we should have 2 built-in wrappers and no servers.
-SELECT fdwname, fdwvalidator::regproc, fdwoptions FROM pg_foreign_data_wrapper ORDER BY 1, 2, 3;
-  fdwname   |       fdwvalidator       | fdwoptions 
-------------+--------------------------+------------
- dummy      | -                        | 
- postgresql | postgresql_fdw_validator | 
+SELECT fdwname, fdwhandler::regproc, fdwvalidator::regproc, fdwoptions FROM pg_foreign_data_wrapper ORDER BY 1, 2, 3;
+  fdwname   | fdwhandler |       fdwvalidator       | fdwoptions 
+------------+------------+--------------------------+------------
+ dummy      | -          | -                        | 
+ postgresql | -          | postgresql_fdw_validator | 
 (2 rows)
 
 SELECT srvname, srvoptions FROM pg_foreign_server;
@@ -38,12 +38,12 @@ CREATE FOREIGN DATA WRAPPER foo VALIDATOR bar;            -- ERROR
 ERROR:  function bar(text[], oid) does not exist
 CREATE FOREIGN DATA WRAPPER foo;
 \dew
-               List of foreign-data wrappers
-    Name    |       Owner       |        Validator         
-------------+-------------------+--------------------------
- dummy      | foreign_data_user | -
- foo        | foreign_data_user | -
- postgresql | foreign_data_user | postgresql_fdw_validator
+                    List of foreign-data wrappers
+    Name    |       Owner       | Handler |        Validator         
+------------+-------------------+---------+--------------------------
+ dummy      | foreign_data_user | -       | -
+ foo        | foreign_data_user | -       | -
+ postgresql | foreign_data_user | -       | postgresql_fdw_validator
 (3 rows)
 
 CREATE FOREIGN DATA WRAPPER foo; -- duplicate
@@ -51,12 +51,12 @@ ERROR:  foreign-data wrapper "foo" already exists
 DROP FOREIGN DATA WRAPPER foo;
 CREATE FOREIGN DATA WRAPPER foo OPTIONS (testing '1');
 \dew+
-                                List of foreign-data wrappers
-    Name    |       Owner       |        Validator         | Access privileges |   Options   
-------------+-------------------+--------------------------+-------------------+-------------
- dummy      | foreign_data_user | -                        |                   | 
- foo        | foreign_data_user | -                        |                   | {testing=1}
- postgresql | foreign_data_user | postgresql_fdw_validator |                   | 
+                                     List of foreign-data wrappers
+    Name    |       Owner       | Handler |        Validator         | Access privileges |   Options   
+------------+-------------------+---------+--------------------------+-------------------+-------------
+ dummy      | foreign_data_user | -       | -                        |                   | 
+ foo        | foreign_data_user | -       | -                        |                   | {testing=1}
+ postgresql | foreign_data_user | -       | postgresql_fdw_validator |                   | 
 (3 rows)
 
 DROP FOREIGN DATA WRAPPER foo;
@@ -64,12 +64,12 @@ CREATE FOREIGN DATA WRAPPER foo OPTIONS (testing '1', testing '2');   -- ERROR
 ERROR:  option "testing" provided more than once
 CREATE FOREIGN DATA WRAPPER foo OPTIONS (testing '1', another '2');
 \dew+
-                                     List of foreign-data wrappers
-    Name    |       Owner       |        Validator         | Access privileges |        Options        
-------------+-------------------+--------------------------+-------------------+-----------------------
- dummy      | foreign_data_user | -                        |                   | 
- foo        | foreign_data_user | -                        |                   | {testing=1,another=2}
- postgresql | foreign_data_user | postgresql_fdw_validator |                   | 
+                                          List of foreign-data wrappers
+    Name    |       Owner       | Handler |        Validator         | Access privileges |        Options        
+------------+-------------------+---------+--------------------------+-------------------+-----------------------
+ dummy      | foreign_data_user | -       | -                        |                   | 
+ foo        | foreign_data_user | -       | -                        |                   | {testing=1,another=2}
+ postgresql | foreign_data_user | -       | postgresql_fdw_validator |                   | 
 (3 rows)
 
 DROP FOREIGN DATA WRAPPER foo;
@@ -80,12 +80,12 @@ HINT:  Must be superuser to create a foreign-data wrapper.
 RESET ROLE;
 CREATE FOREIGN DATA WRAPPER foo VALIDATOR postgresql_fdw_validator;
 \dew+
-                              List of foreign-data wrappers
-    Name    |       Owner       |        Validator         | Access privileges | Options 
-------------+-------------------+--------------------------+-------------------+---------
- dummy      | foreign_data_user | -                        |                   | 
- foo        | foreign_data_user | postgresql_fdw_validator |                   | 
- postgresql | foreign_data_user | postgresql_fdw_validator |                   | 
+                                   List of foreign-data wrappers
+    Name    |       Owner       | Handler |        Validator         | Access privileges | Options 
+------------+-------------------+---------+--------------------------+-------------------+---------
+ dummy      | foreign_data_user | -       | -                        |                   | 
+ foo        | foreign_data_user | -       | postgresql_fdw_validator |                   | 
+ postgresql | foreign_data_user | -       | postgresql_fdw_validator |                   | 
 (3 rows)
 
 -- ALTER FOREIGN DATA WRAPPER
@@ -97,12 +97,12 @@ ALTER FOREIGN DATA WRAPPER foo VALIDATOR bar;               -- ERROR
 ERROR:  function bar(text[], oid) does not exist
 ALTER FOREIGN DATA WRAPPER foo NO VALIDATOR;
 \dew+
-                              List of foreign-data wrappers
-    Name    |       Owner       |        Validator         | Access privileges | Options 
-------------+-------------------+--------------------------+-------------------+---------
- dummy      | foreign_data_user | -                        |                   | 
- foo        | foreign_data_user | -                        |                   | 
- postgresql | foreign_data_user | postgresql_fdw_validator |                   | 
+                                   List of foreign-data wrappers
+    Name    |       Owner       | Handler |        Validator         | Access privileges | Options 
+------------+-------------------+---------+--------------------------+-------------------+---------
+ dummy      | foreign_data_user | -       | -                        |                   | 
+ foo        | foreign_data_user | -       | -                        |                   | 
+ postgresql | foreign_data_user | -       | postgresql_fdw_validator |                   | 
 (3 rows)
 
 ALTER FOREIGN DATA WRAPPER foo OPTIONS (a '1', b '2');
@@ -112,34 +112,34 @@ ALTER FOREIGN DATA WRAPPER foo OPTIONS (DROP c);            -- ERROR
 ERROR:  option "c" not found
 ALTER FOREIGN DATA WRAPPER foo OPTIONS (ADD x '1', DROP x);
 \dew+
-                               List of foreign-data wrappers
-    Name    |       Owner       |        Validator         | Access privileges |  Options  
-------------+-------------------+--------------------------+-------------------+-----------
- dummy      | foreign_data_user | -                        |                   | 
- foo        | foreign_data_user | -                        |                   | {a=1,b=2}
- postgresql | foreign_data_user | postgresql_fdw_validator |                   | 
+                                    List of foreign-data wrappers
+    Name    |       Owner       | Handler |        Validator         | Access privileges |  Options  
+------------+-------------------+---------+--------------------------+-------------------+-----------
+ dummy      | foreign_data_user | -       | -                        |                   | 
+ foo        | foreign_data_user | -       | -                        |                   | {a=1,b=2}
+ postgresql | foreign_data_user | -       | postgresql_fdw_validator |                   | 
 (3 rows)
 
 ALTER FOREIGN DATA WRAPPER foo OPTIONS (DROP a, SET b '3', ADD c '4');
 \dew+
-                               List of foreign-data wrappers
-    Name    |       Owner       |        Validator         | Access privileges |  Options  
-------------+-------------------+--------------------------+-------------------+-----------
- dummy      | foreign_data_user | -                        |                   | 
- foo        | foreign_data_user | -                        |                   | {b=3,c=4}
- postgresql | foreign_data_user | postgresql_fdw_validator |                   | 
+                                    List of foreign-data wrappers
+    Name    |       Owner       | Handler |        Validator         | Access privileges |  Options  
+------------+-------------------+---------+--------------------------+-------------------+-----------
+ dummy      | foreign_data_user | -       | -                        |                   | 
+ foo        | foreign_data_user | -       | -                        |                   | {b=3,c=4}
+ postgresql | foreign_data_user | -       | postgresql_fdw_validator |                   | 
 (3 rows)
 
 ALTER FOREIGN DATA WRAPPER foo OPTIONS (a '2');
 ALTER FOREIGN DATA WRAPPER foo OPTIONS (b '4');             -- ERROR
 ERROR:  option "b" provided more than once
 \dew+
-                                 List of foreign-data wrappers
-    Name    |       Owner       |        Validator         | Access privileges |    Options    
-------------+-------------------+--------------------------+-------------------+---------------
- dummy      | foreign_data_user | -                        |                   | 
- foo        | foreign_data_user | -                        |                   | {b=3,c=4,a=2}
- postgresql | foreign_data_user | postgresql_fdw_validator |                   | 
+                                      List of foreign-data wrappers
+    Name    |       Owner       | Handler |        Validator         | Access privileges |    Options    
+------------+-------------------+---------+--------------------------+-------------------+---------------
+ dummy      | foreign_data_user | -       | -                        |                   | 
+ foo        | foreign_data_user | -       | -                        |                   | {b=3,c=4,a=2}
+ postgresql | foreign_data_user | -       | postgresql_fdw_validator |                   | 
 (3 rows)
 
 SET ROLE regress_test_role;
@@ -149,12 +149,12 @@ HINT:  Must be superuser to alter a foreign-data wrapper.
 SET ROLE regress_test_role_super;
 ALTER FOREIGN DATA WRAPPER foo OPTIONS (ADD d '5');
 \dew+
-                                   List of foreign-data wrappers
-    Name    |       Owner       |        Validator         | Access privileges |      Options      
-------------+-------------------+--------------------------+-------------------+-------------------
- dummy      | foreign_data_user | -                        |                   | 
- foo        | foreign_data_user | -                        |                   | {b=3,c=4,a=2,d=5}
- postgresql | foreign_data_user | postgresql_fdw_validator |                   | 
+                                        List of foreign-data wrappers
+    Name    |       Owner       | Handler |        Validator         | Access privileges |      Options      
+------------+-------------------+---------+--------------------------+-------------------+-------------------
+ dummy      | foreign_data_user | -       | -                        |                   | 
+ foo        | foreign_data_user | -       | -                        |                   | {b=3,c=4,a=2,d=5}
+ postgresql | foreign_data_user | -       | postgresql_fdw_validator |                   | 
 (3 rows)
 
 ALTER FOREIGN DATA WRAPPER foo OWNER TO regress_test_role;  -- ERROR
@@ -168,12 +168,12 @@ ERROR:  permission denied to alter foreign-data wrapper "foo"
 HINT:  Must be superuser to alter a foreign-data wrapper.
 RESET ROLE;
 \dew+
-                                      List of foreign-data wrappers
-    Name    |          Owner          |        Validator         | Access privileges |      Options      
-------------+-------------------------+--------------------------+-------------------+-------------------
- dummy      | foreign_data_user       | -                        |                   | 
- foo        | regress_test_role_super | -                        |                   | {b=3,c=4,a=2,d=5}
- postgresql | foreign_data_user       | postgresql_fdw_validator |                   | 
+                                           List of foreign-data wrappers
+    Name    |          Owner          | Handler |        Validator         | Access privileges |      Options      
+------------+-------------------------+---------+--------------------------+-------------------+-------------------
+ dummy      | foreign_data_user       | -       | -                        |                   | 
+ foo        | regress_test_role_super | -       | -                        |                   | {b=3,c=4,a=2,d=5}
+ postgresql | foreign_data_user       | -       | postgresql_fdw_validator |                   | 
 (3 rows)
 
 -- DROP FOREIGN DATA WRAPPER
@@ -182,12 +182,12 @@ ERROR:  foreign-data wrapper "nonexistent" does not exist
 DROP FOREIGN DATA WRAPPER IF EXISTS nonexistent;
 NOTICE:  foreign-data wrapper "nonexistent" does not exist, skipping
 \dew+
-                                      List of foreign-data wrappers
-    Name    |          Owner          |        Validator         | Access privileges |      Options      
-------------+-------------------------+--------------------------+-------------------+-------------------
- dummy      | foreign_data_user       | -                        |                   | 
- foo        | regress_test_role_super | -                        |                   | {b=3,c=4,a=2,d=5}
- postgresql | foreign_data_user       | postgresql_fdw_validator |                   | 
+                                           List of foreign-data wrappers
+    Name    |          Owner          | Handler |        Validator         | Access privileges |      Options      
+------------+-------------------------+---------+--------------------------+-------------------+-------------------
+ dummy      | foreign_data_user       | -       | -                        |                   | 
+ foo        | regress_test_role_super | -       | -                        |                   | {b=3,c=4,a=2,d=5}
+ postgresql | foreign_data_user       | -       | postgresql_fdw_validator |                   | 
 (3 rows)
 
 DROP ROLE regress_test_role_super;                          -- ERROR
@@ -202,23 +202,23 @@ ALTER ROLE regress_test_role_super SUPERUSER;
 DROP FOREIGN DATA WRAPPER foo;
 DROP ROLE regress_test_role_super;
 \dew+
-                              List of foreign-data wrappers
-    Name    |       Owner       |        Validator         | Access privileges | Options 
-------------+-------------------+--------------------------+-------------------+---------
- dummy      | foreign_data_user | -                        |                   | 
- postgresql | foreign_data_user | postgresql_fdw_validator |                   | 
+                                   List of foreign-data wrappers
+    Name    |       Owner       | Handler |        Validator         | Access privileges | Options 
+------------+-------------------+---------+--------------------------+-------------------+---------
+ dummy      | foreign_data_user | -       | -                        |                   | 
+ postgresql | foreign_data_user | -       | postgresql_fdw_validator |                   | 
 (2 rows)
 
 CREATE FOREIGN DATA WRAPPER foo;
 CREATE SERVER s1 FOREIGN DATA WRAPPER foo;
 CREATE USER MAPPING FOR current_user SERVER s1;
 \dew+
-                              List of foreign-data wrappers
-    Name    |       Owner       |        Validator         | Access privileges | Options 
-------------+-------------------+--------------------------+-------------------+---------
- dummy      | foreign_data_user | -                        |                   | 
- foo        | foreign_data_user | -                        |                   | 
- postgresql | foreign_data_user | postgresql_fdw_validator |                   | 
+                                   List of foreign-data wrappers
+    Name    |       Owner       | Handler |        Validator         | Access privileges | Options 
+------------+-------------------+---------+--------------------------+-------------------+---------
+ dummy      | foreign_data_user | -       | -                        |                   | 
+ foo        | foreign_data_user | -       | -                        |                   | 
+ postgresql | foreign_data_user | -       | postgresql_fdw_validator |                   | 
 (3 rows)
 
 \des+
@@ -250,11 +250,11 @@ NOTICE:  drop cascades to 2 other objects
 DETAIL:  drop cascades to server s1
 drop cascades to user mapping for foreign_data_user
 \dew+
-                              List of foreign-data wrappers
-    Name    |       Owner       |        Validator         | Access privileges | Options 
-------------+-------------------+--------------------------+-------------------+---------
- dummy      | foreign_data_user | -                        |                   | 
- postgresql | foreign_data_user | postgresql_fdw_validator |                   | 
+                                   List of foreign-data wrappers
+    Name    |       Owner       | Handler |        Validator         | Access privileges | Options 
+------------+-------------------+---------+--------------------------+-------------------+---------
+ dummy      | foreign_data_user | -       | -                        |                   | 
+ postgresql | foreign_data_user | -       | postgresql_fdw_validator |                   | 
 (2 rows)
 
 \des+
@@ -669,6 +669,10 @@ Has OIDs: no
 
 CREATE INDEX id_ft1_c2 ON ft1 (c2);                             -- ERROR
 ERROR:  "ft1" is not a table
+SELECT * FROM ft1;                                              -- ERROR
+ERROR:  foreign table scans are not yet supported
+EXPLAIN SELECT * FROM ft1;                                      -- ERROR
+ERROR:  foreign table scans are not yet supported
 -- ALTER FOREIGN TABLE
 COMMENT ON FOREIGN TABLE ft1 IS 'foreign table';
 COMMENT ON FOREIGN TABLE ft1 IS NULL;
@@ -1105,9 +1109,9 @@ NOTICE:  drop cascades to server sc
 \c
 DROP ROLE foreign_data_user;
 -- At this point we should have no wrappers, no servers, and no mappings.
-SELECT fdwname, fdwvalidator, fdwoptions FROM pg_foreign_data_wrapper;
- fdwname | fdwvalidator | fdwoptions 
----------+--------------+------------
+SELECT fdwname, fdwhandler, fdwvalidator, fdwoptions FROM pg_foreign_data_wrapper;
+ fdwname | fdwhandler | fdwvalidator | fdwoptions 
+---------+------------+--------------+------------
 (0 rows)
 
 SELECT srvname, srvoptions FROM pg_foreign_server;
diff --git a/src/test/regress/sql/foreign_data.sql b/src/test/regress/sql/foreign_data.sql
index 86b698a1b61..3f397859031 100644
--- a/src/test/regress/sql/foreign_data.sql
+++ b/src/test/regress/sql/foreign_data.sql
@@ -24,7 +24,7 @@ CREATE FOREIGN DATA WRAPPER dummy;
 CREATE FOREIGN DATA WRAPPER postgresql VALIDATOR postgresql_fdw_validator;
 
 -- At this point we should have 2 built-in wrappers and no servers.
-SELECT fdwname, fdwvalidator::regproc, fdwoptions FROM pg_foreign_data_wrapper ORDER BY 1, 2, 3;
+SELECT fdwname, fdwhandler::regproc, fdwvalidator::regproc, fdwoptions FROM pg_foreign_data_wrapper ORDER BY 1, 2, 3;
 SELECT srvname, srvoptions FROM pg_foreign_server;
 SELECT * FROM pg_user_mapping;
 
@@ -271,6 +271,8 @@ COMMENT ON COLUMN ft1.c1 IS 'ft1.c1';
 \d+ ft1
 \det+
 CREATE INDEX id_ft1_c2 ON ft1 (c2);                             -- ERROR
+SELECT * FROM ft1;                                              -- ERROR
+EXPLAIN SELECT * FROM ft1;                                      -- ERROR
 
 -- ALTER FOREIGN TABLE
 COMMENT ON FOREIGN TABLE ft1 IS 'foreign table';
@@ -453,6 +455,6 @@ DROP FOREIGN DATA WRAPPER dummy CASCADE;
 DROP ROLE foreign_data_user;
 
 -- At this point we should have no wrappers, no servers, and no mappings.
-SELECT fdwname, fdwvalidator, fdwoptions FROM pg_foreign_data_wrapper;
+SELECT fdwname, fdwhandler, fdwvalidator, fdwoptions FROM pg_foreign_data_wrapper;
 SELECT srvname, srvoptions FROM pg_foreign_server;
 SELECT * FROM pg_user_mapping;