Code review for btreefuncs additions: restrict to superusers to avoid

exposing user data to others, and clean up usage of deprecated APIs.

contrib/pageinspect/README.pageinspect

 The functions in this module allow you to inspect the contents of data pages
-at a low level, for debugging purposes.
+at a low level, for debugging purposes.  All of these functions may be used
+only by superusers.
 
 1. Installation
 
@@ -13,12 +14,12 @@ at a low level, for debugging purposes.
     ------------
     get_raw_page reads one block of the named table and returns a copy as a
     bytea field. This allows a single time-consistent copy of the block to be
-    made. Use of this functions is restricted to superusers.
+    made.
 
     page_header
     -----------
     page_header shows fields which are common to all PostgreSQL heap and index
-    pages. Use of this function is restricted to superusers.
+    pages.
 
     A page image obtained with get_raw_page should be passed as argument:
 
@@ -36,8 +37,7 @@ at a low level, for debugging purposes.
     heap_page_items shows all line pointers on a heap page.  For those line
     pointers that are in use, tuple headers are also shown. All tuples are
     shown, whether or not the tuples were visible to an MVCC snapshot at the
-    time the raw page was copied. Use of this function is restricted to
-    superusers.
+    time the raw page was copied.
 
     A heap page image obtained with get_raw_page should be passed as argument:
 
@@ -48,7 +48,7 @@ at a low level, for debugging purposes.
 
     bt_metap
     --------
-    bt_metap() returns information about the btree index metapage:
+    bt_metap() returns information about a btree index's metapage:
 
         test=> SELECT * FROM bt_metap('pg_cast_oid_index');
         -[ RECORD 1 ]-----

contrib/pageinspect/pageinspect.sql.in

@@ -12,98 +12,80 @@ LANGUAGE C STRICT;
 --
 -- page_header()
 --
-CREATE TYPE page_header_type AS (
-	lsn text,
-	tli smallint,
-	flags smallint,
-	lower smallint,
-	upper smallint,
-	special smallint,
-	pagesize smallint,
-	version smallint
-);
-
-CREATE OR REPLACE FUNCTION page_header(bytea)
-RETURNS page_header_type
+CREATE OR REPLACE FUNCTION page_header(IN page bytea,
+    OUT lsn text,
+    OUT tli smallint,
+    OUT flags smallint,
+    OUT lower smallint,
+    OUT upper smallint,
+    OUT special smallint,
+    OUT pagesize smallint,
+    OUT version smallint)
 AS 'MODULE_PATHNAME', 'page_header'
 LANGUAGE C STRICT;
 
 --
 -- heap_page_items()
 --
-CREATE TYPE heap_page_items_type AS (
-	lp smallint,
-	lp_off smallint,
-	lp_flags smallint,
-	lp_len smallint,
-	t_xmin xid,
-	t_xmax xid,
-	t_field3 int4,
-	t_ctid tid,
-	t_infomask2 smallint,
-	t_infomask smallint,
-	t_hoff smallint,
-	t_bits text,
-	t_oid oid
-);
-
-CREATE OR REPLACE FUNCTION heap_page_items(bytea)
-RETURNS SETOF heap_page_items_type
+CREATE OR REPLACE FUNCTION heap_page_items(IN page bytea,
+    OUT lp smallint,
+    OUT lp_off smallint,
+    OUT lp_flags smallint,
+    OUT lp_len smallint,
+    OUT t_xmin xid,
+    OUT t_xmax xid,
+    OUT t_field3 int4,
+    OUT t_ctid tid,
+    OUT t_infomask2 smallint,
+    OUT t_infomask smallint,
+    OUT t_hoff smallint,
+    OUT t_bits text,
+    OUT t_oid oid)
+RETURNS SETOF record
 AS 'MODULE_PATHNAME', 'heap_page_items'
 LANGUAGE C STRICT;
 
 --
 -- bt_metap()
 --
-CREATE TYPE bt_metap_type AS (
-  magic int4,
-  version int4,
-  root int4,
-  level int4,
-  fastroot int4,
-  fastlevel int4
-);
-
-CREATE OR REPLACE FUNCTION bt_metap(text)
-RETURNS bt_metap_type
+CREATE OR REPLACE FUNCTION bt_metap(IN relname text,
+    OUT magic int4,
+    OUT version int4,
+    OUT root int4,
+    OUT level int4,
+    OUT fastroot int4,
+    OUT fastlevel int4)
 AS 'MODULE_PATHNAME', 'bt_metap'
-LANGUAGE 'C' STRICT;
+LANGUAGE C STRICT;
 
 --
 -- bt_page_stats()
 --
-CREATE TYPE bt_page_stats_type AS (
-  blkno int4,
-  type char,
-  live_items int4,
-  dead_items int4,
-  avg_item_size float,
-  page_size int4,
-  free_size int4,
-  btpo_prev int4,
-  btpo_next int4,
-  btpo int4,
-  btpo_flags int4
-);
-
-CREATE OR REPLACE FUNCTION bt_page_stats(text, int4)
-RETURNS bt_page_stats_type
+CREATE OR REPLACE FUNCTION bt_page_stats(IN relname text, IN blkno int4,
+    OUT blkno int4,
+    OUT type "char",
+    OUT live_items int4,
+    OUT dead_items int4,
+    OUT avg_item_size int4,
+    OUT page_size int4,
+    OUT free_size int4,
+    OUT btpo_prev int4,
+    OUT btpo_next int4,
+    OUT btpo int4,
+    OUT btpo_flags int4)
 AS 'MODULE_PATHNAME', 'bt_page_stats'
-LANGUAGE 'C' STRICT;
+LANGUAGE C STRICT;
 
 --
 -- bt_page_items()
 --
-CREATE TYPE bt_page_items_type AS (
-  itemoffset smallint,
-  ctid tid,
-  itemlen smallint,
-  nulls bool,
-  vars bool,
-  data text
-);
-
-CREATE OR REPLACE FUNCTION bt_page_items(text, int4)
-RETURNS SETOF bt_page_items_type
+CREATE OR REPLACE FUNCTION bt_page_items(IN relname text, IN blkno int4,
+    OUT itemoffset smallint,
+    OUT ctid tid,
+    OUT itemlen smallint,
+    OUT nulls bool,
+    OUT vars bool,
+    OUT data text)
+RETURNS SETOF record
 AS 'MODULE_PATHNAME', 'bt_page_items'
-LANGUAGE 'C' STRICT;
+LANGUAGE C STRICT;

contrib/pageinspect/uninstall_pageinspect.sql

@@ -2,19 +2,8 @@
 SET search_path = public;
 
 DROP FUNCTION get_raw_page(text, int4);
-
 DROP FUNCTION page_header(bytea);
-DROP TYPE page_header_type;
-
 DROP FUNCTION heap_page_items(bytea);
-DROP TYPE heap_page_items_type;
-
 DROP FUNCTION bt_metap(text);
-DROP TYPE bt_metap_type;
-
 DROP FUNCTION bt_page_stats(text, int4);
-DROP TYPE bt_page_stats_type;
-
 DROP FUNCTION bt_page_items(text, int4);
-DROP TYPE bt_page_items_type;
-