Adding upstream version 16.2.upstream/16.2

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

12 files changed, 1618 insertions, 0 deletions

diff --git a/contrib/pg_walinspect/.gitignore b/contrib/pg_walinspect/.gitignore
new file mode 100644
index 0000000..5dcb3ff
--- /dev/null
+++ b/contrib/pg_walinspect/.gitignore
@@ -0,0 +1,4 @@
+# Generated subdirectories
+/log/
+/results/
+/tmp_check/
diff --git a/contrib/pg_walinspect/Makefile b/contrib/pg_walinspect/Makefile
new file mode 100644
index 0000000..22090f7
--- /dev/null
+++ b/contrib/pg_walinspect/Makefile
@@ -0,0 +1,29 @@
+# contrib/pg_walinspect/Makefile
+
+MODULE_big = pg_walinspect
+OBJS = \
+	$(WIN32RES) \
+	pg_walinspect.o
+PGFILEDESC = "pg_walinspect - functions to inspect contents of PostgreSQL Write-Ahead Log"
+
+EXTENSION = pg_walinspect
+DATA = pg_walinspect--1.0.sql pg_walinspect--1.0--1.1.sql
+
+REGRESS = pg_walinspect oldextversions
+
+REGRESS_OPTS = --temp-config $(top_srcdir)/contrib/pg_walinspect/walinspect.conf
+
+# Disabled because these tests require "wal_level=replica", which
+# some installcheck users do not have (e.g. buildfarm clients).
+NO_INSTALLCHECK = 1
+
+ifdef USE_PGXS
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+subdir = contrib/pg_walinspect
+top_builddir = ../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif
diff --git a/contrib/pg_walinspect/expected/oldextversions.out b/contrib/pg_walinspect/expected/oldextversions.out
new file mode 100644
index 0000000..89953af
--- /dev/null
+++ b/contrib/pg_walinspect/expected/oldextversions.out
@@ -0,0 +1,69 @@
+-- Test old extension version entry points.
+CREATE EXTENSION pg_walinspect WITH VERSION '1.0';
+-- Mask DETAIL messages as these could refer to current LSN positions.
+\set VERBOSITY terse
+-- List what version 1.0 contains, using a locale-independent sorting.
+SELECT pg_describe_object(classid, objid, 0) AS obj
+  FROM pg_depend
+  WHERE refclassid = 'pg_extension'::regclass AND
+    refobjid = (SELECT oid FROM pg_extension
+                  WHERE extname = 'pg_walinspect') AND deptype = 'e'
+  ORDER BY pg_describe_object(classid, objid, 0) COLLATE "C";
+                            obj                            
+-----------------------------------------------------------
+ function pg_get_wal_record_info(pg_lsn)
+ function pg_get_wal_records_info(pg_lsn,pg_lsn)
+ function pg_get_wal_records_info_till_end_of_wal(pg_lsn)
+ function pg_get_wal_stats(pg_lsn,pg_lsn,boolean)
+ function pg_get_wal_stats_till_end_of_wal(pg_lsn,boolean)
+(5 rows)
+
+-- Make sure checkpoints don't interfere with the test.
+SELECT 'init' FROM pg_create_physical_replication_slot('regress_pg_walinspect_slot', true, false);
+ ?column? 
+----------
+ init
+(1 row)
+
+CREATE TABLE sample_tbl(col1 int, col2 int);
+SELECT pg_current_wal_lsn() AS wal_lsn1 \gset
+INSERT INTO sample_tbl SELECT * FROM generate_series(1, 2);
+-- Tests for the past functions.
+SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_records_info_till_end_of_wal(:'wal_lsn1');
+ ok 
+----
+ t
+(1 row)
+
+SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_stats_till_end_of_wal(:'wal_lsn1');
+ ok 
+----
+ t
+(1 row)
+
+-- Failures with start LSNs.
+SELECT * FROM pg_get_wal_records_info_till_end_of_wal('FFFFFFFF/FFFFFFFF');
+ERROR:  WAL start LSN must be less than current LSN
+SELECT * FROM pg_get_wal_stats_till_end_of_wal('FFFFFFFF/FFFFFFFF');
+ERROR:  WAL start LSN must be less than current LSN
+-- Move to new version 1.1.
+ALTER EXTENSION pg_walinspect UPDATE TO '1.1';
+-- List what version 1.1 contains.
+\dx+ pg_walinspect
+         Objects in extension "pg_walinspect"
+                  Object description                   
+-------------------------------------------------------
+ function pg_get_wal_block_info(pg_lsn,pg_lsn,boolean)
+ function pg_get_wal_record_info(pg_lsn)
+ function pg_get_wal_records_info(pg_lsn,pg_lsn)
+ function pg_get_wal_stats(pg_lsn,pg_lsn,boolean)
+(4 rows)
+
+SELECT pg_drop_replication_slot('regress_pg_walinspect_slot');
+ pg_drop_replication_slot 
+--------------------------
+ 
+(1 row)
+
+DROP TABLE sample_tbl;
+DROP EXTENSION pg_walinspect;
diff --git a/contrib/pg_walinspect/expected/pg_walinspect.out b/contrib/pg_walinspect/expected/pg_walinspect.out
new file mode 100644
index 0000000..a8f4c91
--- /dev/null
+++ b/contrib/pg_walinspect/expected/pg_walinspect.out
@@ -0,0 +1,262 @@
+CREATE EXTENSION pg_walinspect;
+-- Mask DETAIL messages as these could refer to current LSN positions.
+\set VERBOSITY terse
+-- Make sure checkpoints don't interfere with the test.
+SELECT 'init' FROM pg_create_physical_replication_slot('regress_pg_walinspect_slot', true, false);
+ ?column? 
+----------
+ init
+(1 row)
+
+CREATE TABLE sample_tbl(col1 int, col2 int);
+-- Save some LSNs for comparisons.
+SELECT pg_current_wal_lsn() AS wal_lsn1 \gset
+INSERT INTO sample_tbl SELECT * FROM generate_series(1, 2);
+SELECT pg_current_wal_lsn() AS wal_lsn2 \gset
+INSERT INTO sample_tbl SELECT * FROM generate_series(3, 4);
+-- ===================================================================
+-- Tests for input validation
+-- ===================================================================
+-- Invalid input LSN.
+SELECT * FROM pg_get_wal_record_info('0/0');
+ERROR:  could not read WAL at LSN 0/0
+-- Invalid start LSN.
+SELECT * FROM pg_get_wal_records_info('0/0', :'wal_lsn1');
+ERROR:  could not read WAL at LSN 0/0
+SELECT * FROM pg_get_wal_stats('0/0', :'wal_lsn1');
+ERROR:  could not read WAL at LSN 0/0
+SELECT * FROM pg_get_wal_block_info('0/0', :'wal_lsn1');
+ERROR:  could not read WAL at LSN 0/0
+-- Start LSN > End LSN.
+SELECT * FROM pg_get_wal_records_info(:'wal_lsn2', :'wal_lsn1');
+ERROR:  WAL start LSN must be less than end LSN
+SELECT * FROM pg_get_wal_stats(:'wal_lsn2', :'wal_lsn1');
+ERROR:  WAL start LSN must be less than end LSN
+SELECT * FROM pg_get_wal_block_info(:'wal_lsn2', :'wal_lsn1');
+ERROR:  WAL start LSN must be less than end LSN
+-- LSNs with the highest value possible.
+SELECT * FROM pg_get_wal_record_info('FFFFFFFF/FFFFFFFF');
+ERROR:  WAL input LSN must be less than current LSN
+-- Success with end LSNs.
+SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_records_info(:'wal_lsn1', 'FFFFFFFF/FFFFFFFF');
+ ok 
+----
+ t
+(1 row)
+
+SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_stats(:'wal_lsn1', 'FFFFFFFF/FFFFFFFF');
+ ok 
+----
+ t
+(1 row)
+
+SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_block_info(:'wal_lsn1', 'FFFFFFFF/FFFFFFFF');
+ ok 
+----
+ t
+(1 row)
+
+-- Failures with start LSNs.
+SELECT * FROM pg_get_wal_records_info('FFFFFFFF/FFFFFFFE', 'FFFFFFFF/FFFFFFFF');
+ERROR:  WAL start LSN must be less than current LSN
+SELECT * FROM pg_get_wal_stats('FFFFFFFF/FFFFFFFE', 'FFFFFFFF/FFFFFFFF');
+ERROR:  WAL start LSN must be less than current LSN
+SELECT * FROM pg_get_wal_block_info('FFFFFFFF/FFFFFFFE', 'FFFFFFFF/FFFFFFFF');
+ERROR:  WAL start LSN must be less than current LSN
+-- ===================================================================
+-- Tests for all function executions
+-- ===================================================================
+SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_record_info(:'wal_lsn1');
+ ok 
+----
+ t
+(1 row)
+
+SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_records_info(:'wal_lsn1', :'wal_lsn2');
+ ok 
+----
+ t
+(1 row)
+
+SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_stats(:'wal_lsn1', :'wal_lsn2');
+ ok 
+----
+ t
+(1 row)
+
+SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_block_info(:'wal_lsn1', :'wal_lsn2');
+ ok 
+----
+ t
+(1 row)
+
+-- ===================================================================
+-- Test for filtering out WAL records of a particular table
+-- ===================================================================
+SELECT oid AS sample_tbl_oid FROM pg_class WHERE relname = 'sample_tbl' \gset
+SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_records_info(:'wal_lsn1', :'wal_lsn2')
+			WHERE block_ref LIKE concat('%', :'sample_tbl_oid', '%') AND resource_manager = 'Heap';
+ ok 
+----
+ t
+(1 row)
+
+-- ===================================================================
+-- Test for filtering out WAL records based on resource_manager and
+-- record_type
+-- ===================================================================
+SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_records_info(:'wal_lsn1', :'wal_lsn2')
+			WHERE resource_manager = 'Heap' AND record_type = 'INSERT';
+ ok 
+----
+ t
+(1 row)
+
+-- ===================================================================
+-- Tests to get block information from WAL record
+-- ===================================================================
+-- Update table to generate some block data.
+SELECT pg_current_wal_lsn() AS wal_lsn3 \gset
+UPDATE sample_tbl SET col1 = col1 + 1 WHERE col1 = 1;
+SELECT pg_current_wal_lsn() AS wal_lsn4 \gset
+-- Check if we get block data from WAL record.
+SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_block_info(:'wal_lsn3', :'wal_lsn4')
+  WHERE relfilenode = :'sample_tbl_oid' AND block_data IS NOT NULL;
+ ok 
+----
+ t
+(1 row)
+
+-- Force full-page image on the next update.
+SELECT pg_current_wal_lsn() AS wal_lsn5 \gset
+CHECKPOINT;
+UPDATE sample_tbl SET col1 = col1 + 1 WHERE col1 = 2;
+SELECT pg_current_wal_lsn() AS wal_lsn6 \gset
+-- Check if we get FPI from WAL record.
+SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_block_info(:'wal_lsn5', :'wal_lsn6')
+  WHERE relfilenode = :'sample_tbl_oid' AND block_fpi_data IS NOT NULL;
+ ok 
+----
+ t
+(1 row)
+
+-- ===================================================================
+-- Tests for permissions
+-- ===================================================================
+CREATE ROLE regress_pg_walinspect;
+SELECT has_function_privilege('regress_pg_walinspect',
+  'pg_get_wal_record_info(pg_lsn)', 'EXECUTE'); -- no
+ has_function_privilege 
+------------------------
+ f
+(1 row)
+
+SELECT has_function_privilege('regress_pg_walinspect',
+  'pg_get_wal_records_info(pg_lsn, pg_lsn) ', 'EXECUTE'); -- no
+ has_function_privilege 
+------------------------
+ f
+(1 row)
+
+SELECT has_function_privilege('regress_pg_walinspect',
+  'pg_get_wal_stats(pg_lsn, pg_lsn, boolean) ', 'EXECUTE'); -- no
+ has_function_privilege 
+------------------------
+ f
+(1 row)
+
+SELECT has_function_privilege('regress_pg_walinspect',
+  'pg_get_wal_block_info(pg_lsn, pg_lsn, boolean) ', 'EXECUTE'); -- no
+ has_function_privilege 
+------------------------
+ f
+(1 row)
+
+-- Functions accessible by users with role pg_read_server_files.
+GRANT pg_read_server_files TO regress_pg_walinspect;
+SELECT has_function_privilege('regress_pg_walinspect',
+  'pg_get_wal_record_info(pg_lsn)', 'EXECUTE'); -- yes
+ has_function_privilege 
+------------------------
+ t
+(1 row)
+
+SELECT has_function_privilege('regress_pg_walinspect',
+  'pg_get_wal_records_info(pg_lsn, pg_lsn) ', 'EXECUTE'); -- yes
+ has_function_privilege 
+------------------------
+ t
+(1 row)
+
+SELECT has_function_privilege('regress_pg_walinspect',
+  'pg_get_wal_stats(pg_lsn, pg_lsn, boolean) ', 'EXECUTE'); -- yes
+ has_function_privilege 
+------------------------
+ t
+(1 row)
+
+SELECT has_function_privilege('regress_pg_walinspect',
+  'pg_get_wal_block_info(pg_lsn, pg_lsn, boolean) ', 'EXECUTE'); -- yes
+ has_function_privilege 
+------------------------
+ t
+(1 row)
+
+REVOKE pg_read_server_files FROM regress_pg_walinspect;
+-- Superuser can grant execute to other users.
+GRANT EXECUTE ON FUNCTION pg_get_wal_record_info(pg_lsn)
+  TO regress_pg_walinspect;
+GRANT EXECUTE ON FUNCTION pg_get_wal_records_info(pg_lsn, pg_lsn)
+  TO regress_pg_walinspect;
+GRANT EXECUTE ON FUNCTION pg_get_wal_stats(pg_lsn, pg_lsn, boolean)
+  TO regress_pg_walinspect;
+GRANT EXECUTE ON FUNCTION pg_get_wal_block_info(pg_lsn, pg_lsn, boolean)
+  TO regress_pg_walinspect;
+SELECT has_function_privilege('regress_pg_walinspect',
+  'pg_get_wal_record_info(pg_lsn)', 'EXECUTE'); -- yes
+ has_function_privilege 
+------------------------
+ t
+(1 row)
+
+SELECT has_function_privilege('regress_pg_walinspect',
+  'pg_get_wal_records_info(pg_lsn, pg_lsn) ', 'EXECUTE'); -- yes
+ has_function_privilege 
+------------------------
+ t
+(1 row)
+
+SELECT has_function_privilege('regress_pg_walinspect',
+  'pg_get_wal_stats(pg_lsn, pg_lsn, boolean) ', 'EXECUTE'); -- yes
+ has_function_privilege 
+------------------------
+ t
+(1 row)
+
+SELECT has_function_privilege('regress_pg_walinspect',
+  'pg_get_wal_block_info(pg_lsn, pg_lsn, boolean) ', 'EXECUTE'); -- yes
+ has_function_privilege 
+------------------------
+ t
+(1 row)
+
+REVOKE EXECUTE ON FUNCTION pg_get_wal_record_info(pg_lsn)
+  FROM regress_pg_walinspect;
+REVOKE EXECUTE ON FUNCTION pg_get_wal_records_info(pg_lsn, pg_lsn)
+  FROM regress_pg_walinspect;
+REVOKE EXECUTE ON FUNCTION pg_get_wal_stats(pg_lsn, pg_lsn, boolean)
+  FROM regress_pg_walinspect;
+REVOKE EXECUTE ON FUNCTION pg_get_wal_block_info(pg_lsn, pg_lsn, boolean)
+  FROM regress_pg_walinspect;
+-- ===================================================================
+-- Clean up
+-- ===================================================================
+DROP ROLE regress_pg_walinspect;
+SELECT pg_drop_replication_slot('regress_pg_walinspect_slot');
+ pg_drop_replication_slot 
+--------------------------
+ 
+(1 row)
+
+DROP TABLE sample_tbl;
+DROP EXTENSION pg_walinspect;
diff --git a/contrib/pg_walinspect/meson.build b/contrib/pg_walinspect/meson.build
new file mode 100644
index 0000000..80059f6
--- /dev/null
+++ b/contrib/pg_walinspect/meson.build
@@ -0,0 +1,40 @@
+# Copyright (c) 2022-2023, PostgreSQL Global Development Group
+
+pg_walinspect_sources = files('pg_walinspect.c')
+
+if host_system == 'windows'
+  pg_walinspect_sources += rc_lib_gen.process(win32ver_rc, extra_args: [
+    '--NAME', 'pg_walinspect',
+    '--FILEDESC', 'pg_walinspect - functions to inspect contents of PostgreSQL Write-Ahead Log',])
+endif
+
+pg_walinspect = shared_module('pg_walinspect',
+  pg_walinspect_sources,
+  kwargs: contrib_mod_args + {
+      'dependencies': contrib_mod_args['dependencies'],
+  },
+)
+contrib_targets += pg_walinspect
+
+install_data(
+  'pg_walinspect.control',
+  'pg_walinspect--1.0.sql',
+  'pg_walinspect--1.0--1.1.sql',
+  kwargs: contrib_data_args,
+)
+
+tests += {
+  'name': 'pg_walinspect',
+  'sd': meson.current_source_dir(),
+  'bd': meson.current_build_dir(),
+  'regress': {
+    'sql': [
+      'pg_walinspect',
+      'oldextversions',
+    ],
+    # Disabled because these tests require "wal_level=replica", which
+    # some runningcheck users do not have (e.g. buildfarm clients).
+    'regress_args': ['--temp-config', files('walinspect.conf')],
+    'runningcheck': false,
+  },
+}
diff --git a/contrib/pg_walinspect/pg_walinspect--1.0--1.1.sql b/contrib/pg_walinspect/pg_walinspect--1.0--1.1.sql
new file mode 100644
index 0000000..a4d50d3
--- /dev/null
+++ b/contrib/pg_walinspect/pg_walinspect--1.0--1.1.sql
@@ -0,0 +1,42 @@
+/* contrib/pg_walinspect/pg_walinspect--1.0--1.1.sql */
+
+-- complain if script is sourced in psql, rather than via ALTER EXTENSION
+\echo Use "ALTER EXTENSION pg_walinspect UPDATE TO '1.1'" to load this file. \quit
+
+-- Unsupported functions after 1.1.
+DROP FUNCTION pg_get_wal_records_info_till_end_of_wal(pg_lsn);
+DROP FUNCTION pg_get_wal_stats_till_end_of_wal(pg_lsn, boolean);
+
+--
+-- pg_get_wal_block_info()
+--
+CREATE FUNCTION pg_get_wal_block_info(IN start_lsn pg_lsn,
+	IN end_lsn pg_lsn,
+	IN show_data boolean DEFAULT true,
+	OUT start_lsn pg_lsn,
+	OUT end_lsn pg_lsn,
+	OUT prev_lsn pg_lsn,
+	OUT block_id int2,
+	OUT reltablespace oid,
+	OUT reldatabase oid,
+	OUT relfilenode oid,
+	OUT relforknumber int2,
+	OUT relblocknumber int8,
+	OUT xid xid,
+	OUT resource_manager text,
+	OUT record_type text,
+	OUT record_length int4,
+	OUT main_data_length int4,
+	OUT block_data_length int4,
+	OUT block_fpi_length int4,
+	OUT block_fpi_info text[],
+	OUT description text,
+	OUT block_data bytea,
+	OUT block_fpi_data bytea
+)
+RETURNS SETOF record
+AS 'MODULE_PATHNAME', 'pg_get_wal_block_info'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+REVOKE EXECUTE ON FUNCTION pg_get_wal_block_info(pg_lsn, pg_lsn, boolean) FROM PUBLIC;
+GRANT EXECUTE ON FUNCTION pg_get_wal_block_info(pg_lsn, pg_lsn, boolean) TO pg_read_server_files;
diff --git a/contrib/pg_walinspect/pg_walinspect--1.0.sql b/contrib/pg_walinspect/pg_walinspect--1.0.sql
new file mode 100644
index 0000000..08b3dd5
--- /dev/null
+++ b/contrib/pg_walinspect/pg_walinspect--1.0.sql
@@ -0,0 +1,118 @@
+/* contrib/pg_walinspect/pg_walinspect--1.0.sql */
+
+-- complain if script is sourced in psql, rather than via CREATE EXTENSION
+\echo Use "CREATE EXTENSION pg_walinspect" to load this file. \quit
+
+--
+-- pg_get_wal_record_info()
+--
+CREATE FUNCTION pg_get_wal_record_info(IN in_lsn pg_lsn,
+    OUT start_lsn pg_lsn,
+    OUT end_lsn pg_lsn,
+    OUT prev_lsn pg_lsn,
+    OUT xid xid,
+    OUT resource_manager text,
+    OUT record_type text,
+    OUT record_length int4,
+    OUT main_data_length int4,
+    OUT fpi_length int4,
+    OUT description text,
+    OUT block_ref text
+)
+AS 'MODULE_PATHNAME', 'pg_get_wal_record_info'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+REVOKE EXECUTE ON FUNCTION pg_get_wal_record_info(pg_lsn) FROM PUBLIC;
+GRANT EXECUTE ON FUNCTION pg_get_wal_record_info(pg_lsn) TO pg_read_server_files;
+
+--
+-- pg_get_wal_records_info()
+--
+CREATE FUNCTION pg_get_wal_records_info(IN start_lsn pg_lsn,
+    IN end_lsn pg_lsn,
+    OUT start_lsn pg_lsn,
+    OUT end_lsn pg_lsn,
+    OUT prev_lsn pg_lsn,
+    OUT xid xid,
+    OUT resource_manager text,
+    OUT record_type text,
+    OUT record_length int4,
+    OUT main_data_length int4,
+    OUT fpi_length int4,
+    OUT description text,
+    OUT block_ref text
+)
+RETURNS SETOF record
+AS 'MODULE_PATHNAME', 'pg_get_wal_records_info'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+REVOKE EXECUTE ON FUNCTION pg_get_wal_records_info(pg_lsn, pg_lsn) FROM PUBLIC;
+GRANT EXECUTE ON FUNCTION pg_get_wal_records_info(pg_lsn, pg_lsn) TO pg_read_server_files;
+
+--
+-- pg_get_wal_records_info_till_end_of_wal()
+--
+CREATE FUNCTION pg_get_wal_records_info_till_end_of_wal(IN start_lsn pg_lsn,
+    OUT start_lsn pg_lsn,
+    OUT end_lsn pg_lsn,
+    OUT prev_lsn pg_lsn,
+    OUT xid xid,
+    OUT resource_manager text,
+    OUT record_type text,
+    OUT record_length int4,
+    OUT main_data_length int4,
+    OUT fpi_length int4,
+    OUT description text,
+    OUT block_ref text
+)
+RETURNS SETOF record
+AS 'MODULE_PATHNAME', 'pg_get_wal_records_info_till_end_of_wal'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+REVOKE EXECUTE ON FUNCTION pg_get_wal_records_info_till_end_of_wal(pg_lsn) FROM PUBLIC;
+GRANT EXECUTE ON FUNCTION pg_get_wal_records_info_till_end_of_wal(pg_lsn) TO pg_read_server_files;
+
+--
+-- pg_get_wal_stats()
+--
+CREATE FUNCTION pg_get_wal_stats(IN start_lsn pg_lsn,
+    IN end_lsn pg_lsn,
+    IN  per_record boolean DEFAULT false,
+    OUT "resource_manager/record_type" text,
+    OUT count int8,
+    OUT count_percentage float8,
+    OUT record_size int8,
+    OUT record_size_percentage float8,
+    OUT fpi_size int8,
+    OUT fpi_size_percentage float8,
+    OUT combined_size int8,
+    OUT combined_size_percentage float8
+)
+RETURNS SETOF record
+AS 'MODULE_PATHNAME', 'pg_get_wal_stats'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+REVOKE EXECUTE ON FUNCTION pg_get_wal_stats(pg_lsn, pg_lsn, boolean) FROM PUBLIC;
+GRANT EXECUTE ON FUNCTION pg_get_wal_stats(pg_lsn, pg_lsn, boolean) TO pg_read_server_files;
+
+--
+-- pg_get_wal_stats_till_end_of_wal()
+--
+CREATE FUNCTION pg_get_wal_stats_till_end_of_wal(IN start_lsn pg_lsn,
+    IN  per_record boolean DEFAULT false,
+    OUT "resource_manager/record_type" text,
+    OUT count int8,
+    OUT count_percentage float8,
+    OUT record_size int8,
+    OUT record_size_percentage float8,
+    OUT fpi_size int8,
+    OUT fpi_size_percentage float8,
+    OUT combined_size int8,
+    OUT combined_size_percentage float8
+)
+RETURNS SETOF record
+AS 'MODULE_PATHNAME', 'pg_get_wal_stats_till_end_of_wal'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+REVOKE EXECUTE ON FUNCTION pg_get_wal_stats_till_end_of_wal(pg_lsn, boolean) FROM PUBLIC;
+GRANT EXECUTE ON FUNCTION pg_get_wal_stats_till_end_of_wal(pg_lsn, boolean) TO pg_read_server_files;
diff --git a/contrib/pg_walinspect/pg_walinspect.c b/contrib/pg_walinspect/pg_walinspect.c
new file mode 100644
index 0000000..796a74f
--- /dev/null
+++ b/contrib/pg_walinspect/pg_walinspect.c
@@ -0,0 +1,851 @@
+/*-------------------------------------------------------------------------
+ *
+ * pg_walinspect.c
+ *		  Functions to inspect contents of PostgreSQL Write-Ahead Log
+ *
+ * Copyright (c) 2022-2023, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *		  contrib/pg_walinspect/pg_walinspect.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "access/xlog.h"
+#include "access/xlog_internal.h"
+#include "access/xlogreader.h"
+#include "access/xlogrecovery.h"
+#include "access/xlogstats.h"
+#include "access/xlogutils.h"
+#include "funcapi.h"
+#include "miscadmin.h"
+#include "utils/array.h"
+#include "utils/builtins.h"
+#include "utils/pg_lsn.h"
+
+/*
+ * NOTE: For any code change or issue fix here, it is highly recommended to
+ * give a thought about doing the same in pg_waldump tool as well.
+ */
+
+PG_MODULE_MAGIC;
+
+PG_FUNCTION_INFO_V1(pg_get_wal_block_info);
+PG_FUNCTION_INFO_V1(pg_get_wal_record_info);
+PG_FUNCTION_INFO_V1(pg_get_wal_records_info);
+PG_FUNCTION_INFO_V1(pg_get_wal_records_info_till_end_of_wal);
+PG_FUNCTION_INFO_V1(pg_get_wal_stats);
+PG_FUNCTION_INFO_V1(pg_get_wal_stats_till_end_of_wal);
+
+static void ValidateInputLSNs(XLogRecPtr start_lsn, XLogRecPtr *end_lsn);
+static XLogRecPtr GetCurrentLSN(void);
+static XLogReaderState *InitXLogReaderState(XLogRecPtr lsn);
+static XLogRecord *ReadNextXLogRecord(XLogReaderState *xlogreader);
+static void GetWALRecordInfo(XLogReaderState *record, Datum *values,
+							 bool *nulls, uint32 ncols);
+static void GetWALRecordsInfo(FunctionCallInfo fcinfo,
+							  XLogRecPtr start_lsn,
+							  XLogRecPtr end_lsn);
+static void GetXLogSummaryStats(XLogStats *stats, ReturnSetInfo *rsinfo,
+								Datum *values, bool *nulls, uint32 ncols,
+								bool stats_per_record);
+static void FillXLogStatsRow(const char *name, uint64 n, uint64 total_count,
+							 uint64 rec_len, uint64 total_rec_len,
+							 uint64 fpi_len, uint64 total_fpi_len,
+							 uint64 tot_len, uint64 total_len,
+							 Datum *values, bool *nulls, uint32 ncols);
+static void GetWalStats(FunctionCallInfo fcinfo,
+						XLogRecPtr start_lsn,
+						XLogRecPtr end_lsn,
+						bool stats_per_record);
+static void GetWALBlockInfo(FunctionCallInfo fcinfo, XLogReaderState *record,
+							bool show_data);
+
+/*
+ * Return the LSN up to which the server has WAL.
+ */
+static XLogRecPtr
+GetCurrentLSN(void)
+{
+	XLogRecPtr	curr_lsn;
+
+	/*
+	 * We determine the current LSN of the server similar to how page_read
+	 * callback read_local_xlog_page_no_wait does.
+	 */
+	if (!RecoveryInProgress())
+		curr_lsn = GetFlushRecPtr(NULL);
+	else
+		curr_lsn = GetXLogReplayRecPtr(NULL);
+
+	Assert(!XLogRecPtrIsInvalid(curr_lsn));
+
+	return curr_lsn;
+}
+
+/*
+ * Initialize WAL reader and identify first valid LSN.
+ */
+static XLogReaderState *
+InitXLogReaderState(XLogRecPtr lsn)
+{
+	XLogReaderState *xlogreader;
+	ReadLocalXLogPageNoWaitPrivate *private_data;
+	XLogRecPtr	first_valid_record;
+
+	/*
+	 * Reading WAL below the first page of the first segments isn't allowed.
+	 * This is a bootstrap WAL page and the page_read callback fails to read
+	 * it.
+	 */
+	if (lsn < XLOG_BLCKSZ)
+		ereport(ERROR,
+				(errmsg("could not read WAL at LSN %X/%X",
+						LSN_FORMAT_ARGS(lsn))));
+
+	private_data = (ReadLocalXLogPageNoWaitPrivate *)
+		palloc0(sizeof(ReadLocalXLogPageNoWaitPrivate));
+
+	xlogreader = XLogReaderAllocate(wal_segment_size, NULL,
+									XL_ROUTINE(.page_read = &read_local_xlog_page_no_wait,
+											   .segment_open = &wal_segment_open,
+											   .segment_close = &wal_segment_close),
+									private_data);
+
+	if (xlogreader == NULL)
+		ereport(ERROR,
+				(errcode(ERRCODE_OUT_OF_MEMORY),
+				 errmsg("out of memory"),
+				 errdetail("Failed while allocating a WAL reading processor.")));
+
+	/* first find a valid recptr to start from */
+	first_valid_record = XLogFindNextRecord(xlogreader, lsn);
+
+	if (XLogRecPtrIsInvalid(first_valid_record))
+		ereport(ERROR,
+				(errmsg("could not find a valid record after %X/%X",
+						LSN_FORMAT_ARGS(lsn))));
+
+	return xlogreader;
+}
+
+/*
+ * Read next WAL record.
+ *
+ * By design, to be less intrusive in a running system, no slot is allocated
+ * to reserve the WAL we're about to read. Therefore this function can
+ * encounter read errors for historical WAL.
+ *
+ * We guard against ordinary errors trying to read WAL that hasn't been
+ * written yet by limiting end_lsn to the flushed WAL, but that can also
+ * encounter errors if the flush pointer falls in the middle of a record. In
+ * that case we'll return NULL.
+ */
+static XLogRecord *
+ReadNextXLogRecord(XLogReaderState *xlogreader)
+{
+	XLogRecord *record;
+	char	   *errormsg;
+
+	record = XLogReadRecord(xlogreader, &errormsg);
+
+	if (record == NULL)
+	{
+		ReadLocalXLogPageNoWaitPrivate *private_data;
+
+		/* return NULL, if end of WAL is reached */
+		private_data = (ReadLocalXLogPageNoWaitPrivate *)
+			xlogreader->private_data;
+
+		if (private_data->end_of_wal)
+			return NULL;
+
+		if (errormsg)
+			ereport(ERROR,
+					(errcode_for_file_access(),
+					 errmsg("could not read WAL at %X/%X: %s",
+							LSN_FORMAT_ARGS(xlogreader->EndRecPtr), errormsg)));
+		else
+			ereport(ERROR,
+					(errcode_for_file_access(),
+					 errmsg("could not read WAL at %X/%X",
+							LSN_FORMAT_ARGS(xlogreader->EndRecPtr))));
+	}
+
+	return record;
+}
+
+/*
+ * Output values that make up a row describing caller's WAL record.
+ *
+ * This function leaks memory.  Caller may need to use its own custom memory
+ * context.
+ *
+ * Keep this in sync with GetWALBlockInfo.
+ */
+static void
+GetWALRecordInfo(XLogReaderState *record, Datum *values,
+				 bool *nulls, uint32 ncols)
+{
+	const char *record_type;
+	RmgrData	desc;
+	uint32		fpi_len = 0;
+	StringInfoData rec_desc;
+	StringInfoData rec_blk_ref;
+	int			i = 0;
+
+	desc = GetRmgr(XLogRecGetRmid(record));
+	record_type = desc.rm_identify(XLogRecGetInfo(record));
+
+	if (record_type == NULL)
+		record_type = psprintf("UNKNOWN (%x)", XLogRecGetInfo(record) & ~XLR_INFO_MASK);
+
+	initStringInfo(&rec_desc);
+	desc.rm_desc(&rec_desc, record);
+
+	if (XLogRecHasAnyBlockRefs(record))
+	{
+		initStringInfo(&rec_blk_ref);
+		XLogRecGetBlockRefInfo(record, false, true, &rec_blk_ref, &fpi_len);
+	}
+
+	values[i++] = LSNGetDatum(record->ReadRecPtr);
+	values[i++] = LSNGetDatum(record->EndRecPtr);
+	values[i++] = LSNGetDatum(XLogRecGetPrev(record));
+	values[i++] = TransactionIdGetDatum(XLogRecGetXid(record));
+	values[i++] = CStringGetTextDatum(desc.rm_name);
+	values[i++] = CStringGetTextDatum(record_type);
+	values[i++] = UInt32GetDatum(XLogRecGetTotalLen(record));
+	values[i++] = UInt32GetDatum(XLogRecGetDataLen(record));
+	values[i++] = UInt32GetDatum(fpi_len);
+
+	if (rec_desc.len > 0)
+		values[i++] = CStringGetTextDatum(rec_desc.data);
+	else
+		nulls[i++] = true;
+
+	if (XLogRecHasAnyBlockRefs(record))
+		values[i++] = CStringGetTextDatum(rec_blk_ref.data);
+	else
+		nulls[i++] = true;
+
+	Assert(i == ncols);
+}
+
+
+/*
+ * Output one or more rows in rsinfo tuple store, each describing a single
+ * block reference from caller's WAL record. (Should only be called with
+ * records that have block references.)
+ *
+ * This function leaks memory.  Caller may need to use its own custom memory
+ * context.
+ *
+ * Keep this in sync with GetWALRecordInfo.
+ */
+static void
+GetWALBlockInfo(FunctionCallInfo fcinfo, XLogReaderState *record,
+				bool show_data)
+{
+#define PG_GET_WAL_BLOCK_INFO_COLS 20
+	int			block_id;
+	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	RmgrData	desc;
+	const char *record_type;
+	StringInfoData rec_desc;
+
+	Assert(XLogRecHasAnyBlockRefs(record));
+
+	desc = GetRmgr(XLogRecGetRmid(record));
+	record_type = desc.rm_identify(XLogRecGetInfo(record));
+
+	if (record_type == NULL)
+		record_type = psprintf("UNKNOWN (%x)",
+							   XLogRecGetInfo(record) & ~XLR_INFO_MASK);
+
+	initStringInfo(&rec_desc);
+	desc.rm_desc(&rec_desc, record);
+
+	for (block_id = 0; block_id <= XLogRecMaxBlockId(record); block_id++)
+	{
+		DecodedBkpBlock *blk;
+		BlockNumber blkno;
+		RelFileLocator rnode;
+		ForkNumber	forknum;
+		Datum		values[PG_GET_WAL_BLOCK_INFO_COLS] = {0};
+		bool		nulls[PG_GET_WAL_BLOCK_INFO_COLS] = {0};
+		uint32		block_data_len = 0,
+					block_fpi_len = 0;
+		ArrayType  *block_fpi_info = NULL;
+		int			i = 0;
+
+		if (!XLogRecHasBlockRef(record, block_id))
+			continue;
+
+		blk = XLogRecGetBlock(record, block_id);
+
+		(void) XLogRecGetBlockTagExtended(record, block_id,
+										  &rnode, &forknum, &blkno, NULL);
+
+		/* Save block_data_len */
+		if (blk->has_data)
+			block_data_len = blk->data_len;
+
+		if (blk->has_image)
+		{
+			/* Block reference has an FPI, so prepare relevant output */
+			int			bitcnt;
+			int			cnt = 0;
+			Datum	   *flags;
+
+			/* Save block_fpi_len */
+			block_fpi_len = blk->bimg_len;
+
+			/* Construct and save block_fpi_info */
+			bitcnt = pg_popcount((const char *) &blk->bimg_info,
+								 sizeof(uint8));
+			flags = (Datum *) palloc0(sizeof(Datum) * bitcnt);
+			if ((blk->bimg_info & BKPIMAGE_HAS_HOLE) != 0)
+				flags[cnt++] = CStringGetTextDatum("HAS_HOLE");
+			if (blk->apply_image)
+				flags[cnt++] = CStringGetTextDatum("APPLY");
+			if ((blk->bimg_info & BKPIMAGE_COMPRESS_PGLZ) != 0)
+				flags[cnt++] = CStringGetTextDatum("COMPRESS_PGLZ");
+			if ((blk->bimg_info & BKPIMAGE_COMPRESS_LZ4) != 0)
+				flags[cnt++] = CStringGetTextDatum("COMPRESS_LZ4");
+			if ((blk->bimg_info & BKPIMAGE_COMPRESS_ZSTD) != 0)
+				flags[cnt++] = CStringGetTextDatum("COMPRESS_ZSTD");
+
+			Assert(cnt <= bitcnt);
+			block_fpi_info = construct_array_builtin(flags, cnt, TEXTOID);
+		}
+
+		/* start_lsn, end_lsn, prev_lsn, and blockid outputs */
+		values[i++] = LSNGetDatum(record->ReadRecPtr);
+		values[i++] = LSNGetDatum(record->EndRecPtr);
+		values[i++] = LSNGetDatum(XLogRecGetPrev(record));
+		values[i++] = Int16GetDatum(block_id);
+
+		/* relfile and block related outputs */
+		values[i++] = ObjectIdGetDatum(blk->rlocator.spcOid);
+		values[i++] = ObjectIdGetDatum(blk->rlocator.dbOid);
+		values[i++] = ObjectIdGetDatum(blk->rlocator.relNumber);
+		values[i++] = Int16GetDatum(forknum);
+		values[i++] = Int64GetDatum((int64) blkno);
+
+		/* xid, resource_manager, and record_type outputs */
+		values[i++] = TransactionIdGetDatum(XLogRecGetXid(record));
+		values[i++] = CStringGetTextDatum(desc.rm_name);
+		values[i++] = CStringGetTextDatum(record_type);
+
+		/*
+		 * record_length, main_data_length, block_data_len, and
+		 * block_fpi_length outputs
+		 */
+		values[i++] = UInt32GetDatum(XLogRecGetTotalLen(record));
+		values[i++] = UInt32GetDatum(XLogRecGetDataLen(record));
+		values[i++] = UInt32GetDatum(block_data_len);
+		values[i++] = UInt32GetDatum(block_fpi_len);
+
+		/* block_fpi_info (text array) output */
+		if (block_fpi_info)
+			values[i++] = PointerGetDatum(block_fpi_info);
+		else
+			nulls[i++] = true;
+
+		/* description output (describes WAL record) */
+		if (rec_desc.len > 0)
+			values[i++] = CStringGetTextDatum(rec_desc.data);
+		else
+			nulls[i++] = true;
+
+		/* block_data output */
+		if (blk->has_data && show_data)
+		{
+			bytea	   *block_data;
+
+			block_data = (bytea *) palloc(block_data_len + VARHDRSZ);
+			SET_VARSIZE(block_data, block_data_len + VARHDRSZ);
+			memcpy(VARDATA(block_data), blk->data, block_data_len);
+			values[i++] = PointerGetDatum(block_data);
+		}
+		else
+			nulls[i++] = true;
+
+		/* block_fpi_data output */
+		if (blk->has_image && show_data)
+		{
+			PGAlignedBlock buf;
+			Page		page;
+			bytea	   *block_fpi_data;
+
+			page = (Page) buf.data;
+			if (!RestoreBlockImage(record, block_id, page))
+				ereport(ERROR,
+						(errcode(ERRCODE_INTERNAL_ERROR),
+						 errmsg_internal("%s", record->errormsg_buf)));
+
+			block_fpi_data = (bytea *) palloc(BLCKSZ + VARHDRSZ);
+			SET_VARSIZE(block_fpi_data, BLCKSZ + VARHDRSZ);
+			memcpy(VARDATA(block_fpi_data), page, BLCKSZ);
+			values[i++] = PointerGetDatum(block_fpi_data);
+		}
+		else
+			nulls[i++] = true;
+
+		Assert(i == PG_GET_WAL_BLOCK_INFO_COLS);
+
+		/* Store a tuple for this block reference */
+		tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc,
+							 values, nulls);
+	}
+
+#undef PG_GET_WAL_BLOCK_INFO_COLS
+}
+
+/*
+ * Get WAL record info, unnested by block reference
+ */
+Datum
+pg_get_wal_block_info(PG_FUNCTION_ARGS)
+{
+	XLogRecPtr	start_lsn = PG_GETARG_LSN(0);
+	XLogRecPtr	end_lsn = PG_GETARG_LSN(1);
+	bool		show_data = PG_GETARG_BOOL(2);
+	XLogReaderState *xlogreader;
+	MemoryContext old_cxt;
+	MemoryContext tmp_cxt;
+
+	ValidateInputLSNs(start_lsn, &end_lsn);
+
+	InitMaterializedSRF(fcinfo, 0);
+
+	xlogreader = InitXLogReaderState(start_lsn);
+
+	tmp_cxt = AllocSetContextCreate(CurrentMemoryContext,
+									"pg_get_wal_block_info temporary cxt",
+									ALLOCSET_DEFAULT_SIZES);
+
+	while (ReadNextXLogRecord(xlogreader) &&
+		   xlogreader->EndRecPtr <= end_lsn)
+	{
+		CHECK_FOR_INTERRUPTS();
+
+		if (!XLogRecHasAnyBlockRefs(xlogreader))
+			continue;
+
+		/* Use the tmp context so we can clean up after each tuple is done */
+		old_cxt = MemoryContextSwitchTo(tmp_cxt);
+
+		GetWALBlockInfo(fcinfo, xlogreader, show_data);
+
+		/* clean up and switch back */
+		MemoryContextSwitchTo(old_cxt);
+		MemoryContextReset(tmp_cxt);
+	}
+
+	MemoryContextDelete(tmp_cxt);
+	pfree(xlogreader->private_data);
+	XLogReaderFree(xlogreader);
+
+	PG_RETURN_VOID();
+}
+
+/*
+ * Get WAL record info.
+ */
+Datum
+pg_get_wal_record_info(PG_FUNCTION_ARGS)
+{
+#define PG_GET_WAL_RECORD_INFO_COLS 11
+	Datum		result;
+	Datum		values[PG_GET_WAL_RECORD_INFO_COLS] = {0};
+	bool		nulls[PG_GET_WAL_RECORD_INFO_COLS] = {0};
+	XLogRecPtr	lsn;
+	XLogRecPtr	curr_lsn;
+	XLogReaderState *xlogreader;
+	TupleDesc	tupdesc;
+	HeapTuple	tuple;
+
+	lsn = PG_GETARG_LSN(0);
+	curr_lsn = GetCurrentLSN();
+
+	if (lsn > curr_lsn)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("WAL input LSN must be less than current LSN"),
+				 errdetail("Current WAL LSN on the database system is at %X/%X.",
+						   LSN_FORMAT_ARGS(curr_lsn))));
+
+	/* Build a tuple descriptor for our result type. */
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	xlogreader = InitXLogReaderState(lsn);
+
+	if (!ReadNextXLogRecord(xlogreader))
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("could not read WAL at %X/%X",
+						LSN_FORMAT_ARGS(xlogreader->EndRecPtr))));
+
+	GetWALRecordInfo(xlogreader, values, nulls, PG_GET_WAL_RECORD_INFO_COLS);
+
+	pfree(xlogreader->private_data);
+	XLogReaderFree(xlogreader);
+
+	tuple = heap_form_tuple(tupdesc, values, nulls);
+	result = HeapTupleGetDatum(tuple);
+
+	PG_RETURN_DATUM(result);
+#undef PG_GET_WAL_RECORD_INFO_COLS
+}
+
+/*
+ * Validate start and end LSNs coming from the function inputs.
+ *
+ * If end_lsn is found to be higher than the current LSN reported by the
+ * cluster, use the current LSN as the upper bound.
+ */
+static void
+ValidateInputLSNs(XLogRecPtr start_lsn, XLogRecPtr *end_lsn)
+{
+	XLogRecPtr	curr_lsn = GetCurrentLSN();
+
+	if (start_lsn > curr_lsn)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("WAL start LSN must be less than current LSN"),
+				 errdetail("Current WAL LSN on the database system is at %X/%X.",
+						   LSN_FORMAT_ARGS(curr_lsn))));
+
+	if (start_lsn > *end_lsn)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("WAL start LSN must be less than end LSN")));
+
+	if (*end_lsn > curr_lsn)
+		*end_lsn = curr_lsn;
+}
+
+/*
+ * Get info of all WAL records between start LSN and end LSN.
+ */
+static void
+GetWALRecordsInfo(FunctionCallInfo fcinfo, XLogRecPtr start_lsn,
+				  XLogRecPtr end_lsn)
+{
+#define PG_GET_WAL_RECORDS_INFO_COLS 11
+	XLogReaderState *xlogreader;
+	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	MemoryContext old_cxt;
+	MemoryContext tmp_cxt;
+
+	Assert(start_lsn <= end_lsn);
+
+	InitMaterializedSRF(fcinfo, 0);
+
+	xlogreader = InitXLogReaderState(start_lsn);
+
+	tmp_cxt = AllocSetContextCreate(CurrentMemoryContext,
+									"GetWALRecordsInfo temporary cxt",
+									ALLOCSET_DEFAULT_SIZES);
+
+	while (ReadNextXLogRecord(xlogreader) &&
+		   xlogreader->EndRecPtr <= end_lsn)
+	{
+		Datum		values[PG_GET_WAL_RECORDS_INFO_COLS] = {0};
+		bool		nulls[PG_GET_WAL_RECORDS_INFO_COLS] = {0};
+
+		/* Use the tmp context so we can clean up after each tuple is done */
+		old_cxt = MemoryContextSwitchTo(tmp_cxt);
+
+		GetWALRecordInfo(xlogreader, values, nulls,
+						 PG_GET_WAL_RECORDS_INFO_COLS);
+
+		tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc,
+							 values, nulls);
+
+		/* clean up and switch back */
+		MemoryContextSwitchTo(old_cxt);
+		MemoryContextReset(tmp_cxt);
+
+		CHECK_FOR_INTERRUPTS();
+	}
+
+	MemoryContextDelete(tmp_cxt);
+	pfree(xlogreader->private_data);
+	XLogReaderFree(xlogreader);
+
+#undef PG_GET_WAL_RECORDS_INFO_COLS
+}
+
+/*
+ * Get info of all WAL records between start LSN and end LSN.
+ */
+Datum
+pg_get_wal_records_info(PG_FUNCTION_ARGS)
+{
+	XLogRecPtr	start_lsn = PG_GETARG_LSN(0);
+	XLogRecPtr	end_lsn = PG_GETARG_LSN(1);
+
+	ValidateInputLSNs(start_lsn, &end_lsn);
+	GetWALRecordsInfo(fcinfo, start_lsn, end_lsn);
+
+	PG_RETURN_VOID();
+}
+
+/*
+ * Fill single row of record counts and sizes for an rmgr or record.
+ */
+static void
+FillXLogStatsRow(const char *name,
+				 uint64 n, uint64 total_count,
+				 uint64 rec_len, uint64 total_rec_len,
+				 uint64 fpi_len, uint64 total_fpi_len,
+				 uint64 tot_len, uint64 total_len,
+				 Datum *values, bool *nulls, uint32 ncols)
+{
+	double		n_pct,
+				rec_len_pct,
+				fpi_len_pct,
+				tot_len_pct;
+	int			i = 0;
+
+	n_pct = 0;
+	if (total_count != 0)
+		n_pct = 100 * (double) n / total_count;
+
+	rec_len_pct = 0;
+	if (total_rec_len != 0)
+		rec_len_pct = 100 * (double) rec_len / total_rec_len;
+
+	fpi_len_pct = 0;
+	if (total_fpi_len != 0)
+		fpi_len_pct = 100 * (double) fpi_len / total_fpi_len;
+
+	tot_len_pct = 0;
+	if (total_len != 0)
+		tot_len_pct = 100 * (double) tot_len / total_len;
+
+	values[i++] = CStringGetTextDatum(name);
+	values[i++] = Int64GetDatum(n);
+	values[i++] = Float8GetDatum(n_pct);
+	values[i++] = Int64GetDatum(rec_len);
+	values[i++] = Float8GetDatum(rec_len_pct);
+	values[i++] = Int64GetDatum(fpi_len);
+	values[i++] = Float8GetDatum(fpi_len_pct);
+	values[i++] = Int64GetDatum(tot_len);
+	values[i++] = Float8GetDatum(tot_len_pct);
+
+	Assert(i == ncols);
+}
+
+/*
+ * Get summary statistics about the records seen so far.
+ */
+static void
+GetXLogSummaryStats(XLogStats *stats, ReturnSetInfo *rsinfo,
+					Datum *values, bool *nulls, uint32 ncols,
+					bool stats_per_record)
+{
+	MemoryContext old_cxt;
+	MemoryContext tmp_cxt;
+	uint64		total_count = 0;
+	uint64		total_rec_len = 0;
+	uint64		total_fpi_len = 0;
+	uint64		total_len = 0;
+	int			ri;
+
+	/*
+	 * Each row shows its percentages of the total, so make a first pass to
+	 * calculate column totals.
+	 */
+	for (ri = 0; ri <= RM_MAX_ID; ri++)
+	{
+		if (!RmgrIdIsValid(ri))
+			continue;
+
+		total_count += stats->rmgr_stats[ri].count;
+		total_rec_len += stats->rmgr_stats[ri].rec_len;
+		total_fpi_len += stats->rmgr_stats[ri].fpi_len;
+	}
+	total_len = total_rec_len + total_fpi_len;
+
+	tmp_cxt = AllocSetContextCreate(CurrentMemoryContext,
+									"GetXLogSummaryStats temporary cxt",
+									ALLOCSET_DEFAULT_SIZES);
+
+	for (ri = 0; ri <= RM_MAX_ID; ri++)
+	{
+		uint64		count;
+		uint64		rec_len;
+		uint64		fpi_len;
+		uint64		tot_len;
+		RmgrData	desc;
+
+		if (!RmgrIdIsValid(ri))
+			continue;
+
+		if (!RmgrIdExists(ri))
+			continue;
+
+		desc = GetRmgr(ri);
+
+		if (stats_per_record)
+		{
+			int			rj;
+
+			for (rj = 0; rj < MAX_XLINFO_TYPES; rj++)
+			{
+				const char *id;
+
+				count = stats->record_stats[ri][rj].count;
+				rec_len = stats->record_stats[ri][rj].rec_len;
+				fpi_len = stats->record_stats[ri][rj].fpi_len;
+				tot_len = rec_len + fpi_len;
+
+				/* Skip undefined combinations and ones that didn't occur */
+				if (count == 0)
+					continue;
+
+				old_cxt = MemoryContextSwitchTo(tmp_cxt);
+
+				/* the upper four bits in xl_info are the rmgr's */
+				id = desc.rm_identify(rj << 4);
+				if (id == NULL)
+					id = psprintf("UNKNOWN (%x)", rj << 4);
+
+				FillXLogStatsRow(psprintf("%s/%s", desc.rm_name, id), count,
+								 total_count, rec_len, total_rec_len, fpi_len,
+								 total_fpi_len, tot_len, total_len,
+								 values, nulls, ncols);
+
+				tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc,
+									 values, nulls);
+
+				/* clean up and switch back */
+				MemoryContextSwitchTo(old_cxt);
+				MemoryContextReset(tmp_cxt);
+			}
+		}
+		else
+		{
+			count = stats->rmgr_stats[ri].count;
+			rec_len = stats->rmgr_stats[ri].rec_len;
+			fpi_len = stats->rmgr_stats[ri].fpi_len;
+			tot_len = rec_len + fpi_len;
+
+			old_cxt = MemoryContextSwitchTo(tmp_cxt);
+
+			FillXLogStatsRow(desc.rm_name, count, total_count, rec_len,
+							 total_rec_len, fpi_len, total_fpi_len, tot_len,
+							 total_len, values, nulls, ncols);
+
+			tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc,
+								 values, nulls);
+
+			/* clean up and switch back */
+			MemoryContextSwitchTo(old_cxt);
+			MemoryContextReset(tmp_cxt);
+		}
+	}
+
+	MemoryContextDelete(tmp_cxt);
+}
+
+/*
+ * Get WAL stats between start LSN and end LSN.
+ */
+static void
+GetWalStats(FunctionCallInfo fcinfo, XLogRecPtr start_lsn, XLogRecPtr end_lsn,
+			bool stats_per_record)
+{
+#define PG_GET_WAL_STATS_COLS 9
+	XLogReaderState *xlogreader;
+	XLogStats	stats = {0};
+	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	Datum		values[PG_GET_WAL_STATS_COLS] = {0};
+	bool		nulls[PG_GET_WAL_STATS_COLS] = {0};
+
+	Assert(start_lsn <= end_lsn);
+
+	InitMaterializedSRF(fcinfo, 0);
+
+	xlogreader = InitXLogReaderState(start_lsn);
+
+	while (ReadNextXLogRecord(xlogreader) &&
+		   xlogreader->EndRecPtr <= end_lsn)
+	{
+		XLogRecStoreStats(&stats, xlogreader);
+
+		CHECK_FOR_INTERRUPTS();
+	}
+
+	pfree(xlogreader->private_data);
+	XLogReaderFree(xlogreader);
+
+	GetXLogSummaryStats(&stats, rsinfo, values, nulls,
+						PG_GET_WAL_STATS_COLS,
+						stats_per_record);
+
+#undef PG_GET_WAL_STATS_COLS
+}
+
+/*
+ * Get stats of all WAL records between start LSN and end LSN.
+ */
+Datum
+pg_get_wal_stats(PG_FUNCTION_ARGS)
+{
+	XLogRecPtr	start_lsn = PG_GETARG_LSN(0);
+	XLogRecPtr	end_lsn = PG_GETARG_LSN(1);
+	bool		stats_per_record = PG_GETARG_BOOL(2);
+
+	ValidateInputLSNs(start_lsn, &end_lsn);
+	GetWalStats(fcinfo, start_lsn, end_lsn, stats_per_record);
+
+	PG_RETURN_VOID();
+}
+
+/*
+ * The following functions have been removed in newer versions in 1.1, but
+ * they are kept around for compatibility.
+ */
+Datum
+pg_get_wal_records_info_till_end_of_wal(PG_FUNCTION_ARGS)
+{
+	XLogRecPtr	start_lsn = PG_GETARG_LSN(0);
+	XLogRecPtr	end_lsn = GetCurrentLSN();
+
+	if (start_lsn > end_lsn)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("WAL start LSN must be less than current LSN"),
+				 errdetail("Current WAL LSN on the database system is at %X/%X.",
+						   LSN_FORMAT_ARGS(end_lsn))));
+
+	GetWALRecordsInfo(fcinfo, start_lsn, end_lsn);
+
+	PG_RETURN_VOID();
+}
+
+Datum
+pg_get_wal_stats_till_end_of_wal(PG_FUNCTION_ARGS)
+{
+	XLogRecPtr	start_lsn = PG_GETARG_LSN(0);
+	XLogRecPtr	end_lsn = GetCurrentLSN();
+	bool		stats_per_record = PG_GETARG_BOOL(1);
+
+	if (start_lsn > end_lsn)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("WAL start LSN must be less than current LSN"),
+				 errdetail("Current WAL LSN on the database system is at %X/%X.",
+						   LSN_FORMAT_ARGS(end_lsn))));
+
+	GetWalStats(fcinfo, start_lsn, end_lsn, stats_per_record);
+
+	PG_RETURN_VOID();
+}
diff --git a/contrib/pg_walinspect/pg_walinspect.control b/contrib/pg_walinspect/pg_walinspect.control
new file mode 100644
index 0000000..efa3cb2
--- /dev/null
+++ b/contrib/pg_walinspect/pg_walinspect.control
@@ -0,0 +1,5 @@
+# pg_walinspect extension
+comment = 'functions to inspect contents of PostgreSQL Write-Ahead Log'
+default_version = '1.1'
+module_pathname = '$libdir/pg_walinspect'
+relocatable = true
diff --git a/contrib/pg_walinspect/sql/oldextversions.sql b/contrib/pg_walinspect/sql/oldextversions.sql
new file mode 100644
index 0000000..e35c4f3
--- /dev/null
+++ b/contrib/pg_walinspect/sql/oldextversions.sql
@@ -0,0 +1,39 @@
+-- Test old extension version entry points.
+
+CREATE EXTENSION pg_walinspect WITH VERSION '1.0';
+
+-- Mask DETAIL messages as these could refer to current LSN positions.
+\set VERBOSITY terse
+
+-- List what version 1.0 contains, using a locale-independent sorting.
+SELECT pg_describe_object(classid, objid, 0) AS obj
+  FROM pg_depend
+  WHERE refclassid = 'pg_extension'::regclass AND
+    refobjid = (SELECT oid FROM pg_extension
+                  WHERE extname = 'pg_walinspect') AND deptype = 'e'
+  ORDER BY pg_describe_object(classid, objid, 0) COLLATE "C";
+
+-- Make sure checkpoints don't interfere with the test.
+SELECT 'init' FROM pg_create_physical_replication_slot('regress_pg_walinspect_slot', true, false);
+
+CREATE TABLE sample_tbl(col1 int, col2 int);
+SELECT pg_current_wal_lsn() AS wal_lsn1 \gset
+INSERT INTO sample_tbl SELECT * FROM generate_series(1, 2);
+
+-- Tests for the past functions.
+SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_records_info_till_end_of_wal(:'wal_lsn1');
+SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_stats_till_end_of_wal(:'wal_lsn1');
+-- Failures with start LSNs.
+SELECT * FROM pg_get_wal_records_info_till_end_of_wal('FFFFFFFF/FFFFFFFF');
+SELECT * FROM pg_get_wal_stats_till_end_of_wal('FFFFFFFF/FFFFFFFF');
+
+-- Move to new version 1.1.
+ALTER EXTENSION pg_walinspect UPDATE TO '1.1';
+
+-- List what version 1.1 contains.
+\dx+ pg_walinspect
+
+SELECT pg_drop_replication_slot('regress_pg_walinspect_slot');
+
+DROP TABLE sample_tbl;
+DROP EXTENSION pg_walinspect;
diff --git a/contrib/pg_walinspect/sql/pg_walinspect.sql b/contrib/pg_walinspect/sql/pg_walinspect.sql
new file mode 100644
index 0000000..f987ca3
--- /dev/null
+++ b/contrib/pg_walinspect/sql/pg_walinspect.sql
@@ -0,0 +1,157 @@
+CREATE EXTENSION pg_walinspect;
+
+-- Mask DETAIL messages as these could refer to current LSN positions.
+\set VERBOSITY terse
+
+-- Make sure checkpoints don't interfere with the test.
+SELECT 'init' FROM pg_create_physical_replication_slot('regress_pg_walinspect_slot', true, false);
+
+CREATE TABLE sample_tbl(col1 int, col2 int);
+
+-- Save some LSNs for comparisons.
+SELECT pg_current_wal_lsn() AS wal_lsn1 \gset
+INSERT INTO sample_tbl SELECT * FROM generate_series(1, 2);
+SELECT pg_current_wal_lsn() AS wal_lsn2 \gset
+INSERT INTO sample_tbl SELECT * FROM generate_series(3, 4);
+
+-- ===================================================================
+-- Tests for input validation
+-- ===================================================================
+
+-- Invalid input LSN.
+SELECT * FROM pg_get_wal_record_info('0/0');
+
+-- Invalid start LSN.
+SELECT * FROM pg_get_wal_records_info('0/0', :'wal_lsn1');
+SELECT * FROM pg_get_wal_stats('0/0', :'wal_lsn1');
+SELECT * FROM pg_get_wal_block_info('0/0', :'wal_lsn1');
+
+-- Start LSN > End LSN.
+SELECT * FROM pg_get_wal_records_info(:'wal_lsn2', :'wal_lsn1');
+SELECT * FROM pg_get_wal_stats(:'wal_lsn2', :'wal_lsn1');
+SELECT * FROM pg_get_wal_block_info(:'wal_lsn2', :'wal_lsn1');
+
+-- LSNs with the highest value possible.
+SELECT * FROM pg_get_wal_record_info('FFFFFFFF/FFFFFFFF');
+-- Success with end LSNs.
+SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_records_info(:'wal_lsn1', 'FFFFFFFF/FFFFFFFF');
+SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_stats(:'wal_lsn1', 'FFFFFFFF/FFFFFFFF');
+SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_block_info(:'wal_lsn1', 'FFFFFFFF/FFFFFFFF');
+-- Failures with start LSNs.
+SELECT * FROM pg_get_wal_records_info('FFFFFFFF/FFFFFFFE', 'FFFFFFFF/FFFFFFFF');
+SELECT * FROM pg_get_wal_stats('FFFFFFFF/FFFFFFFE', 'FFFFFFFF/FFFFFFFF');
+SELECT * FROM pg_get_wal_block_info('FFFFFFFF/FFFFFFFE', 'FFFFFFFF/FFFFFFFF');
+
+-- ===================================================================
+-- Tests for all function executions
+-- ===================================================================
+
+SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_record_info(:'wal_lsn1');
+SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_records_info(:'wal_lsn1', :'wal_lsn2');
+SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_stats(:'wal_lsn1', :'wal_lsn2');
+SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_block_info(:'wal_lsn1', :'wal_lsn2');
+
+-- ===================================================================
+-- Test for filtering out WAL records of a particular table
+-- ===================================================================
+
+SELECT oid AS sample_tbl_oid FROM pg_class WHERE relname = 'sample_tbl' \gset
+
+SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_records_info(:'wal_lsn1', :'wal_lsn2')
+			WHERE block_ref LIKE concat('%', :'sample_tbl_oid', '%') AND resource_manager = 'Heap';
+
+-- ===================================================================
+-- Test for filtering out WAL records based on resource_manager and
+-- record_type
+-- ===================================================================
+
+SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_records_info(:'wal_lsn1', :'wal_lsn2')
+			WHERE resource_manager = 'Heap' AND record_type = 'INSERT';
+
+-- ===================================================================
+-- Tests to get block information from WAL record
+-- ===================================================================
+
+-- Update table to generate some block data.
+SELECT pg_current_wal_lsn() AS wal_lsn3 \gset
+UPDATE sample_tbl SET col1 = col1 + 1 WHERE col1 = 1;
+SELECT pg_current_wal_lsn() AS wal_lsn4 \gset
+-- Check if we get block data from WAL record.
+SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_block_info(:'wal_lsn3', :'wal_lsn4')
+  WHERE relfilenode = :'sample_tbl_oid' AND block_data IS NOT NULL;
+
+-- Force full-page image on the next update.
+SELECT pg_current_wal_lsn() AS wal_lsn5 \gset
+CHECKPOINT;
+UPDATE sample_tbl SET col1 = col1 + 1 WHERE col1 = 2;
+SELECT pg_current_wal_lsn() AS wal_lsn6 \gset
+-- Check if we get FPI from WAL record.
+SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_block_info(:'wal_lsn5', :'wal_lsn6')
+  WHERE relfilenode = :'sample_tbl_oid' AND block_fpi_data IS NOT NULL;
+
+-- ===================================================================
+-- Tests for permissions
+-- ===================================================================
+CREATE ROLE regress_pg_walinspect;
+
+SELECT has_function_privilege('regress_pg_walinspect',
+  'pg_get_wal_record_info(pg_lsn)', 'EXECUTE'); -- no
+SELECT has_function_privilege('regress_pg_walinspect',
+  'pg_get_wal_records_info(pg_lsn, pg_lsn) ', 'EXECUTE'); -- no
+SELECT has_function_privilege('regress_pg_walinspect',
+  'pg_get_wal_stats(pg_lsn, pg_lsn, boolean) ', 'EXECUTE'); -- no
+SELECT has_function_privilege('regress_pg_walinspect',
+  'pg_get_wal_block_info(pg_lsn, pg_lsn, boolean) ', 'EXECUTE'); -- no
+
+-- Functions accessible by users with role pg_read_server_files.
+GRANT pg_read_server_files TO regress_pg_walinspect;
+
+SELECT has_function_privilege('regress_pg_walinspect',
+  'pg_get_wal_record_info(pg_lsn)', 'EXECUTE'); -- yes
+SELECT has_function_privilege('regress_pg_walinspect',
+  'pg_get_wal_records_info(pg_lsn, pg_lsn) ', 'EXECUTE'); -- yes
+SELECT has_function_privilege('regress_pg_walinspect',
+  'pg_get_wal_stats(pg_lsn, pg_lsn, boolean) ', 'EXECUTE'); -- yes
+SELECT has_function_privilege('regress_pg_walinspect',
+  'pg_get_wal_block_info(pg_lsn, pg_lsn, boolean) ', 'EXECUTE'); -- yes
+
+REVOKE pg_read_server_files FROM regress_pg_walinspect;
+
+-- Superuser can grant execute to other users.
+GRANT EXECUTE ON FUNCTION pg_get_wal_record_info(pg_lsn)
+  TO regress_pg_walinspect;
+GRANT EXECUTE ON FUNCTION pg_get_wal_records_info(pg_lsn, pg_lsn)
+  TO regress_pg_walinspect;
+GRANT EXECUTE ON FUNCTION pg_get_wal_stats(pg_lsn, pg_lsn, boolean)
+  TO regress_pg_walinspect;
+GRANT EXECUTE ON FUNCTION pg_get_wal_block_info(pg_lsn, pg_lsn, boolean)
+  TO regress_pg_walinspect;
+
+SELECT has_function_privilege('regress_pg_walinspect',
+  'pg_get_wal_record_info(pg_lsn)', 'EXECUTE'); -- yes
+SELECT has_function_privilege('regress_pg_walinspect',
+  'pg_get_wal_records_info(pg_lsn, pg_lsn) ', 'EXECUTE'); -- yes
+SELECT has_function_privilege('regress_pg_walinspect',
+  'pg_get_wal_stats(pg_lsn, pg_lsn, boolean) ', 'EXECUTE'); -- yes
+SELECT has_function_privilege('regress_pg_walinspect',
+  'pg_get_wal_block_info(pg_lsn, pg_lsn, boolean) ', 'EXECUTE'); -- yes
+
+REVOKE EXECUTE ON FUNCTION pg_get_wal_record_info(pg_lsn)
+  FROM regress_pg_walinspect;
+REVOKE EXECUTE ON FUNCTION pg_get_wal_records_info(pg_lsn, pg_lsn)
+  FROM regress_pg_walinspect;
+REVOKE EXECUTE ON FUNCTION pg_get_wal_stats(pg_lsn, pg_lsn, boolean)
+  FROM regress_pg_walinspect;
+REVOKE EXECUTE ON FUNCTION pg_get_wal_block_info(pg_lsn, pg_lsn, boolean)
+  FROM regress_pg_walinspect;
+
+-- ===================================================================
+-- Clean up
+-- ===================================================================
+
+DROP ROLE regress_pg_walinspect;
+
+SELECT pg_drop_replication_slot('regress_pg_walinspect_slot');
+
+DROP TABLE sample_tbl;
+DROP EXTENSION pg_walinspect;
diff --git a/contrib/pg_walinspect/walinspect.conf b/contrib/pg_walinspect/walinspect.conf
new file mode 100644
index 0000000..67ceb2b
--- /dev/null
+++ b/contrib/pg_walinspect/walinspect.conf
@@ -0,0 +1,2 @@
+wal_level = replica
+max_replication_slots = 4