Adding upstream version 13.4.upstream/13.4upstream

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

33 files changed, 4605 insertions, 0 deletions

diff --git a/contrib/pageinspect/.gitignore b/contrib/pageinspect/.gitignore
new file mode 100644
index 0000000..5dcb3ff
--- /dev/null
+++ b/contrib/pageinspect/.gitignore
@@ -0,0 +1,4 @@
+# Generated subdirectories
+/log/
+/results/
+/tmp_check/
diff --git a/contrib/pageinspect/Makefile b/contrib/pageinspect/Makefile
new file mode 100644
index 0000000..d9d8177
--- /dev/null
+++ b/contrib/pageinspect/Makefile
@@ -0,0 +1,33 @@
+# contrib/pageinspect/Makefile
+
+MODULE_big	= pageinspect
+OBJS = \
+	$(WIN32RES) \
+	brinfuncs.o \
+	btreefuncs.o \
+	fsmfuncs.o \
+	ginfuncs.o \
+	hashfuncs.o \
+	heapfuncs.o \
+	rawpage.o
+
+EXTENSION = pageinspect
+DATA =  pageinspect--1.7--1.8.sql pageinspect--1.6--1.7.sql \
+	pageinspect--1.5.sql pageinspect--1.5--1.6.sql \
+	pageinspect--1.4--1.5.sql pageinspect--1.3--1.4.sql \
+	pageinspect--1.2--1.3.sql pageinspect--1.1--1.2.sql \
+	pageinspect--1.0--1.1.sql
+PGFILEDESC = "pageinspect - functions to inspect contents of database pages"
+
+REGRESS = page btree brin gin hash checksum
+
+ifdef USE_PGXS
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+subdir = contrib/pageinspect
+top_builddir = ../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif
diff --git a/contrib/pageinspect/brinfuncs.c b/contrib/pageinspect/brinfuncs.c
new file mode 100644
index 0000000..fb32d74
--- /dev/null
+++ b/contrib/pageinspect/brinfuncs.c
@@ -0,0 +1,410 @@
+/*
+ * brinfuncs.c
+ *		Functions to investigate BRIN indexes
+ *
+ * Copyright (c) 2014-2020, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *		contrib/pageinspect/brinfuncs.c
+ */
+#include "postgres.h"
+
+#include "access/brin.h"
+#include "access/brin_internal.h"
+#include "access/brin_page.h"
+#include "access/brin_revmap.h"
+#include "access/brin_tuple.h"
+#include "access/htup_details.h"
+#include "catalog/index.h"
+#include "catalog/pg_type.h"
+#include "funcapi.h"
+#include "lib/stringinfo.h"
+#include "miscadmin.h"
+#include "pageinspect.h"
+#include "utils/array.h"
+#include "utils/builtins.h"
+#include "utils/lsyscache.h"
+#include "utils/rel.h"
+
+PG_FUNCTION_INFO_V1(brin_page_type);
+PG_FUNCTION_INFO_V1(brin_page_items);
+PG_FUNCTION_INFO_V1(brin_metapage_info);
+PG_FUNCTION_INFO_V1(brin_revmap_data);
+
+typedef struct brin_column_state
+{
+	int			nstored;
+	FmgrInfo	outputFn[FLEXIBLE_ARRAY_MEMBER];
+} brin_column_state;
+
+
+static Page verify_brin_page(bytea *raw_page, uint16 type,
+							 const char *strtype);
+
+Datum
+brin_page_type(PG_FUNCTION_ARGS)
+{
+	bytea	   *raw_page = PG_GETARG_BYTEA_P(0);
+	Page		page = VARDATA(raw_page);
+	int			raw_page_size;
+	char	   *type;
+
+	if (!superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("must be superuser to use raw page functions")));
+
+	raw_page_size = VARSIZE(raw_page) - VARHDRSZ;
+
+	if (raw_page_size != BLCKSZ)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("input page too small"),
+				 errdetail("Expected size %d, got %d",
+						   BLCKSZ, raw_page_size)));
+
+	switch (BrinPageType(page))
+	{
+		case BRIN_PAGETYPE_META:
+			type = "meta";
+			break;
+		case BRIN_PAGETYPE_REVMAP:
+			type = "revmap";
+			break;
+		case BRIN_PAGETYPE_REGULAR:
+			type = "regular";
+			break;
+		default:
+			type = psprintf("unknown (%02x)", BrinPageType(page));
+			break;
+	}
+
+	PG_RETURN_TEXT_P(cstring_to_text(type));
+}
+
+/*
+ * Verify that the given bytea contains a BRIN page of the indicated page
+ * type, or die in the attempt.  A pointer to the page is returned.
+ */
+static Page
+verify_brin_page(bytea *raw_page, uint16 type, const char *strtype)
+{
+	Page		page;
+	int			raw_page_size;
+
+	raw_page_size = VARSIZE(raw_page) - VARHDRSZ;
+
+	if (raw_page_size != BLCKSZ)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("input page too small"),
+				 errdetail("Expected size %d, got %d",
+						   BLCKSZ, raw_page_size)));
+
+	page = VARDATA(raw_page);
+
+	/* verify the special space says this page is what we want */
+	if (BrinPageType(page) != type)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("page is not a BRIN page of type \"%s\"", strtype),
+				 errdetail("Expected special type %08x, got %08x.",
+						   type, BrinPageType(page))));
+
+	return page;
+}
+
+
+/*
+ * Extract all item values from a BRIN index page
+ *
+ * Usage: SELECT * FROM brin_page_items(get_raw_page('idx', 1), 'idx'::regclass);
+ */
+Datum
+brin_page_items(PG_FUNCTION_ARGS)
+{
+	bytea	   *raw_page = PG_GETARG_BYTEA_P(0);
+	Oid			indexRelid = PG_GETARG_OID(1);
+	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc	tupdesc;
+	MemoryContext oldcontext;
+	Tuplestorestate *tupstore;
+	Relation	indexRel;
+	brin_column_state **columns;
+	BrinDesc   *bdesc;
+	BrinMemTuple *dtup;
+	Page		page;
+	OffsetNumber offset;
+	AttrNumber	attno;
+	bool		unusedItem;
+
+	if (!superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("must be superuser to use raw page functions")));
+
+	/* check to see if caller supports us returning a tuplestore */
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize) ||
+		rsinfo->expectedDesc == NULL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	/* 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");
+
+	/* Build tuplestore to hold the result rows */
+	oldcontext = MemoryContextSwitchTo(rsinfo->econtext->ecxt_per_query_memory);
+
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+
+	MemoryContextSwitchTo(oldcontext);
+
+	indexRel = index_open(indexRelid, AccessShareLock);
+	bdesc = brin_build_desc(indexRel);
+
+	/* minimally verify the page we got */
+	page = verify_brin_page(raw_page, BRIN_PAGETYPE_REGULAR, "regular");
+
+	/*
+	 * Initialize output functions for all indexed datatypes; simplifies
+	 * calling them later.
+	 */
+	columns = palloc(sizeof(brin_column_state *) * RelationGetDescr(indexRel)->natts);
+	for (attno = 1; attno <= bdesc->bd_tupdesc->natts; attno++)
+	{
+		Oid			output;
+		bool		isVarlena;
+		BrinOpcInfo *opcinfo;
+		int			i;
+		brin_column_state *column;
+
+		opcinfo = bdesc->bd_info[attno - 1];
+		column = palloc(offsetof(brin_column_state, outputFn) +
+						sizeof(FmgrInfo) * opcinfo->oi_nstored);
+
+		column->nstored = opcinfo->oi_nstored;
+		for (i = 0; i < opcinfo->oi_nstored; i++)
+		{
+			getTypeOutputInfo(opcinfo->oi_typcache[i]->type_id, &output, &isVarlena);
+			fmgr_info(output, &column->outputFn[i]);
+		}
+
+		columns[attno - 1] = column;
+	}
+
+	offset = FirstOffsetNumber;
+	unusedItem = false;
+	dtup = NULL;
+	for (;;)
+	{
+		Datum		values[7];
+		bool		nulls[7];
+
+		/*
+		 * This loop is called once for every attribute of every tuple in the
+		 * page.  At the start of a tuple, we get a NULL dtup; that's our
+		 * signal for obtaining and decoding the next one.  If that's not the
+		 * case, we output the next attribute.
+		 */
+		if (dtup == NULL)
+		{
+			ItemId		itemId;
+
+			/* verify item status: if there's no data, we can't decode */
+			itemId = PageGetItemId(page, offset);
+			if (ItemIdIsUsed(itemId))
+			{
+				dtup = brin_deform_tuple(bdesc,
+										 (BrinTuple *) PageGetItem(page, itemId),
+										 NULL);
+				attno = 1;
+				unusedItem = false;
+			}
+			else
+				unusedItem = true;
+		}
+		else
+			attno++;
+
+		MemSet(nulls, 0, sizeof(nulls));
+
+		if (unusedItem)
+		{
+			values[0] = UInt16GetDatum(offset);
+			nulls[1] = true;
+			nulls[2] = true;
+			nulls[3] = true;
+			nulls[4] = true;
+			nulls[5] = true;
+			nulls[6] = true;
+		}
+		else
+		{
+			int			att = attno - 1;
+
+			values[0] = UInt16GetDatum(offset);
+			values[1] = UInt32GetDatum(dtup->bt_blkno);
+			values[2] = UInt16GetDatum(attno);
+			values[3] = BoolGetDatum(dtup->bt_columns[att].bv_allnulls);
+			values[4] = BoolGetDatum(dtup->bt_columns[att].bv_hasnulls);
+			values[5] = BoolGetDatum(dtup->bt_placeholder);
+			if (!dtup->bt_columns[att].bv_allnulls)
+			{
+				BrinValues *bvalues = &dtup->bt_columns[att];
+				StringInfoData s;
+				bool		first;
+				int			i;
+
+				initStringInfo(&s);
+				appendStringInfoChar(&s, '{');
+
+				first = true;
+				for (i = 0; i < columns[att]->nstored; i++)
+				{
+					char	   *val;
+
+					if (!first)
+						appendStringInfoString(&s, " .. ");
+					first = false;
+					val = OutputFunctionCall(&columns[att]->outputFn[i],
+											 bvalues->bv_values[i]);
+					appendStringInfoString(&s, val);
+					pfree(val);
+				}
+				appendStringInfoChar(&s, '}');
+
+				values[6] = CStringGetTextDatum(s.data);
+				pfree(s.data);
+			}
+			else
+			{
+				nulls[6] = true;
+			}
+		}
+
+		tuplestore_putvalues(tupstore, tupdesc, values, nulls);
+
+		/*
+		 * If the item was unused, jump straight to the next one; otherwise,
+		 * the only cleanup needed here is to set our signal to go to the next
+		 * tuple in the following iteration, by freeing the current one.
+		 */
+		if (unusedItem)
+			offset = OffsetNumberNext(offset);
+		else if (attno >= bdesc->bd_tupdesc->natts)
+		{
+			pfree(dtup);
+			dtup = NULL;
+			offset = OffsetNumberNext(offset);
+		}
+
+		/*
+		 * If we're beyond the end of the page, we're done.
+		 */
+		if (offset > PageGetMaxOffsetNumber(page))
+			break;
+	}
+
+	/* clean up and return the tuplestore */
+	brin_free_desc(bdesc);
+	tuplestore_donestoring(tupstore);
+	index_close(indexRel, AccessShareLock);
+
+	return (Datum) 0;
+}
+
+Datum
+brin_metapage_info(PG_FUNCTION_ARGS)
+{
+	bytea	   *raw_page = PG_GETARG_BYTEA_P(0);
+	Page		page;
+	BrinMetaPageData *meta;
+	TupleDesc	tupdesc;
+	Datum		values[4];
+	bool		nulls[4];
+	HeapTuple	htup;
+
+	if (!superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("must be superuser to use raw page functions")));
+
+	page = verify_brin_page(raw_page, BRIN_PAGETYPE_META, "metapage");
+
+	/* 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");
+	tupdesc = BlessTupleDesc(tupdesc);
+
+	/* Extract values from the metapage */
+	meta = (BrinMetaPageData *) PageGetContents(page);
+	MemSet(nulls, 0, sizeof(nulls));
+	values[0] = CStringGetTextDatum(psprintf("0x%08X", meta->brinMagic));
+	values[1] = Int32GetDatum(meta->brinVersion);
+	values[2] = Int32GetDatum(meta->pagesPerRange);
+	values[3] = Int64GetDatum(meta->lastRevmapPage);
+
+	htup = heap_form_tuple(tupdesc, values, nulls);
+
+	PG_RETURN_DATUM(HeapTupleGetDatum(htup));
+}
+
+/*
+ * Return the TID array stored in a BRIN revmap page
+ */
+Datum
+brin_revmap_data(PG_FUNCTION_ARGS)
+{
+	struct
+	{
+		ItemPointerData *tids;
+		int			idx;
+	}		   *state;
+	FuncCallContext *fctx;
+
+	if (!superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("must be superuser to use raw page functions")));
+
+	if (SRF_IS_FIRSTCALL())
+	{
+		bytea	   *raw_page = PG_GETARG_BYTEA_P(0);
+		MemoryContext mctx;
+		Page		page;
+
+		/* minimally verify the page we got */
+		page = verify_brin_page(raw_page, BRIN_PAGETYPE_REVMAP, "revmap");
+
+		/* create a function context for cross-call persistence */
+		fctx = SRF_FIRSTCALL_INIT();
+
+		/* switch to memory context appropriate for multiple function calls */
+		mctx = MemoryContextSwitchTo(fctx->multi_call_memory_ctx);
+
+		state = palloc(sizeof(*state));
+		state->tids = ((RevmapContents *) PageGetContents(page))->rm_tids;
+		state->idx = 0;
+
+		fctx->user_fctx = state;
+
+		MemoryContextSwitchTo(mctx);
+	}
+
+	fctx = SRF_PERCALL_SETUP();
+	state = fctx->user_fctx;
+
+	if (state->idx < REVMAP_PAGE_MAXITEMS)
+		SRF_RETURN_NEXT(fctx, PointerGetDatum(&state->tids[state->idx++]));
+
+	SRF_RETURN_DONE(fctx);
+}
diff --git a/contrib/pageinspect/btreefuncs.c b/contrib/pageinspect/btreefuncs.c
new file mode 100644
index 0000000..e7a3230
--- /dev/null
+++ b/contrib/pageinspect/btreefuncs.c
@@ -0,0 +1,704 @@
+/*
+ * contrib/pageinspect/btreefuncs.c
+ *
+ *
+ * btreefuncs.c
+ *
+ * Copyright (c) 2006 Satoshi Nagayasu <nagayasus@nttdata.co.jp>
+ *
+ * Permission to use, copy, modify, and distribute this software and
+ * its documentation for any purpose, without fee, and without a
+ * written agreement is hereby granted, provided that the above
+ * copyright notice and this paragraph and the following two
+ * paragraphs appear in all copies.
+ *
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE TO ANY PARTY FOR DIRECT,
+ * INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING
+ * LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
+ * DOCUMENTATION, EVEN IF THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * THE AUTHOR SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS
+ * IS" BASIS, AND THE AUTHOR HAS NO OBLIGATIONS TO PROVIDE MAINTENANCE,
+ * SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+ */
+
+#include "postgres.h"
+
+#include "access/nbtree.h"
+#include "access/relation.h"
+#include "catalog/namespace.h"
+#include "catalog/pg_am.h"
+#include "catalog/pg_type.h"
+#include "funcapi.h"
+#include "miscadmin.h"
+#include "pageinspect.h"
+#include "utils/array.h"
+#include "utils/builtins.h"
+#include "utils/rel.h"
+#include "utils/varlena.h"
+
+PG_FUNCTION_INFO_V1(bt_metap);
+PG_FUNCTION_INFO_V1(bt_page_items);
+PG_FUNCTION_INFO_V1(bt_page_items_bytea);
+PG_FUNCTION_INFO_V1(bt_page_stats);
+
+#define IS_INDEX(r) ((r)->rd_rel->relkind == RELKIND_INDEX)
+#define IS_BTREE(r) ((r)->rd_rel->relam == BTREE_AM_OID)
+#define DatumGetItemPointer(X)	 ((ItemPointer) DatumGetPointer(X))
+#define ItemPointerGetDatum(X)	 PointerGetDatum(X)
+
+/* note: BlockNumber is unsigned, hence can't be negative */
+#define CHECK_RELATION_BLOCK_RANGE(rel, blkno) { \
+		if ( RelationGetNumberOfBlocks(rel) <= (BlockNumber) (blkno) ) \
+			 elog(ERROR, "block number out of range"); }
+
+/* ------------------------------------------------
+ * structure for single btree page statistics
+ * ------------------------------------------------
+ */
+typedef struct BTPageStat
+{
+	uint32		blkno;
+	uint32		live_items;
+	uint32		dead_items;
+	uint32		page_size;
+	uint32		max_avail;
+	uint32		free_size;
+	uint32		avg_item_size;
+	char		type;
+
+	/* opaque data */
+	BlockNumber btpo_prev;
+	BlockNumber btpo_next;
+	union
+	{
+		uint32		level;
+		TransactionId xact;
+	}			btpo;
+	uint16		btpo_flags;
+	BTCycleId	btpo_cycleid;
+} BTPageStat;
+
+
+/* -------------------------------------------------
+ * GetBTPageStatistics()
+ *
+ * Collect statistics of single b-tree page
+ * -------------------------------------------------
+ */
+static void
+GetBTPageStatistics(BlockNumber blkno, Buffer buffer, BTPageStat *stat)
+{
+	Page		page = BufferGetPage(buffer);
+	PageHeader	phdr = (PageHeader) page;
+	OffsetNumber maxoff = PageGetMaxOffsetNumber(page);
+	BTPageOpaque opaque = (BTPageOpaque) PageGetSpecialPointer(page);
+	int			item_size = 0;
+	int			off;
+
+	stat->blkno = blkno;
+
+	stat->max_avail = BLCKSZ - (BLCKSZ - phdr->pd_special + SizeOfPageHeaderData);
+
+	stat->dead_items = stat->live_items = 0;
+
+	stat->page_size = PageGetPageSize(page);
+
+	/* page type (flags) */
+	if (P_ISDELETED(opaque))
+	{
+		stat->type = 'd';
+		stat->btpo.xact = opaque->btpo.xact;
+		return;
+	}
+	else if (P_IGNORE(opaque))
+		stat->type = 'e';
+	else if (P_ISLEAF(opaque))
+		stat->type = 'l';
+	else if (P_ISROOT(opaque))
+		stat->type = 'r';
+	else
+		stat->type = 'i';
+
+	/* btpage opaque data */
+	stat->btpo_prev = opaque->btpo_prev;
+	stat->btpo_next = opaque->btpo_next;
+	stat->btpo.level = opaque->btpo.level;
+	stat->btpo_flags = opaque->btpo_flags;
+	stat->btpo_cycleid = opaque->btpo_cycleid;
+
+	/* count live and dead tuples, and free space */
+	for (off = FirstOffsetNumber; off <= maxoff; off++)
+	{
+		IndexTuple	itup;
+
+		ItemId		id = PageGetItemId(page, off);
+
+		itup = (IndexTuple) PageGetItem(page, id);
+
+		item_size += IndexTupleSize(itup);
+
+		if (!ItemIdIsDead(id))
+			stat->live_items++;
+		else
+			stat->dead_items++;
+	}
+	stat->free_size = PageGetFreeSpace(page);
+
+	if ((stat->live_items + stat->dead_items) > 0)
+		stat->avg_item_size = item_size / (stat->live_items + stat->dead_items);
+	else
+		stat->avg_item_size = 0;
+}
+
+/* -----------------------------------------------
+ * bt_page_stats()
+ *
+ * Usage: SELECT * FROM bt_page_stats('t1_pkey', 1);
+ * -----------------------------------------------
+ */
+Datum
+bt_page_stats(PG_FUNCTION_ARGS)
+{
+	text	   *relname = PG_GETARG_TEXT_PP(0);
+	uint32		blkno = PG_GETARG_UINT32(1);
+	Buffer		buffer;
+	Relation	rel;
+	RangeVar   *relrv;
+	Datum		result;
+	HeapTuple	tuple;
+	TupleDesc	tupleDesc;
+	int			j;
+	char	   *values[11];
+	BTPageStat	stat;
+
+	if (!superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("must be superuser to use pageinspect functions")));
+
+	relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
+	rel = relation_openrv(relrv, AccessShareLock);
+
+	if (!IS_INDEX(rel) || !IS_BTREE(rel))
+		elog(ERROR, "relation \"%s\" is not a btree index",
+			 RelationGetRelationName(rel));
+
+	/*
+	 * Reject attempts to read non-local temporary relations; we would be
+	 * likely to get wrong data since we have no visibility into the owning
+	 * session's local buffers.
+	 */
+	if (RELATION_IS_OTHER_TEMP(rel))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot access temporary tables of other sessions")));
+
+	if (blkno == 0)
+		elog(ERROR, "block 0 is a meta page");
+
+	CHECK_RELATION_BLOCK_RANGE(rel, blkno);
+
+	buffer = ReadBuffer(rel, blkno);
+	LockBuffer(buffer, BUFFER_LOCK_SHARE);
+
+	/* keep compiler quiet */
+	stat.btpo_prev = stat.btpo_next = InvalidBlockNumber;
+	stat.btpo_flags = stat.free_size = stat.avg_item_size = 0;
+
+	GetBTPageStatistics(blkno, buffer, &stat);
+
+	UnlockReleaseBuffer(buffer);
+	relation_close(rel, AccessShareLock);
+
+	/* Build a tuple descriptor for our result type */
+	if (get_call_result_type(fcinfo, NULL, &tupleDesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	j = 0;
+	values[j++] = psprintf("%d", stat.blkno);
+	values[j++] = psprintf("%c", stat.type);
+	values[j++] = psprintf("%d", stat.live_items);
+	values[j++] = psprintf("%d", stat.dead_items);
+	values[j++] = psprintf("%d", stat.avg_item_size);
+	values[j++] = psprintf("%d", stat.page_size);
+	values[j++] = psprintf("%d", stat.free_size);
+	values[j++] = psprintf("%d", stat.btpo_prev);
+	values[j++] = psprintf("%d", stat.btpo_next);
+	values[j++] = psprintf("%d", (stat.type == 'd') ? stat.btpo.xact : stat.btpo.level);
+	values[j++] = psprintf("%d", stat.btpo_flags);
+
+	tuple = BuildTupleFromCStrings(TupleDescGetAttInMetadata(tupleDesc),
+								   values);
+
+	result = HeapTupleGetDatum(tuple);
+
+	PG_RETURN_DATUM(result);
+}
+
+
+/*
+ * cross-call data structure for SRF
+ */
+struct user_args
+{
+	Page		page;
+	OffsetNumber offset;
+	bool		leafpage;
+	bool		rightmost;
+	TupleDesc	tupd;
+};
+
+/*-------------------------------------------------------
+ * bt_page_print_tuples()
+ *
+ * Form a tuple describing index tuple at a given offset
+ * ------------------------------------------------------
+ */
+static Datum
+bt_page_print_tuples(FuncCallContext *fctx, struct user_args *uargs)
+{
+	Page		page = uargs->page;
+	OffsetNumber offset = uargs->offset;
+	bool		leafpage = uargs->leafpage;
+	bool		rightmost = uargs->rightmost;
+	bool		ispivottuple;
+	Datum		values[9];
+	bool		nulls[9];
+	HeapTuple	tuple;
+	ItemId		id;
+	IndexTuple	itup;
+	int			j;
+	int			off;
+	int			dlen;
+	char	   *dump,
+			   *datacstring;
+	char	   *ptr;
+	ItemPointer htid;
+
+	id = PageGetItemId(page, offset);
+
+	if (!ItemIdIsValid(id))
+		elog(ERROR, "invalid ItemId");
+
+	itup = (IndexTuple) PageGetItem(page, id);
+
+	j = 0;
+	memset(nulls, 0, sizeof(nulls));
+	values[j++] = DatumGetInt16(offset);
+	values[j++] = ItemPointerGetDatum(&itup->t_tid);
+	values[j++] = Int32GetDatum((int) IndexTupleSize(itup));
+	values[j++] = BoolGetDatum(IndexTupleHasNulls(itup));
+	values[j++] = BoolGetDatum(IndexTupleHasVarwidths(itup));
+
+	ptr = (char *) itup + IndexInfoFindDataOffset(itup->t_info);
+	dlen = IndexTupleSize(itup) - IndexInfoFindDataOffset(itup->t_info);
+
+	/*
+	 * Make sure that "data" column does not include posting list or pivot
+	 * tuple representation of heap TID(s).
+	 *
+	 * Note: BTreeTupleIsPivot() won't work reliably on !heapkeyspace indexes
+	 * (those built before BTREE_VERSION 4), but we have no way of determining
+	 * if this page came from a !heapkeyspace index.  We may only have a bytea
+	 * nbtree page image to go on, so in general there is no metapage that we
+	 * can check.
+	 *
+	 * That's okay here because BTreeTupleIsPivot() can only return false for
+	 * a !heapkeyspace pivot, never true for a !heapkeyspace non-pivot.  Since
+	 * heap TID isn't part of the keyspace in a !heapkeyspace index anyway,
+	 * there cannot possibly be a pivot tuple heap TID representation that we
+	 * fail to make an adjustment for.  A !heapkeyspace index can have
+	 * BTreeTupleIsPivot() return true (due to things like suffix truncation
+	 * for INCLUDE indexes in Postgres v11), but when that happens
+	 * BTreeTupleGetHeapTID() can be trusted to work reliably (i.e. return
+	 * NULL).
+	 *
+	 * Note: BTreeTupleIsPosting() always works reliably, even with
+	 * !heapkeyspace indexes.
+	 */
+	if (BTreeTupleIsPosting(itup))
+		dlen -= IndexTupleSize(itup) - BTreeTupleGetPostingOffset(itup);
+	else if (BTreeTupleIsPivot(itup) && BTreeTupleGetHeapTID(itup) != NULL)
+		dlen -= MAXALIGN(sizeof(ItemPointerData));
+
+	if (dlen < 0 || dlen > INDEX_SIZE_MASK)
+		elog(ERROR, "invalid tuple length %d for tuple at offset number %u",
+			 dlen, offset);
+	dump = palloc0(dlen * 3 + 1);
+	datacstring = dump;
+	for (off = 0; off < dlen; off++)
+	{
+		if (off > 0)
+			*dump++ = ' ';
+		sprintf(dump, "%02x", *(ptr + off) & 0xff);
+		dump += 2;
+	}
+	values[j++] = CStringGetTextDatum(datacstring);
+	pfree(datacstring);
+
+	/*
+	 * We need to work around the BTreeTupleIsPivot() !heapkeyspace limitation
+	 * again.  Deduce whether or not tuple must be a pivot tuple based on
+	 * whether or not the page is a leaf page, as well as the page offset
+	 * number of the tuple.
+	 */
+	ispivottuple = (!leafpage || (!rightmost && offset == P_HIKEY));
+
+	/* LP_DEAD bit can never be set for pivot tuples, so show a NULL there */
+	if (!ispivottuple)
+		values[j++] = BoolGetDatum(ItemIdIsDead(id));
+	else
+	{
+		Assert(!ItemIdIsDead(id));
+		nulls[j++] = true;
+	}
+
+	htid = BTreeTupleGetHeapTID(itup);
+	if (ispivottuple && !BTreeTupleIsPivot(itup))
+	{
+		/* Don't show bogus heap TID in !heapkeyspace pivot tuple */
+		htid = NULL;
+	}
+
+	if (htid)
+		values[j++] = ItemPointerGetDatum(htid);
+	else
+		nulls[j++] = true;
+
+	if (BTreeTupleIsPosting(itup))
+	{
+		/* Build an array of item pointers */
+		ItemPointer tids;
+		Datum	   *tids_datum;
+		int			nposting;
+
+		tids = BTreeTupleGetPosting(itup);
+		nposting = BTreeTupleGetNPosting(itup);
+		tids_datum = (Datum *) palloc(nposting * sizeof(Datum));
+		for (int i = 0; i < nposting; i++)
+			tids_datum[i] = ItemPointerGetDatum(&tids[i]);
+		values[j++] = PointerGetDatum(construct_array(tids_datum,
+													  nposting,
+													  TIDOID,
+													  sizeof(ItemPointerData),
+													  false, TYPALIGN_SHORT));
+		pfree(tids_datum);
+	}
+	else
+		nulls[j++] = true;
+
+	/* Build and return the result tuple */
+	tuple = heap_form_tuple(uargs->tupd, values, nulls);
+
+	return HeapTupleGetDatum(tuple);
+}
+
+/*-------------------------------------------------------
+ * bt_page_items()
+ *
+ * Get IndexTupleData set in a btree page
+ *
+ * Usage: SELECT * FROM bt_page_items('t1_pkey', 1);
+ *-------------------------------------------------------
+ */
+Datum
+bt_page_items(PG_FUNCTION_ARGS)
+{
+	text	   *relname = PG_GETARG_TEXT_PP(0);
+	uint32		blkno = PG_GETARG_UINT32(1);
+	Datum		result;
+	FuncCallContext *fctx;
+	MemoryContext mctx;
+	struct user_args *uargs;
+
+	if (!superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("must be superuser to use pageinspect functions")));
+
+	if (SRF_IS_FIRSTCALL())
+	{
+		RangeVar   *relrv;
+		Relation	rel;
+		Buffer		buffer;
+		BTPageOpaque opaque;
+		TupleDesc	tupleDesc;
+
+		fctx = SRF_FIRSTCALL_INIT();
+
+		relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
+		rel = relation_openrv(relrv, AccessShareLock);
+
+		if (!IS_INDEX(rel) || !IS_BTREE(rel))
+			elog(ERROR, "relation \"%s\" is not a btree index",
+				 RelationGetRelationName(rel));
+
+		/*
+		 * Reject attempts to read non-local temporary relations; we would be
+		 * likely to get wrong data since we have no visibility into the
+		 * owning session's local buffers.
+		 */
+		if (RELATION_IS_OTHER_TEMP(rel))
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("cannot access temporary tables of other sessions")));
+
+		if (blkno == 0)
+			elog(ERROR, "block 0 is a meta page");
+
+		CHECK_RELATION_BLOCK_RANGE(rel, blkno);
+
+		buffer = ReadBuffer(rel, blkno);
+		LockBuffer(buffer, BUFFER_LOCK_SHARE);
+
+		/*
+		 * We copy the page into local storage to avoid holding pin on the
+		 * buffer longer than we must, and possibly failing to release it at
+		 * all if the calling query doesn't fetch all rows.
+		 */
+		mctx = MemoryContextSwitchTo(fctx->multi_call_memory_ctx);
+
+		uargs = palloc(sizeof(struct user_args));
+
+		uargs->page = palloc(BLCKSZ);
+		memcpy(uargs->page, BufferGetPage(buffer), BLCKSZ);
+
+		UnlockReleaseBuffer(buffer);
+		relation_close(rel, AccessShareLock);
+
+		uargs->offset = FirstOffsetNumber;
+
+		opaque = (BTPageOpaque) PageGetSpecialPointer(uargs->page);
+
+		if (P_ISDELETED(opaque))
+			elog(NOTICE, "page is deleted");
+
+		fctx->max_calls = PageGetMaxOffsetNumber(uargs->page);
+		uargs->leafpage = P_ISLEAF(opaque);
+		uargs->rightmost = P_RIGHTMOST(opaque);
+
+		/* Build a tuple descriptor for our result type */
+		if (get_call_result_type(fcinfo, NULL, &tupleDesc) != TYPEFUNC_COMPOSITE)
+			elog(ERROR, "return type must be a row type");
+		tupleDesc = BlessTupleDesc(tupleDesc);
+
+		uargs->tupd = tupleDesc;
+
+		fctx->user_fctx = uargs;
+
+		MemoryContextSwitchTo(mctx);
+	}
+
+	fctx = SRF_PERCALL_SETUP();
+	uargs = fctx->user_fctx;
+
+	if (fctx->call_cntr < fctx->max_calls)
+	{
+		result = bt_page_print_tuples(fctx, uargs);
+		uargs->offset++;
+		SRF_RETURN_NEXT(fctx, result);
+	}
+
+	SRF_RETURN_DONE(fctx);
+}
+
+/*-------------------------------------------------------
+ * bt_page_items_bytea()
+ *
+ * Get IndexTupleData set in a btree page
+ *
+ * Usage: SELECT * FROM bt_page_items(get_raw_page('t1_pkey', 1));
+ *-------------------------------------------------------
+ */
+
+Datum
+bt_page_items_bytea(PG_FUNCTION_ARGS)
+{
+	bytea	   *raw_page = PG_GETARG_BYTEA_P(0);
+	Datum		result;
+	FuncCallContext *fctx;
+	struct user_args *uargs;
+	int			raw_page_size;
+
+	if (!superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("must be superuser to use raw page functions")));
+
+	if (SRF_IS_FIRSTCALL())
+	{
+		BTPageOpaque opaque;
+		MemoryContext mctx;
+		TupleDesc	tupleDesc;
+
+		raw_page_size = VARSIZE(raw_page) - VARHDRSZ;
+
+		if (raw_page_size < SizeOfPageHeaderData)
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("input page too small (%d bytes)", raw_page_size)));
+
+		fctx = SRF_FIRSTCALL_INIT();
+		mctx = MemoryContextSwitchTo(fctx->multi_call_memory_ctx);
+
+		uargs = palloc(sizeof(struct user_args));
+
+		uargs->page = VARDATA(raw_page);
+
+		uargs->offset = FirstOffsetNumber;
+
+		opaque = (BTPageOpaque) PageGetSpecialPointer(uargs->page);
+
+		if (P_ISMETA(opaque))
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("block is a meta page")));
+
+		if (P_ISDELETED(opaque))
+			elog(NOTICE, "page is deleted");
+
+		fctx->max_calls = PageGetMaxOffsetNumber(uargs->page);
+		uargs->leafpage = P_ISLEAF(opaque);
+		uargs->rightmost = P_RIGHTMOST(opaque);
+
+		/* Build a tuple descriptor for our result type */
+		if (get_call_result_type(fcinfo, NULL, &tupleDesc) != TYPEFUNC_COMPOSITE)
+			elog(ERROR, "return type must be a row type");
+		tupleDesc = BlessTupleDesc(tupleDesc);
+
+		uargs->tupd = tupleDesc;
+
+		fctx->user_fctx = uargs;
+
+		MemoryContextSwitchTo(mctx);
+	}
+
+	fctx = SRF_PERCALL_SETUP();
+	uargs = fctx->user_fctx;
+
+	if (fctx->call_cntr < fctx->max_calls)
+	{
+		result = bt_page_print_tuples(fctx, uargs);
+		uargs->offset++;
+		SRF_RETURN_NEXT(fctx, result);
+	}
+
+	SRF_RETURN_DONE(fctx);
+}
+
+/* Number of output arguments (columns) for bt_metap() */
+#define BT_METAP_COLS_V1_8		9
+
+/* ------------------------------------------------
+ * bt_metap()
+ *
+ * Get a btree's meta-page information
+ *
+ * Usage: SELECT * FROM bt_metap('t1_pkey')
+ * ------------------------------------------------
+ */
+Datum
+bt_metap(PG_FUNCTION_ARGS)
+{
+	text	   *relname = PG_GETARG_TEXT_PP(0);
+	Datum		result;
+	Relation	rel;
+	RangeVar   *relrv;
+	BTMetaPageData *metad;
+	TupleDesc	tupleDesc;
+	int			j;
+	char	   *values[9];
+	Buffer		buffer;
+	Page		page;
+	HeapTuple	tuple;
+
+	if (!superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("must be superuser to use pageinspect functions")));
+
+	relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
+	rel = relation_openrv(relrv, AccessShareLock);
+
+	if (!IS_INDEX(rel) || !IS_BTREE(rel))
+		elog(ERROR, "relation \"%s\" is not a btree index",
+			 RelationGetRelationName(rel));
+
+	/*
+	 * Reject attempts to read non-local temporary relations; we would be
+	 * likely to get wrong data since we have no visibility into the owning
+	 * session's local buffers.
+	 */
+	if (RELATION_IS_OTHER_TEMP(rel))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot access temporary tables of other sessions")));
+
+	buffer = ReadBuffer(rel, 0);
+	LockBuffer(buffer, BUFFER_LOCK_SHARE);
+
+	page = BufferGetPage(buffer);
+	metad = BTPageGetMeta(page);
+
+	/* Build a tuple descriptor for our result type */
+	if (get_call_result_type(fcinfo, NULL, &tupleDesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	/*
+	 * We need a kluge here to detect API versions prior to 1.8.  Earlier
+	 * versions incorrectly used int4 for certain columns.  This caused
+	 * various problems.  For example, an int4 version of the "oldest_xact"
+	 * column would not work with TransactionId values that happened to exceed
+	 * PG_INT32_MAX.
+	 *
+	 * There is no way to reliably avoid the problems created by the old
+	 * function definition at this point, so insist that the user update the
+	 * extension.
+	 */
+	if (tupleDesc->natts < BT_METAP_COLS_V1_8)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
+				 errmsg("function has wrong number of declared columns"),
+				 errhint("To resolve the problem, update the \"pageinspect\" extension to the latest version.")));
+
+	j = 0;
+	values[j++] = psprintf("%d", metad->btm_magic);
+	values[j++] = psprintf("%d", metad->btm_version);
+	values[j++] = psprintf(INT64_FORMAT, (int64) metad->btm_root);
+	values[j++] = psprintf(INT64_FORMAT, (int64) metad->btm_level);
+	values[j++] = psprintf(INT64_FORMAT, (int64) metad->btm_fastroot);
+	values[j++] = psprintf(INT64_FORMAT, (int64) metad->btm_fastlevel);
+
+	/*
+	 * Get values of extended metadata if available, use default values
+	 * otherwise.  Note that we rely on the assumption that btm_allequalimage
+	 * is initialized to zero with indexes that were built on versions prior
+	 * to Postgres 13 (just like _bt_metaversion()).
+	 */
+	if (metad->btm_version >= BTREE_NOVAC_VERSION)
+	{
+		values[j++] = psprintf("%u", metad->btm_oldest_btpo_xact);
+		values[j++] = psprintf("%f", metad->btm_last_cleanup_num_heap_tuples);
+		values[j++] = metad->btm_allequalimage ? "t" : "f";
+	}
+	else
+	{
+		values[j++] = "0";
+		values[j++] = "-1";
+		values[j++] = "f";
+	}
+
+	tuple = BuildTupleFromCStrings(TupleDescGetAttInMetadata(tupleDesc),
+								   values);
+
+	result = HeapTupleGetDatum(tuple);
+
+	UnlockReleaseBuffer(buffer);
+	relation_close(rel, AccessShareLock);
+
+	PG_RETURN_DATUM(result);
+}
diff --git a/contrib/pageinspect/expected/brin.out b/contrib/pageinspect/expected/brin.out
new file mode 100644
index 0000000..71eb190
--- /dev/null
+++ b/contrib/pageinspect/expected/brin.out
@@ -0,0 +1,51 @@
+CREATE TABLE test1 (a int, b text);
+INSERT INTO test1 VALUES (1, 'one');
+CREATE INDEX test1_a_idx ON test1 USING brin (a);
+SELECT brin_page_type(get_raw_page('test1_a_idx', 0));
+ brin_page_type 
+----------------
+ meta
+(1 row)
+
+SELECT brin_page_type(get_raw_page('test1_a_idx', 1));
+ brin_page_type 
+----------------
+ revmap
+(1 row)
+
+SELECT brin_page_type(get_raw_page('test1_a_idx', 2));
+ brin_page_type 
+----------------
+ regular
+(1 row)
+
+SELECT * FROM brin_metapage_info(get_raw_page('test1_a_idx', 0));
+   magic    | version | pagesperrange | lastrevmappage 
+------------+---------+---------------+----------------
+ 0xA8109CFA |       1 |           128 |              1
+(1 row)
+
+SELECT * FROM brin_metapage_info(get_raw_page('test1_a_idx', 1));
+ERROR:  page is not a BRIN page of type "metapage"
+DETAIL:  Expected special type 0000f091, got 0000f092.
+SELECT * FROM brin_revmap_data(get_raw_page('test1_a_idx', 0)) LIMIT 5;
+ERROR:  page is not a BRIN page of type "revmap"
+DETAIL:  Expected special type 0000f092, got 0000f091.
+SELECT * FROM brin_revmap_data(get_raw_page('test1_a_idx', 1)) LIMIT 5;
+ pages 
+-------
+ (2,1)
+ (0,0)
+ (0,0)
+ (0,0)
+ (0,0)
+(5 rows)
+
+SELECT * FROM brin_page_items(get_raw_page('test1_a_idx', 2), 'test1_a_idx')
+    ORDER BY blknum, attnum LIMIT 5;
+ itemoffset | blknum | attnum | allnulls | hasnulls | placeholder |  value   
+------------+--------+--------+----------+----------+-------------+----------
+          1 |      0 |      1 | f        | f        | f           | {1 .. 1}
+(1 row)
+
+DROP TABLE test1;
diff --git a/contrib/pageinspect/expected/btree.out b/contrib/pageinspect/expected/btree.out
new file mode 100644
index 0000000..17bf0c5
--- /dev/null
+++ b/contrib/pageinspect/expected/btree.out
@@ -0,0 +1,67 @@
+CREATE TABLE test1 (a int8, b text);
+INSERT INTO test1 VALUES (72057594037927937, 'text');
+CREATE INDEX test1_a_idx ON test1 USING btree (a);
+\x
+SELECT * FROM bt_metap('test1_a_idx');
+-[ RECORD 1 ]-----------+-------
+magic                   | 340322
+version                 | 4
+root                    | 1
+level                   | 0
+fastroot                | 1
+fastlevel               | 0
+oldest_xact             | 0
+last_cleanup_num_tuples | -1
+allequalimage           | t
+
+SELECT * FROM bt_page_stats('test1_a_idx', 0);
+ERROR:  block 0 is a meta page
+SELECT * FROM bt_page_stats('test1_a_idx', 1);
+-[ RECORD 1 ]-+-----
+blkno         | 1
+type          | l
+live_items    | 1
+dead_items    | 0
+avg_item_size | 16
+page_size     | 8192
+free_size     | 8128
+btpo_prev     | 0
+btpo_next     | 0
+btpo          | 0
+btpo_flags    | 3
+
+SELECT * FROM bt_page_stats('test1_a_idx', 2);
+ERROR:  block number out of range
+SELECT * FROM bt_page_items('test1_a_idx', 0);
+ERROR:  block 0 is a meta page
+SELECT * FROM bt_page_items('test1_a_idx', 1);
+-[ RECORD 1 ]-----------------------
+itemoffset | 1
+ctid       | (0,1)
+itemlen    | 16
+nulls      | f
+vars       | f
+data       | 01 00 00 00 00 00 00 01
+dead       | f
+htid       | (0,1)
+tids       | 
+
+SELECT * FROM bt_page_items('test1_a_idx', 2);
+ERROR:  block number out of range
+SELECT * FROM bt_page_items(get_raw_page('test1_a_idx', 0));
+ERROR:  block is a meta page
+SELECT * FROM bt_page_items(get_raw_page('test1_a_idx', 1));
+-[ RECORD 1 ]-----------------------
+itemoffset | 1
+ctid       | (0,1)
+itemlen    | 16
+nulls      | f
+vars       | f
+data       | 01 00 00 00 00 00 00 01
+dead       | f
+htid       | (0,1)
+tids       | 
+
+SELECT * FROM bt_page_items(get_raw_page('test1_a_idx', 2));
+ERROR:  block number 2 is out of range for relation "test1_a_idx"
+DROP TABLE test1;
diff --git a/contrib/pageinspect/expected/checksum.out b/contrib/pageinspect/expected/checksum.out
new file mode 100644
index 0000000..a85388e
--- /dev/null
+++ b/contrib/pageinspect/expected/checksum.out
@@ -0,0 +1,40 @@
+--
+-- Verify correct calculation of checksums
+--
+-- Postgres' checksum algorithm produces different answers on little-endian
+-- and big-endian machines.  The results of this test also vary depending
+-- on the configured block size.  This test has several different expected
+-- results files to handle the following possibilities:
+--
+--	BLCKSZ	end	file
+--	8K	LE	checksum.out
+--	8K	BE	checksum_1.out
+--
+-- In future we might provide additional expected-results files for other
+-- block sizes, but there seems little point as long as so many other
+-- test scripts also show false failures for non-default block sizes.
+--
+-- This is to label the results files with blocksize:
+SHOW block_size;
+ block_size 
+------------
+ 8192
+(1 row)
+
+SHOW block_size \gset
+-- Apply page_checksum() to some different data patterns and block numbers
+SELECT blkno,
+    page_checksum(decode(repeat('01', :block_size), 'hex'), blkno) AS checksum_01,
+    page_checksum(decode(repeat('04', :block_size), 'hex'), blkno) AS checksum_04,
+    page_checksum(decode(repeat('ff', :block_size), 'hex'), blkno) AS checksum_ff,
+    page_checksum(decode(repeat('abcd', :block_size / 2), 'hex'), blkno) AS checksum_abcd,
+    page_checksum(decode(repeat('e6d6', :block_size / 2), 'hex'), blkno) AS checksum_e6d6,
+    page_checksum(decode(repeat('4a5e', :block_size / 2), 'hex'), blkno) AS checksum_4a5e
+  FROM generate_series(0, 100, 50) AS a (blkno);
+ blkno | checksum_01 | checksum_04 | checksum_ff | checksum_abcd | checksum_e6d6 | checksum_4a5e 
+-------+-------------+-------------+-------------+---------------+---------------+---------------
+     0 |        1175 |       28338 |        3612 |        -30781 |        -16269 |        -27377
+    50 |        1225 |       28352 |        3598 |        -30795 |        -16251 |        -27391
+   100 |        1139 |       28438 |        3648 |        -30881 |        -16305 |        -27349
+(3 rows)
+
diff --git a/contrib/pageinspect/expected/checksum_1.out b/contrib/pageinspect/expected/checksum_1.out
new file mode 100644
index 0000000..6fb1b1b
--- /dev/null
+++ b/contrib/pageinspect/expected/checksum_1.out
@@ -0,0 +1,40 @@
+--
+-- Verify correct calculation of checksums
+--
+-- Postgres' checksum algorithm produces different answers on little-endian
+-- and big-endian machines.  The results of this test also vary depending
+-- on the configured block size.  This test has several different expected
+-- results files to handle the following possibilities:
+--
+--	BLCKSZ	end	file
+--	8K	LE	checksum.out
+--	8K	BE	checksum_1.out
+--
+-- In future we might provide additional expected-results files for other
+-- block sizes, but there seems little point as long as so many other
+-- test scripts also show false failures for non-default block sizes.
+--
+-- This is to label the results files with blocksize:
+SHOW block_size;
+ block_size 
+------------
+ 8192
+(1 row)
+
+SHOW block_size \gset
+-- Apply page_checksum() to some different data patterns and block numbers
+SELECT blkno,
+    page_checksum(decode(repeat('01', :block_size), 'hex'), blkno) AS checksum_01,
+    page_checksum(decode(repeat('04', :block_size), 'hex'), blkno) AS checksum_04,
+    page_checksum(decode(repeat('ff', :block_size), 'hex'), blkno) AS checksum_ff,
+    page_checksum(decode(repeat('abcd', :block_size / 2), 'hex'), blkno) AS checksum_abcd,
+    page_checksum(decode(repeat('e6d6', :block_size / 2), 'hex'), blkno) AS checksum_e6d6,
+    page_checksum(decode(repeat('4a5e', :block_size / 2), 'hex'), blkno) AS checksum_4a5e
+  FROM generate_series(0, 100, 50) AS a (blkno);
+ blkno | checksum_01 | checksum_04 | checksum_ff | checksum_abcd | checksum_e6d6 | checksum_4a5e 
+-------+-------------+-------------+-------------+---------------+---------------+---------------
+     0 |      -16327 |        8766 |       -2722 |         13757 |        -11485 |        -31426
+    50 |      -16281 |        8780 |       -2708 |         13771 |        -11503 |        -31440
+   100 |      -16235 |        8866 |       -2758 |         13721 |        -11577 |        -31518
+(3 rows)
+
diff --git a/contrib/pageinspect/expected/gin.out b/contrib/pageinspect/expected/gin.out
new file mode 100644
index 0000000..82f63b2
--- /dev/null
+++ b/contrib/pageinspect/expected/gin.out
@@ -0,0 +1,37 @@
+CREATE TABLE test1 (x int, y int[]);
+INSERT INTO test1 VALUES (1, ARRAY[11, 111]);
+CREATE INDEX test1_y_idx ON test1 USING gin (y) WITH (fastupdate = off);
+\x
+SELECT * FROM gin_metapage_info(get_raw_page('test1_y_idx', 0));
+-[ RECORD 1 ]----+-----------
+pending_head     | 4294967295
+pending_tail     | 4294967295
+tail_free_size   | 0
+n_pending_pages  | 0
+n_pending_tuples | 0
+n_total_pages    | 2
+n_entry_pages    | 1
+n_data_pages     | 0
+n_entries        | 2
+version          | 2
+
+SELECT * FROM gin_metapage_info(get_raw_page('test1_y_idx', 1));
+ERROR:  input page is not a GIN metapage
+DETAIL:  Flags 0002, expected 0008
+SELECT * FROM gin_page_opaque_info(get_raw_page('test1_y_idx', 1));
+-[ RECORD 1 ]---------
+rightlink | 4294967295
+maxoff    | 0
+flags     | {leaf}
+
+SELECT * FROM gin_leafpage_items(get_raw_page('test1_y_idx', 1));
+ERROR:  input page is not a compressed GIN data leaf page
+DETAIL:  Flags 0002, expected 0083
+INSERT INTO test1 SELECT x, ARRAY[1,10] FROM generate_series(2,10000) x;
+SELECT COUNT(*) > 0
+FROM gin_leafpage_items(get_raw_page('test1_y_idx',
+                        (pg_relation_size('test1_y_idx') /
+                         current_setting('block_size')::bigint)::int - 1));
+-[ RECORD 1 ]
+?column? | t
+
diff --git a/contrib/pageinspect/expected/hash.out b/contrib/pageinspect/expected/hash.out
new file mode 100644
index 0000000..75d7bcf
--- /dev/null
+++ b/contrib/pageinspect/expected/hash.out
@@ -0,0 +1,162 @@
+CREATE TABLE test_hash (a int, b text);
+INSERT INTO test_hash VALUES (1, 'one');
+CREATE INDEX test_hash_a_idx ON test_hash USING hash (a);
+\x
+SELECT hash_page_type(get_raw_page('test_hash_a_idx', 0));
+-[ RECORD 1 ]--+---------
+hash_page_type | metapage
+
+SELECT hash_page_type(get_raw_page('test_hash_a_idx', 1));
+-[ RECORD 1 ]--+-------
+hash_page_type | bucket
+
+SELECT hash_page_type(get_raw_page('test_hash_a_idx', 2));
+-[ RECORD 1 ]--+-------
+hash_page_type | bucket
+
+SELECT hash_page_type(get_raw_page('test_hash_a_idx', 3));
+-[ RECORD 1 ]--+-------
+hash_page_type | bucket
+
+SELECT hash_page_type(get_raw_page('test_hash_a_idx', 4));
+-[ RECORD 1 ]--+-------
+hash_page_type | bucket
+
+SELECT hash_page_type(get_raw_page('test_hash_a_idx', 5));
+-[ RECORD 1 ]--+-------
+hash_page_type | bitmap
+
+SELECT hash_page_type(get_raw_page('test_hash_a_idx', 6));
+ERROR:  block number 6 is out of range for relation "test_hash_a_idx"
+SELECT * FROM hash_bitmap_info('test_hash_a_idx', 0);
+ERROR:  invalid overflow block number 0
+SELECT * FROM hash_bitmap_info('test_hash_a_idx', 1);
+ERROR:  invalid overflow block number 1
+SELECT * FROM hash_bitmap_info('test_hash_a_idx', 2);
+ERROR:  invalid overflow block number 2
+SELECT * FROM hash_bitmap_info('test_hash_a_idx', 3);
+ERROR:  invalid overflow block number 3
+SELECT * FROM hash_bitmap_info('test_hash_a_idx', 4);
+ERROR:  invalid overflow block number 4
+SELECT * FROM hash_bitmap_info('test_hash_a_idx', 5);
+ERROR:  invalid overflow block number 5
+SELECT magic, version, ntuples, bsize, bmsize, bmshift, maxbucket, highmask,
+lowmask, ovflpoint, firstfree, nmaps, procid, spares, mapp FROM
+hash_metapage_info(get_raw_page('test_hash_a_idx', 0));
+-[ RECORD 1 ]--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+magic     | 105121344
+version   | 4
+ntuples   | 1
+bsize     | 8152
+bmsize    | 4096
+bmshift   | 15
+maxbucket | 3
+highmask  | 7
+lowmask   | 3
+ovflpoint | 2
+firstfree | 0
+nmaps     | 1
+procid    | 450
+spares    | {0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}
+mapp      | {5,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}
+
+SELECT magic, version, ntuples, bsize, bmsize, bmshift, maxbucket, highmask,
+lowmask, ovflpoint, firstfree, nmaps, procid, spares, mapp FROM
+hash_metapage_info(get_raw_page('test_hash_a_idx', 1));
+ERROR:  page is not a hash meta page
+SELECT magic, version, ntuples, bsize, bmsize, bmshift, maxbucket, highmask,
+lowmask, ovflpoint, firstfree, nmaps, procid, spares, mapp FROM
+hash_metapage_info(get_raw_page('test_hash_a_idx', 2));
+ERROR:  page is not a hash meta page
+SELECT magic, version, ntuples, bsize, bmsize, bmshift, maxbucket, highmask,
+lowmask, ovflpoint, firstfree, nmaps, procid, spares, mapp FROM
+hash_metapage_info(get_raw_page('test_hash_a_idx', 3));
+ERROR:  page is not a hash meta page
+SELECT magic, version, ntuples, bsize, bmsize, bmshift, maxbucket, highmask,
+lowmask, ovflpoint, firstfree, nmaps, procid, spares, mapp FROM
+hash_metapage_info(get_raw_page('test_hash_a_idx', 4));
+ERROR:  page is not a hash meta page
+SELECT magic, version, ntuples, bsize, bmsize, bmshift, maxbucket, highmask,
+lowmask, ovflpoint, firstfree, nmaps, procid, spares, mapp FROM
+hash_metapage_info(get_raw_page('test_hash_a_idx', 5));
+ERROR:  page is not a hash meta page
+SELECT live_items, dead_items, page_size, hasho_prevblkno, hasho_nextblkno,
+hasho_bucket, hasho_flag, hasho_page_id FROM
+hash_page_stats(get_raw_page('test_hash_a_idx', 0));
+ERROR:  page is not a hash bucket or overflow page
+SELECT live_items, dead_items, page_size, hasho_prevblkno, hasho_nextblkno,
+hasho_bucket, hasho_flag, hasho_page_id FROM
+hash_page_stats(get_raw_page('test_hash_a_idx', 1));
+-[ RECORD 1 ]---+-----------
+live_items      | 0
+dead_items      | 0
+page_size       | 8192
+hasho_prevblkno | 3
+hasho_nextblkno | 4294967295
+hasho_bucket    | 0
+hasho_flag      | 2
+hasho_page_id   | 65408
+
+SELECT live_items, dead_items, page_size, hasho_prevblkno, hasho_nextblkno,
+hasho_bucket, hasho_flag, hasho_page_id FROM
+hash_page_stats(get_raw_page('test_hash_a_idx', 2));
+-[ RECORD 1 ]---+-----------
+live_items      | 0
+dead_items      | 0
+page_size       | 8192
+hasho_prevblkno | 3
+hasho_nextblkno | 4294967295
+hasho_bucket    | 1
+hasho_flag      | 2
+hasho_page_id   | 65408
+
+SELECT live_items, dead_items, page_size, hasho_prevblkno, hasho_nextblkno,
+hasho_bucket, hasho_flag, hasho_page_id FROM
+hash_page_stats(get_raw_page('test_hash_a_idx', 3));
+-[ RECORD 1 ]---+-----------
+live_items      | 1
+dead_items      | 0
+page_size       | 8192
+hasho_prevblkno | 3
+hasho_nextblkno | 4294967295
+hasho_bucket    | 2
+hasho_flag      | 2
+hasho_page_id   | 65408
+
+SELECT live_items, dead_items, page_size, hasho_prevblkno, hasho_nextblkno,
+hasho_bucket, hasho_flag, hasho_page_id FROM
+hash_page_stats(get_raw_page('test_hash_a_idx', 4));
+-[ RECORD 1 ]---+-----------
+live_items      | 0
+dead_items      | 0
+page_size       | 8192
+hasho_prevblkno | 3
+hasho_nextblkno | 4294967295
+hasho_bucket    | 3
+hasho_flag      | 2
+hasho_page_id   | 65408
+
+SELECT live_items, dead_items, page_size, hasho_prevblkno, hasho_nextblkno,
+hasho_bucket, hasho_flag, hasho_page_id FROM
+hash_page_stats(get_raw_page('test_hash_a_idx', 5));
+ERROR:  page is not a hash bucket or overflow page
+SELECT * FROM hash_page_items(get_raw_page('test_hash_a_idx', 0));
+ERROR:  page is not a hash bucket or overflow page
+SELECT * FROM hash_page_items(get_raw_page('test_hash_a_idx', 1));
+(0 rows)
+
+SELECT * FROM hash_page_items(get_raw_page('test_hash_a_idx', 2));
+(0 rows)
+
+SELECT * FROM hash_page_items(get_raw_page('test_hash_a_idx', 3));
+-[ RECORD 1 ]----------
+itemoffset | 1
+ctid       | (0,1)
+data       | 2389907270
+
+SELECT * FROM hash_page_items(get_raw_page('test_hash_a_idx', 4));
+(0 rows)
+
+SELECT * FROM hash_page_items(get_raw_page('test_hash_a_idx', 5));
+ERROR:  page is not a hash bucket or overflow page
+DROP TABLE test_hash;
diff --git a/contrib/pageinspect/expected/page.out b/contrib/pageinspect/expected/page.out
new file mode 100644
index 0000000..29ea911
--- /dev/null
+++ b/contrib/pageinspect/expected/page.out
@@ -0,0 +1,203 @@
+CREATE EXTENSION pageinspect;
+CREATE TABLE test1 (a int, b int);
+INSERT INTO test1 VALUES (16777217, 131584);
+VACUUM (DISABLE_PAGE_SKIPPING) test1;  -- set up FSM
+-- The page contents can vary, so just test that it can be read
+-- successfully, but don't keep the output.
+SELECT octet_length(get_raw_page('test1', 'main', 0)) AS main_0;
+ main_0 
+--------
+   8192
+(1 row)
+
+SELECT octet_length(get_raw_page('test1', 'main', 1)) AS main_1;
+ERROR:  block number 1 is out of range for relation "test1"
+SELECT octet_length(get_raw_page('test1', 'fsm', 0)) AS fsm_0;
+ fsm_0 
+-------
+  8192
+(1 row)
+
+SELECT octet_length(get_raw_page('test1', 'fsm', 1)) AS fsm_1;
+ fsm_1 
+-------
+  8192
+(1 row)
+
+SELECT octet_length(get_raw_page('test1', 'vm', 0)) AS vm_0;
+ vm_0 
+------
+ 8192
+(1 row)
+
+SELECT octet_length(get_raw_page('test1', 'vm', 1)) AS vm_1;
+ERROR:  block number 1 is out of range for relation "test1"
+SELECT octet_length(get_raw_page('xxx', 'main', 0));
+ERROR:  relation "xxx" does not exist
+SELECT octet_length(get_raw_page('test1', 'xxx', 0));
+ERROR:  invalid fork name
+HINT:  Valid fork names are "main", "fsm", "vm", and "init".
+SELECT get_raw_page('test1', 0) = get_raw_page('test1', 'main', 0);
+ ?column? 
+----------
+ t
+(1 row)
+
+SELECT pagesize, version FROM page_header(get_raw_page('test1', 0));
+ pagesize | version 
+----------+---------
+     8192 |       4
+(1 row)
+
+SELECT page_checksum(get_raw_page('test1', 0), 0) IS NOT NULL AS silly_checksum_test;
+ silly_checksum_test 
+---------------------
+ t
+(1 row)
+
+SELECT tuple_data_split('test1'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    FROM heap_page_items(get_raw_page('test1', 0));
+       tuple_data_split        
+-------------------------------
+ {"\\x01000001","\\x00020200"}
+(1 row)
+
+SELECT * FROM fsm_page_contents(get_raw_page('test1', 'fsm', 0));
+ fsm_page_contents 
+-------------------
+ 0: 254           +
+ 1: 254           +
+ 3: 254           +
+ 7: 254           +
+ 15: 254          +
+ 31: 254          +
+ 63: 254          +
+ 127: 254         +
+ 255: 254         +
+ 511: 254         +
+ 1023: 254        +
+ 2047: 254        +
+ 4095: 254        +
+ fp_next_slot: 0  +
+ 
+(1 row)
+
+-- If we freeze the only tuple on test1, the infomask should
+-- always be the same in all test runs.
+VACUUM (FREEZE, DISABLE_PAGE_SKIPPING) test1;
+SELECT t_infomask, t_infomask2, raw_flags, combined_flags
+FROM heap_page_items(get_raw_page('test1', 0)),
+     LATERAL heap_tuple_infomask_flags(t_infomask, t_infomask2);
+ t_infomask | t_infomask2 |                         raw_flags                         |   combined_flags   
+------------+-------------+-----------------------------------------------------------+--------------------
+       2816 |           2 | {HEAP_XMIN_COMMITTED,HEAP_XMIN_INVALID,HEAP_XMAX_INVALID} | {HEAP_XMIN_FROZEN}
+(1 row)
+
+-- tests for decoding of combined flags
+-- HEAP_XMAX_SHR_LOCK = (HEAP_XMAX_EXCL_LOCK | HEAP_XMAX_KEYSHR_LOCK)
+SELECT * FROM heap_tuple_infomask_flags(x'0050'::int, 0);
+                  raw_flags                  |    combined_flags    
+---------------------------------------------+----------------------
+ {HEAP_XMAX_KEYSHR_LOCK,HEAP_XMAX_EXCL_LOCK} | {HEAP_XMAX_SHR_LOCK}
+(1 row)
+
+-- HEAP_XMIN_FROZEN = (HEAP_XMIN_COMMITTED | HEAP_XMIN_INVALID)
+SELECT * FROM heap_tuple_infomask_flags(x'0300'::int, 0);
+                raw_flags                |   combined_flags   
+-----------------------------------------+--------------------
+ {HEAP_XMIN_COMMITTED,HEAP_XMIN_INVALID} | {HEAP_XMIN_FROZEN}
+(1 row)
+
+-- HEAP_MOVED = (HEAP_MOVED_IN | HEAP_MOVED_OFF)
+SELECT * FROM heap_tuple_infomask_flags(x'C000'::int, 0);
+           raw_flags            | combined_flags 
+--------------------------------+----------------
+ {HEAP_MOVED_OFF,HEAP_MOVED_IN} | {HEAP_MOVED}
+(1 row)
+
+SELECT * FROM heap_tuple_infomask_flags(x'C000'::int, 0);
+           raw_flags            | combined_flags 
+--------------------------------+----------------
+ {HEAP_MOVED_OFF,HEAP_MOVED_IN} | {HEAP_MOVED}
+(1 row)
+
+-- test all flags of t_infomask and t_infomask2
+SELECT unnest(raw_flags)
+  FROM heap_tuple_infomask_flags(x'FFFF'::int, x'FFFF'::int) ORDER BY 1;
+        unnest         
+-----------------------
+ HEAP_COMBOCID
+ HEAP_HASEXTERNAL
+ HEAP_HASNULL
+ HEAP_HASOID_OLD
+ HEAP_HASVARWIDTH
+ HEAP_HOT_UPDATED
+ HEAP_KEYS_UPDATED
+ HEAP_MOVED_IN
+ HEAP_MOVED_OFF
+ HEAP_ONLY_TUPLE
+ HEAP_UPDATED
+ HEAP_XMAX_COMMITTED
+ HEAP_XMAX_EXCL_LOCK
+ HEAP_XMAX_INVALID
+ HEAP_XMAX_IS_MULTI
+ HEAP_XMAX_KEYSHR_LOCK
+ HEAP_XMAX_LOCK_ONLY
+ HEAP_XMIN_COMMITTED
+ HEAP_XMIN_INVALID
+(19 rows)
+
+SELECT unnest(combined_flags)
+  FROM heap_tuple_infomask_flags(x'FFFF'::int, x'FFFF'::int) ORDER BY 1;
+       unnest       
+--------------------
+ HEAP_MOVED
+ HEAP_XMAX_SHR_LOCK
+ HEAP_XMIN_FROZEN
+(3 rows)
+
+-- no flags at all
+SELECT * FROM heap_tuple_infomask_flags(0, 0);
+ raw_flags | combined_flags 
+-----------+----------------
+ {}        | {}
+(1 row)
+
+-- no combined flags
+SELECT * FROM heap_tuple_infomask_flags(x'0010'::int, 0);
+        raw_flags        | combined_flags 
+-------------------------+----------------
+ {HEAP_XMAX_KEYSHR_LOCK} | {}
+(1 row)
+
+DROP TABLE test1;
+-- check that using any of these functions with a partitioned table or index
+-- would fail
+create table test_partitioned (a int) partition by range (a);
+create index test_partitioned_index on test_partitioned (a);
+select get_raw_page('test_partitioned', 0); -- error about partitioned table
+ERROR:  cannot get raw page from partitioned table "test_partitioned"
+select get_raw_page('test_partitioned_index', 0); -- error about partitioned index
+ERROR:  cannot get raw page from partitioned index "test_partitioned_index"
+-- a regular table which is a member of a partition set should work though
+create table test_part1 partition of test_partitioned for values from ( 1 ) to (100);
+select get_raw_page('test_part1', 0); -- get farther and error about empty table
+ERROR:  block number 0 is out of range for relation "test_part1"
+drop table test_partitioned;
+-- check null bitmap alignment for table whose number of attributes is multiple of 8
+create table test8 (f1 int, f2 int, f3 int, f4 int, f5 int, f6 int, f7 int, f8 int);
+insert into test8(f1, f8) values (x'7f00007f'::int, 0);
+select t_bits, t_data from heap_page_items(get_raw_page('test8', 0));
+  t_bits  |       t_data       
+----------+--------------------
+ 10000001 | \x7f00007f00000000
+(1 row)
+
+select tuple_data_split('test8'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test8', 0));
+                      tuple_data_split                       
+-------------------------------------------------------------
+ {"\\x7f00007f",NULL,NULL,NULL,NULL,NULL,NULL,"\\x00000000"}
+(1 row)
+
+drop table test8;
diff --git a/contrib/pageinspect/fsmfuncs.c b/contrib/pageinspect/fsmfuncs.c
new file mode 100644
index 0000000..099acbb
--- /dev/null
+++ b/contrib/pageinspect/fsmfuncs.c
@@ -0,0 +1,59 @@
+/*-------------------------------------------------------------------------
+ *
+ * fsmfuncs.c
+ *	  Functions to investigate FSM pages
+ *
+ * These functions are restricted to superusers for the fear of introducing
+ * security holes if the input checking isn't as water-tight as it should.
+ * You'd need to be superuser to obtain a raw page image anyway, so
+ * there's hardly any use case for using these without superuser-rights
+ * anyway.
+ *
+ * Copyright (c) 2007-2020, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *	  contrib/pageinspect/fsmfuncs.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "funcapi.h"
+#include "lib/stringinfo.h"
+#include "miscadmin.h"
+#include "pageinspect.h"
+#include "storage/fsm_internals.h"
+#include "utils/builtins.h"
+
+/*
+ * Dumps the contents of a FSM page.
+ */
+PG_FUNCTION_INFO_V1(fsm_page_contents);
+
+Datum
+fsm_page_contents(PG_FUNCTION_ARGS)
+{
+	bytea	   *raw_page = PG_GETARG_BYTEA_P(0);
+	StringInfoData sinfo;
+	FSMPage		fsmpage;
+	int			i;
+
+	if (!superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("must be superuser to use raw page functions")));
+
+	fsmpage = (FSMPage) PageGetContents(VARDATA(raw_page));
+
+	initStringInfo(&sinfo);
+
+	for (i = 0; i < NodesPerPage; i++)
+	{
+		if (fsmpage->fp_nodes[i] != 0)
+			appendStringInfo(&sinfo, "%d: %d\n", i, fsmpage->fp_nodes[i]);
+	}
+	appendStringInfo(&sinfo, "fp_next_slot: %d\n", fsmpage->fp_next_slot);
+
+	PG_RETURN_TEXT_P(cstring_to_text_with_len(sinfo.data, sinfo.len));
+}
diff --git a/contrib/pageinspect/ginfuncs.c b/contrib/pageinspect/ginfuncs.c
new file mode 100644
index 0000000..7114735
--- /dev/null
+++ b/contrib/pageinspect/ginfuncs.c
@@ -0,0 +1,265 @@
+/*
+ * ginfuncs.c
+ *		Functions to investigate the content of GIN indexes
+ *
+ * Copyright (c) 2014-2020, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *		contrib/pageinspect/ginfuncs.c
+ */
+#include "postgres.h"
+
+#include "access/gin.h"
+#include "access/gin_private.h"
+#include "access/htup_details.h"
+#include "catalog/namespace.h"
+#include "catalog/pg_type.h"
+#include "funcapi.h"
+#include "miscadmin.h"
+#include "pageinspect.h"
+#include "utils/array.h"
+#include "utils/builtins.h"
+#include "utils/rel.h"
+
+#define DatumGetItemPointer(X)	 ((ItemPointer) DatumGetPointer(X))
+#define ItemPointerGetDatum(X)	 PointerGetDatum(X)
+
+
+PG_FUNCTION_INFO_V1(gin_metapage_info);
+PG_FUNCTION_INFO_V1(gin_page_opaque_info);
+PG_FUNCTION_INFO_V1(gin_leafpage_items);
+
+
+Datum
+gin_metapage_info(PG_FUNCTION_ARGS)
+{
+	bytea	   *raw_page = PG_GETARG_BYTEA_P(0);
+	TupleDesc	tupdesc;
+	Page		page;
+	GinPageOpaque opaq;
+	GinMetaPageData *metadata;
+	HeapTuple	resultTuple;
+	Datum		values[10];
+	bool		nulls[10];
+
+	if (!superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("must be superuser to use raw page functions")));
+
+	page = get_page_from_raw(raw_page);
+
+	opaq = (GinPageOpaque) PageGetSpecialPointer(page);
+	if (opaq->flags != GIN_META)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("input page is not a GIN metapage"),
+				 errdetail("Flags %04X, expected %04X",
+						   opaq->flags, GIN_META)));
+
+	/* 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");
+
+	metadata = GinPageGetMeta(page);
+
+	memset(nulls, 0, sizeof(nulls));
+
+	values[0] = Int64GetDatum(metadata->head);
+	values[1] = Int64GetDatum(metadata->tail);
+	values[2] = Int32GetDatum(metadata->tailFreeSize);
+	values[3] = Int64GetDatum(metadata->nPendingPages);
+	values[4] = Int64GetDatum(metadata->nPendingHeapTuples);
+
+	/* statistics, updated by VACUUM */
+	values[5] = Int64GetDatum(metadata->nTotalPages);
+	values[6] = Int64GetDatum(metadata->nEntryPages);
+	values[7] = Int64GetDatum(metadata->nDataPages);
+	values[8] = Int64GetDatum(metadata->nEntries);
+
+	values[9] = Int32GetDatum(metadata->ginVersion);
+
+	/* Build and return the result tuple. */
+	resultTuple = heap_form_tuple(tupdesc, values, nulls);
+
+	return HeapTupleGetDatum(resultTuple);
+}
+
+
+Datum
+gin_page_opaque_info(PG_FUNCTION_ARGS)
+{
+	bytea	   *raw_page = PG_GETARG_BYTEA_P(0);
+	TupleDesc	tupdesc;
+	Page		page;
+	GinPageOpaque opaq;
+	HeapTuple	resultTuple;
+	Datum		values[3];
+	bool		nulls[3];
+	Datum		flags[16];
+	int			nflags = 0;
+	uint16		flagbits;
+
+	if (!superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("must be superuser to use raw page functions")));
+
+	page = get_page_from_raw(raw_page);
+
+	opaq = (GinPageOpaque) PageGetSpecialPointer(page);
+
+	/* 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");
+
+	/* Convert the flags bitmask to an array of human-readable names */
+	flagbits = opaq->flags;
+	if (flagbits & GIN_DATA)
+		flags[nflags++] = CStringGetTextDatum("data");
+	if (flagbits & GIN_LEAF)
+		flags[nflags++] = CStringGetTextDatum("leaf");
+	if (flagbits & GIN_DELETED)
+		flags[nflags++] = CStringGetTextDatum("deleted");
+	if (flagbits & GIN_META)
+		flags[nflags++] = CStringGetTextDatum("meta");
+	if (flagbits & GIN_LIST)
+		flags[nflags++] = CStringGetTextDatum("list");
+	if (flagbits & GIN_LIST_FULLROW)
+		flags[nflags++] = CStringGetTextDatum("list_fullrow");
+	if (flagbits & GIN_INCOMPLETE_SPLIT)
+		flags[nflags++] = CStringGetTextDatum("incomplete_split");
+	if (flagbits & GIN_COMPRESSED)
+		flags[nflags++] = CStringGetTextDatum("compressed");
+	flagbits &= ~(GIN_DATA | GIN_LEAF | GIN_DELETED | GIN_META | GIN_LIST |
+				  GIN_LIST_FULLROW | GIN_INCOMPLETE_SPLIT | GIN_COMPRESSED);
+	if (flagbits)
+	{
+		/* any flags we don't recognize are printed in hex */
+		flags[nflags++] = DirectFunctionCall1(to_hex32, Int32GetDatum(flagbits));
+	}
+
+	memset(nulls, 0, sizeof(nulls));
+
+	values[0] = Int64GetDatum(opaq->rightlink);
+	values[1] = Int32GetDatum(opaq->maxoff);
+	values[2] = PointerGetDatum(construct_array(flags, nflags,
+												TEXTOID,
+												-1, false, TYPALIGN_INT));
+
+	/* Build and return the result tuple. */
+	resultTuple = heap_form_tuple(tupdesc, values, nulls);
+
+	return HeapTupleGetDatum(resultTuple);
+}
+
+typedef struct gin_leafpage_items_state
+{
+	TupleDesc	tupd;
+	GinPostingList *seg;
+	GinPostingList *lastseg;
+} gin_leafpage_items_state;
+
+Datum
+gin_leafpage_items(PG_FUNCTION_ARGS)
+{
+	bytea	   *raw_page = PG_GETARG_BYTEA_P(0);
+	FuncCallContext *fctx;
+	gin_leafpage_items_state *inter_call_data;
+
+	if (!superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("must be superuser to use raw page functions")));
+
+	if (SRF_IS_FIRSTCALL())
+	{
+		TupleDesc	tupdesc;
+		MemoryContext mctx;
+		Page		page;
+		GinPageOpaque opaq;
+
+		fctx = SRF_FIRSTCALL_INIT();
+		mctx = MemoryContextSwitchTo(fctx->multi_call_memory_ctx);
+
+		page = get_page_from_raw(raw_page);
+
+		if (PageGetSpecialSize(page) != MAXALIGN(sizeof(GinPageOpaqueData)))
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("input page is not a valid GIN data leaf page"),
+					 errdetail("Special size %d, expected %d",
+							   (int) PageGetSpecialSize(page),
+							   (int) MAXALIGN(sizeof(GinPageOpaqueData)))));
+
+		opaq = (GinPageOpaque) PageGetSpecialPointer(page);
+		if (opaq->flags != (GIN_DATA | GIN_LEAF | GIN_COMPRESSED))
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("input page is not a compressed GIN data leaf page"),
+					 errdetail("Flags %04X, expected %04X",
+							   opaq->flags,
+							   (GIN_DATA | GIN_LEAF | GIN_COMPRESSED))));
+
+		inter_call_data = palloc(sizeof(gin_leafpage_items_state));
+
+		/* 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");
+
+		inter_call_data->tupd = tupdesc;
+
+		inter_call_data->seg = GinDataLeafPageGetPostingList(page);
+		inter_call_data->lastseg = (GinPostingList *)
+			(((char *) inter_call_data->seg) +
+			 GinDataLeafPageGetPostingListSize(page));
+
+		fctx->user_fctx = inter_call_data;
+
+		MemoryContextSwitchTo(mctx);
+	}
+
+	fctx = SRF_PERCALL_SETUP();
+	inter_call_data = fctx->user_fctx;
+
+	if (inter_call_data->seg != inter_call_data->lastseg)
+	{
+		GinPostingList *cur = inter_call_data->seg;
+		HeapTuple	resultTuple;
+		Datum		result;
+		Datum		values[3];
+		bool		nulls[3];
+		int			ndecoded,
+					i;
+		ItemPointer tids;
+		Datum	   *tids_datum;
+
+		memset(nulls, 0, sizeof(nulls));
+
+		values[0] = ItemPointerGetDatum(&cur->first);
+		values[1] = UInt16GetDatum(cur->nbytes);
+
+		/* build an array of decoded item pointers */
+		tids = ginPostingListDecode(cur, &ndecoded);
+		tids_datum = (Datum *) palloc(ndecoded * sizeof(Datum));
+		for (i = 0; i < ndecoded; i++)
+			tids_datum[i] = ItemPointerGetDatum(&tids[i]);
+		values[2] = PointerGetDatum(construct_array(tids_datum,
+													ndecoded,
+													TIDOID,
+													sizeof(ItemPointerData),
+													false, TYPALIGN_SHORT));
+		pfree(tids_datum);
+		pfree(tids);
+
+		/* Build and return the result tuple. */
+		resultTuple = heap_form_tuple(inter_call_data->tupd, values, nulls);
+		result = HeapTupleGetDatum(resultTuple);
+
+		inter_call_data->seg = GinNextPostingListSegment(cur);
+
+		SRF_RETURN_NEXT(fctx, result);
+	}
+
+	SRF_RETURN_DONE(fctx);
+}
diff --git a/contrib/pageinspect/hashfuncs.c b/contrib/pageinspect/hashfuncs.c
new file mode 100644
index 0000000..3b2f033
--- /dev/null
+++ b/contrib/pageinspect/hashfuncs.c
@@ -0,0 +1,576 @@
+/*
+ * hashfuncs.c
+ *		Functions to investigate the content of HASH indexes
+ *
+ * Copyright (c) 2017-2020, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *		contrib/pageinspect/hashfuncs.c
+ */
+
+#include "postgres.h"
+
+#include "access/hash.h"
+#include "access/htup_details.h"
+#include "catalog/pg_am.h"
+#include "catalog/pg_type.h"
+#include "funcapi.h"
+#include "miscadmin.h"
+#include "pageinspect.h"
+#include "utils/array.h"
+#include "utils/builtins.h"
+#include "utils/rel.h"
+
+PG_FUNCTION_INFO_V1(hash_page_type);
+PG_FUNCTION_INFO_V1(hash_page_stats);
+PG_FUNCTION_INFO_V1(hash_page_items);
+PG_FUNCTION_INFO_V1(hash_bitmap_info);
+PG_FUNCTION_INFO_V1(hash_metapage_info);
+
+#define IS_HASH(r) ((r)->rd_rel->relam == HASH_AM_OID)
+
+/* ------------------------------------------------
+ * structure for single hash page statistics
+ * ------------------------------------------------
+ */
+typedef struct HashPageStat
+{
+	int			live_items;
+	int			dead_items;
+	int			page_size;
+	int			free_size;
+
+	/* opaque data */
+	BlockNumber hasho_prevblkno;
+	BlockNumber hasho_nextblkno;
+	Bucket		hasho_bucket;
+	uint16		hasho_flag;
+	uint16		hasho_page_id;
+} HashPageStat;
+
+
+/*
+ * Verify that the given bytea contains a HASH page, or die in the attempt.
+ * A pointer to a palloc'd, properly aligned copy of the page is returned.
+ */
+static Page
+verify_hash_page(bytea *raw_page, int flags)
+{
+	Page		page = get_page_from_raw(raw_page);
+	int			pagetype = LH_UNUSED_PAGE;
+
+	/* Treat new pages as unused. */
+	if (!PageIsNew(page))
+	{
+		HashPageOpaque pageopaque;
+
+		if (PageGetSpecialSize(page) != MAXALIGN(sizeof(HashPageOpaqueData)))
+			ereport(ERROR,
+					(errcode(ERRCODE_INDEX_CORRUPTED),
+					 errmsg("index table contains corrupted page")));
+
+		pageopaque = (HashPageOpaque) PageGetSpecialPointer(page);
+		if (pageopaque->hasho_page_id != HASHO_PAGE_ID)
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("page is not a hash page"),
+					 errdetail("Expected %08x, got %08x.",
+							   HASHO_PAGE_ID, pageopaque->hasho_page_id)));
+
+		pagetype = pageopaque->hasho_flag & LH_PAGE_TYPE;
+	}
+
+	/* Check that page type is sane. */
+	if (pagetype != LH_OVERFLOW_PAGE && pagetype != LH_BUCKET_PAGE &&
+		pagetype != LH_BITMAP_PAGE && pagetype != LH_META_PAGE &&
+		pagetype != LH_UNUSED_PAGE)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("invalid hash page type %08x", pagetype)));
+
+	/* If requested, verify page type. */
+	if (flags != 0 && (pagetype & flags) == 0)
+	{
+		switch (flags)
+		{
+			case LH_META_PAGE:
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+						 errmsg("page is not a hash meta page")));
+				break;
+			case LH_BUCKET_PAGE | LH_OVERFLOW_PAGE:
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+						 errmsg("page is not a hash bucket or overflow page")));
+				break;
+			case LH_OVERFLOW_PAGE:
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+						 errmsg("page is not a hash overflow page")));
+				break;
+			default:
+				elog(ERROR,
+					 "hash page of type %08x not in mask %08x",
+					 pagetype, flags);
+				break;
+		}
+	}
+
+	/*
+	 * If it is the metapage, also verify magic number and version.
+	 */
+	if (pagetype == LH_META_PAGE)
+	{
+		HashMetaPage metap = HashPageGetMeta(page);
+
+		if (metap->hashm_magic != HASH_MAGIC)
+			ereport(ERROR,
+					(errcode(ERRCODE_INDEX_CORRUPTED),
+					 errmsg("invalid magic number for metadata"),
+					 errdetail("Expected 0x%08x, got 0x%08x.",
+							   HASH_MAGIC, metap->hashm_magic)));
+
+		if (metap->hashm_version != HASH_VERSION)
+			ereport(ERROR,
+					(errcode(ERRCODE_INDEX_CORRUPTED),
+					 errmsg("invalid version for metadata"),
+					 errdetail("Expected %d, got %d",
+							   HASH_VERSION, metap->hashm_version)));
+	}
+
+	return page;
+}
+
+/* -------------------------------------------------
+ * GetHashPageStatistics()
+ *
+ * Collect statistics of single hash page
+ * -------------------------------------------------
+ */
+static void
+GetHashPageStatistics(Page page, HashPageStat *stat)
+{
+	OffsetNumber maxoff = PageGetMaxOffsetNumber(page);
+	HashPageOpaque opaque = (HashPageOpaque) PageGetSpecialPointer(page);
+	int			off;
+
+	stat->dead_items = stat->live_items = 0;
+	stat->page_size = PageGetPageSize(page);
+
+	/* hash page opaque data */
+	stat->hasho_prevblkno = opaque->hasho_prevblkno;
+	stat->hasho_nextblkno = opaque->hasho_nextblkno;
+	stat->hasho_bucket = opaque->hasho_bucket;
+	stat->hasho_flag = opaque->hasho_flag;
+	stat->hasho_page_id = opaque->hasho_page_id;
+
+	/* count live and dead tuples, and free space */
+	for (off = FirstOffsetNumber; off <= maxoff; off++)
+	{
+		ItemId		id = PageGetItemId(page, off);
+
+		if (!ItemIdIsDead(id))
+			stat->live_items++;
+		else
+			stat->dead_items++;
+	}
+	stat->free_size = PageGetFreeSpace(page);
+}
+
+/* ---------------------------------------------------
+ * hash_page_type()
+ *
+ * Usage: SELECT hash_page_type(get_raw_page('con_hash_index', 1));
+ * ---------------------------------------------------
+ */
+Datum
+hash_page_type(PG_FUNCTION_ARGS)
+{
+	bytea	   *raw_page = PG_GETARG_BYTEA_P(0);
+	Page		page;
+	HashPageOpaque opaque;
+	int			pagetype;
+	const char *type;
+
+	if (!superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("must be superuser to use raw page functions")));
+
+	page = verify_hash_page(raw_page, 0);
+
+	if (PageIsNew(page))
+		type = "unused";
+	else
+	{
+		opaque = (HashPageOpaque) PageGetSpecialPointer(page);
+
+		/* page type (flags) */
+		pagetype = opaque->hasho_flag & LH_PAGE_TYPE;
+		if (pagetype == LH_META_PAGE)
+			type = "metapage";
+		else if (pagetype == LH_OVERFLOW_PAGE)
+			type = "overflow";
+		else if (pagetype == LH_BUCKET_PAGE)
+			type = "bucket";
+		else if (pagetype == LH_BITMAP_PAGE)
+			type = "bitmap";
+		else
+			type = "unused";
+	}
+
+	PG_RETURN_TEXT_P(cstring_to_text(type));
+}
+
+/* ---------------------------------------------------
+ * hash_page_stats()
+ *
+ * Usage: SELECT * FROM hash_page_stats(get_raw_page('con_hash_index', 1));
+ * ---------------------------------------------------
+ */
+Datum
+hash_page_stats(PG_FUNCTION_ARGS)
+{
+	bytea	   *raw_page = PG_GETARG_BYTEA_P(0);
+	Page		page;
+	int			j;
+	Datum		values[9];
+	bool		nulls[9];
+	HashPageStat stat;
+	HeapTuple	tuple;
+	TupleDesc	tupleDesc;
+
+	if (!superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("must be superuser to use raw page functions")));
+
+	page = verify_hash_page(raw_page, LH_BUCKET_PAGE | LH_OVERFLOW_PAGE);
+
+	/* keep compiler quiet */
+	stat.hasho_prevblkno = stat.hasho_nextblkno = InvalidBlockNumber;
+	stat.hasho_flag = stat.hasho_page_id = stat.free_size = 0;
+
+	GetHashPageStatistics(page, &stat);
+
+	/* Build a tuple descriptor for our result type */
+	if (get_call_result_type(fcinfo, NULL, &tupleDesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+	tupleDesc = BlessTupleDesc(tupleDesc);
+
+	MemSet(nulls, 0, sizeof(nulls));
+
+	j = 0;
+	values[j++] = Int32GetDatum(stat.live_items);
+	values[j++] = Int32GetDatum(stat.dead_items);
+	values[j++] = Int32GetDatum(stat.page_size);
+	values[j++] = Int32GetDatum(stat.free_size);
+	values[j++] = Int64GetDatum((int64) stat.hasho_prevblkno);
+	values[j++] = Int64GetDatum((int64) stat.hasho_nextblkno);
+	values[j++] = Int64GetDatum((int64) stat.hasho_bucket);
+	values[j++] = Int32GetDatum((int32) stat.hasho_flag);
+	values[j++] = Int32GetDatum((int32) stat.hasho_page_id);
+
+	tuple = heap_form_tuple(tupleDesc, values, nulls);
+
+	PG_RETURN_DATUM(HeapTupleGetDatum(tuple));
+}
+
+/*
+ * cross-call data structure for SRF
+ */
+struct user_args
+{
+	Page		page;
+	OffsetNumber offset;
+};
+
+/*-------------------------------------------------------
+ * hash_page_items()
+ *
+ * Get IndexTupleData set in a hash page
+ *
+ * Usage: SELECT * FROM hash_page_items(get_raw_page('con_hash_index', 1));
+ *-------------------------------------------------------
+ */
+Datum
+hash_page_items(PG_FUNCTION_ARGS)
+{
+	bytea	   *raw_page = PG_GETARG_BYTEA_P(0);
+	Page		page;
+	Datum		result;
+	Datum		values[3];
+	bool		nulls[3];
+	uint32		hashkey;
+	HeapTuple	tuple;
+	FuncCallContext *fctx;
+	MemoryContext mctx;
+	struct user_args *uargs;
+
+	if (!superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("must be superuser to use raw page functions")));
+
+	if (SRF_IS_FIRSTCALL())
+	{
+		TupleDesc	tupleDesc;
+
+		fctx = SRF_FIRSTCALL_INIT();
+
+		mctx = MemoryContextSwitchTo(fctx->multi_call_memory_ctx);
+
+		page = verify_hash_page(raw_page, LH_BUCKET_PAGE | LH_OVERFLOW_PAGE);
+
+		uargs = palloc(sizeof(struct user_args));
+
+		uargs->page = page;
+
+		uargs->offset = FirstOffsetNumber;
+
+		fctx->max_calls = PageGetMaxOffsetNumber(uargs->page);
+
+		/* Build a tuple descriptor for our result type */
+		if (get_call_result_type(fcinfo, NULL, &tupleDesc) != TYPEFUNC_COMPOSITE)
+			elog(ERROR, "return type must be a row type");
+		tupleDesc = BlessTupleDesc(tupleDesc);
+
+		fctx->attinmeta = TupleDescGetAttInMetadata(tupleDesc);
+
+		fctx->user_fctx = uargs;
+
+		MemoryContextSwitchTo(mctx);
+	}
+
+	fctx = SRF_PERCALL_SETUP();
+	uargs = fctx->user_fctx;
+
+	if (fctx->call_cntr < fctx->max_calls)
+	{
+		ItemId		id;
+		IndexTuple	itup;
+		int			j;
+
+		id = PageGetItemId(uargs->page, uargs->offset);
+
+		if (!ItemIdIsValid(id))
+			elog(ERROR, "invalid ItemId");
+
+		itup = (IndexTuple) PageGetItem(uargs->page, id);
+
+		MemSet(nulls, 0, sizeof(nulls));
+
+		j = 0;
+		values[j++] = Int32GetDatum((int32) uargs->offset);
+		values[j++] = PointerGetDatum(&itup->t_tid);
+
+		hashkey = _hash_get_indextuple_hashkey(itup);
+		values[j] = Int64GetDatum((int64) hashkey);
+
+		tuple = heap_form_tuple(fctx->attinmeta->tupdesc, values, nulls);
+		result = HeapTupleGetDatum(tuple);
+
+		uargs->offset = uargs->offset + 1;
+
+		SRF_RETURN_NEXT(fctx, result);
+	}
+
+	SRF_RETURN_DONE(fctx);
+}
+
+/* ------------------------------------------------
+ * hash_bitmap_info()
+ *
+ * Get bitmap information for a particular overflow page
+ *
+ * Usage: SELECT * FROM hash_bitmap_info('con_hash_index'::regclass, 5);
+ * ------------------------------------------------
+ */
+Datum
+hash_bitmap_info(PG_FUNCTION_ARGS)
+{
+	Oid			indexRelid = PG_GETARG_OID(0);
+	uint64		ovflblkno = PG_GETARG_INT64(1);
+	HashMetaPage metap;
+	Buffer		metabuf,
+				mapbuf;
+	BlockNumber bitmapblkno;
+	Page		mappage;
+	bool		bit = false;
+	TupleDesc	tupleDesc;
+	Relation	indexRel;
+	uint32		ovflbitno;
+	int32		bitmappage,
+				bitmapbit;
+	HeapTuple	tuple;
+	int			i,
+				j;
+	Datum		values[3];
+	bool		nulls[3];
+	uint32	   *freep;
+
+	if (!superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("must be superuser to use raw page functions")));
+
+	indexRel = index_open(indexRelid, AccessShareLock);
+
+	if (!IS_HASH(indexRel))
+		elog(ERROR, "relation \"%s\" is not a hash index",
+			 RelationGetRelationName(indexRel));
+
+	if (RELATION_IS_OTHER_TEMP(indexRel))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot access temporary tables of other sessions")));
+
+	if (ovflblkno >= RelationGetNumberOfBlocks(indexRel))
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("block number " UINT64_FORMAT " is out of range for relation \"%s\"",
+						ovflblkno, RelationGetRelationName(indexRel))));
+
+	/* Read the metapage so we can determine which bitmap page to use */
+	metabuf = _hash_getbuf(indexRel, HASH_METAPAGE, HASH_READ, LH_META_PAGE);
+	metap = HashPageGetMeta(BufferGetPage(metabuf));
+
+	/*
+	 * Reject attempt to read the bit for a metapage or bitmap page; this is
+	 * only meaningful for overflow pages.
+	 */
+	if (ovflblkno == 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("invalid overflow block number %u",
+						(BlockNumber) ovflblkno)));
+	for (i = 0; i < metap->hashm_nmaps; i++)
+		if (metap->hashm_mapp[i] == ovflblkno)
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("invalid overflow block number %u",
+							(BlockNumber) ovflblkno)));
+
+	/*
+	 * Identify overflow bit number.  This will error out for primary bucket
+	 * pages, and we've already rejected the metapage and bitmap pages above.
+	 */
+	ovflbitno = _hash_ovflblkno_to_bitno(metap, (BlockNumber) ovflblkno);
+
+	bitmappage = ovflbitno >> BMPG_SHIFT(metap);
+	bitmapbit = ovflbitno & BMPG_MASK(metap);
+
+	if (bitmappage >= metap->hashm_nmaps)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("invalid overflow block number %u",
+						(BlockNumber) ovflblkno)));
+
+	bitmapblkno = metap->hashm_mapp[bitmappage];
+
+	_hash_relbuf(indexRel, metabuf);
+
+	/* Check the status of bitmap bit for overflow page */
+	mapbuf = _hash_getbuf(indexRel, bitmapblkno, HASH_READ, LH_BITMAP_PAGE);
+	mappage = BufferGetPage(mapbuf);
+	freep = HashPageGetBitmap(mappage);
+
+	bit = ISSET(freep, bitmapbit) != 0;
+
+	_hash_relbuf(indexRel, mapbuf);
+	index_close(indexRel, AccessShareLock);
+
+	/* Build a tuple descriptor for our result type */
+	if (get_call_result_type(fcinfo, NULL, &tupleDesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+	tupleDesc = BlessTupleDesc(tupleDesc);
+
+	MemSet(nulls, 0, sizeof(nulls));
+
+	j = 0;
+	values[j++] = Int64GetDatum((int64) bitmapblkno);
+	values[j++] = Int32GetDatum(bitmapbit);
+	values[j++] = BoolGetDatum(bit);
+
+	tuple = heap_form_tuple(tupleDesc, values, nulls);
+
+	PG_RETURN_DATUM(HeapTupleGetDatum(tuple));
+}
+
+/* ------------------------------------------------
+ * hash_metapage_info()
+ *
+ * Get the meta-page information for a hash index
+ *
+ * Usage: SELECT * FROM hash_metapage_info(get_raw_page('con_hash_index', 0))
+ * ------------------------------------------------
+ */
+Datum
+hash_metapage_info(PG_FUNCTION_ARGS)
+{
+	bytea	   *raw_page = PG_GETARG_BYTEA_P(0);
+	Page		page;
+	HashMetaPageData *metad;
+	TupleDesc	tupleDesc;
+	HeapTuple	tuple;
+	int			i,
+				j;
+	Datum		values[16];
+	bool		nulls[16];
+	Datum		spares[HASH_MAX_SPLITPOINTS];
+	Datum		mapp[HASH_MAX_BITMAPS];
+
+	if (!superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("must be superuser to use raw page functions")));
+
+	page = verify_hash_page(raw_page, LH_META_PAGE);
+
+	/* Build a tuple descriptor for our result type */
+	if (get_call_result_type(fcinfo, NULL, &tupleDesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+	tupleDesc = BlessTupleDesc(tupleDesc);
+
+	metad = HashPageGetMeta(page);
+
+	MemSet(nulls, 0, sizeof(nulls));
+
+	j = 0;
+	values[j++] = Int64GetDatum((int64) metad->hashm_magic);
+	values[j++] = Int64GetDatum((int64) metad->hashm_version);
+	values[j++] = Float8GetDatum(metad->hashm_ntuples);
+	values[j++] = Int32GetDatum((int32) metad->hashm_ffactor);
+	values[j++] = Int32GetDatum((int32) metad->hashm_bsize);
+	values[j++] = Int32GetDatum((int32) metad->hashm_bmsize);
+	values[j++] = Int32GetDatum((int32) metad->hashm_bmshift);
+	values[j++] = Int64GetDatum((int64) metad->hashm_maxbucket);
+	values[j++] = Int64GetDatum((int64) metad->hashm_highmask);
+	values[j++] = Int64GetDatum((int64) metad->hashm_lowmask);
+	values[j++] = Int64GetDatum((int64) metad->hashm_ovflpoint);
+	values[j++] = Int64GetDatum((int64) metad->hashm_firstfree);
+	values[j++] = Int64GetDatum((int64) metad->hashm_nmaps);
+	values[j++] = ObjectIdGetDatum((Oid) metad->hashm_procid);
+
+	for (i = 0; i < HASH_MAX_SPLITPOINTS; i++)
+		spares[i] = Int64GetDatum((int64) metad->hashm_spares[i]);
+	values[j++] = PointerGetDatum(construct_array(spares,
+												  HASH_MAX_SPLITPOINTS,
+												  INT8OID,
+												  sizeof(int64),
+												  FLOAT8PASSBYVAL,
+												  TYPALIGN_DOUBLE));
+
+	for (i = 0; i < HASH_MAX_BITMAPS; i++)
+		mapp[i] = Int64GetDatum((int64) metad->hashm_mapp[i]);
+	values[j++] = PointerGetDatum(construct_array(mapp,
+												  HASH_MAX_BITMAPS,
+												  INT8OID,
+												  sizeof(int64),
+												  FLOAT8PASSBYVAL,
+												  TYPALIGN_DOUBLE));
+
+	tuple = heap_form_tuple(tupleDesc, values, nulls);
+
+	PG_RETURN_DATUM(HeapTupleGetDatum(tuple));
+}
diff --git a/contrib/pageinspect/heapfuncs.c b/contrib/pageinspect/heapfuncs.c
new file mode 100644
index 0000000..11a9101
--- /dev/null
+++ b/contrib/pageinspect/heapfuncs.c
@@ -0,0 +1,621 @@
+/*-------------------------------------------------------------------------
+ *
+ * heapfuncs.c
+ *	  Functions to investigate heap pages
+ *
+ * We check the input to these functions for corrupt pointers etc. that
+ * might cause crashes, but at the same time we try to print out as much
+ * information as possible, even if it's nonsense. That's because if a
+ * page is corrupt, we don't know why and how exactly it is corrupt, so we
+ * let the user judge it.
+ *
+ * These functions are restricted to superusers for the fear of introducing
+ * security holes if the input checking isn't as water-tight as it should be.
+ * You'd need to be superuser to obtain a raw page image anyway, so
+ * there's hardly any use case for using these without superuser-rights
+ * anyway.
+ *
+ * Copyright (c) 2007-2020, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *	  contrib/pageinspect/heapfuncs.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "access/htup_details.h"
+#include "access/relation.h"
+#include "catalog/pg_am_d.h"
+#include "catalog/pg_type.h"
+#include "funcapi.h"
+#include "miscadmin.h"
+#include "pageinspect.h"
+#include "port/pg_bitutils.h"
+#include "utils/array.h"
+#include "utils/builtins.h"
+#include "utils/rel.h"
+
+/*
+ * It's not supported to create tuples with oids anymore, but when pg_upgrade
+ * was used to upgrade from an older version, tuples might still have an
+ * oid. Seems worthwhile to display that.
+ */
+#define HeapTupleHeaderGetOidOld(tup) \
+( \
+	((tup)->t_infomask & HEAP_HASOID_OLD) ? \
+	   *((Oid *) ((char *)(tup) + (tup)->t_hoff - sizeof(Oid))) \
+	: \
+		InvalidOid \
+)
+
+
+/*
+ * bits_to_text
+ *
+ * Converts a bits8-array of 'len' bits to a human-readable
+ * c-string representation.
+ */
+static char *
+bits_to_text(bits8 *bits, int len)
+{
+	int			i;
+	char	   *str;
+
+	str = palloc(len + 1);
+
+	for (i = 0; i < len; i++)
+		str[i] = (bits[(i / 8)] & (1 << (i % 8))) ? '1' : '0';
+
+	str[i] = '\0';
+
+	return str;
+}
+
+
+/*
+ * text_to_bits
+ *
+ * Converts a c-string representation of bits into a bits8-array. This is
+ * the reverse operation of previous routine.
+ */
+static bits8 *
+text_to_bits(char *str, int len)
+{
+	bits8	   *bits;
+	int			off = 0;
+	char		byte = 0;
+
+	bits = palloc(len + 1);
+
+	while (off < len)
+	{
+		if (off % 8 == 0)
+			byte = 0;
+
+		if ((str[off] == '0') || (str[off] == '1'))
+			byte = byte | ((str[off] - '0') << off % 8);
+		else
+			ereport(ERROR,
+					(errcode(ERRCODE_DATA_CORRUPTED),
+					 errmsg("illegal character '%c' in t_bits string", str[off])));
+
+		if (off % 8 == 7)
+			bits[off / 8] = byte;
+
+		off++;
+	}
+
+	return bits;
+}
+
+/*
+ * heap_page_items
+ *
+ * Allows inspection of line pointers and tuple headers of a heap page.
+ */
+PG_FUNCTION_INFO_V1(heap_page_items);
+
+typedef struct heap_page_items_state
+{
+	TupleDesc	tupd;
+	Page		page;
+	uint16		offset;
+} heap_page_items_state;
+
+Datum
+heap_page_items(PG_FUNCTION_ARGS)
+{
+	bytea	   *raw_page = PG_GETARG_BYTEA_P(0);
+	heap_page_items_state *inter_call_data = NULL;
+	FuncCallContext *fctx;
+	int			raw_page_size;
+
+	if (!superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("must be superuser to use raw page functions")));
+
+	raw_page_size = VARSIZE(raw_page) - VARHDRSZ;
+
+	if (SRF_IS_FIRSTCALL())
+	{
+		TupleDesc	tupdesc;
+		MemoryContext mctx;
+
+		if (raw_page_size < SizeOfPageHeaderData)
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("input page too small (%d bytes)", raw_page_size)));
+
+		fctx = SRF_FIRSTCALL_INIT();
+		mctx = MemoryContextSwitchTo(fctx->multi_call_memory_ctx);
+
+		inter_call_data = palloc(sizeof(heap_page_items_state));
+
+		/* 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");
+
+		inter_call_data->tupd = tupdesc;
+
+		inter_call_data->offset = FirstOffsetNumber;
+		inter_call_data->page = VARDATA(raw_page);
+
+		fctx->max_calls = PageGetMaxOffsetNumber(inter_call_data->page);
+		fctx->user_fctx = inter_call_data;
+
+		MemoryContextSwitchTo(mctx);
+	}
+
+	fctx = SRF_PERCALL_SETUP();
+	inter_call_data = fctx->user_fctx;
+
+	if (fctx->call_cntr < fctx->max_calls)
+	{
+		Page		page = inter_call_data->page;
+		HeapTuple	resultTuple;
+		Datum		result;
+		ItemId		id;
+		Datum		values[14];
+		bool		nulls[14];
+		uint16		lp_offset;
+		uint16		lp_flags;
+		uint16		lp_len;
+
+		memset(nulls, 0, sizeof(nulls));
+
+		/* Extract information from the line pointer */
+
+		id = PageGetItemId(page, inter_call_data->offset);
+
+		lp_offset = ItemIdGetOffset(id);
+		lp_flags = ItemIdGetFlags(id);
+		lp_len = ItemIdGetLength(id);
+
+		values[0] = UInt16GetDatum(inter_call_data->offset);
+		values[1] = UInt16GetDatum(lp_offset);
+		values[2] = UInt16GetDatum(lp_flags);
+		values[3] = UInt16GetDatum(lp_len);
+
+		/*
+		 * We do just enough validity checking to make sure we don't reference
+		 * data outside the page passed to us. The page could be corrupt in
+		 * many other ways, but at least we won't crash.
+		 */
+		if (ItemIdHasStorage(id) &&
+			lp_len >= MinHeapTupleSize &&
+			lp_offset == MAXALIGN(lp_offset) &&
+			lp_offset + lp_len <= raw_page_size)
+		{
+			HeapTupleHeader tuphdr;
+			bytea	   *tuple_data_bytea;
+			int			tuple_data_len;
+
+			/* Extract information from the tuple header */
+
+			tuphdr = (HeapTupleHeader) PageGetItem(page, id);
+
+			values[4] = UInt32GetDatum(HeapTupleHeaderGetRawXmin(tuphdr));
+			values[5] = UInt32GetDatum(HeapTupleHeaderGetRawXmax(tuphdr));
+			/* shared with xvac */
+			values[6] = UInt32GetDatum(HeapTupleHeaderGetRawCommandId(tuphdr));
+			values[7] = PointerGetDatum(&tuphdr->t_ctid);
+			values[8] = UInt32GetDatum(tuphdr->t_infomask2);
+			values[9] = UInt32GetDatum(tuphdr->t_infomask);
+			values[10] = UInt8GetDatum(tuphdr->t_hoff);
+
+			/* Copy raw tuple data into bytea attribute */
+			tuple_data_len = lp_len - tuphdr->t_hoff;
+			tuple_data_bytea = (bytea *) palloc(tuple_data_len + VARHDRSZ);
+			SET_VARSIZE(tuple_data_bytea, tuple_data_len + VARHDRSZ);
+			memcpy(VARDATA(tuple_data_bytea), (char *) tuphdr + tuphdr->t_hoff,
+				   tuple_data_len);
+			values[13] = PointerGetDatum(tuple_data_bytea);
+
+			/*
+			 * We already checked that the item is completely within the raw
+			 * page passed to us, with the length given in the line pointer.
+			 * Let's check that t_hoff doesn't point over lp_len, before using
+			 * it to access t_bits and oid.
+			 */
+			if (tuphdr->t_hoff >= SizeofHeapTupleHeader &&
+				tuphdr->t_hoff <= lp_len &&
+				tuphdr->t_hoff == MAXALIGN(tuphdr->t_hoff))
+			{
+				if (tuphdr->t_infomask & HEAP_HASNULL)
+				{
+					int			bits_len;
+
+					bits_len =
+						BITMAPLEN(HeapTupleHeaderGetNatts(tuphdr)) * BITS_PER_BYTE;
+					values[11] = CStringGetTextDatum(bits_to_text(tuphdr->t_bits, bits_len));
+				}
+				else
+					nulls[11] = true;
+
+				if (tuphdr->t_infomask & HEAP_HASOID_OLD)
+					values[12] = HeapTupleHeaderGetOidOld(tuphdr);
+				else
+					nulls[12] = true;
+			}
+			else
+			{
+				nulls[11] = true;
+				nulls[12] = true;
+			}
+		}
+		else
+		{
+			/*
+			 * The line pointer is not used, or it's invalid. Set the rest of
+			 * the fields to NULL
+			 */
+			int			i;
+
+			for (i = 4; i <= 13; i++)
+				nulls[i] = true;
+		}
+
+		/* Build and return the result tuple. */
+		resultTuple = heap_form_tuple(inter_call_data->tupd, values, nulls);
+		result = HeapTupleGetDatum(resultTuple);
+
+		inter_call_data->offset++;
+
+		SRF_RETURN_NEXT(fctx, result);
+	}
+	else
+		SRF_RETURN_DONE(fctx);
+}
+
+/*
+ * tuple_data_split_internal
+ *
+ * Split raw tuple data taken directly from a page into an array of bytea
+ * elements. This routine does a lookup on NULL values and creates array
+ * elements accordingly. This is a reimplementation of nocachegetattr()
+ * in heaptuple.c simplified for educational purposes.
+ */
+static Datum
+tuple_data_split_internal(Oid relid, char *tupdata,
+						  uint16 tupdata_len, uint16 t_infomask,
+						  uint16 t_infomask2, bits8 *t_bits,
+						  bool do_detoast)
+{
+	ArrayBuildState *raw_attrs;
+	int			nattrs;
+	int			i;
+	int			off = 0;
+	Relation	rel;
+	TupleDesc	tupdesc;
+
+	/* Get tuple descriptor from relation OID */
+	rel = relation_open(relid, AccessShareLock);
+	tupdesc = RelationGetDescr(rel);
+
+	raw_attrs = initArrayResult(BYTEAOID, CurrentMemoryContext, false);
+	nattrs = tupdesc->natts;
+
+	if (rel->rd_rel->relam != HEAP_TABLE_AM_OID)
+		ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						errmsg("only heap AM is supported")));
+
+	if (nattrs < (t_infomask2 & HEAP_NATTS_MASK))
+		ereport(ERROR,
+				(errcode(ERRCODE_DATA_CORRUPTED),
+				 errmsg("number of attributes in tuple header is greater than number of attributes in tuple descriptor")));
+
+	for (i = 0; i < nattrs; i++)
+	{
+		Form_pg_attribute attr;
+		bool		is_null;
+		bytea	   *attr_data = NULL;
+
+		attr = TupleDescAttr(tupdesc, i);
+
+		/*
+		 * Tuple header can specify less attributes than tuple descriptor as
+		 * ALTER TABLE ADD COLUMN without DEFAULT keyword does not actually
+		 * change tuples in pages, so attributes with numbers greater than
+		 * (t_infomask2 & HEAP_NATTS_MASK) should be treated as NULL.
+		 */
+		if (i >= (t_infomask2 & HEAP_NATTS_MASK))
+			is_null = true;
+		else
+			is_null = (t_infomask & HEAP_HASNULL) && att_isnull(i, t_bits);
+
+		if (!is_null)
+		{
+			int			len;
+
+			if (attr->attlen == -1)
+			{
+				off = att_align_pointer(off, attr->attalign, -1,
+										tupdata + off);
+
+				/*
+				 * As VARSIZE_ANY throws an exception if it can't properly
+				 * detect the type of external storage in macros VARTAG_SIZE,
+				 * this check is repeated to have a nicer error handling.
+				 */
+				if (VARATT_IS_EXTERNAL(tupdata + off) &&
+					!VARATT_IS_EXTERNAL_ONDISK(tupdata + off) &&
+					!VARATT_IS_EXTERNAL_INDIRECT(tupdata + off))
+					ereport(ERROR,
+							(errcode(ERRCODE_DATA_CORRUPTED),
+							 errmsg("first byte of varlena attribute is incorrect for attribute %d", i)));
+
+				len = VARSIZE_ANY(tupdata + off);
+			}
+			else
+			{
+				off = att_align_nominal(off, attr->attalign);
+				len = attr->attlen;
+			}
+
+			if (tupdata_len < off + len)
+				ereport(ERROR,
+						(errcode(ERRCODE_DATA_CORRUPTED),
+						 errmsg("unexpected end of tuple data")));
+
+			if (attr->attlen == -1 && do_detoast)
+				attr_data = DatumGetByteaPCopy(tupdata + off);
+			else
+			{
+				attr_data = (bytea *) palloc(len + VARHDRSZ);
+				SET_VARSIZE(attr_data, len + VARHDRSZ);
+				memcpy(VARDATA(attr_data), tupdata + off, len);
+			}
+
+			off = att_addlength_pointer(off, attr->attlen,
+										tupdata + off);
+		}
+
+		raw_attrs = accumArrayResult(raw_attrs, PointerGetDatum(attr_data),
+									 is_null, BYTEAOID, CurrentMemoryContext);
+		if (attr_data)
+			pfree(attr_data);
+	}
+
+	if (tupdata_len != off)
+		ereport(ERROR,
+				(errcode(ERRCODE_DATA_CORRUPTED),
+				 errmsg("end of tuple reached without looking at all its data")));
+
+	relation_close(rel, AccessShareLock);
+
+	return makeArrayResult(raw_attrs, CurrentMemoryContext);
+}
+
+/*
+ * tuple_data_split
+ *
+ * Split raw tuple data taken directly from page into distinct elements
+ * taking into account null values.
+ */
+PG_FUNCTION_INFO_V1(tuple_data_split);
+
+Datum
+tuple_data_split(PG_FUNCTION_ARGS)
+{
+	Oid			relid;
+	bytea	   *raw_data;
+	uint16		t_infomask;
+	uint16		t_infomask2;
+	char	   *t_bits_str;
+	bool		do_detoast = false;
+	bits8	   *t_bits = NULL;
+	Datum		res;
+
+	relid = PG_GETARG_OID(0);
+	raw_data = PG_ARGISNULL(1) ? NULL : PG_GETARG_BYTEA_P(1);
+	t_infomask = PG_GETARG_INT16(2);
+	t_infomask2 = PG_GETARG_INT16(3);
+	t_bits_str = PG_ARGISNULL(4) ? NULL :
+		text_to_cstring(PG_GETARG_TEXT_PP(4));
+
+	if (PG_NARGS() >= 6)
+		do_detoast = PG_GETARG_BOOL(5);
+
+	if (!superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("must be superuser to use raw page functions")));
+
+	if (!raw_data)
+		PG_RETURN_NULL();
+
+	/*
+	 * Convert t_bits string back to the bits8 array as represented in the
+	 * tuple header.
+	 */
+	if (t_infomask & HEAP_HASNULL)
+	{
+		int			bits_str_len;
+		int			bits_len;
+
+		bits_len = BITMAPLEN(t_infomask2 & HEAP_NATTS_MASK) * BITS_PER_BYTE;
+		if (!t_bits_str)
+			ereport(ERROR,
+					(errcode(ERRCODE_DATA_CORRUPTED),
+					 errmsg("argument of t_bits is null, but it is expected to be null and %d character long",
+							bits_len)));
+
+		bits_str_len = strlen(t_bits_str);
+		if (bits_len != bits_str_len)
+			ereport(ERROR,
+					(errcode(ERRCODE_DATA_CORRUPTED),
+					 errmsg("unexpected length of t_bits %u, expected %d",
+							bits_str_len, bits_len)));
+
+		/* do the conversion */
+		t_bits = text_to_bits(t_bits_str, bits_str_len);
+	}
+	else
+	{
+		if (t_bits_str)
+			ereport(ERROR,
+					(errcode(ERRCODE_DATA_CORRUPTED),
+					 errmsg("t_bits string is expected to be NULL, but instead it is %zu bytes length",
+							strlen(t_bits_str))));
+	}
+
+	/* Split tuple data */
+	res = tuple_data_split_internal(relid, (char *) raw_data + VARHDRSZ,
+									VARSIZE(raw_data) - VARHDRSZ,
+									t_infomask, t_infomask2, t_bits,
+									do_detoast);
+
+	if (t_bits)
+		pfree(t_bits);
+
+	PG_RETURN_ARRAYTYPE_P(res);
+}
+
+/*
+ * heap_tuple_infomask_flags
+ *
+ * Decode into a human-readable format t_infomask and t_infomask2 associated
+ * to a tuple.  All the flags are described in access/htup_details.h.
+ */
+PG_FUNCTION_INFO_V1(heap_tuple_infomask_flags);
+
+Datum
+heap_tuple_infomask_flags(PG_FUNCTION_ARGS)
+{
+#define HEAP_TUPLE_INFOMASK_COLS 2
+	Datum		values[HEAP_TUPLE_INFOMASK_COLS];
+	bool		nulls[HEAP_TUPLE_INFOMASK_COLS];
+	uint16		t_infomask = PG_GETARG_INT16(0);
+	uint16		t_infomask2 = PG_GETARG_INT16(1);
+	int			cnt = 0;
+	ArrayType  *a;
+	int			bitcnt;
+	Datum	   *flags;
+	TupleDesc	tupdesc;
+	HeapTuple	tuple;
+
+	if (!superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("must be superuser to use raw page functions")));
+
+	/* 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");
+
+	bitcnt = pg_popcount((const char *) &t_infomask, sizeof(uint16)) +
+		pg_popcount((const char *) &t_infomask2, sizeof(uint16));
+
+	/* Initialize values and NULL flags arrays */
+	MemSet(values, 0, sizeof(values));
+	MemSet(nulls, 0, sizeof(nulls));
+
+	/* If no flags, return a set of empty arrays */
+	if (bitcnt <= 0)
+	{
+		values[0] = PointerGetDatum(construct_empty_array(TEXTOID));
+		values[1] = PointerGetDatum(construct_empty_array(TEXTOID));
+		tuple = heap_form_tuple(tupdesc, values, nulls);
+		PG_RETURN_DATUM(HeapTupleGetDatum(tuple));
+	}
+
+	/* build set of raw flags */
+	flags = (Datum *) palloc0(sizeof(Datum) * bitcnt);
+
+	/* decode t_infomask */
+	if ((t_infomask & HEAP_HASNULL) != 0)
+		flags[cnt++] = CStringGetTextDatum("HEAP_HASNULL");
+	if ((t_infomask & HEAP_HASVARWIDTH) != 0)
+		flags[cnt++] = CStringGetTextDatum("HEAP_HASVARWIDTH");
+	if ((t_infomask & HEAP_HASEXTERNAL) != 0)
+		flags[cnt++] = CStringGetTextDatum("HEAP_HASEXTERNAL");
+	if ((t_infomask & HEAP_HASOID_OLD) != 0)
+		flags[cnt++] = CStringGetTextDatum("HEAP_HASOID_OLD");
+	if ((t_infomask & HEAP_XMAX_KEYSHR_LOCK) != 0)
+		flags[cnt++] = CStringGetTextDatum("HEAP_XMAX_KEYSHR_LOCK");
+	if ((t_infomask & HEAP_COMBOCID) != 0)
+		flags[cnt++] = CStringGetTextDatum("HEAP_COMBOCID");
+	if ((t_infomask & HEAP_XMAX_EXCL_LOCK) != 0)
+		flags[cnt++] = CStringGetTextDatum("HEAP_XMAX_EXCL_LOCK");
+	if ((t_infomask & HEAP_XMAX_LOCK_ONLY) != 0)
+		flags[cnt++] = CStringGetTextDatum("HEAP_XMAX_LOCK_ONLY");
+	if ((t_infomask & HEAP_XMIN_COMMITTED) != 0)
+		flags[cnt++] = CStringGetTextDatum("HEAP_XMIN_COMMITTED");
+	if ((t_infomask & HEAP_XMIN_INVALID) != 0)
+		flags[cnt++] = CStringGetTextDatum("HEAP_XMIN_INVALID");
+	if ((t_infomask & HEAP_XMAX_COMMITTED) != 0)
+		flags[cnt++] = CStringGetTextDatum("HEAP_XMAX_COMMITTED");
+	if ((t_infomask & HEAP_XMAX_INVALID) != 0)
+		flags[cnt++] = CStringGetTextDatum("HEAP_XMAX_INVALID");
+	if ((t_infomask & HEAP_XMAX_IS_MULTI) != 0)
+		flags[cnt++] = CStringGetTextDatum("HEAP_XMAX_IS_MULTI");
+	if ((t_infomask & HEAP_UPDATED) != 0)
+		flags[cnt++] = CStringGetTextDatum("HEAP_UPDATED");
+	if ((t_infomask & HEAP_MOVED_OFF) != 0)
+		flags[cnt++] = CStringGetTextDatum("HEAP_MOVED_OFF");
+	if ((t_infomask & HEAP_MOVED_IN) != 0)
+		flags[cnt++] = CStringGetTextDatum("HEAP_MOVED_IN");
+
+	/* decode t_infomask2 */
+	if ((t_infomask2 & HEAP_KEYS_UPDATED) != 0)
+		flags[cnt++] = CStringGetTextDatum("HEAP_KEYS_UPDATED");
+	if ((t_infomask2 & HEAP_HOT_UPDATED) != 0)
+		flags[cnt++] = CStringGetTextDatum("HEAP_HOT_UPDATED");
+	if ((t_infomask2 & HEAP_ONLY_TUPLE) != 0)
+		flags[cnt++] = CStringGetTextDatum("HEAP_ONLY_TUPLE");
+
+	/* build value */
+	Assert(cnt <= bitcnt);
+	a = construct_array(flags, cnt, TEXTOID, -1, false, TYPALIGN_INT);
+	values[0] = PointerGetDatum(a);
+
+	/*
+	 * Build set of combined flags.  Use the same array as previously, this
+	 * keeps the code simple.
+	 */
+	cnt = 0;
+	MemSet(flags, 0, sizeof(Datum) * bitcnt);
+
+	/* decode combined masks of t_infomask */
+	if ((t_infomask & HEAP_XMAX_SHR_LOCK) == HEAP_XMAX_SHR_LOCK)
+		flags[cnt++] = CStringGetTextDatum("HEAP_XMAX_SHR_LOCK");
+	if ((t_infomask & HEAP_XMIN_FROZEN) == HEAP_XMIN_FROZEN)
+		flags[cnt++] = CStringGetTextDatum("HEAP_XMIN_FROZEN");
+	if ((t_infomask & HEAP_MOVED) == HEAP_MOVED)
+		flags[cnt++] = CStringGetTextDatum("HEAP_MOVED");
+
+	/* Build an empty array if there are no combined flags */
+	if (cnt == 0)
+		a = construct_empty_array(TEXTOID);
+	else
+		a = construct_array(flags, cnt, TEXTOID, -1, false, TYPALIGN_INT);
+	pfree(flags);
+	values[1] = PointerGetDatum(a);
+
+	/* Returns the record as Datum */
+	tuple = heap_form_tuple(tupdesc, values, nulls);
+	PG_RETURN_DATUM(HeapTupleGetDatum(tuple));
+}
diff --git a/contrib/pageinspect/pageinspect--1.0--1.1.sql b/contrib/pageinspect/pageinspect--1.0--1.1.sql
new file mode 100644
index 0000000..0e2c3f4
--- /dev/null
+++ b/contrib/pageinspect/pageinspect--1.0--1.1.sql
@@ -0,0 +1,18 @@
+/* contrib/pageinspect/pageinspect--1.0--1.1.sql */
+
+-- complain if script is sourced in psql, rather than via ALTER EXTENSION
+\echo Use "ALTER EXTENSION pageinspect UPDATE TO '1.1'" to load this file. \quit
+
+DROP FUNCTION page_header(bytea);
+CREATE FUNCTION page_header(IN page bytea,
+    OUT lsn text,
+    OUT checksum smallint,
+    OUT flags smallint,
+    OUT lower smallint,
+    OUT upper smallint,
+    OUT special smallint,
+    OUT pagesize smallint,
+    OUT version smallint,
+    OUT prune_xid xid)
+AS 'MODULE_PATHNAME', 'page_header'
+LANGUAGE C STRICT;
diff --git a/contrib/pageinspect/pageinspect--1.1--1.2.sql b/contrib/pageinspect/pageinspect--1.1--1.2.sql
new file mode 100644
index 0000000..31ffbb0
--- /dev/null
+++ b/contrib/pageinspect/pageinspect--1.1--1.2.sql
@@ -0,0 +1,18 @@
+/* contrib/pageinspect/pageinspect--1.1--1.2.sql */
+
+-- complain if script is sourced in psql, rather than via ALTER EXTENSION
+\echo Use "ALTER EXTENSION pageinspect UPDATE TO '1.2'" to load this file. \quit
+
+DROP FUNCTION page_header(bytea);
+CREATE FUNCTION page_header(IN page bytea,
+    OUT lsn pg_lsn,
+    OUT checksum smallint,
+    OUT flags smallint,
+    OUT lower smallint,
+    OUT upper smallint,
+    OUT special smallint,
+    OUT pagesize smallint,
+    OUT version smallint,
+    OUT prune_xid xid)
+AS 'MODULE_PATHNAME', 'page_header'
+LANGUAGE C STRICT;
diff --git a/contrib/pageinspect/pageinspect--1.2--1.3.sql b/contrib/pageinspect/pageinspect--1.2--1.3.sql
new file mode 100644
index 0000000..9c55a6e
--- /dev/null
+++ b/contrib/pageinspect/pageinspect--1.2--1.3.sql
@@ -0,0 +1,82 @@
+/* contrib/pageinspect/pageinspect--1.2--1.3.sql */
+
+-- complain if script is sourced in psql, rather than via ALTER EXTENSION
+\echo Use "ALTER EXTENSION pageinspect UPDATE TO '1.3'" to load this file. \quit
+
+--
+-- brin_page_type()
+--
+CREATE FUNCTION brin_page_type(IN page bytea)
+RETURNS text
+AS 'MODULE_PATHNAME', 'brin_page_type'
+LANGUAGE C STRICT;
+
+--
+-- brin_metapage_info()
+--
+CREATE FUNCTION brin_metapage_info(IN page bytea, OUT magic text,
+	OUT version integer, OUT pagesperrange integer, OUT lastrevmappage bigint)
+AS 'MODULE_PATHNAME', 'brin_metapage_info'
+LANGUAGE C STRICT;
+
+--
+-- brin_revmap_data()
+--
+CREATE FUNCTION brin_revmap_data(IN page bytea,
+	OUT pages tid)
+RETURNS SETOF tid
+AS 'MODULE_PATHNAME', 'brin_revmap_data'
+LANGUAGE C STRICT;
+
+--
+-- brin_page_items()
+--
+CREATE FUNCTION brin_page_items(IN page bytea, IN index_oid regclass,
+	OUT itemoffset int,
+	OUT blknum int,
+	OUT attnum int,
+	OUT allnulls bool,
+	OUT hasnulls bool,
+	OUT placeholder bool,
+	OUT value text)
+RETURNS SETOF record
+AS 'MODULE_PATHNAME', 'brin_page_items'
+LANGUAGE C STRICT;
+
+--
+-- gin_metapage_info()
+--
+CREATE FUNCTION gin_metapage_info(IN page bytea,
+    OUT pending_head bigint,
+    OUT pending_tail bigint,
+    OUT tail_free_size int4,
+    OUT n_pending_pages bigint,
+    OUT n_pending_tuples bigint,
+    OUT n_total_pages bigint,
+    OUT n_entry_pages bigint,
+    OUT n_data_pages bigint,
+    OUT n_entries bigint,
+    OUT version int4)
+AS 'MODULE_PATHNAME', 'gin_metapage_info'
+LANGUAGE C STRICT;
+
+--
+-- gin_page_opaque_info()
+--
+CREATE FUNCTION gin_page_opaque_info(IN page bytea,
+    OUT rightlink bigint,
+    OUT maxoff int4,
+    OUT flags text[])
+AS 'MODULE_PATHNAME', 'gin_page_opaque_info'
+LANGUAGE C STRICT;
+
+--
+-- gin_leafpage_items()
+--
+CREATE FUNCTION gin_leafpage_items(IN page bytea,
+    OUT first_tid tid,
+    OUT nbytes int2,
+    OUT tids tid[])
+RETURNS SETOF record
+AS 'MODULE_PATHNAME', 'gin_leafpage_items'
+LANGUAGE C STRICT;
diff --git a/contrib/pageinspect/pageinspect--1.3--1.4.sql b/contrib/pageinspect/pageinspect--1.3--1.4.sql
new file mode 100644
index 0000000..86e0dfa
--- /dev/null
+++ b/contrib/pageinspect/pageinspect--1.3--1.4.sql
@@ -0,0 +1,118 @@
+/* contrib/pageinspect/pageinspect--1.3--1.4.sql */
+
+-- complain if script is sourced in psql, rather than via ALTER EXTENSION
+\echo Use "ALTER EXTENSION pageinspect UPDATE TO '1.4'" to load this file. \quit
+
+--
+-- heap_page_items()
+--
+DROP FUNCTION heap_page_items(bytea);
+CREATE 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 integer,
+    OUT t_infomask integer,
+    OUT t_hoff smallint,
+    OUT t_bits text,
+    OUT t_oid oid,
+    OUT t_data bytea)
+RETURNS SETOF record
+AS 'MODULE_PATHNAME', 'heap_page_items'
+LANGUAGE C STRICT;
+
+--
+-- tuple_data_split()
+--
+CREATE FUNCTION tuple_data_split(rel_oid oid,
+    t_data bytea,
+    t_infomask integer,
+    t_infomask2 integer,
+    t_bits text)
+RETURNS bytea[]
+AS 'MODULE_PATHNAME','tuple_data_split'
+LANGUAGE C;
+
+CREATE FUNCTION tuple_data_split(rel_oid oid,
+    t_data bytea,
+    t_infomask integer,
+    t_infomask2 integer,
+    t_bits text,
+    do_detoast bool)
+RETURNS bytea[]
+AS 'MODULE_PATHNAME','tuple_data_split'
+LANGUAGE C;
+
+--
+-- heap_page_item_attrs()
+--
+CREATE FUNCTION heap_page_item_attrs(
+    IN page bytea,
+    IN rel_oid regclass,
+    IN do_detoast bool,
+    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 integer,
+    OUT t_infomask integer,
+    OUT t_hoff smallint,
+    OUT t_bits text,
+    OUT t_oid oid,
+    OUT t_attrs bytea[]
+    )
+RETURNS SETOF record AS $$
+SELECT lp,
+       lp_off,
+       lp_flags,
+       lp_len,
+       t_xmin,
+       t_xmax,
+       t_field3,
+       t_ctid,
+       t_infomask2,
+       t_infomask,
+       t_hoff,
+       t_bits,
+       t_oid,
+       tuple_data_split(
+         rel_oid,
+         t_data,
+	 t_infomask,
+	 t_infomask2,
+	 t_bits,
+	 do_detoast)
+	 AS t_attrs
+  FROM heap_page_items(page);
+$$ LANGUAGE SQL;
+
+CREATE FUNCTION heap_page_item_attrs(
+    IN page bytea,
+    IN rel_oid regclass,
+    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 integer,
+    OUT t_infomask integer,
+    OUT t_hoff smallint,
+    OUT t_bits text,
+    OUT t_oid oid,
+    OUT t_attrs bytea[]
+    )
+RETURNS SETOF record AS $$
+SELECT * from heap_page_item_attrs(page, rel_oid, false);
+$$ LANGUAGE SQL;
diff --git a/contrib/pageinspect/pageinspect--1.4--1.5.sql b/contrib/pageinspect/pageinspect--1.4--1.5.sql
new file mode 100644
index 0000000..7ed7b54
--- /dev/null
+++ b/contrib/pageinspect/pageinspect--1.4--1.5.sql
@@ -0,0 +1,24 @@
+/* contrib/pageinspect/pageinspect--1.4--1.5.sql */
+
+-- complain if script is sourced in psql, rather than via ALTER EXTENSION
+\echo Use "ALTER EXTENSION pageinspect UPDATE TO '1.5'" to load this file. \quit
+
+ALTER FUNCTION get_raw_page(text, int4) PARALLEL SAFE;
+ALTER FUNCTION get_raw_page(text, text, int4) PARALLEL SAFE;
+ALTER FUNCTION page_header(bytea) PARALLEL SAFE;
+ALTER FUNCTION heap_page_items(bytea) PARALLEL SAFE;
+ALTER FUNCTION tuple_data_split(oid, bytea, integer, integer, text) PARALLEL SAFE;
+ALTER FUNCTION tuple_data_split(oid, bytea, integer, integer, text, bool) PARALLEL SAFE;
+ALTER FUNCTION heap_page_item_attrs(bytea, regclass, bool) PARALLEL SAFE;
+ALTER FUNCTION heap_page_item_attrs(bytea, regclass) PARALLEL SAFE;
+ALTER FUNCTION bt_metap(text) PARALLEL SAFE;
+ALTER FUNCTION bt_page_stats(text, int4) PARALLEL SAFE;
+ALTER FUNCTION bt_page_items(text, int4) PARALLEL SAFE;
+ALTER FUNCTION brin_page_type(bytea) PARALLEL SAFE;
+ALTER FUNCTION brin_metapage_info(bytea) PARALLEL SAFE;
+ALTER FUNCTION brin_revmap_data(bytea) PARALLEL SAFE;
+ALTER FUNCTION brin_page_items(bytea, regclass) PARALLEL SAFE;
+ALTER FUNCTION fsm_page_contents(bytea) PARALLEL SAFE;
+ALTER FUNCTION gin_metapage_info(bytea) PARALLEL SAFE;
+ALTER FUNCTION gin_page_opaque_info(bytea) PARALLEL SAFE;
+ALTER FUNCTION gin_leafpage_items(bytea) PARALLEL SAFE;
diff --git a/contrib/pageinspect/pageinspect--1.5--1.6.sql b/contrib/pageinspect/pageinspect--1.5--1.6.sql
new file mode 100644
index 0000000..c435628
--- /dev/null
+++ b/contrib/pageinspect/pageinspect--1.5--1.6.sql
@@ -0,0 +1,99 @@
+/* contrib/pageinspect/pageinspect--1.5--1.6.sql */
+
+-- complain if script is sourced in psql, rather than via ALTER EXTENSION
+\echo Use "ALTER EXTENSION pageinspect UPDATE TO '1.6'" to load this file. \quit
+
+--
+-- HASH functions
+--
+
+--
+-- hash_page_type()
+--
+CREATE FUNCTION hash_page_type(IN page bytea)
+RETURNS text
+AS 'MODULE_PATHNAME', 'hash_page_type'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+--
+-- hash_page_stats()
+--
+CREATE FUNCTION hash_page_stats(IN page bytea,
+    OUT live_items int4,
+    OUT dead_items int4,
+    OUT page_size int4,
+    OUT free_size int4,
+    OUT hasho_prevblkno int8,
+    OUT hasho_nextblkno int8,
+    OUT hasho_bucket int8,
+	OUT hasho_flag int4,
+	OUT hasho_page_id int4)
+AS 'MODULE_PATHNAME', 'hash_page_stats'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+--
+-- hash_page_items()
+--
+CREATE FUNCTION hash_page_items(IN page bytea,
+	OUT itemoffset int4,
+	OUT ctid tid,
+	OUT data int8)
+RETURNS SETOF record
+AS 'MODULE_PATHNAME', 'hash_page_items'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+--
+-- hash_bitmap_info()
+--
+CREATE FUNCTION hash_bitmap_info(IN index_oid regclass, IN blkno int8,
+	OUT bitmapblkno int8,
+	OUT bitmapbit int4,
+	OUT bitstatus bool)
+RETURNS SETOF record
+AS 'MODULE_PATHNAME', 'hash_bitmap_info'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+--
+-- hash_metapage_info()
+--
+CREATE FUNCTION hash_metapage_info(IN page bytea,
+    OUT magic int8,
+    OUT version int8,
+    OUT ntuples double precision,
+    OUT ffactor int4,
+    OUT bsize int4,
+    OUT bmsize int4,
+    OUT bmshift int4,
+    OUT maxbucket int8,
+    OUT highmask int8,
+    OUT lowmask int8,
+    OUT ovflpoint int8,
+    OUT firstfree int8,
+    OUT nmaps int8,
+    OUT procid oid,
+    OUT spares int8[],
+    OUT mapp int8[])
+AS 'MODULE_PATHNAME', 'hash_metapage_info'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+--
+-- page_checksum()
+--
+CREATE FUNCTION page_checksum(IN page bytea, IN blkno int4)
+RETURNS smallint
+AS 'MODULE_PATHNAME', 'page_checksum'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+--
+-- bt_page_items_bytea()
+--
+CREATE FUNCTION bt_page_items(IN page bytea,
+    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_bytea'
+LANGUAGE C STRICT PARALLEL SAFE;
diff --git a/contrib/pageinspect/pageinspect--1.5.sql b/contrib/pageinspect/pageinspect--1.5.sql
new file mode 100644
index 0000000..1e40c3c
--- /dev/null
+++ b/contrib/pageinspect/pageinspect--1.5.sql
@@ -0,0 +1,279 @@
+/* contrib/pageinspect/pageinspect--1.5.sql */
+
+-- complain if script is sourced in psql, rather than via CREATE EXTENSION
+\echo Use "CREATE EXTENSION pageinspect" to load this file. \quit
+
+--
+-- get_raw_page()
+--
+CREATE FUNCTION get_raw_page(text, int4)
+RETURNS bytea
+AS 'MODULE_PATHNAME', 'get_raw_page'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+CREATE FUNCTION get_raw_page(text, text, int4)
+RETURNS bytea
+AS 'MODULE_PATHNAME', 'get_raw_page_fork'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+--
+-- page_header()
+--
+CREATE FUNCTION page_header(IN page bytea,
+    OUT lsn pg_lsn,
+    OUT checksum smallint,
+    OUT flags smallint,
+    OUT lower smallint,
+    OUT upper smallint,
+    OUT special smallint,
+    OUT pagesize smallint,
+    OUT version smallint,
+    OUT prune_xid xid)
+AS 'MODULE_PATHNAME', 'page_header'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+--
+-- heap_page_items()
+--
+CREATE 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 integer,
+    OUT t_infomask integer,
+    OUT t_hoff smallint,
+    OUT t_bits text,
+    OUT t_oid oid,
+    OUT t_data bytea)
+RETURNS SETOF record
+AS 'MODULE_PATHNAME', 'heap_page_items'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+--
+-- tuple_data_split()
+--
+CREATE FUNCTION tuple_data_split(rel_oid oid,
+    t_data bytea,
+    t_infomask integer,
+    t_infomask2 integer,
+    t_bits text)
+RETURNS bytea[]
+AS 'MODULE_PATHNAME','tuple_data_split'
+LANGUAGE C PARALLEL SAFE;
+
+CREATE FUNCTION tuple_data_split(rel_oid oid,
+    t_data bytea,
+    t_infomask integer,
+    t_infomask2 integer,
+    t_bits text,
+    do_detoast bool)
+RETURNS bytea[]
+AS 'MODULE_PATHNAME','tuple_data_split'
+LANGUAGE C PARALLEL SAFE;
+
+--
+-- heap_page_item_attrs()
+--
+CREATE FUNCTION heap_page_item_attrs(
+    IN page bytea,
+    IN rel_oid regclass,
+    IN do_detoast bool,
+    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 integer,
+    OUT t_infomask integer,
+    OUT t_hoff smallint,
+    OUT t_bits text,
+    OUT t_oid oid,
+    OUT t_attrs bytea[]
+    )
+RETURNS SETOF record AS $$
+SELECT lp,
+       lp_off,
+       lp_flags,
+       lp_len,
+       t_xmin,
+       t_xmax,
+       t_field3,
+       t_ctid,
+       t_infomask2,
+       t_infomask,
+       t_hoff,
+       t_bits,
+       t_oid,
+       tuple_data_split(
+         rel_oid,
+         t_data,
+         t_infomask,
+         t_infomask2,
+         t_bits,
+         do_detoast)
+         AS t_attrs
+  FROM heap_page_items(page);
+$$ LANGUAGE SQL PARALLEL SAFE;
+
+CREATE FUNCTION heap_page_item_attrs(IN page bytea, IN rel_oid regclass,
+    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 integer,
+    OUT t_infomask integer,
+    OUT t_hoff smallint,
+    OUT t_bits text,
+    OUT t_oid oid,
+    OUT t_attrs bytea[]
+    )
+RETURNS SETOF record AS $$
+SELECT * from heap_page_item_attrs(page, rel_oid, false);
+$$ LANGUAGE SQL PARALLEL SAFE;
+
+--
+-- bt_metap()
+--
+CREATE 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 PARALLEL SAFE;
+
+--
+-- bt_page_stats()
+--
+CREATE 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 PARALLEL SAFE;
+
+--
+-- bt_page_items()
+--
+CREATE 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 PARALLEL SAFE;
+
+--
+-- brin_page_type()
+--
+CREATE FUNCTION brin_page_type(IN page bytea)
+RETURNS text
+AS 'MODULE_PATHNAME', 'brin_page_type'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+--
+-- brin_metapage_info()
+--
+CREATE FUNCTION brin_metapage_info(IN page bytea, OUT magic text,
+	OUT version integer, OUT pagesperrange integer, OUT lastrevmappage bigint)
+AS 'MODULE_PATHNAME', 'brin_metapage_info'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+--
+-- brin_revmap_data()
+--
+CREATE FUNCTION brin_revmap_data(IN page bytea,
+	OUT pages tid)
+RETURNS SETOF tid
+AS 'MODULE_PATHNAME', 'brin_revmap_data'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+--
+-- brin_page_items()
+--
+CREATE FUNCTION brin_page_items(IN page bytea, IN index_oid regclass,
+	OUT itemoffset int,
+	OUT blknum int,
+	OUT attnum int,
+	OUT allnulls bool,
+	OUT hasnulls bool,
+	OUT placeholder bool,
+	OUT value text)
+RETURNS SETOF record
+AS 'MODULE_PATHNAME', 'brin_page_items'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+--
+-- fsm_page_contents()
+--
+CREATE FUNCTION fsm_page_contents(IN page bytea)
+RETURNS text
+AS 'MODULE_PATHNAME', 'fsm_page_contents'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+--
+-- GIN functions
+--
+
+--
+-- gin_metapage_info()
+--
+CREATE FUNCTION gin_metapage_info(IN page bytea,
+    OUT pending_head bigint,
+    OUT pending_tail bigint,
+    OUT tail_free_size int4,
+    OUT n_pending_pages bigint,
+    OUT n_pending_tuples bigint,
+    OUT n_total_pages bigint,
+    OUT n_entry_pages bigint,
+    OUT n_data_pages bigint,
+    OUT n_entries bigint,
+    OUT version int4)
+AS 'MODULE_PATHNAME', 'gin_metapage_info'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+--
+-- gin_page_opaque_info()
+--
+CREATE FUNCTION gin_page_opaque_info(IN page bytea,
+    OUT rightlink bigint,
+    OUT maxoff int4,
+    OUT flags text[])
+AS 'MODULE_PATHNAME', 'gin_page_opaque_info'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+--
+-- gin_leafpage_items()
+--
+CREATE FUNCTION gin_leafpage_items(IN page bytea,
+    OUT first_tid tid,
+    OUT nbytes int2,
+    OUT tids tid[])
+RETURNS SETOF record
+AS 'MODULE_PATHNAME', 'gin_leafpage_items'
+LANGUAGE C STRICT PARALLEL SAFE;
diff --git a/contrib/pageinspect/pageinspect--1.6--1.7.sql b/contrib/pageinspect/pageinspect--1.6--1.7.sql
new file mode 100644
index 0000000..2433a21
--- /dev/null
+++ b/contrib/pageinspect/pageinspect--1.6--1.7.sql
@@ -0,0 +1,26 @@
+/* contrib/pageinspect/pageinspect--1.6--1.7.sql */
+
+-- complain if script is sourced in psql, rather than via ALTER EXTENSION
+\echo Use "ALTER EXTENSION pageinspect UPDATE TO '1.7'" to load this file. \quit
+
+--
+-- bt_metap()
+--
+DROP FUNCTION bt_metap(IN relname text,
+    OUT magic int4,
+    OUT version int4,
+    OUT root int4,
+    OUT level int4,
+    OUT fastroot int4,
+    OUT fastlevel int4);
+CREATE FUNCTION bt_metap(IN relname text,
+    OUT magic int4,
+    OUT version int4,
+    OUT root int4,
+    OUT level int4,
+    OUT fastroot int4,
+    OUT fastlevel int4,
+    OUT oldest_xact int4,
+    OUT last_cleanup_num_tuples real)
+AS 'MODULE_PATHNAME', 'bt_metap'
+LANGUAGE C STRICT PARALLEL SAFE;
diff --git a/contrib/pageinspect/pageinspect--1.7--1.8.sql b/contrib/pageinspect/pageinspect--1.7--1.8.sql
new file mode 100644
index 0000000..45031a0
--- /dev/null
+++ b/contrib/pageinspect/pageinspect--1.7--1.8.sql
@@ -0,0 +1,69 @@
+/* contrib/pageinspect/pageinspect--1.7--1.8.sql */
+
+-- complain if script is sourced in psql, rather than via ALTER EXTENSION
+\echo Use "ALTER EXTENSION pageinspect UPDATE TO '1.8'" to load this file. \quit
+
+--
+-- heap_tuple_infomask_flags()
+--
+CREATE FUNCTION heap_tuple_infomask_flags(
+       t_infomask integer,
+       t_infomask2 integer,
+       raw_flags OUT text[],
+       combined_flags OUT text[])
+RETURNS record
+AS 'MODULE_PATHNAME', 'heap_tuple_infomask_flags'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+--
+-- bt_metap()
+--
+DROP FUNCTION bt_metap(text);
+CREATE FUNCTION bt_metap(IN relname text,
+    OUT magic int4,
+    OUT version int4,
+    OUT root int8,
+    OUT level int8,
+    OUT fastroot int8,
+    OUT fastlevel int8,
+    OUT oldest_xact xid,
+    OUT last_cleanup_num_tuples float8,
+    OUT allequalimage boolean)
+AS 'MODULE_PATHNAME', 'bt_metap'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+--
+-- bt_page_items(text, int4)
+--
+DROP FUNCTION bt_page_items(text, int4);
+CREATE 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,
+    OUT dead boolean,
+    OUT htid tid,
+    OUT tids tid[])
+RETURNS SETOF record
+AS 'MODULE_PATHNAME', 'bt_page_items'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+--
+-- bt_page_items(bytea)
+--
+DROP FUNCTION bt_page_items(bytea);
+CREATE FUNCTION bt_page_items(IN page bytea,
+    OUT itemoffset smallint,
+    OUT ctid tid,
+    OUT itemlen smallint,
+    OUT nulls bool,
+    OUT vars bool,
+    OUT data text,
+    OUT dead boolean,
+    OUT htid tid,
+    OUT tids tid[])
+RETURNS SETOF record
+AS 'MODULE_PATHNAME', 'bt_page_items_bytea'
+LANGUAGE C STRICT PARALLEL SAFE;
diff --git a/contrib/pageinspect/pageinspect.control b/contrib/pageinspect/pageinspect.control
new file mode 100644
index 0000000..f8cdf52
--- /dev/null
+++ b/contrib/pageinspect/pageinspect.control
@@ -0,0 +1,5 @@
+# pageinspect extension
+comment = 'inspect the contents of database pages at a low level'
+default_version = '1.8'
+module_pathname = '$libdir/pageinspect'
+relocatable = true
diff --git a/contrib/pageinspect/pageinspect.h b/contrib/pageinspect/pageinspect.h
new file mode 100644
index 0000000..478e0d2
--- /dev/null
+++ b/contrib/pageinspect/pageinspect.h
@@ -0,0 +1,21 @@
+/*-------------------------------------------------------------------------
+ *
+ * pageinspect.h
+ *	  Common functions for pageinspect.
+ *
+ * Copyright (c) 2017-2020, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *	  contrib/pageinspect/pageinspect.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef _PAGEINSPECT_H_
+#define _PAGEINSPECT_H_
+
+#include "storage/bufpage.h"
+
+/* in rawpage.c */
+extern Page get_page_from_raw(bytea *raw_page);
+
+#endif							/* _PAGEINSPECT_H_ */
diff --git a/contrib/pageinspect/rawpage.c b/contrib/pageinspect/rawpage.c
new file mode 100644
index 0000000..c018150
--- /dev/null
+++ b/contrib/pageinspect/rawpage.c
@@ -0,0 +1,323 @@
+/*-------------------------------------------------------------------------
+ *
+ * rawpage.c
+ *	  Functions to extract a raw page as bytea and inspect it
+ *
+ * Access-method specific inspection functions are in separate files.
+ *
+ * Copyright (c) 2007-2020, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *	  contrib/pageinspect/rawpage.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "access/htup_details.h"
+#include "access/relation.h"
+#include "catalog/namespace.h"
+#include "catalog/pg_type.h"
+#include "funcapi.h"
+#include "miscadmin.h"
+#include "pageinspect.h"
+#include "storage/bufmgr.h"
+#include "storage/checksum.h"
+#include "utils/builtins.h"
+#include "utils/pg_lsn.h"
+#include "utils/rel.h"
+#include "utils/varlena.h"
+
+PG_MODULE_MAGIC;
+
+static bytea *get_raw_page_internal(text *relname, ForkNumber forknum,
+									BlockNumber blkno);
+
+
+/*
+ * get_raw_page
+ *
+ * Returns a copy of a page from shared buffers as a bytea
+ */
+PG_FUNCTION_INFO_V1(get_raw_page);
+
+Datum
+get_raw_page(PG_FUNCTION_ARGS)
+{
+	text	   *relname = PG_GETARG_TEXT_PP(0);
+	uint32		blkno = PG_GETARG_UINT32(1);
+	bytea	   *raw_page;
+
+	/*
+	 * We don't normally bother to check the number of arguments to a C
+	 * function, but here it's needed for safety because early 8.4 beta
+	 * releases mistakenly redefined get_raw_page() as taking three arguments.
+	 */
+	if (PG_NARGS() != 2)
+		ereport(ERROR,
+				(errmsg("wrong number of arguments to get_raw_page()"),
+				 errhint("Run the updated pageinspect.sql script.")));
+
+	raw_page = get_raw_page_internal(relname, MAIN_FORKNUM, blkno);
+
+	PG_RETURN_BYTEA_P(raw_page);
+}
+
+/*
+ * get_raw_page_fork
+ *
+ * Same, for any fork
+ */
+PG_FUNCTION_INFO_V1(get_raw_page_fork);
+
+Datum
+get_raw_page_fork(PG_FUNCTION_ARGS)
+{
+	text	   *relname = PG_GETARG_TEXT_PP(0);
+	text	   *forkname = PG_GETARG_TEXT_PP(1);
+	uint32		blkno = PG_GETARG_UINT32(2);
+	bytea	   *raw_page;
+	ForkNumber	forknum;
+
+	forknum = forkname_to_number(text_to_cstring(forkname));
+
+	raw_page = get_raw_page_internal(relname, forknum, blkno);
+
+	PG_RETURN_BYTEA_P(raw_page);
+}
+
+/*
+ * workhorse
+ */
+static bytea *
+get_raw_page_internal(text *relname, ForkNumber forknum, BlockNumber blkno)
+{
+	bytea	   *raw_page;
+	RangeVar   *relrv;
+	Relation	rel;
+	char	   *raw_page_data;
+	Buffer		buf;
+
+	if (!superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("must be superuser to use raw page functions")));
+
+	relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
+	rel = relation_openrv(relrv, AccessShareLock);
+
+	/* Check that this relation has storage */
+	if (rel->rd_rel->relkind == RELKIND_VIEW)
+		ereport(ERROR,
+				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+				 errmsg("cannot get raw page from view \"%s\"",
+						RelationGetRelationName(rel))));
+	if (rel->rd_rel->relkind == RELKIND_COMPOSITE_TYPE)
+		ereport(ERROR,
+				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+				 errmsg("cannot get raw page from composite type \"%s\"",
+						RelationGetRelationName(rel))));
+	if (rel->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
+		ereport(ERROR,
+				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+				 errmsg("cannot get raw page from foreign table \"%s\"",
+						RelationGetRelationName(rel))));
+	if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
+		ereport(ERROR,
+				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+				 errmsg("cannot get raw page from partitioned table \"%s\"",
+						RelationGetRelationName(rel))));
+	if (rel->rd_rel->relkind == RELKIND_PARTITIONED_INDEX)
+		ereport(ERROR,
+				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+				 errmsg("cannot get raw page from partitioned index \"%s\"",
+						RelationGetRelationName(rel))));
+
+	/*
+	 * Reject attempts to read non-local temporary relations; we would be
+	 * likely to get wrong data since we have no visibility into the owning
+	 * session's local buffers.
+	 */
+	if (RELATION_IS_OTHER_TEMP(rel))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot access temporary tables of other sessions")));
+
+	if (blkno >= RelationGetNumberOfBlocksInFork(rel, forknum))
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("block number %u is out of range for relation \"%s\"",
+						blkno, RelationGetRelationName(rel))));
+
+	/* Initialize buffer to copy to */
+	raw_page = (bytea *) palloc(BLCKSZ + VARHDRSZ);
+	SET_VARSIZE(raw_page, BLCKSZ + VARHDRSZ);
+	raw_page_data = VARDATA(raw_page);
+
+	/* Take a verbatim copy of the page */
+
+	buf = ReadBufferExtended(rel, forknum, blkno, RBM_NORMAL, NULL);
+	LockBuffer(buf, BUFFER_LOCK_SHARE);
+
+	memcpy(raw_page_data, BufferGetPage(buf), BLCKSZ);
+
+	LockBuffer(buf, BUFFER_LOCK_UNLOCK);
+	ReleaseBuffer(buf);
+
+	relation_close(rel, AccessShareLock);
+
+	return raw_page;
+}
+
+
+/*
+ * get_page_from_raw
+ *
+ * Get a palloc'd, maxalign'ed page image from the result of get_raw_page()
+ *
+ * On machines with MAXALIGN = 8, the payload of a bytea is not maxaligned,
+ * since it will start 4 bytes into a palloc'd value.  On alignment-picky
+ * machines, this will cause failures in accesses to 8-byte-wide values
+ * within the page.  We don't need to worry if accessing only 4-byte or
+ * smaller fields, but when examining a struct that contains 8-byte fields,
+ * use this function for safety.
+ */
+Page
+get_page_from_raw(bytea *raw_page)
+{
+	Page		page;
+	int			raw_page_size;
+
+	raw_page_size = VARSIZE_ANY_EXHDR(raw_page);
+
+	if (raw_page_size != BLCKSZ)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("invalid page size"),
+				 errdetail("Expected %d bytes, got %d.",
+						   BLCKSZ, raw_page_size)));
+
+	page = palloc(raw_page_size);
+
+	memcpy(page, VARDATA_ANY(raw_page), raw_page_size);
+
+	return page;
+}
+
+
+/*
+ * page_header
+ *
+ * Allows inspection of page header fields of a raw page
+ */
+
+PG_FUNCTION_INFO_V1(page_header);
+
+Datum
+page_header(PG_FUNCTION_ARGS)
+{
+	bytea	   *raw_page = PG_GETARG_BYTEA_P(0);
+	int			raw_page_size;
+
+	TupleDesc	tupdesc;
+
+	Datum		result;
+	HeapTuple	tuple;
+	Datum		values[9];
+	bool		nulls[9];
+
+	PageHeader	page;
+	XLogRecPtr	lsn;
+
+	if (!superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("must be superuser to use raw page functions")));
+
+	raw_page_size = VARSIZE(raw_page) - VARHDRSZ;
+
+	/*
+	 * Check that enough data was supplied, so that we don't try to access
+	 * fields outside the supplied buffer.
+	 */
+	if (raw_page_size < SizeOfPageHeaderData)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("input page too small (%d bytes)", raw_page_size)));
+
+	page = (PageHeader) VARDATA(raw_page);
+
+	/* 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");
+
+	/* Extract information from the page header */
+
+	lsn = PageGetLSN(page);
+
+	/* pageinspect >= 1.2 uses pg_lsn instead of text for the LSN field. */
+	if (TupleDescAttr(tupdesc, 0)->atttypid == TEXTOID)
+	{
+		char		lsnchar[64];
+
+		snprintf(lsnchar, sizeof(lsnchar), "%X/%X",
+				 (uint32) (lsn >> 32), (uint32) lsn);
+		values[0] = CStringGetTextDatum(lsnchar);
+	}
+	else
+		values[0] = LSNGetDatum(lsn);
+	values[1] = UInt16GetDatum(page->pd_checksum);
+	values[2] = UInt16GetDatum(page->pd_flags);
+	values[3] = UInt16GetDatum(page->pd_lower);
+	values[4] = UInt16GetDatum(page->pd_upper);
+	values[5] = UInt16GetDatum(page->pd_special);
+	values[6] = UInt16GetDatum(PageGetPageSize(page));
+	values[7] = UInt16GetDatum(PageGetPageLayoutVersion(page));
+	values[8] = TransactionIdGetDatum(page->pd_prune_xid);
+
+	/* Build and return the tuple. */
+
+	memset(nulls, 0, sizeof(nulls));
+
+	tuple = heap_form_tuple(tupdesc, values, nulls);
+	result = HeapTupleGetDatum(tuple);
+
+	PG_RETURN_DATUM(result);
+}
+
+/*
+ * page_checksum
+ *
+ * Compute checksum of a raw page
+ */
+
+PG_FUNCTION_INFO_V1(page_checksum);
+
+Datum
+page_checksum(PG_FUNCTION_ARGS)
+{
+	bytea	   *raw_page = PG_GETARG_BYTEA_P(0);
+	uint32		blkno = PG_GETARG_INT32(1);
+	int			raw_page_size;
+	PageHeader	page;
+
+	if (!superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("must be superuser to use raw page functions")));
+
+	raw_page_size = VARSIZE(raw_page) - VARHDRSZ;
+
+	/*
+	 * Check that the supplied page is of the right size.
+	 */
+	if (raw_page_size != BLCKSZ)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("incorrect size of input page (%d bytes)", raw_page_size)));
+
+	page = (PageHeader) VARDATA(raw_page);
+
+	PG_RETURN_INT16(pg_checksum_page((char *) page, blkno));
+}
diff --git a/contrib/pageinspect/sql/brin.sql b/contrib/pageinspect/sql/brin.sql
new file mode 100644
index 0000000..735bc3b
--- /dev/null
+++ b/contrib/pageinspect/sql/brin.sql
@@ -0,0 +1,18 @@
+CREATE TABLE test1 (a int, b text);
+INSERT INTO test1 VALUES (1, 'one');
+CREATE INDEX test1_a_idx ON test1 USING brin (a);
+
+SELECT brin_page_type(get_raw_page('test1_a_idx', 0));
+SELECT brin_page_type(get_raw_page('test1_a_idx', 1));
+SELECT brin_page_type(get_raw_page('test1_a_idx', 2));
+
+SELECT * FROM brin_metapage_info(get_raw_page('test1_a_idx', 0));
+SELECT * FROM brin_metapage_info(get_raw_page('test1_a_idx', 1));
+
+SELECT * FROM brin_revmap_data(get_raw_page('test1_a_idx', 0)) LIMIT 5;
+SELECT * FROM brin_revmap_data(get_raw_page('test1_a_idx', 1)) LIMIT 5;
+
+SELECT * FROM brin_page_items(get_raw_page('test1_a_idx', 2), 'test1_a_idx')
+    ORDER BY blknum, attnum LIMIT 5;
+
+DROP TABLE test1;
diff --git a/contrib/pageinspect/sql/btree.sql b/contrib/pageinspect/sql/btree.sql
new file mode 100644
index 0000000..8eac64c
--- /dev/null
+++ b/contrib/pageinspect/sql/btree.sql
@@ -0,0 +1,21 @@
+CREATE TABLE test1 (a int8, b text);
+INSERT INTO test1 VALUES (72057594037927937, 'text');
+CREATE INDEX test1_a_idx ON test1 USING btree (a);
+
+\x
+
+SELECT * FROM bt_metap('test1_a_idx');
+
+SELECT * FROM bt_page_stats('test1_a_idx', 0);
+SELECT * FROM bt_page_stats('test1_a_idx', 1);
+SELECT * FROM bt_page_stats('test1_a_idx', 2);
+
+SELECT * FROM bt_page_items('test1_a_idx', 0);
+SELECT * FROM bt_page_items('test1_a_idx', 1);
+SELECT * FROM bt_page_items('test1_a_idx', 2);
+
+SELECT * FROM bt_page_items(get_raw_page('test1_a_idx', 0));
+SELECT * FROM bt_page_items(get_raw_page('test1_a_idx', 1));
+SELECT * FROM bt_page_items(get_raw_page('test1_a_idx', 2));
+
+DROP TABLE test1;
diff --git a/contrib/pageinspect/sql/checksum.sql b/contrib/pageinspect/sql/checksum.sql
new file mode 100644
index 0000000..b877db0
--- /dev/null
+++ b/contrib/pageinspect/sql/checksum.sql
@@ -0,0 +1,31 @@
+--
+-- Verify correct calculation of checksums
+--
+-- Postgres' checksum algorithm produces different answers on little-endian
+-- and big-endian machines.  The results of this test also vary depending
+-- on the configured block size.  This test has several different expected
+-- results files to handle the following possibilities:
+--
+--	BLCKSZ	end	file
+--	8K	LE	checksum.out
+--	8K	BE	checksum_1.out
+--
+-- In future we might provide additional expected-results files for other
+-- block sizes, but there seems little point as long as so many other
+-- test scripts also show false failures for non-default block sizes.
+--
+
+-- This is to label the results files with blocksize:
+SHOW block_size;
+
+SHOW block_size \gset
+
+-- Apply page_checksum() to some different data patterns and block numbers
+SELECT blkno,
+    page_checksum(decode(repeat('01', :block_size), 'hex'), blkno) AS checksum_01,
+    page_checksum(decode(repeat('04', :block_size), 'hex'), blkno) AS checksum_04,
+    page_checksum(decode(repeat('ff', :block_size), 'hex'), blkno) AS checksum_ff,
+    page_checksum(decode(repeat('abcd', :block_size / 2), 'hex'), blkno) AS checksum_abcd,
+    page_checksum(decode(repeat('e6d6', :block_size / 2), 'hex'), blkno) AS checksum_e6d6,
+    page_checksum(decode(repeat('4a5e', :block_size / 2), 'hex'), blkno) AS checksum_4a5e
+  FROM generate_series(0, 100, 50) AS a (blkno);
diff --git a/contrib/pageinspect/sql/gin.sql b/contrib/pageinspect/sql/gin.sql
new file mode 100644
index 0000000..d516ed3
--- /dev/null
+++ b/contrib/pageinspect/sql/gin.sql
@@ -0,0 +1,19 @@
+CREATE TABLE test1 (x int, y int[]);
+INSERT INTO test1 VALUES (1, ARRAY[11, 111]);
+CREATE INDEX test1_y_idx ON test1 USING gin (y) WITH (fastupdate = off);
+
+\x
+
+SELECT * FROM gin_metapage_info(get_raw_page('test1_y_idx', 0));
+SELECT * FROM gin_metapage_info(get_raw_page('test1_y_idx', 1));
+
+SELECT * FROM gin_page_opaque_info(get_raw_page('test1_y_idx', 1));
+
+SELECT * FROM gin_leafpage_items(get_raw_page('test1_y_idx', 1));
+
+INSERT INTO test1 SELECT x, ARRAY[1,10] FROM generate_series(2,10000) x;
+
+SELECT COUNT(*) > 0
+FROM gin_leafpage_items(get_raw_page('test1_y_idx',
+                        (pg_relation_size('test1_y_idx') /
+                         current_setting('block_size')::bigint)::int - 1));
diff --git a/contrib/pageinspect/sql/hash.sql b/contrib/pageinspect/sql/hash.sql
new file mode 100644
index 0000000..87ee549
--- /dev/null
+++ b/contrib/pageinspect/sql/hash.sql
@@ -0,0 +1,80 @@
+CREATE TABLE test_hash (a int, b text);
+INSERT INTO test_hash VALUES (1, 'one');
+CREATE INDEX test_hash_a_idx ON test_hash USING hash (a);
+
+\x
+
+SELECT hash_page_type(get_raw_page('test_hash_a_idx', 0));
+SELECT hash_page_type(get_raw_page('test_hash_a_idx', 1));
+SELECT hash_page_type(get_raw_page('test_hash_a_idx', 2));
+SELECT hash_page_type(get_raw_page('test_hash_a_idx', 3));
+SELECT hash_page_type(get_raw_page('test_hash_a_idx', 4));
+SELECT hash_page_type(get_raw_page('test_hash_a_idx', 5));
+SELECT hash_page_type(get_raw_page('test_hash_a_idx', 6));
+
+
+SELECT * FROM hash_bitmap_info('test_hash_a_idx', 0);
+SELECT * FROM hash_bitmap_info('test_hash_a_idx', 1);
+SELECT * FROM hash_bitmap_info('test_hash_a_idx', 2);
+SELECT * FROM hash_bitmap_info('test_hash_a_idx', 3);
+SELECT * FROM hash_bitmap_info('test_hash_a_idx', 4);
+SELECT * FROM hash_bitmap_info('test_hash_a_idx', 5);
+
+
+SELECT magic, version, ntuples, bsize, bmsize, bmshift, maxbucket, highmask,
+lowmask, ovflpoint, firstfree, nmaps, procid, spares, mapp FROM
+hash_metapage_info(get_raw_page('test_hash_a_idx', 0));
+
+SELECT magic, version, ntuples, bsize, bmsize, bmshift, maxbucket, highmask,
+lowmask, ovflpoint, firstfree, nmaps, procid, spares, mapp FROM
+hash_metapage_info(get_raw_page('test_hash_a_idx', 1));
+
+SELECT magic, version, ntuples, bsize, bmsize, bmshift, maxbucket, highmask,
+lowmask, ovflpoint, firstfree, nmaps, procid, spares, mapp FROM
+hash_metapage_info(get_raw_page('test_hash_a_idx', 2));
+
+SELECT magic, version, ntuples, bsize, bmsize, bmshift, maxbucket, highmask,
+lowmask, ovflpoint, firstfree, nmaps, procid, spares, mapp FROM
+hash_metapage_info(get_raw_page('test_hash_a_idx', 3));
+
+SELECT magic, version, ntuples, bsize, bmsize, bmshift, maxbucket, highmask,
+lowmask, ovflpoint, firstfree, nmaps, procid, spares, mapp FROM
+hash_metapage_info(get_raw_page('test_hash_a_idx', 4));
+
+SELECT magic, version, ntuples, bsize, bmsize, bmshift, maxbucket, highmask,
+lowmask, ovflpoint, firstfree, nmaps, procid, spares, mapp FROM
+hash_metapage_info(get_raw_page('test_hash_a_idx', 5));
+
+SELECT live_items, dead_items, page_size, hasho_prevblkno, hasho_nextblkno,
+hasho_bucket, hasho_flag, hasho_page_id FROM
+hash_page_stats(get_raw_page('test_hash_a_idx', 0));
+
+SELECT live_items, dead_items, page_size, hasho_prevblkno, hasho_nextblkno,
+hasho_bucket, hasho_flag, hasho_page_id FROM
+hash_page_stats(get_raw_page('test_hash_a_idx', 1));
+
+SELECT live_items, dead_items, page_size, hasho_prevblkno, hasho_nextblkno,
+hasho_bucket, hasho_flag, hasho_page_id FROM
+hash_page_stats(get_raw_page('test_hash_a_idx', 2));
+
+SELECT live_items, dead_items, page_size, hasho_prevblkno, hasho_nextblkno,
+hasho_bucket, hasho_flag, hasho_page_id FROM
+hash_page_stats(get_raw_page('test_hash_a_idx', 3));
+
+SELECT live_items, dead_items, page_size, hasho_prevblkno, hasho_nextblkno,
+hasho_bucket, hasho_flag, hasho_page_id FROM
+hash_page_stats(get_raw_page('test_hash_a_idx', 4));
+
+SELECT live_items, dead_items, page_size, hasho_prevblkno, hasho_nextblkno,
+hasho_bucket, hasho_flag, hasho_page_id FROM
+hash_page_stats(get_raw_page('test_hash_a_idx', 5));
+
+SELECT * FROM hash_page_items(get_raw_page('test_hash_a_idx', 0));
+SELECT * FROM hash_page_items(get_raw_page('test_hash_a_idx', 1));
+SELECT * FROM hash_page_items(get_raw_page('test_hash_a_idx', 2));
+SELECT * FROM hash_page_items(get_raw_page('test_hash_a_idx', 3));
+SELECT * FROM hash_page_items(get_raw_page('test_hash_a_idx', 4));
+SELECT * FROM hash_page_items(get_raw_page('test_hash_a_idx', 5));
+
+
+DROP TABLE test_hash;
diff --git a/contrib/pageinspect/sql/page.sql b/contrib/pageinspect/sql/page.sql
new file mode 100644
index 0000000..9a3bc95
--- /dev/null
+++ b/contrib/pageinspect/sql/page.sql
@@ -0,0 +1,82 @@
+CREATE EXTENSION pageinspect;
+
+CREATE TABLE test1 (a int, b int);
+INSERT INTO test1 VALUES (16777217, 131584);
+
+VACUUM (DISABLE_PAGE_SKIPPING) test1;  -- set up FSM
+
+-- The page contents can vary, so just test that it can be read
+-- successfully, but don't keep the output.
+
+SELECT octet_length(get_raw_page('test1', 'main', 0)) AS main_0;
+SELECT octet_length(get_raw_page('test1', 'main', 1)) AS main_1;
+
+SELECT octet_length(get_raw_page('test1', 'fsm', 0)) AS fsm_0;
+SELECT octet_length(get_raw_page('test1', 'fsm', 1)) AS fsm_1;
+
+SELECT octet_length(get_raw_page('test1', 'vm', 0)) AS vm_0;
+SELECT octet_length(get_raw_page('test1', 'vm', 1)) AS vm_1;
+
+SELECT octet_length(get_raw_page('xxx', 'main', 0));
+SELECT octet_length(get_raw_page('test1', 'xxx', 0));
+
+SELECT get_raw_page('test1', 0) = get_raw_page('test1', 'main', 0);
+
+SELECT pagesize, version FROM page_header(get_raw_page('test1', 0));
+
+SELECT page_checksum(get_raw_page('test1', 0), 0) IS NOT NULL AS silly_checksum_test;
+
+SELECT tuple_data_split('test1'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    FROM heap_page_items(get_raw_page('test1', 0));
+
+SELECT * FROM fsm_page_contents(get_raw_page('test1', 'fsm', 0));
+
+-- If we freeze the only tuple on test1, the infomask should
+-- always be the same in all test runs.
+VACUUM (FREEZE, DISABLE_PAGE_SKIPPING) test1;
+
+SELECT t_infomask, t_infomask2, raw_flags, combined_flags
+FROM heap_page_items(get_raw_page('test1', 0)),
+     LATERAL heap_tuple_infomask_flags(t_infomask, t_infomask2);
+
+-- tests for decoding of combined flags
+-- HEAP_XMAX_SHR_LOCK = (HEAP_XMAX_EXCL_LOCK | HEAP_XMAX_KEYSHR_LOCK)
+SELECT * FROM heap_tuple_infomask_flags(x'0050'::int, 0);
+-- HEAP_XMIN_FROZEN = (HEAP_XMIN_COMMITTED | HEAP_XMIN_INVALID)
+SELECT * FROM heap_tuple_infomask_flags(x'0300'::int, 0);
+-- HEAP_MOVED = (HEAP_MOVED_IN | HEAP_MOVED_OFF)
+SELECT * FROM heap_tuple_infomask_flags(x'C000'::int, 0);
+SELECT * FROM heap_tuple_infomask_flags(x'C000'::int, 0);
+
+-- test all flags of t_infomask and t_infomask2
+SELECT unnest(raw_flags)
+  FROM heap_tuple_infomask_flags(x'FFFF'::int, x'FFFF'::int) ORDER BY 1;
+SELECT unnest(combined_flags)
+  FROM heap_tuple_infomask_flags(x'FFFF'::int, x'FFFF'::int) ORDER BY 1;
+
+-- no flags at all
+SELECT * FROM heap_tuple_infomask_flags(0, 0);
+-- no combined flags
+SELECT * FROM heap_tuple_infomask_flags(x'0010'::int, 0);
+
+DROP TABLE test1;
+
+-- check that using any of these functions with a partitioned table or index
+-- would fail
+create table test_partitioned (a int) partition by range (a);
+create index test_partitioned_index on test_partitioned (a);
+select get_raw_page('test_partitioned', 0); -- error about partitioned table
+select get_raw_page('test_partitioned_index', 0); -- error about partitioned index
+
+-- a regular table which is a member of a partition set should work though
+create table test_part1 partition of test_partitioned for values from ( 1 ) to (100);
+select get_raw_page('test_part1', 0); -- get farther and error about empty table
+drop table test_partitioned;
+
+-- check null bitmap alignment for table whose number of attributes is multiple of 8
+create table test8 (f1 int, f2 int, f3 int, f4 int, f5 int, f6 int, f7 int, f8 int);
+insert into test8(f1, f8) values (x'7f00007f'::int, 0);
+select t_bits, t_data from heap_page_items(get_raw_page('test8', 0));
+select tuple_data_split('test8'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test8', 0));
+drop table test8;