On 10/12/2020 12:16, Andrey Borodin wrote:
9 дек. 2020 г., в 14:47, Andrey Borodin <x4...@yandex-team.ru> написал(а):
7 дек. 2020 г., в 23:56, Peter Geoghegan <p...@bowt.ie> написал(а):
On Mon, Dec 7, 2020 at 2:05 AM Andrey Borodin <x4...@yandex-team.ru> wrote:
Here's version with tests and docs. I still have no idea how to print some
useful information about tuples keys.
I suggest calling BuildIndexValueDescription() from your own custom
debug instrumentation code.
Thanks for the hint, Peter!
This function does exactly what I want to do. But I have no Relation inside
gist_page_items(bytea) function... probably, I'll add gist_page_items(relname,
blockno) overload to fetch keys.
PFA patch with implementation.
I did a bit of cleanup on the function signature. The .sql script
claimed that gist_page_items() took bytea as argument, but in reality it
was a relation name, as text. I changed it so that it takes a page image
as argument, instead of reading the block straight from the index.
Mainly to make it consistent with brin_page_items(), if it wasn't for
that precedence I might've gone either way on it.
Fixed the docs accordingly, and ran pgindent. New patch version attached.
- Heikki
>From 791e45bcc86b205b372ea0679c8c036fff941f56 Mon Sep 17 00:00:00 2001
From: Heikki Linnakangas <heikki.linnakan...@iki.fi>
Date: Tue, 12 Jan 2021 15:43:09 +0200
Subject: [PATCH v4 1/1] Add functions to 'pageinspect' to inspect GiST
indexes.
Author: Andrey Borodin and me
Discussion: https://www.postgresql.org/message-id/3E4F9093-A1B5-4DF8-A292-0B48692E3954%40yandex-team.ru
---
contrib/pageinspect/Makefile | 6 +-
contrib/pageinspect/expected/gist.out | 152 ++++++++++
contrib/pageinspect/gistfuncs.c | 287 ++++++++++++++++++
contrib/pageinspect/pageinspect--1.8--1.9.sql | 41 +++
contrib/pageinspect/pageinspect.control | 2 +-
contrib/pageinspect/sql/gist.sql | 23 ++
doc/src/sgml/pageinspect.sgml | 89 ++++++
7 files changed, 597 insertions(+), 3 deletions(-)
create mode 100644 contrib/pageinspect/expected/gist.out
create mode 100644 contrib/pageinspect/gistfuncs.c
create mode 100644 contrib/pageinspect/pageinspect--1.8--1.9.sql
create mode 100644 contrib/pageinspect/sql/gist.sql
diff --git a/contrib/pageinspect/Makefile b/contrib/pageinspect/Makefile
index d9d8177116..4539f0aef7 100644
--- a/contrib/pageinspect/Makefile
+++ b/contrib/pageinspect/Makefile
@@ -7,19 +7,21 @@ OBJS = \
btreefuncs.o \
fsmfuncs.o \
ginfuncs.o \
+ gistfuncs.o \
hashfuncs.o \
heapfuncs.o \
rawpage.o
EXTENSION = pageinspect
-DATA = pageinspect--1.7--1.8.sql pageinspect--1.6--1.7.sql \
+DATA = pageinspect--1.8--1.9.sql \
+ 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
+REGRESS = page btree brin gin gist hash checksum
ifdef USE_PGXS
PG_CONFIG = pg_config
diff --git a/contrib/pageinspect/expected/gist.out b/contrib/pageinspect/expected/gist.out
new file mode 100644
index 0000000000..3c7e08b710
--- /dev/null
+++ b/contrib/pageinspect/expected/gist.out
@@ -0,0 +1,152 @@
+CREATE TABLE test_gist AS SELECT point(i,i) p, i::text t FROM
+ generate_series(1,1000) i;
+CREATE INDEX test_gist_idx ON test_gist USING gist (p);
+-- Page 0 is the root, the rest are leaf pages
+SELECT * FROM gist_page_opaque_info(get_raw_page('test_gist_idx', 0));
+ lsn | nsn | rightlink | flags
+-----+-----+------------+-------
+ 0/1 | 0/0 | 4294967295 | {}
+(1 row)
+
+SELECT * FROM gist_page_opaque_info(get_raw_page('test_gist_idx', 1));
+ lsn | nsn | rightlink | flags
+-----+-----+------------+--------
+ 0/1 | 0/0 | 4294967295 | {leaf}
+(1 row)
+
+SELECT * FROM gist_page_opaque_info(get_raw_page('test_gist_idx', 2));
+ lsn | nsn | rightlink | flags
+-----+-----+-----------+--------
+ 0/1 | 0/0 | 1 | {leaf}
+(1 row)
+
+SELECT * FROM gist_page_items(get_raw_page('test_gist_idx', 0), 'test_gist_idx');
+ itemoffset | ctid | itemlen | keys
+------------+-----------+---------+-------------------
+ 1 | (1,65535) | 40 | (p)=((166,166))
+ 2 | (2,65535) | 40 | (p)=((332,332))
+ 3 | (3,65535) | 40 | (p)=((498,498))
+ 4 | (4,65535) | 40 | (p)=((664,664))
+ 5 | (5,65535) | 40 | (p)=((830,830))
+ 6 | (6,65535) | 40 | (p)=((996,996))
+ 7 | (7,65535) | 40 | (p)=((1000,1000))
+(7 rows)
+
+SELECT * FROM gist_page_items(get_raw_page('test_gist_idx', 1), 'test_gist_idx') LIMIT 5;
+ itemoffset | ctid | itemlen | keys
+------------+-------+---------+-------------
+ 1 | (0,1) | 40 | (p)=((1,1))
+ 2 | (0,2) | 40 | (p)=((2,2))
+ 3 | (0,3) | 40 | (p)=((3,3))
+ 4 | (0,4) | 40 | (p)=((4,4))
+ 5 | (0,5) | 40 | (p)=((5,5))
+(5 rows)
+
+SELECT * FROM gist_page_items(get_raw_page('test_gist_idx', 2), 'test_gist_idx') LIMIT 5;
+ itemoffset | ctid | itemlen | keys
+------------+--------+---------+-----------------
+ 1 | (1,10) | 40 | (p)=((167,167))
+ 2 | (1,11) | 40 | (p)=((168,168))
+ 3 | (1,12) | 40 | (p)=((169,169))
+ 4 | (1,13) | 40 | (p)=((170,170))
+ 5 | (1,14) | 40 | (p)=((171,171))
+(5 rows)
+
+\x
+SELECT * FROM gist_page_items_bytea(get_raw_page('test_gist_idx', 0));
+-[ RECORD 1 ]----------------------------------------------------------------------------------
+itemoffset | 1
+ctid | (1,65535)
+itemlen | 40
+tuple_data | \x00000100ffff28000000000000c064400000000000c06440000000000000f03f000000000000f03f
+-[ RECORD 2 ]----------------------------------------------------------------------------------
+itemoffset | 2
+ctid | (2,65535)
+itemlen | 40
+tuple_data | \x00000200ffff28000000000000c074400000000000c074400000000000e064400000000000e06440
+-[ RECORD 3 ]----------------------------------------------------------------------------------
+itemoffset | 3
+ctid | (3,65535)
+itemlen | 40
+tuple_data | \x00000300ffff28000000000000207f400000000000207f400000000000d074400000000000d07440
+-[ RECORD 4 ]----------------------------------------------------------------------------------
+itemoffset | 4
+ctid | (4,65535)
+itemlen | 40
+tuple_data | \x00000400ffff28000000000000c084400000000000c084400000000000307f400000000000307f40
+-[ RECORD 5 ]----------------------------------------------------------------------------------
+itemoffset | 5
+ctid | (5,65535)
+itemlen | 40
+tuple_data | \x00000500ffff28000000000000f089400000000000f089400000000000c884400000000000c88440
+-[ RECORD 6 ]----------------------------------------------------------------------------------
+itemoffset | 6
+ctid | (6,65535)
+itemlen | 40
+tuple_data | \x00000600ffff28000000000000208f400000000000208f400000000000f889400000000000f88940
+-[ RECORD 7 ]----------------------------------------------------------------------------------
+itemoffset | 7
+ctid | (7,65535)
+itemlen | 40
+tuple_data | \x00000700ffff28000000000000408f400000000000408f400000000000288f400000000000288f40
+
+SELECT * FROM gist_page_items_bytea(get_raw_page('test_gist_idx', 1)) LIMIT 5;
+-[ RECORD 1 ]----------------------------------------------------------------------------------
+itemoffset | 1
+ctid | (0,1)
+itemlen | 40
+tuple_data | \x0000000001002800000000000000f03f000000000000f03f000000000000f03f000000000000f03f
+-[ RECORD 2 ]----------------------------------------------------------------------------------
+itemoffset | 2
+ctid | (0,2)
+itemlen | 40
+tuple_data | \x00000000020028000000000000000040000000000000004000000000000000400000000000000040
+-[ RECORD 3 ]----------------------------------------------------------------------------------
+itemoffset | 3
+ctid | (0,3)
+itemlen | 40
+tuple_data | \x00000000030028000000000000000840000000000000084000000000000008400000000000000840
+-[ RECORD 4 ]----------------------------------------------------------------------------------
+itemoffset | 4
+ctid | (0,4)
+itemlen | 40
+tuple_data | \x00000000040028000000000000001040000000000000104000000000000010400000000000001040
+-[ RECORD 5 ]----------------------------------------------------------------------------------
+itemoffset | 5
+ctid | (0,5)
+itemlen | 40
+tuple_data | \x00000000050028000000000000001440000000000000144000000000000014400000000000001440
+
+SELECT * FROM gist_page_items_bytea(get_raw_page('test_gist_idx', 2)) LIMIT 5;
+-[ RECORD 1 ]----------------------------------------------------------------------------------
+itemoffset | 1
+ctid | (1,10)
+itemlen | 40
+tuple_data | \x000001000a0028000000000000e064400000000000e064400000000000e064400000000000e06440
+-[ RECORD 2 ]----------------------------------------------------------------------------------
+itemoffset | 2
+ctid | (1,11)
+itemlen | 40
+tuple_data | \x000001000b0028000000000000006540000000000000654000000000000065400000000000006540
+-[ RECORD 3 ]----------------------------------------------------------------------------------
+itemoffset | 3
+ctid | (1,12)
+itemlen | 40
+tuple_data | \x000001000c0028000000000000206540000000000020654000000000002065400000000000206540
+-[ RECORD 4 ]----------------------------------------------------------------------------------
+itemoffset | 4
+ctid | (1,13)
+itemlen | 40
+tuple_data | \x000001000d0028000000000000406540000000000040654000000000004065400000000000406540
+-[ RECORD 5 ]----------------------------------------------------------------------------------
+itemoffset | 5
+ctid | (1,14)
+itemlen | 40
+tuple_data | \x000001000e0028000000000000606540000000000060654000000000006065400000000000606540
+
+-- error cases
+SELECT * FROM gist_page_items_bytea(get_raw_page('nonexistent_idx', 0));
+ERROR: relation "nonexistent_idx" does not exist
+SELECT * FROM gist_page_items_bytea(get_raw_page('test_gist_idx', 20000));
+ERROR: block number 20000 is out of range for relation "test_gist_idx"
+DROP TABLE test_gist;
diff --git a/contrib/pageinspect/gistfuncs.c b/contrib/pageinspect/gistfuncs.c
new file mode 100644
index 0000000000..146b2e91b6
--- /dev/null
+++ b/contrib/pageinspect/gistfuncs.c
@@ -0,0 +1,287 @@
+/*
+ * gistfuncs.c
+ * Functions to investigate the content of GiST indexes
+ *
+ * Copyright (c) 2014-2020, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ * contrib/pageinspect/gistfuncs.c
+ */
+#include "postgres.h"
+
+#include "access/gist.h"
+#include "access/gist_private.h"
+#include "access/htup.h"
+#include "access/relation.h"
+#include "catalog/namespace.h"
+#include "funcapi.h"
+#include "miscadmin.h"
+#include "pageinspect.h"
+#include "storage/itemptr.h"
+#include "utils/array.h"
+#include "utils/builtins.h"
+#include "utils/rel.h"
+#include "utils/pg_lsn.h"
+#include "utils/varlena.h"
+
+PG_FUNCTION_INFO_V1(gist_page_opaque_info);
+PG_FUNCTION_INFO_V1(gist_page_items);
+PG_FUNCTION_INFO_V1(gist_page_items_bytea);
+
+#define ItemPointerGetDatum(X) PointerGetDatum(X)
+
+
+Datum
+gist_page_opaque_info(PG_FUNCTION_ARGS)
+{
+ bytea *raw_page = PG_GETARG_BYTEA_P(0);
+ TupleDesc tupdesc;
+ Page page;
+ GISTPageOpaque opaq;
+ HeapTuple resultTuple;
+ Datum values[4];
+ bool nulls[4];
+ 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 = (GISTPageOpaque) 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 & F_LEAF)
+ flags[nflags++] = CStringGetTextDatum("leaf");
+ if (flagbits & F_DELETED)
+ flags[nflags++] = CStringGetTextDatum("deleted");
+ if (flagbits & F_TUPLES_DELETED)
+ flags[nflags++] = CStringGetTextDatum("tuples_deleted");
+ if (flagbits & F_FOLLOW_RIGHT)
+ flags[nflags++] = CStringGetTextDatum("follow_right");
+ if (flagbits & F_HAS_GARBAGE)
+ flags[nflags++] = CStringGetTextDatum("has_garbage");
+ flagbits &= ~(F_LEAF | F_DELETED | F_TUPLES_DELETED | F_FOLLOW_RIGHT | F_HAS_GARBAGE);
+ 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] = LSNGetDatum(PageGetLSN(page));
+ values[1] = LSNGetDatum(GistPageGetNSN(page));
+ values[2] = Int64GetDatum(opaq->rightlink);
+ values[3] = 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 gist_page_items_state
+{
+ Page page;
+ TupleDesc tupd;
+ OffsetNumber offset;
+ Relation rel;
+} gist_page_items_state;
+
+Datum
+gist_page_items_bytea(PG_FUNCTION_ARGS)
+{
+ bytea *raw_page = PG_GETARG_BYTEA_P(0);
+ FuncCallContext *fctx;
+ gist_page_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;
+
+ fctx = SRF_FIRSTCALL_INIT();
+ mctx = MemoryContextSwitchTo(fctx->multi_call_memory_ctx);
+
+ page = get_page_from_raw(raw_page);
+
+ inter_call_data = palloc(sizeof(gist_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");
+
+ if (GistPageIsDeleted(page))
+ elog(NOTICE, "page is deleted");
+
+ inter_call_data->page = page;
+ inter_call_data->tupd = tupdesc;
+ inter_call_data->offset = FirstOffsetNumber;
+
+ fctx->max_calls = PageGetMaxOffsetNumber(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;
+ OffsetNumber offset = inter_call_data->offset;
+ HeapTuple resultTuple;
+ Datum result;
+ Datum values[4];
+ bool nulls[4];
+ ItemId id;
+ IndexTuple itup;
+ bytea *tuple_bytea;
+ int tuple_len;
+
+ id = PageGetItemId(page, offset);
+
+ if (!ItemIdIsValid(id))
+ elog(ERROR, "invalid ItemId");
+
+ itup = (IndexTuple) PageGetItem(page, id);
+ tuple_len = IndexTupleSize(itup);
+
+ memset(nulls, 0, sizeof(nulls));
+
+ values[0] = DatumGetInt16(offset);
+ values[1] = ItemPointerGetDatum(&itup->t_tid);
+ values[2] = Int32GetDatum((int) IndexTupleSize(itup));
+
+ tuple_bytea = (bytea *) palloc(tuple_len + VARHDRSZ);
+ SET_VARSIZE(tuple_bytea, tuple_len + VARHDRSZ);
+ memcpy(VARDATA(tuple_bytea), itup, tuple_len);
+ values[3] = PointerGetDatum(tuple_bytea);
+
+ /* 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);
+ }
+
+ SRF_RETURN_DONE(fctx);
+}
+
+Datum
+gist_page_items(PG_FUNCTION_ARGS)
+{
+ bytea *raw_page = PG_GETARG_BYTEA_P(0);
+ Oid indexRelid = PG_GETARG_OID(1);
+ FuncCallContext *fctx;
+ gist_page_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())
+ {
+ Relation indexRel;
+ TupleDesc tupdesc;
+ MemoryContext mctx;
+ Page page;
+
+ fctx = SRF_FIRSTCALL_INIT();
+ mctx = MemoryContextSwitchTo(fctx->multi_call_memory_ctx);
+
+ page = get_page_from_raw(raw_page);
+
+ inter_call_data = palloc(sizeof(gist_page_items_state));
+
+ /* Open the relation */
+ indexRel = index_open(indexRelid, AccessShareLock);
+
+ /* 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");
+
+ if (GistPageIsDeleted(page))
+ elog(NOTICE, "page is deleted");
+
+ inter_call_data->page = page;
+ inter_call_data->tupd = tupdesc;
+ inter_call_data->offset = FirstOffsetNumber;
+ inter_call_data->rel = indexRel;
+
+ fctx->max_calls = PageGetMaxOffsetNumber(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;
+ OffsetNumber offset = inter_call_data->offset;
+ HeapTuple resultTuple;
+ Datum result;
+ Datum values[4];
+ bool nulls[4];
+ ItemId id;
+ IndexTuple itup;
+ Datum itup_values[INDEX_MAX_KEYS];
+ bool itup_isnull[INDEX_MAX_KEYS];
+ char *key_desc;
+
+ id = PageGetItemId(page, offset);
+
+ if (!ItemIdIsValid(id))
+ elog(ERROR, "invalid ItemId");
+
+ itup = (IndexTuple) PageGetItem(page, id);
+
+ index_deform_tuple(itup, RelationGetDescr(inter_call_data->rel),
+ itup_values, itup_isnull);
+
+ key_desc = BuildIndexValueDescription(inter_call_data->rel, itup_values,
+ itup_isnull);
+
+ memset(nulls, 0, sizeof(nulls));
+
+ values[0] = DatumGetInt16(offset);
+ values[1] = ItemPointerGetDatum(&itup->t_tid);
+ values[2] = Int32GetDatum((int) IndexTupleSize(itup));
+ values[3] = CStringGetTextDatum(key_desc);
+
+ /* 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);
+ }
+
+ relation_close(inter_call_data->rel, AccessShareLock);
+
+ SRF_RETURN_DONE(fctx);
+}
diff --git a/contrib/pageinspect/pageinspect--1.8--1.9.sql b/contrib/pageinspect/pageinspect--1.8--1.9.sql
new file mode 100644
index 0000000000..9dc342fabc
--- /dev/null
+++ b/contrib/pageinspect/pageinspect--1.8--1.9.sql
@@ -0,0 +1,41 @@
+/* contrib/pageinspect/pageinspect--1.8--1.9.sql */
+
+-- complain if script is sourced in psql, rather than via ALTER EXTENSION
+\echo Use "ALTER EXTENSION pageinspect UPDATE TO '1.9'" to load this file. \quit
+
+--
+-- gist_page_opaque_info()
+--
+CREATE FUNCTION gist_page_opaque_info(IN page bytea,
+ OUT lsn pg_lsn,
+ OUT nsn pg_lsn,
+ OUT rightlink bigint,
+ OUT flags text[])
+AS 'MODULE_PATHNAME', 'gist_page_opaque_info'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+
+--
+-- gist_page_items_bytea()
+--
+CREATE FUNCTION gist_page_items_bytea(IN page bytea,
+ OUT itemoffset smallint,
+ OUT ctid tid,
+ OUT itemlen smallint,
+ OUT key_data bytea)
+RETURNS SETOF record
+AS 'MODULE_PATHNAME', 'gist_page_items_bytea'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+--
+-- gist_page_items()
+--
+CREATE FUNCTION gist_page_items(IN page bytea,
+ IN index_oid regclass,
+ OUT itemoffset smallint,
+ OUT ctid tid,
+ OUT itemlen smallint,
+ OUT keys text)
+RETURNS SETOF record
+AS 'MODULE_PATHNAME', 'gist_page_items'
+LANGUAGE C STRICT PARALLEL SAFE;
diff --git a/contrib/pageinspect/pageinspect.control b/contrib/pageinspect/pageinspect.control
index f8cdf526c6..bd716769a1 100644
--- a/contrib/pageinspect/pageinspect.control
+++ b/contrib/pageinspect/pageinspect.control
@@ -1,5 +1,5 @@
# pageinspect extension
comment = 'inspect the contents of database pages at a low level'
-default_version = '1.8'
+default_version = '1.9'
module_pathname = '$libdir/pageinspect'
relocatable = true
diff --git a/contrib/pageinspect/sql/gist.sql b/contrib/pageinspect/sql/gist.sql
new file mode 100644
index 0000000000..a6b17ef919
--- /dev/null
+++ b/contrib/pageinspect/sql/gist.sql
@@ -0,0 +1,23 @@
+CREATE TABLE test_gist AS SELECT point(i,i) p, i::text t FROM
+ generate_series(1,1000) i;
+CREATE INDEX test_gist_idx ON test_gist USING gist (p);
+
+-- Page 0 is the root, the rest are leaf pages
+SELECT * FROM gist_page_opaque_info(get_raw_page('test_gist_idx', 0));
+SELECT * FROM gist_page_opaque_info(get_raw_page('test_gist_idx', 1));
+SELECT * FROM gist_page_opaque_info(get_raw_page('test_gist_idx', 2));
+
+SELECT * FROM gist_page_items(get_raw_page('test_gist_idx', 0), 'test_gist_idx');
+SELECT * FROM gist_page_items(get_raw_page('test_gist_idx', 1), 'test_gist_idx') LIMIT 5;
+SELECT * FROM gist_page_items(get_raw_page('test_gist_idx', 2), 'test_gist_idx') LIMIT 5;
+
+\x
+SELECT * FROM gist_page_items_bytea(get_raw_page('test_gist_idx', 0));
+SELECT * FROM gist_page_items_bytea(get_raw_page('test_gist_idx', 1)) LIMIT 5;
+SELECT * FROM gist_page_items_bytea(get_raw_page('test_gist_idx', 2)) LIMIT 5;
+
+-- error cases
+SELECT * FROM gist_page_items_bytea(get_raw_page('nonexistent_idx', 0));
+SELECT * FROM gist_page_items_bytea(get_raw_page('test_gist_idx', 20000));
+
+DROP TABLE test_gist;
diff --git a/doc/src/sgml/pageinspect.sgml b/doc/src/sgml/pageinspect.sgml
index 687c3606ba..35858e1557 100644
--- a/doc/src/sgml/pageinspect.sgml
+++ b/doc/src/sgml/pageinspect.sgml
@@ -671,6 +671,95 @@ test=# SELECT first_tid, nbytes, tids[0:5] AS some_tids
</variablelist>
</sect2>
+ <sect2>
+ <title>GiST Functions</title>
+
+ <variablelist>
+ <varlistentry>
+ <term>
+ <function>gist_page_opaque_info(page bytea) returns record</function>
+ <indexterm>
+ <primary>gist_page_opaque_info</primary>
+ </indexterm>
+ </term>
+
+ <listitem>
+ <para>
+ <function>gist_page_opaque_info</function> returns information about
+ a <acronym>GiST</acronym> index opaque area, like the NSN, rightlink and
+ page type.
+ For example:
+<screen>
+test=# SELECT * FROM gist_page_opaque_info(get_raw_page('test_gist_idx', 2));
+ lsn | nsn | rightlink | flags
+-----+-----+-----------+--------
+ 0/1 | 0/0 | 1 | {leaf}
+(1 row)
+</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>
+ <function>gist_page_items(page bytea, index oid) returns setof record</function>
+ <indexterm>
+ <primary>gist_page_items</primary>
+ </indexterm>
+ </term>
+
+ <listitem>
+ <para>
+ <function>gist_page_items</function> returns information about
+ the data stored in a page of <acronym>GiST</acronym> index. For example:
+<screen>
+test=# SELECT * FROM gist_page_items(get_raw_page('test_gist_idx', 0), 'test_gist_idx');
+ itemoffset | ctid | itemlen | keys
+------------+-----------+---------+-------------------
+ 1 | (1,65535) | 40 | (p)=((166,166))
+ 2 | (2,65535) | 40 | (p)=((332,332))
+ 3 | (3,65535) | 40 | (p)=((498,498))
+ 4 | (4,65535) | 40 | (p)=((664,664))
+ 5 | (5,65535) | 40 | (p)=((830,830))
+ 6 | (6,65535) | 40 | (p)=((996,996))
+ 7 | (7,65535) | 40 | (p)=((1000,1000))
+(7 rows)
+</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>
+ <function>gist_page_items_bytea(page bytea) returns setof record</function>
+ <indexterm>
+ <primary>gist_page_items_bytea</primary>
+ </indexterm>
+ </term>
+
+ <listitem>
+ <para>
+ Same as <function>gist_page_items</function>, but returns the key data as a raw
+ bytea blob. For example:
+<screen>
+test=# SELECT * FROM gist_page_items_bytea(get_raw_page('test_gist_idx', 0));
+ itemoffset | ctid | itemlen | key_data
+------------+-----------+---------+------------------------------------------------------------------------------------
+ 1 | (1,65535) | 40 | \x00000100ffff28000000000000c064400000000000c06440000000000000f03f000000000000f03f
+ 2 | (2,65535) | 40 | \x00000200ffff28000000000000c074400000000000c074400000000000e064400000000000e06440
+ 3 | (3,65535) | 40 | \x00000300ffff28000000000000207f400000000000207f400000000000d074400000000000d07440
+ 4 | (4,65535) | 40 | \x00000400ffff28000000000000c084400000000000c084400000000000307f400000000000307f40
+ 5 | (5,65535) | 40 | \x00000500ffff28000000000000f089400000000000f089400000000000c884400000000000c88440
+ 6 | (6,65535) | 40 | \x00000600ffff28000000000000208f400000000000208f400000000000f889400000000000f88940
+ 7 | (7,65535) | 40 | \x00000700ffff28000000000000408f400000000000408f400000000000288f400000000000288f40
+(7 rows)
+</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </sect2>
+
<sect2>
<title>Hash Functions</title>
--
2.29.2
