postgresql/contrib/pageinspect/expected/gist.out
Michael Paquier 076f4d9539 pageinspect: Fix handling of page sizes and AM types
This commit fixes a set of issues related to the use of the SQL
functions in this module when the caller is able to pass down raw page
data as input argument:
- The page size check was fuzzy in a couple of places, sometimes
looking after only a sub-range, but what we are looking for is an exact
match on BLCKSZ.  After considering a few options here, I have settled
down to do a generalization of get_page_from_raw().  Most of the SQL
functions already used that, and this is not strictly required if not
accessing an 8-byte-wide value from a raw page, but this feels safer in
the long run for alignment-picky environment, particularly if a code
path begins to access such values.  This also reduces the number of
strings that need to be translated.
- The BRIN function brin_page_items() uses a Relation but it did not
check the access method of the opened index, potentially leading to
crashes.  All the other functions in need of a Relation already did
that.
- Some code paths could fail on elog(), but we should to use ereport()
for failures that can be triggered by the user.

Tests are added to stress all the cases that are fixed as of this
commit, with some junk raw pages (\set VERBOSITY ensures that this works
across all page sizes) and unexpected index types when functions open
relations.

Author: Michael Paquier, Justin Prysby
Discussion: https://postgr.es/m/20220218030020.GA1137@telsasoft.com
Backpatch-through: 10
2022-03-16 11:19:39 +09:00

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3.4 KiB
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-- The gist_page_opaque_info() function prints the page's LSN. Normally,
-- that's constant 1 (GistBuildLSN) on every page of a freshly built GiST
-- index. But with wal_level=minimal, the whole relation is dumped to WAL at
-- the end of the transaction if it's smaller than wal_skip_threshold, which
-- updates the LSNs. Wrap the tests on gist_page_opaque_info() in the
-- same transaction with the CREATE INDEX so that we see the LSNs before
-- they are possibly overwritten at end of transaction.
BEGIN;
-- Create a test table and GiST index.
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)
COMMIT;
SELECT * FROM gist_page_items(get_raw_page('test_gist_idx', 0), 'test_gist_idx');
itemoffset | ctid | itemlen | dead | keys
------------+-----------+---------+------+-------------------
1 | (1,65535) | 40 | f | (p)=((185,185))
2 | (2,65535) | 40 | f | (p)=((370,370))
3 | (3,65535) | 40 | f | (p)=((555,555))
4 | (4,65535) | 40 | f | (p)=((740,740))
5 | (5,65535) | 40 | f | (p)=((870,870))
6 | (6,65535) | 40 | f | (p)=((1000,1000))
(6 rows)
SELECT * FROM gist_page_items(get_raw_page('test_gist_idx', 1), 'test_gist_idx') LIMIT 5;
itemoffset | ctid | itemlen | dead | keys
------------+-------+---------+------+-------------
1 | (0,1) | 40 | f | (p)=((1,1))
2 | (0,2) | 40 | f | (p)=((2,2))
3 | (0,3) | 40 | f | (p)=((3,3))
4 | (0,4) | 40 | f | (p)=((4,4))
5 | (0,5) | 40 | f | (p)=((5,5))
(5 rows)
-- gist_page_items_bytea prints the raw key data as a bytea. The output of that is
-- platform-dependent (endianness), so omit the actual key data from the output.
SELECT itemoffset, ctid, itemlen FROM gist_page_items_bytea(get_raw_page('test_gist_idx', 0));
itemoffset | ctid | itemlen
------------+-----------+---------
1 | (1,65535) | 40
2 | (2,65535) | 40
3 | (3,65535) | 40
4 | (4,65535) | 40
5 | (5,65535) | 40
6 | (6,65535) | 40
(6 rows)
-- Failure with non-GiST index.
CREATE INDEX test_gist_btree on test_gist(t);
SELECT gist_page_items(get_raw_page('test_gist_btree', 0), 'test_gist_btree');
ERROR: "test_gist_btree" is not a GiST index
-- Failure with incorrect page size
-- Suppress the DETAIL message, to allow the tests to work across various
-- page sizes.
\set VERBOSITY terse
SELECT gist_page_items_bytea('aaa'::bytea);
ERROR: invalid page size
SELECT gist_page_items('aaa'::bytea, 'test_gist_idx'::regclass);
ERROR: invalid page size
SELECT gist_page_opaque_info('aaa'::bytea);
ERROR: invalid page size
\set VERBOSITY default
DROP TABLE test_gist;