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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;
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