70 lines
2.9 KiB
Plaintext
70 lines
2.9 KiB
Plaintext
-- 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)=((166,166))
|
|
2 | (2,65535) | 40 | f | (p)=((332,332))
|
|
3 | (3,65535) | 40 | f | (p)=((498,498))
|
|
4 | (4,65535) | 40 | f | (p)=((664,664))
|
|
5 | (5,65535) | 40 | f | (p)=((830,830))
|
|
6 | (6,65535) | 40 | f | (p)=((996,996))
|
|
7 | (7,65535) | 40 | f | (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 | 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 (endianess), 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
|
|
7 | (7,65535) | 40
|
|
(7 rows)
|
|
|
|
DROP TABLE test_gist;
|