-- 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),(1,1)") 2 | (2,65535) | 40 | f | (p)=("(370,370),(186,186)") 3 | (3,65535) | 40 | f | (p)=("(555,555),(371,371)") 4 | (4,65535) | 40 | f | (p)=("(740,740),(556,556)") 5 | (5,65535) | 40 | f | (p)=("(870,870),(741,741)") 6 | (6,65535) | 40 | f | (p)=("(1000,1000),(871,871)") (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),(1,1)") 2 | (0,2) | 40 | f | (p)=("(2,2),(2,2)") 3 | (0,3) | 40 | f | (p)=("(3,3),(3,3)") 4 | (0,4) | 40 | f | (p)=("(4,4),(4,4)") 5 | (0,5) | 40 | f | (p)=("(5,5),(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) -- Suppress the DETAIL message, to allow the tests to work across various -- page sizes and architectures. \set VERBOSITY terse -- Failures 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 SELECT gist_page_items(get_raw_page('test_gist_btree', 0), 'test_gist_idx'); ERROR: input page is not a valid GiST page -- Failure with various modes. -- invalid page size 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 -- invalid special area size SELECT * FROM gist_page_opaque_info(get_raw_page('test_gist', 0)); ERROR: input page is not a valid GiST page SELECT gist_page_items_bytea(get_raw_page('test_gist', 0)); ERROR: input page is not a valid GiST page SELECT gist_page_items_bytea(get_raw_page('test_gist_btree', 0)); ERROR: input page is not a valid GiST page \set VERBOSITY default -- Tests with all-zero pages. SHOW block_size \gset SELECT gist_page_items_bytea(decode(repeat('00', :block_size), 'hex')); gist_page_items_bytea ----------------------- (0 rows) SELECT gist_page_items(decode(repeat('00', :block_size), 'hex'), 'test_gist_idx'::regclass); gist_page_items ----------------- (0 rows) SELECT gist_page_opaque_info(decode(repeat('00', :block_size), 'hex')); gist_page_opaque_info ----------------------- (1 row) -- Test gist_page_items with included columns. -- Non-leaf pages contain only the key attributes, and leaf pages contain -- the included attributes. ALTER TABLE test_gist ADD COLUMN i int DEFAULT NULL; CREATE INDEX test_gist_idx_inc ON test_gist USING gist (p) INCLUDE (t, i); -- Mask the value of the key attribute to avoid alignment issues. SELECT regexp_replace(keys, '\(p\)=\("(.*?)"\)', '(p)=("")') AS keys_nonleaf_1 FROM gist_page_items(get_raw_page('test_gist_idx_inc', 0), 'test_gist_idx_inc') WHERE itemoffset = 1; keys_nonleaf_1 ---------------- (p)=("") (1 row) SELECT keys AS keys_leaf_1 FROM gist_page_items(get_raw_page('test_gist_idx_inc', 1), 'test_gist_idx_inc') WHERE itemoffset = 1; keys_leaf_1 ------------------------------------------------------ (p) INCLUDE (t, i)=("(1,1),(1,1)") INCLUDE (1, null) (1 row) DROP TABLE test_gist;