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6bdf1a1400
Some words were duplicated while other places were grammatically incorrect, including one variable name in the code. Author: Otto Kekalainen, Justin Pryzby Discussion: https://postgr.es/m/7DDBEFC5-09B6-4325-B942-B563D1A24BDC@amazon.com
30 lines
1.4 KiB
PL/PgSQL
30 lines
1.4 KiB
PL/PgSQL
-- The gist_page_opaque_info() function prints the page's LSN. Normally,
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-- that's constant 1 (GistBuildLSN) on every page of a freshly built GiST
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-- index. But with wal_level=minimal, the whole relation is dumped to WAL at
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-- the end of the transaction if it's smaller than wal_skip_threshold, which
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-- updates the LSNs. Wrap the tests on gist_page_opaque_info() in the
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-- same transaction with the CREATE INDEX so that we see the LSNs before
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-- they are possibly overwritten at end of transaction.
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BEGIN;
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-- Create a test table and GiST index.
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CREATE TABLE test_gist AS SELECT point(i,i) p, i::text t FROM
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generate_series(1,1000) i;
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CREATE INDEX test_gist_idx ON test_gist USING gist (p);
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-- Page 0 is the root, the rest are leaf pages
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SELECT * FROM gist_page_opaque_info(get_raw_page('test_gist_idx', 0));
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SELECT * FROM gist_page_opaque_info(get_raw_page('test_gist_idx', 1));
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SELECT * FROM gist_page_opaque_info(get_raw_page('test_gist_idx', 2));
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COMMIT;
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SELECT * FROM gist_page_items(get_raw_page('test_gist_idx', 0), 'test_gist_idx');
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SELECT * FROM gist_page_items(get_raw_page('test_gist_idx', 1), 'test_gist_idx') LIMIT 5;
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-- gist_page_items_bytea prints the raw key data as a bytea. The output of that is
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-- platform-dependent (endianness), so omit the actual key data from the output.
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SELECT itemoffset, ctid, itemlen FROM gist_page_items_bytea(get_raw_page('test_gist_idx', 0));
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DROP TABLE test_gist;
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