mirror of
https://github.com/HypoPG/hypopg
synced 2026-05-24 09:38:21 +00:00
77 lines
2 KiB
PL/PgSQL
77 lines
2 KiB
PL/PgSQL
-- SETUP
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CREATE OR REPLACE FUNCTION do_explain(stmt text) RETURNS table(a text) AS
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$_$
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DECLARE
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ret text;
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BEGIN
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FOR ret IN EXECUTE format('EXPLAIN (FORMAT text) %s', stmt) LOOP
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a := ret;
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RETURN next ;
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END LOOP;
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END;
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$_$
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LANGUAGE plpgsql;
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CREATE EXTENSION hypopg;
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CREATE TABLE hypo (id integer, val text);
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INSERT INTO hypo SELECT i, 'line ' || i
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FROM generate_series(1,100000) f(i);
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ANALYZE hypo;
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-- TESTS
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SELECT COUNT(*) AS nb
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FROM public.hypopg_create_index('SELECT 1;CREATE INDEX ON hypo(id); SELECT 2');
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SELECT nspname, relname, amname FROM public.hypopg_list_indexes();
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-- Should use hypothetical index
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SELECT COUNT(*) FROM do_explain('SELECT * FROM hypo WHERE id = 1') e
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WHERE e ~ 'Index.*<\d+>btree_hypo.*';
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-- Should use hypothetical index
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SELECT COUNT(*) FROM do_explain('SELECT * FROM hypo ORDER BY id') e
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WHERE e ~ 'Index.*<\d+>btree_hypo.*';
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-- Should not use hypothetical index
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SELECT COUNT(*) FROM do_explain('SELECT * FROM hypo') e
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WHERE e ~ 'Index.*<\d+>btree_hypo.*';
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-- Add predicate index
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SELECT COUNT(*) AS nb
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FROM public.hypopg_create_index('CREATE INDEX ON hypo(id) WHERE id < 5');
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-- This specific index should be used
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WITH ind AS (
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SELECT indexrelid, row_number() OVER (ORDER BY indexrelid) AS num
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FROM public.hypopg()
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),
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regexp AS (
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SELECT regexp_replace(e, '.*<(\d+)>.*', E'\\1', 'g') AS r
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FROM do_explain('SELECT * FROM hypo WHERE id < 3') AS e
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)
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SELECT num
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FROM ind
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JOIN regexp ON ind.indexrelid::text = regexp.r;
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-- Specify fillfactor
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SELECT COUNT(*) AS NB
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FROM public.hypopg_create_index('CREATE INDEX ON hypo(id) WITH (fillfactor = 10)');
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-- Specify an incorrect fillfactor
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SELECT COUNT(*) AS NB
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FROM public.hypopg_create_index('CREATE INDEX ON hypo(id) WITH (fillfactor = 1)');
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-- Index size estimation
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SELECT pg_size_pretty(hypopg_relation_size(indexrelid))
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FROM hypopg()
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ORDER BY indexrelid;
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-- Remove one hypothetical index
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SELECT hypopg_drop_index(indexrelid) FROM hypopg() ORDER BY indexrelid LIMIT 1;
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-- Remove all the hypothetical indexes
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SELECT hypopg_reset();
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