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9fbc3f318d
If more distinct statements than pg_stat_statements.max are observed, pg_stat_statements entries about the least-executed statements are deallocated. This commit enables us to track the total number of times those entries were deallocated. That number can be viewed in the pg_stat_statements_info view that this commit adds. It's useful when tuning pg_stat_statements.max parameter. If it's high, i.e., the entries are deallocated very frequently, which might cause the performance regression and we can increase pg_stat_statements.max to avoid those frequent deallocations. The pg_stat_statements_info view is intended to display the statistics of pg_stat_statements module itself. Currently it has only one column "dealloc" indicating the number of times entries were deallocated. But an upcoming patch will add other columns (for example, the time at which pg_stat_statements statistics were last reset) into the view. Author: Katsuragi Yuta, Yuki Seino Reviewed-by: Fujii Masao Discussion: https://postgr.es/m/0d9f1107772cf5c3f954e985464c7298@oss.nttdata.com
368 lines
9.3 KiB
PL/PgSQL
368 lines
9.3 KiB
PL/PgSQL
CREATE EXTENSION pg_stat_statements;
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--
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-- simple and compound statements
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--
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SET pg_stat_statements.track_utility = FALSE;
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SET pg_stat_statements.track_planning = TRUE;
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SELECT pg_stat_statements_reset();
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SELECT 1 AS "int";
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SELECT 'hello'
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-- multiline
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AS "text";
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SELECT 'world' AS "text";
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-- transaction
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BEGIN;
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SELECT 1 AS "int";
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SELECT 'hello' AS "text";
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COMMIT;
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-- compound transaction
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BEGIN \;
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SELECT 2.0 AS "float" \;
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SELECT 'world' AS "text" \;
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COMMIT;
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-- compound with empty statements and spurious leading spacing
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\;\; SELECT 3 + 3 \;\;\; SELECT ' ' || ' !' \;\; SELECT 1 + 4 \;;
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-- non ;-terminated statements
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SELECT 1 + 1 + 1 AS "add" \gset
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SELECT :add + 1 + 1 AS "add" \;
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SELECT :add + 1 + 1 AS "add" \gset
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-- set operator
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SELECT 1 AS i UNION SELECT 2 ORDER BY i;
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-- ? operator
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select '{"a":1, "b":2}'::jsonb ? 'b';
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-- cte
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WITH t(f) AS (
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VALUES (1.0), (2.0)
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)
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SELECT f FROM t ORDER BY f;
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-- prepared statement with parameter
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PREPARE pgss_test (int) AS SELECT $1, 'test' LIMIT 1;
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EXECUTE pgss_test(1);
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DEALLOCATE pgss_test;
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SELECT query, calls, rows FROM pg_stat_statements ORDER BY query COLLATE "C";
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--
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-- CRUD: INSERT SELECT UPDATE DELETE on test table
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--
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SELECT pg_stat_statements_reset();
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-- utility "create table" should not be shown
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CREATE TEMP TABLE test (a int, b char(20));
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INSERT INTO test VALUES(generate_series(1, 10), 'aaa');
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UPDATE test SET b = 'bbb' WHERE a > 7;
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DELETE FROM test WHERE a > 9;
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-- explicit transaction
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BEGIN;
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UPDATE test SET b = '111' WHERE a = 1 ;
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COMMIT;
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BEGIN \;
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UPDATE test SET b = '222' WHERE a = 2 \;
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COMMIT ;
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UPDATE test SET b = '333' WHERE a = 3 \;
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UPDATE test SET b = '444' WHERE a = 4 ;
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BEGIN \;
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UPDATE test SET b = '555' WHERE a = 5 \;
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UPDATE test SET b = '666' WHERE a = 6 \;
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COMMIT ;
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-- many INSERT values
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INSERT INTO test (a, b) VALUES (1, 'a'), (2, 'b'), (3, 'c');
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-- SELECT with constants
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SELECT * FROM test WHERE a > 5 ORDER BY a ;
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SELECT *
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FROM test
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WHERE a > 9
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ORDER BY a ;
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-- SELECT without constants
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SELECT * FROM test ORDER BY a;
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-- SELECT with IN clause
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SELECT * FROM test WHERE a IN (1, 2, 3, 4, 5);
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SELECT query, calls, rows FROM pg_stat_statements ORDER BY query COLLATE "C";
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--
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-- INSERT, UPDATE, DELETE on test table to validate WAL generation metrics
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--
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SELECT pg_stat_statements_reset();
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-- utility "create table" should not be shown
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CREATE TABLE pgss_test (a int, b char(20));
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INSERT INTO pgss_test VALUES(generate_series(1, 10), 'aaa');
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UPDATE pgss_test SET b = 'bbb' WHERE a > 7;
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DELETE FROM pgss_test WHERE a > 9;
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-- DROP test table
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SET pg_stat_statements.track_utility = TRUE;
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DROP TABLE pgss_test;
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SET pg_stat_statements.track_utility = FALSE;
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-- Check WAL is generated for the above statements
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SELECT query, calls, rows,
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wal_bytes > 0 as wal_bytes_generated,
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wal_records > 0 as wal_records_generated,
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wal_records = rows as wal_records_as_rows
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FROM pg_stat_statements ORDER BY query COLLATE "C";
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--
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-- pg_stat_statements.track = none
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--
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SET pg_stat_statements.track = 'none';
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SELECT pg_stat_statements_reset();
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SELECT 1 AS "one";
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SELECT 1 + 1 AS "two";
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SELECT query, calls, rows FROM pg_stat_statements ORDER BY query COLLATE "C";
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--
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-- pg_stat_statements.track = top
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--
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SET pg_stat_statements.track = 'top';
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SELECT pg_stat_statements_reset();
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DO LANGUAGE plpgsql $$
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BEGIN
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-- this is a SELECT
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PERFORM 'hello world'::TEXT;
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END;
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$$;
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-- PL/pgSQL function
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CREATE FUNCTION PLUS_TWO(i INTEGER) RETURNS INTEGER AS $$
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DECLARE
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r INTEGER;
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BEGIN
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SELECT (i + 1 + 1.0)::INTEGER INTO r;
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RETURN r;
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END; $$ LANGUAGE plpgsql;
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SELECT PLUS_TWO(3);
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SELECT PLUS_TWO(7);
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-- SQL function --- use LIMIT to keep it from being inlined
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CREATE FUNCTION PLUS_ONE(i INTEGER) RETURNS INTEGER AS
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$$ SELECT (i + 1.0)::INTEGER LIMIT 1 $$ LANGUAGE SQL;
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SELECT PLUS_ONE(8);
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SELECT PLUS_ONE(10);
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SELECT query, calls, rows FROM pg_stat_statements ORDER BY query COLLATE "C";
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--
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-- pg_stat_statements.track = all
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--
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SET pg_stat_statements.track = 'all';
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SELECT pg_stat_statements_reset();
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-- we drop and recreate the functions to avoid any caching funnies
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DROP FUNCTION PLUS_ONE(INTEGER);
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DROP FUNCTION PLUS_TWO(INTEGER);
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-- PL/pgSQL function
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CREATE FUNCTION PLUS_TWO(i INTEGER) RETURNS INTEGER AS $$
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DECLARE
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r INTEGER;
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BEGIN
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SELECT (i + 1 + 1.0)::INTEGER INTO r;
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RETURN r;
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END; $$ LANGUAGE plpgsql;
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SELECT PLUS_TWO(-1);
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SELECT PLUS_TWO(2);
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-- SQL function --- use LIMIT to keep it from being inlined
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CREATE FUNCTION PLUS_ONE(i INTEGER) RETURNS INTEGER AS
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$$ SELECT (i + 1.0)::INTEGER LIMIT 1 $$ LANGUAGE SQL;
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SELECT PLUS_ONE(3);
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SELECT PLUS_ONE(1);
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SELECT query, calls, rows FROM pg_stat_statements ORDER BY query COLLATE "C";
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--
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-- queries with locking clauses
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--
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CREATE TABLE pgss_a (id integer PRIMARY KEY);
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CREATE TABLE pgss_b (id integer PRIMARY KEY, a_id integer REFERENCES pgss_a);
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SELECT pg_stat_statements_reset();
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-- control query
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SELECT * FROM pgss_a JOIN pgss_b ON pgss_b.a_id = pgss_a.id;
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-- test range tables
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SELECT * FROM pgss_a JOIN pgss_b ON pgss_b.a_id = pgss_a.id FOR UPDATE;
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SELECT * FROM pgss_a JOIN pgss_b ON pgss_b.a_id = pgss_a.id FOR UPDATE OF pgss_a;
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SELECT * FROM pgss_a JOIN pgss_b ON pgss_b.a_id = pgss_a.id FOR UPDATE OF pgss_b;
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SELECT * FROM pgss_a JOIN pgss_b ON pgss_b.a_id = pgss_a.id FOR UPDATE OF pgss_a, pgss_b; -- matches plain "FOR UPDATE"
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SELECT * FROM pgss_a JOIN pgss_b ON pgss_b.a_id = pgss_a.id FOR UPDATE OF pgss_b, pgss_a;
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-- test strengths
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SELECT * FROM pgss_a JOIN pgss_b ON pgss_b.a_id = pgss_a.id FOR NO KEY UPDATE;
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SELECT * FROM pgss_a JOIN pgss_b ON pgss_b.a_id = pgss_a.id FOR SHARE;
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SELECT * FROM pgss_a JOIN pgss_b ON pgss_b.a_id = pgss_a.id FOR KEY SHARE;
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-- test wait policies
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SELECT * FROM pgss_a JOIN pgss_b ON pgss_b.a_id = pgss_a.id FOR UPDATE NOWAIT;
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SELECT * FROM pgss_a JOIN pgss_b ON pgss_b.a_id = pgss_a.id FOR UPDATE SKIP LOCKED;
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SELECT calls, query FROM pg_stat_statements ORDER BY query COLLATE "C";
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DROP TABLE pgss_a, pgss_b CASCADE;
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--
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-- utility commands
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--
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SET pg_stat_statements.track_utility = TRUE;
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SELECT pg_stat_statements_reset();
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SELECT 1;
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CREATE INDEX test_b ON test(b);
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DROP TABLE test \;
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DROP TABLE IF EXISTS test \;
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DROP FUNCTION PLUS_ONE(INTEGER);
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DROP TABLE IF EXISTS test \;
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DROP TABLE IF EXISTS test \;
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DROP FUNCTION IF EXISTS PLUS_ONE(INTEGER);
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DROP FUNCTION PLUS_TWO(INTEGER);
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SELECT query, calls, rows FROM pg_stat_statements ORDER BY query COLLATE "C";
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--
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-- Track the total number of rows retrieved or affected by the utility
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-- commands of COPY, FETCH, CREATE TABLE AS, CREATE MATERIALIZED VIEW,
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-- REFRESH MATERIALIZED VIEW and SELECT INTO
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--
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SELECT pg_stat_statements_reset();
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CREATE TABLE pgss_ctas AS SELECT a, 'ctas' b FROM generate_series(1, 10) a;
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SELECT generate_series(1, 10) c INTO pgss_select_into;
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COPY pgss_ctas (a, b) FROM STDIN;
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11 copy
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12 copy
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13 copy
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\.
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CREATE MATERIALIZED VIEW pgss_matv AS SELECT * FROM pgss_ctas;
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REFRESH MATERIALIZED VIEW pgss_matv;
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BEGIN;
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DECLARE pgss_cursor CURSOR FOR SELECT * FROM pgss_matv;
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FETCH NEXT pgss_cursor;
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FETCH FORWARD 5 pgss_cursor;
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FETCH FORWARD ALL pgss_cursor;
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COMMIT;
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SELECT query, plans, calls, rows FROM pg_stat_statements ORDER BY query COLLATE "C";
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--
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-- Track user activity and reset them
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--
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SELECT pg_stat_statements_reset();
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CREATE ROLE regress_stats_user1;
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CREATE ROLE regress_stats_user2;
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SET ROLE regress_stats_user1;
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SELECT 1 AS "ONE";
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SELECT 1+1 AS "TWO";
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RESET ROLE;
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SET ROLE regress_stats_user2;
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SELECT 1 AS "ONE";
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SELECT 1+1 AS "TWO";
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RESET ROLE;
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SELECT query, calls, rows FROM pg_stat_statements ORDER BY query COLLATE "C";
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--
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-- Don't reset anything if any of the parameter is NULL
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--
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SELECT pg_stat_statements_reset(NULL);
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SELECT query, calls, rows FROM pg_stat_statements ORDER BY query COLLATE "C";
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--
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-- remove query ('SELECT $1+$2 AS "TWO"') executed by regress_stats_user2
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-- in the current_database
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--
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SELECT pg_stat_statements_reset(
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(SELECT r.oid FROM pg_roles AS r WHERE r.rolname = 'regress_stats_user2'),
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(SELECT d.oid FROM pg_database As d where datname = current_database()),
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(SELECT s.queryid FROM pg_stat_statements AS s
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WHERE s.query = 'SELECT $1+$2 AS "TWO"' LIMIT 1));
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SELECT query, calls, rows FROM pg_stat_statements ORDER BY query COLLATE "C";
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--
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-- remove query ('SELECT $1 AS "ONE"') executed by two users
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--
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SELECT pg_stat_statements_reset(0,0,s.queryid)
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FROM pg_stat_statements AS s WHERE s.query = 'SELECT $1 AS "ONE"';
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SELECT query, calls, rows FROM pg_stat_statements ORDER BY query COLLATE "C";
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--
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-- remove query of a user (regress_stats_user1)
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--
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SELECT pg_stat_statements_reset(r.oid)
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FROM pg_roles AS r WHERE r.rolname = 'regress_stats_user1';
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SELECT query, calls, rows FROM pg_stat_statements ORDER BY query COLLATE "C";
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--
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-- reset all
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--
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SELECT pg_stat_statements_reset(0,0,0);
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SELECT query, calls, rows FROM pg_stat_statements ORDER BY query COLLATE "C";
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--
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-- cleanup
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--
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DROP ROLE regress_stats_user1;
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DROP ROLE regress_stats_user2;
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DROP MATERIALIZED VIEW pgss_matv;
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DROP TABLE pgss_ctas;
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DROP TABLE pgss_select_into;
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--
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-- [re]plan counting
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--
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SELECT pg_stat_statements_reset();
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CREATE TABLE test ();
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PREPARE prep1 AS SELECT COUNT(*) FROM test;
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EXECUTE prep1;
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EXECUTE prep1;
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EXECUTE prep1;
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ALTER TABLE test ADD COLUMN x int;
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EXECUTE prep1;
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SELECT 42;
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SELECT 42;
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SELECT 42;
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SELECT query, plans, calls, rows FROM pg_stat_statements ORDER BY query COLLATE "C";
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--
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-- access to pg_stat_statements_info view
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--
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SELECT pg_stat_statements_reset();
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SELECT dealloc FROM pg_stat_statements_info;
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DROP EXTENSION pg_stat_statements;
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