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postgres/contrib/pg_stat_statements/sql/level_tracking.sql
Michael Paquier 06450c7b8c Fix regression with location calculation of nested statements
The statement location calculated for some nested query cases was wrong
when multiple queries are sent as a single string, these being separated
by semicolons.  As pointed by Sami Imseih, the location calculation was
incorrect when the last query of nested statement with multiple queries
does **NOT** finish with a semicolon for the last statement.  In this
case, the statement length tracked by RawStmt is 0, which is equivalent
to say that the string should be used until its end.  The code
previously discarded this case entirely, causing the location to remain
at 0, the same as pointing at the beginning of the string.  This caused
pg_stat_statements to store incorrect query strings.

This issue has been introduced in 499edb09741b.  I have looked at the
diffs generated by pgaudit back then, and noticed the difference
generated for this nested query case, but I have missed the point that
it was an actual regression with an existing case.  A test case is added
in pg_stat_statements to provide some coverage, restoring the pre-17
behavior for the calculation of the query locations.  Special thanks to
David Steele, who, through an analysis of the test diffs generated by
pgaudit with the new v18 logic, has poked me about the fact that my
original analysis of the matter was wrong.

The test output of pg_overexplain is updated to reflect the new logic,
as the new locations refer to the beginning of the argument passed to
the function explain_filter().  When the module was introduced in
8d5ceb113e3f, which was after 499edb09741b (for the new calculation
method), the locations of the test were not actually right: the plan
generated for the query string given in input of the function pointed to
the top-level query, not the nested one.

Reported-by: David Steele <david@pgbackrest.org>
Author: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Anthonin Bonnefoy <anthonin.bonnefoy@datadoghq.com>
Reviewed-by: Jian He <jian.universality@gmail.com>
Reviewed-by: Sami Imseih <samimseih@gmail.com>
Reviewed-by: David Steele <david@pgbackrest.org>
Discussion: https://postgr.es/m/844a3b38-bbf1-4fb2-9fd6-f58c35c09917@pgbackrest.org
2025-05-21 10:22:12 +09:00

446 lines
17 KiB
PL/PgSQL

--
-- Statement level tracking
--
SET pg_stat_statements.track_utility = TRUE;
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
-- DO block - top-level tracking.
CREATE TABLE stats_track_tab (x int);
SET pg_stat_statements.track = 'top';
DELETE FROM stats_track_tab;
DO $$
BEGIN
DELETE FROM stats_track_tab;
END;
$$ LANGUAGE plpgsql;
SELECT toplevel, calls, query FROM pg_stat_statements
WHERE query LIKE '%DELETE%' ORDER BY query COLLATE "C", toplevel;
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
-- DO block - all-level tracking.
SET pg_stat_statements.track = 'all';
DELETE FROM stats_track_tab;
DO $$
BEGIN
DELETE FROM stats_track_tab;
END; $$;
DO LANGUAGE plpgsql $$
BEGIN
-- this is a SELECT
PERFORM 'hello world'::TEXT;
END; $$;
SELECT toplevel, calls, query FROM pg_stat_statements
ORDER BY query COLLATE "C", toplevel;
-- Procedure with multiple utility statements.
CREATE OR REPLACE PROCEDURE proc_with_utility_stmt()
LANGUAGE SQL
AS $$
SHOW pg_stat_statements.track;
show pg_stat_statements.track;
SHOW pg_stat_statements.track_utility;
$$;
SET pg_stat_statements.track_utility = TRUE;
-- all-level tracking.
SET pg_stat_statements.track = 'all';
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
CALL proc_with_utility_stmt();
SELECT toplevel, calls, query FROM pg_stat_statements
ORDER BY query COLLATE "C", toplevel;
-- top-level tracking.
SET pg_stat_statements.track = 'top';
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
CALL proc_with_utility_stmt();
SELECT toplevel, calls, query FROM pg_stat_statements
ORDER BY query COLLATE "C", toplevel;
-- EXPLAIN - all-level tracking.
CREATE TABLE test_table (x int);
SET pg_stat_statements.track = 'all';
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
EXPLAIN (COSTS OFF) SELECT 1;
EXPLAIN (COSTS OFF) (SELECT 1, 2);
EXPLAIN (COSTS OFF) TABLE stats_track_tab;
EXPLAIN (COSTS OFF) (TABLE test_table);
EXPLAIN (COSTS OFF) VALUES (1);
EXPLAIN (COSTS OFF) (VALUES (1, 2));
EXPLAIN (COSTS OFF) UPDATE stats_track_tab SET x = 1 WHERE x = 1;
EXPLAIN (COSTS OFF) DELETE FROM stats_track_tab;
EXPLAIN (COSTS OFF) INSERT INTO stats_track_tab VALUES ((1));
EXPLAIN (COSTS OFF) MERGE INTO stats_track_tab
USING (SELECT id FROM generate_series(1, 10) id) ON x = id
WHEN MATCHED THEN UPDATE SET x = id
WHEN NOT MATCHED THEN INSERT (x) VALUES (id);
EXPLAIN (COSTS OFF) SELECT 1 UNION SELECT 2;
SELECT toplevel, calls, query FROM pg_stat_statements
ORDER BY query COLLATE "C";
-- EXPLAIN - top-level tracking.
SET pg_stat_statements.track = 'top';
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
EXPLAIN (COSTS OFF) SELECT 1;
EXPLAIN (COSTS OFF) (SELECT 1, 2);
EXPLAIN (COSTS OFF) TABLE stats_track_tab;
EXPLAIN (COSTS OFF) (TABLE test_table);
EXPLAIN (COSTS OFF) VALUES (1);
EXPLAIN (COSTS OFF) (VALUES (1, 2));
EXPLAIN (COSTS OFF) UPDATE stats_track_tab SET x = 1 WHERE x = 1;
EXPLAIN (COSTS OFF) DELETE FROM stats_track_tab;
EXPLAIN (COSTS OFF) INSERT INTO stats_track_tab VALUES ((1));
EXPLAIN (COSTS OFF) MERGE INTO stats_track_tab
USING (SELECT id FROM generate_series(1, 10) id) ON x = id
WHEN MATCHED THEN UPDATE SET x = id
WHEN NOT MATCHED THEN INSERT (x) VALUES (id);
EXPLAIN (COSTS OFF) SELECT 1 UNION SELECT 2;
SELECT toplevel, calls, query FROM pg_stat_statements
ORDER BY query COLLATE "C";
-- EXPLAIN - all-level tracking with multi-statement strings.
SET pg_stat_statements.track = 'all';
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
-- SELECT queries
EXPLAIN (COSTS OFF) SELECT 1\; EXPLAIN (COSTS OFF) SELECT 1, 2;
EXPLAIN (COSTS OFF) (SELECT 1, 2, 3)\; EXPLAIN (COSTS OFF) (SELECT 1, 2, 3, 4);
EXPLAIN (COSTS OFF) SELECT 1, 2 UNION SELECT 3, 4\; EXPLAIN (COSTS OFF) (SELECT 1, 2, 3) UNION SELECT 3, 4, 5;
SELECT toplevel, calls, query FROM pg_stat_statements
ORDER BY query COLLATE "C";
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
-- Most DMLs
EXPLAIN (COSTS OFF) TABLE stats_track_tab\; EXPLAIN (COSTS OFF) (TABLE test_table);
EXPLAIN (COSTS OFF) VALUES (1)\; EXPLAIN (COSTS OFF) (VALUES (1, 2));
EXPLAIN (COSTS OFF) UPDATE stats_track_tab SET x = 1 WHERE x = 1\; EXPLAIN (COSTS OFF) UPDATE stats_track_tab SET x = 1;
EXPLAIN (COSTS OFF) DELETE FROM stats_track_tab\; EXPLAIN (COSTS OFF) DELETE FROM stats_track_tab WHERE x = 1;
EXPLAIN (COSTS OFF) INSERT INTO stats_track_tab VALUES ((1))\; EXPLAIN (COSTS OFF) INSERT INTO stats_track_tab VALUES (1), (2);
SELECT toplevel, calls, query FROM pg_stat_statements
ORDER BY query COLLATE "C";
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
-- MERGE, worth its own.
EXPLAIN (COSTS OFF) MERGE INTO stats_track_tab
USING (SELECT id FROM generate_series(1, 10) id) ON x = id
WHEN MATCHED THEN UPDATE SET x = id
WHEN NOT MATCHED THEN INSERT (x) VALUES (id)\; EXPLAIN (COSTS OFF) SELECT 1, 2, 3, 4, 5;
SELECT toplevel, calls, query FROM pg_stat_statements
ORDER BY query COLLATE "C";
-- EXPLAIN - top-level tracking with multi-statement strings.
SET pg_stat_statements.track = 'top';
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
EXPLAIN (COSTS OFF) SELECT 1\; EXPLAIN (COSTS OFF) SELECT 1, 2;
EXPLAIN (COSTS OFF) (SELECT 1, 2, 3)\; EXPLAIN (COSTS OFF) (SELECT 1, 2, 3, 4);
EXPLAIN (COSTS OFF) TABLE stats_track_tab\; EXPLAIN (COSTS OFF) (TABLE test_table);
EXPLAIN (COSTS OFF) VALUES (1)\; EXPLAIN (COSTS OFF) (VALUES (1, 2));
EXPLAIN (COSTS OFF) UPDATE stats_track_tab SET x = 1 WHERE x = 1\; EXPLAIN (COSTS OFF) UPDATE stats_track_tab SET x = 1;
EXPLAIN (COSTS OFF) DELETE FROM stats_track_tab\; EXPLAIN (COSTS OFF) DELETE FROM stats_track_tab WHERE x = 1;
EXPLAIN (COSTS OFF) INSERT INTO stats_track_tab VALUES ((1))\; EXPLAIN (COSTS OFF) INSERT INTO stats_track_tab VALUES ((1), (2));
EXPLAIN (COSTS OFF) MERGE INTO stats_track_tab USING (SELECT id FROM generate_series(1, 10) id) ON x = id
WHEN MATCHED THEN UPDATE SET x = id
WHEN NOT MATCHED THEN INSERT (x) VALUES (id)\; EXPLAIN (COSTS OFF) SELECT 1, 2, 3, 4, 5;
EXPLAIN (COSTS OFF) SELECT 1, 2 UNION SELECT 3, 4\; EXPLAIN (COSTS OFF) (SELECT 1, 2, 3) UNION SELECT 3, 4, 5;
SELECT toplevel, calls, query FROM pg_stat_statements
ORDER BY query COLLATE "C";
-- EXPLAIN with CTEs - all-level tracking
SET pg_stat_statements.track = 'all';
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
EXPLAIN (COSTS OFF) WITH a AS (SELECT 4) SELECT 1;
EXPLAIN (COSTS OFF) (WITH a AS (SELECT 4) (SELECT 1, 2));
EXPLAIN (COSTS OFF) WITH a AS (SELECT 4) UPDATE stats_track_tab SET x = 1 WHERE x = 1;
EXPLAIN (COSTS OFF) WITH a AS (SELECT 4) DELETE FROM stats_track_tab;
EXPLAIN (COSTS OFF) WITH a AS (SELECT 4) INSERT INTO stats_track_tab VALUES ((1));
EXPLAIN (COSTS OFF) WITH a AS (SELECT 4) MERGE INTO stats_track_tab
USING (SELECT id FROM generate_series(1, 10) id) ON x = id
WHEN MATCHED THEN UPDATE SET x = id
WHEN NOT MATCHED THEN INSERT (x) VALUES (id);
EXPLAIN (COSTS OFF) WITH a AS (select 4) SELECT 1 UNION SELECT 2;
SELECT toplevel, calls, query FROM pg_stat_statements
ORDER BY query COLLATE "C";
-- EXPLAIN with CTEs - top-level tracking
SET pg_stat_statements.track = 'top';
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
EXPLAIN (COSTS OFF) WITH a AS (SELECT 4) SELECT 1;
EXPLAIN (COSTS OFF) (WITH a AS (SELECT 4) (SELECT 1, 2));
EXPLAIN (COSTS OFF) WITH a AS (SELECT 4) UPDATE stats_track_tab SET x = 1 WHERE x = 1;
EXPLAIN (COSTS OFF) WITH a AS (SELECT 4) DELETE FROM stats_track_tab;
EXPLAIN (COSTS OFF) WITH a AS (SELECT 4) INSERT INTO stats_track_tab VALUES ((1));
EXPLAIN (COSTS OFF) WITH a AS (SELECT 4) MERGE INTO stats_track_tab
USING (SELECT id FROM generate_series(1, 10) id) ON x = id
WHEN MATCHED THEN UPDATE SET x = id
WHEN NOT MATCHED THEN INSERT (x) VALUES (id);
EXPLAIN (COSTS OFF) WITH a AS (select 4) SELECT 1 UNION SELECT 2;
SELECT toplevel, calls, query FROM pg_stat_statements
ORDER BY query COLLATE "C";
-- Explain analyze, all-level tracking.
SET pg_stat_statements.track = 'all';
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
EXPLAIN (ANALYZE, COSTS OFF, SUMMARY OFF, TIMING OFF, BUFFERS OFF) SELECT 100;
EXPLAIN (ANALYZE, COSTS OFF, SUMMARY OFF, TIMING OFF, BUFFERS OFF)
DECLARE foocur CURSOR FOR SELECT * FROM stats_track_tab;
SELECT toplevel, calls, query FROM pg_stat_statements
ORDER BY query COLLATE "C";
-- Explain analyze, top tracking.
SET pg_stat_statements.track = 'top';
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
EXPLAIN (ANALYZE, COSTS OFF, SUMMARY OFF, TIMING OFF, BUFFERS OFF) SELECT 100;
EXPLAIN (ANALYZE, COSTS OFF, SUMMARY OFF, TIMING OFF, BUFFERS OFF)
DECLARE foocur CURSOR FOR SELECT * FROM stats_track_tab;
SELECT toplevel, calls, query FROM pg_stat_statements
ORDER BY query COLLATE "C";
-- Create Materialized View, all-level tracking.
SET pg_stat_statements.track = 'all';
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
CREATE MATERIALIZED VIEW pgss_materialized_view AS
SELECT * FROM generate_series(1, 5) as id;
SELECT toplevel, calls, query FROM pg_stat_statements
ORDER BY query COLLATE "C";
-- CREATE MATERIALIZED VIEW, top-level tracking.
SET pg_stat_statements.track = 'top';
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
CREATE MATERIALIZED VIEW pgss_materialized_view_2 AS
SELECT * FROM generate_series(1, 5) as id;
SELECT toplevel, calls, query FROM pg_stat_statements
ORDER BY query COLLATE "C";
-- REFRESH MATERIALIZED VIEW, all-level tracking.
SET pg_stat_statements.track = 'all';
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
REFRESH MATERIALIZED VIEW pgss_materialized_view;
SELECT toplevel, calls, query FROM pg_stat_statements
ORDER BY query COLLATE "C";
-- REFRESH MATERIALIZED VIEW, top-level tracking.
SET pg_stat_statements.track = 'top';
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
REFRESH MATERIALIZED VIEW pgss_materialized_view;
SELECT toplevel, calls, query FROM pg_stat_statements
ORDER BY query COLLATE "C";
-- CREATE TABLE AS, all-level tracking.
SET pg_stat_statements.track = 'all';
PREPARE test_prepare_pgss AS select generate_series(1, 10);
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
CREATE TEMPORARY TABLE pgss_ctas_1 AS SELECT 1;
CREATE TEMPORARY TABLE pgss_ctas_2 AS EXECUTE test_prepare_pgss;
SELECT toplevel, calls, query FROM pg_stat_statements
ORDER BY query COLLATE "C";
-- CREATE TABLE AS, top-level tracking.
SET pg_stat_statements.track = 'top';
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
CREATE TEMPORARY TABLE pgss_ctas_3 AS SELECT 1;
CREATE TEMPORARY TABLE pgss_ctas_4 AS EXECUTE test_prepare_pgss;
SELECT toplevel, calls, query FROM pg_stat_statements
ORDER BY query COLLATE "C";
-- EXPLAIN with CREATE TABLE AS - all-level tracking.
SET pg_stat_statements.track = 'all';
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
EXPLAIN (COSTS OFF) CREATE TEMPORARY TABLE pgss_explain_ctas AS SELECT 1;
SELECT toplevel, calls, query FROM pg_stat_statements
ORDER BY query COLLATE "C";
-- EXPLAIN with CREATE TABLE AS - top-level tracking.
SET pg_stat_statements.track = 'top';
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
EXPLAIN (COSTS OFF) CREATE TEMPORARY TABLE pgss_explain_ctas AS SELECT 1;
SELECT toplevel, calls, query FROM pg_stat_statements
ORDER BY query COLLATE "C";
-- DECLARE CURSOR, all-level tracking.
SET pg_stat_statements.track = 'all';
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
BEGIN;
DECLARE FOOCUR CURSOR FOR SELECT * from stats_track_tab;
FETCH FORWARD 1 FROM foocur;
CLOSE foocur;
COMMIT;
SELECT toplevel, calls, query FROM pg_stat_statements
ORDER BY query COLLATE "C";
-- DECLARE CURSOR, top-level tracking.
SET pg_stat_statements.track = 'top';
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
BEGIN;
DECLARE FOOCUR CURSOR FOR SELECT * FROM stats_track_tab;
FETCH FORWARD 1 FROM foocur;
CLOSE foocur;
COMMIT;
SELECT toplevel, calls, query FROM pg_stat_statements
ORDER BY query COLLATE "C";
-- COPY - all-level tracking.
SET pg_stat_statements.track = 'all';
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
COPY (SELECT 1) TO stdout;
COPY (SELECT 1 UNION SELECT 2) TO stdout;
COPY (MERGE INTO stats_track_tab USING (SELECT 1 id) ON x = id
WHEN MATCHED THEN UPDATE SET x = id
WHEN NOT MATCHED THEN INSERT (x) VALUES (id) RETURNING x) TO stdout;
COPY (INSERT INTO stats_track_tab (x) VALUES (1) RETURNING x) TO stdout;
COPY (UPDATE stats_track_tab SET x = 2 WHERE x = 1 RETURNING x) TO stdout;
COPY (DELETE FROM stats_track_tab WHERE x = 2 RETURNING x) TO stdout;
SELECT toplevel, calls, query FROM pg_stat_statements
ORDER BY query COLLATE "C";
-- COPY - top-level tracking.
SET pg_stat_statements.track = 'top';
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
COPY (SELECT 1) TO stdout;
COPY (SELECT 1 UNION SELECT 2) TO stdout;
COPY (MERGE INTO stats_track_tab USING (SELECT 1 id) ON x = id
WHEN MATCHED THEN UPDATE SET x = id
WHEN NOT MATCHED THEN INSERT (x) VALUES (id) RETURNING x) TO stdout;
COPY (INSERT INTO stats_track_tab (x) VALUES (1) RETURNING x) TO stdout;
COPY (UPDATE stats_track_tab SET x = 2 WHERE x = 1 RETURNING x) TO stdout;
COPY (DELETE FROM stats_track_tab WHERE x = 2 RETURNING x) TO stdout;
SELECT toplevel, calls, query FROM pg_stat_statements
ORDER BY query COLLATE "C";
-- DO block - top-level tracking without utility.
SET pg_stat_statements.track = 'top';
SET pg_stat_statements.track_utility = FALSE;
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
DELETE FROM stats_track_tab;
DO $$
BEGIN
DELETE FROM stats_track_tab;
END; $$;
DO LANGUAGE plpgsql $$
BEGIN
-- this is a SELECT
PERFORM 'hello world'::TEXT;
END; $$;
SELECT toplevel, calls, query FROM pg_stat_statements
ORDER BY query COLLATE "C", toplevel;
-- DO block - all-level tracking without utility.
SET pg_stat_statements.track = 'all';
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
DELETE FROM stats_track_tab;
DO $$
BEGIN
DELETE FROM stats_track_tab;
END; $$;
DO LANGUAGE plpgsql $$
BEGIN
-- this is a SELECT
PERFORM 'hello world'::TEXT;
END; $$;
SELECT toplevel, calls, query FROM pg_stat_statements
ORDER BY query COLLATE "C", toplevel;
-- DO block --- multiple inner queries with separators
SET pg_stat_statements.track = 'all';
SET pg_stat_statements.track_utility = TRUE;
CREATE TABLE pgss_do_util_tab_1 (a int);
CREATE TABLE pgss_do_util_tab_2 (a int);
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
DO $$
DECLARE BEGIN
EXECUTE 'CREATE TABLE pgss_do_table (id INT); DROP TABLE pgss_do_table';
EXECUTE 'SELECT a FROM pgss_do_util_tab_1; SELECT a FROM pgss_do_util_tab_2';
END $$;
SELECT toplevel, calls, rows, query FROM pg_stat_statements
WHERE toplevel IS FALSE
ORDER BY query COLLATE "C";
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
-- Note the extra semicolon at the end of the query.
DO $$
DECLARE BEGIN
EXECUTE 'CREATE TABLE pgss_do_table (id INT); DROP TABLE pgss_do_table;';
EXECUTE 'SELECT a FROM pgss_do_util_tab_1; SELECT a FROM pgss_do_util_tab_2;';
END $$;
SELECT toplevel, calls, rows, query FROM pg_stat_statements
WHERE toplevel IS FALSE
ORDER BY query COLLATE "C";
DROP TABLE pgss_do_util_tab_1, pgss_do_util_tab_2;
-- PL/pgSQL function - top-level tracking.
SET pg_stat_statements.track = 'top';
SET pg_stat_statements.track_utility = FALSE;
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
CREATE FUNCTION PLUS_TWO(i INTEGER) RETURNS INTEGER AS $$
DECLARE
r INTEGER;
BEGIN
SELECT (i + 1 + 1.0)::INTEGER INTO r;
RETURN r;
END; $$ LANGUAGE plpgsql;
SELECT PLUS_TWO(3);
SELECT PLUS_TWO(7);
-- SQL function --- use LIMIT to keep it from being inlined
CREATE FUNCTION PLUS_ONE(i INTEGER) RETURNS INTEGER AS
$$ SELECT (i + 1.0)::INTEGER LIMIT 1 $$ LANGUAGE SQL;
SELECT PLUS_ONE(8);
SELECT PLUS_ONE(10);
SELECT calls, rows, query FROM pg_stat_statements ORDER BY query COLLATE "C";
-- immutable SQL function --- can be executed at plan time
CREATE FUNCTION PLUS_THREE(i INTEGER) RETURNS INTEGER AS
$$ SELECT i + 3 LIMIT 1 $$ IMMUTABLE LANGUAGE SQL;
SELECT PLUS_THREE(8);
SELECT PLUS_THREE(10);
SELECT toplevel, calls, rows, query FROM pg_stat_statements ORDER BY query COLLATE "C";
-- PL/pgSQL function - all-level tracking.
SET pg_stat_statements.track = 'all';
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
-- we drop and recreate the functions to avoid any caching funnies
DROP FUNCTION PLUS_ONE(INTEGER);
DROP FUNCTION PLUS_TWO(INTEGER);
DROP FUNCTION PLUS_THREE(INTEGER);
-- PL/pgSQL function
CREATE FUNCTION PLUS_TWO(i INTEGER) RETURNS INTEGER AS $$
DECLARE
r INTEGER;
BEGIN
SELECT (i + 1 + 1.0)::INTEGER INTO r;
RETURN r;
END; $$ LANGUAGE plpgsql;
SELECT PLUS_TWO(-1);
SELECT PLUS_TWO(2);
-- SQL function --- use LIMIT to keep it from being inlined
CREATE FUNCTION PLUS_ONE(i INTEGER) RETURNS INTEGER AS
$$ SELECT (i + 1.0)::INTEGER LIMIT 1 $$ LANGUAGE SQL;
SELECT PLUS_ONE(3);
SELECT PLUS_ONE(1);
SELECT calls, rows, query FROM pg_stat_statements ORDER BY query COLLATE "C";
-- immutable SQL function --- can be executed at plan time
CREATE FUNCTION PLUS_THREE(i INTEGER) RETURNS INTEGER AS
$$ SELECT i + 3 LIMIT 1 $$ IMMUTABLE LANGUAGE SQL;
SELECT PLUS_THREE(8);
SELECT PLUS_THREE(10);
SELECT toplevel, calls, rows, query FROM pg_stat_statements ORDER BY query COLLATE "C";
--
-- pg_stat_statements.track = none
--
SET pg_stat_statements.track = 'none';
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
SELECT 1 AS "one";
SELECT 1 + 1 AS "two";
SELECT calls, rows, query FROM pg_stat_statements ORDER BY query COLLATE "C";
SELECT pg_stat_statements_reset() IS NOT NULL AS t;