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postgresql/src/test/regress/expected/stats_ext.out

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-- Generic extended statistics support
--
-- Note: tables for which we check estimated row counts should be created
-- with autovacuum_enabled = off, so that we don't have unstable results
-- from auto-analyze happening when we didn't expect it.
--
-- check the number of estimated/actual rows in the top node
create function check_estimated_rows(text) returns table (estimated int, actual int)
language plpgsql as
$$
declare
ln text;
tmp text[];
first_row bool := true;
begin
for ln in
execute format('explain analyze %s', $1)
loop
if first_row then
first_row := false;
tmp := regexp_match(ln, 'rows=(\d*) .* rows=(\d*)');
return query select tmp[1]::int, tmp[2]::int;
end if;
end loop;
end;
$$;
-- Verify failures
CREATE TABLE ext_stats_test (x text, y int, z int);
CREATE STATISTICS tst;
ERROR: syntax error at or near ";"
LINE 1: CREATE STATISTICS tst;
^
CREATE STATISTICS tst ON a, b;
ERROR: syntax error at or near ";"
LINE 1: CREATE STATISTICS tst ON a, b;
^
CREATE STATISTICS tst FROM sometab;
ERROR: syntax error at or near "FROM"
LINE 1: CREATE STATISTICS tst FROM sometab;
^
CREATE STATISTICS tst ON a, b FROM nonexistent;
ERROR: relation "nonexistent" does not exist
CREATE STATISTICS tst ON a, b FROM ext_stats_test;
ERROR: column "a" does not exist
CREATE STATISTICS tst ON x, x, y FROM ext_stats_test;
ERROR: duplicate column name in statistics definition
CREATE STATISTICS tst ON x, x, y, x, x, y, x, x, y FROM ext_stats_test;
ERROR: cannot have more than 8 columns in statistics
CREATE STATISTICS tst ON x, x, y, x, x, (x || 'x'), (y + 1), (x || 'x'), (x || 'x'), (y + 1) FROM ext_stats_test;
ERROR: cannot have more than 8 columns in statistics
CREATE STATISTICS tst ON (x || 'x'), (x || 'x'), (y + 1), (x || 'x'), (x || 'x'), (y + 1), (x || 'x'), (x || 'x'), (y + 1) FROM ext_stats_test;
ERROR: cannot have more than 8 columns in statistics
CREATE STATISTICS tst ON (x || 'x'), (x || 'x'), y FROM ext_stats_test;
ERROR: duplicate expression in statistics definition
CREATE STATISTICS tst (unrecognized) ON x, y FROM ext_stats_test;
ERROR: unrecognized statistics kind "unrecognized"
-- incorrect expressions
CREATE STATISTICS tst ON (y) FROM ext_stats_test; -- single column reference
ERROR: extended statistics require at least 2 columns
CREATE STATISTICS tst ON y + z FROM ext_stats_test; -- missing parentheses
ERROR: syntax error at or near "+"
LINE 1: CREATE STATISTICS tst ON y + z FROM ext_stats_test;
^
CREATE STATISTICS tst ON (x, y) FROM ext_stats_test; -- tuple expression
ERROR: syntax error at or near ","
LINE 1: CREATE STATISTICS tst ON (x, y) FROM ext_stats_test;
^
DROP TABLE ext_stats_test;
-- Ensure stats are dropped sanely, and test IF NOT EXISTS while at it
CREATE TABLE ab1 (a INTEGER, b INTEGER, c INTEGER);
CREATE STATISTICS IF NOT EXISTS ab1_a_b_stats ON a, b FROM ab1;
COMMENT ON STATISTICS ab1_a_b_stats IS 'new comment';
CREATE ROLE regress_stats_ext;
SET SESSION AUTHORIZATION regress_stats_ext;
COMMENT ON STATISTICS ab1_a_b_stats IS 'changed comment';
ERROR: must be owner of statistics object ab1_a_b_stats
DROP STATISTICS ab1_a_b_stats;
ERROR: must be owner of statistics object ab1_a_b_stats
ALTER STATISTICS ab1_a_b_stats RENAME TO ab1_a_b_stats_new;
ERROR: must be owner of statistics object ab1_a_b_stats
RESET SESSION AUTHORIZATION;
DROP ROLE regress_stats_ext;
CREATE STATISTICS IF NOT EXISTS ab1_a_b_stats ON a, b FROM ab1;
NOTICE: statistics object "ab1_a_b_stats" already exists, skipping
DROP STATISTICS ab1_a_b_stats;
CREATE SCHEMA regress_schema_2;
CREATE STATISTICS regress_schema_2.ab1_a_b_stats ON a, b FROM ab1;
-- Let's also verify the pg_get_statisticsobjdef output looks sane.
SELECT pg_get_statisticsobjdef(oid) FROM pg_statistic_ext WHERE stxname = 'ab1_a_b_stats';
pg_get_statisticsobjdef
-------------------------------------------------------------------
CREATE STATISTICS regress_schema_2.ab1_a_b_stats ON a, b FROM ab1
(1 row)
DROP STATISTICS regress_schema_2.ab1_a_b_stats;
-- Ensure statistics are dropped when columns are
CREATE STATISTICS ab1_b_c_stats ON b, c FROM ab1;
CREATE STATISTICS ab1_a_b_c_stats ON a, b, c FROM ab1;
CREATE STATISTICS ab1_b_a_stats ON b, a FROM ab1;
ALTER TABLE ab1 DROP COLUMN a;
\d ab1
Table "public.ab1"
Column | Type | Collation | Nullable | Default
--------+---------+-----------+----------+---------
b | integer | | |
c | integer | | |
Statistics objects:
"public.ab1_b_c_stats" ON b, c FROM ab1
-- Ensure statistics are dropped when table is
SELECT stxname FROM pg_statistic_ext WHERE stxname LIKE 'ab1%';
stxname
---------------
ab1_b_c_stats
(1 row)
DROP TABLE ab1;
SELECT stxname FROM pg_statistic_ext WHERE stxname LIKE 'ab1%';
stxname
---------
(0 rows)
-- Ensure things work sanely with SET STATISTICS 0
CREATE TABLE ab1 (a INTEGER, b INTEGER);
ALTER TABLE ab1 ALTER a SET STATISTICS 0;
INSERT INTO ab1 SELECT a, a%23 FROM generate_series(1, 1000) a;
CREATE STATISTICS ab1_a_b_stats ON a, b FROM ab1;
ANALYZE ab1;
WARNING: statistics object "public.ab1_a_b_stats" could not be computed for relation "public.ab1"
ALTER TABLE ab1 ALTER a SET STATISTICS -1;
-- setting statistics target 0 skips the statistics, without printing any message, so check catalog
ALTER STATISTICS ab1_a_b_stats SET STATISTICS 0;
\d ab1
Table "public.ab1"
Column | Type | Collation | Nullable | Default
--------+---------+-----------+----------+---------
a | integer | | |
b | integer | | |
Statistics objects:
"public.ab1_a_b_stats" ON a, b FROM ab1; STATISTICS 0
ANALYZE ab1;
SELECT stxname, stxdndistinct, stxddependencies, stxdmcv, stxdinherit
FROM pg_statistic_ext s LEFT JOIN pg_statistic_ext_data d ON (d.stxoid = s.oid)
WHERE s.stxname = 'ab1_a_b_stats';
stxname | stxdndistinct | stxddependencies | stxdmcv | stxdinherit
---------------+---------------+------------------+---------+-------------
ab1_a_b_stats | | | |
(1 row)
ALTER STATISTICS ab1_a_b_stats SET STATISTICS -1;
\d+ ab1
Table "public.ab1"
Column | Type | Collation | Nullable | Default | Storage | Stats target | Description
--------+---------+-----------+----------+---------+---------+--------------+-------------
a | integer | | | | plain | |
b | integer | | | | plain | |
Statistics objects:
"public.ab1_a_b_stats" ON a, b FROM ab1
-- partial analyze doesn't build stats either
ANALYZE ab1 (a);
WARNING: statistics object "public.ab1_a_b_stats" could not be computed for relation "public.ab1"
ANALYZE ab1;
DROP TABLE ab1;
ALTER STATISTICS ab1_a_b_stats SET STATISTICS 0;
ERROR: statistics object "ab1_a_b_stats" does not exist
ALTER STATISTICS IF EXISTS ab1_a_b_stats SET STATISTICS 0;
NOTICE: statistics object "ab1_a_b_stats" does not exist, skipping
-- Ensure we can build statistics for tables with inheritance.
CREATE TABLE ab1 (a INTEGER, b INTEGER);
CREATE TABLE ab1c () INHERITS (ab1);
INSERT INTO ab1 VALUES (1,1);
CREATE STATISTICS ab1_a_b_stats ON a, b FROM ab1;
ANALYZE ab1;
DROP TABLE ab1 CASCADE;
NOTICE: drop cascades to table ab1c
-- Tests for stats with inheritance
CREATE TABLE stxdinh(a int, b int);
CREATE TABLE stxdinh1() INHERITS(stxdinh);
CREATE TABLE stxdinh2() INHERITS(stxdinh);
INSERT INTO stxdinh SELECT mod(a,50), mod(a,100) FROM generate_series(0, 1999) a;
INSERT INTO stxdinh1 SELECT mod(a,100), mod(a,100) FROM generate_series(0, 999) a;
INSERT INTO stxdinh2 SELECT mod(a,100), mod(a,100) FROM generate_series(0, 999) a;
VACUUM ANALYZE stxdinh, stxdinh1, stxdinh2;
-- Ensure non-inherited stats are not applied to inherited query
-- Without stats object, it looks like this
SELECT * FROM check_estimated_rows('SELECT a, b FROM stxdinh* GROUP BY 1, 2');
estimated | actual
-----------+--------
400 | 150
(1 row)
SELECT * FROM check_estimated_rows('SELECT a, b FROM stxdinh* WHERE a = 0 AND b = 0');
estimated | actual
-----------+--------
3 | 40
(1 row)
CREATE STATISTICS stxdinh ON a, b FROM stxdinh;
VACUUM ANALYZE stxdinh, stxdinh1, stxdinh2;
-- See if the extended stats affect the estimates
SELECT * FROM check_estimated_rows('SELECT a, b FROM stxdinh* GROUP BY 1, 2');
estimated | actual
-----------+--------
150 | 150
(1 row)
-- Dependencies are applied at individual relations (within append), so
-- this estimate changes a bit because we improve estimates for the parent
SELECT * FROM check_estimated_rows('SELECT a, b FROM stxdinh* WHERE a = 0 AND b = 0');
estimated | actual
-----------+--------
22 | 40
(1 row)
-- Ensure correct (non-inherited) stats are applied to inherited query
SELECT * FROM check_estimated_rows('SELECT a, b FROM ONLY stxdinh GROUP BY 1, 2');
estimated | actual
-----------+--------
100 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT a, b FROM ONLY stxdinh WHERE a = 0 AND b = 0');
estimated | actual
-----------+--------
20 | 20
(1 row)
DROP TABLE stxdinh, stxdinh1, stxdinh2;
-- Ensure inherited stats ARE applied to inherited query in partitioned table
CREATE TABLE stxdinp(i int, a int, b int) PARTITION BY RANGE (i);
CREATE TABLE stxdinp1 PARTITION OF stxdinp FOR VALUES FROM (1) TO (100);
INSERT INTO stxdinp SELECT 1, a/100, a/100 FROM generate_series(1, 999) a;
CREATE STATISTICS stxdinp ON (a + 1), a, b FROM stxdinp;
VACUUM ANALYZE stxdinp; -- partitions are processed recursively
SELECT 1 FROM pg_statistic_ext WHERE stxrelid = 'stxdinp'::regclass;
?column?
----------
1
(1 row)
SELECT * FROM check_estimated_rows('SELECT a, b FROM stxdinp GROUP BY 1, 2');
estimated | actual
-----------+--------
10 | 10
(1 row)
SELECT * FROM check_estimated_rows('SELECT a + 1, b FROM ONLY stxdinp GROUP BY 1, 2');
estimated | actual
-----------+--------
1 | 0
(1 row)
DROP TABLE stxdinp;
-- basic test for statistics on expressions
CREATE TABLE ab1 (a INTEGER, b INTEGER, c TIMESTAMP, d TIMESTAMPTZ);
-- expression stats may be built on a single expression column
CREATE STATISTICS ab1_exprstat_1 ON (a+b) FROM ab1;
-- with a single expression, we only enable expression statistics
CREATE STATISTICS ab1_exprstat_2 ON (a+b) FROM ab1;
SELECT stxkind FROM pg_statistic_ext WHERE stxname = 'ab1_exprstat_2';
stxkind
---------
{e}
(1 row)
-- adding anything to the expression builds all statistics kinds
CREATE STATISTICS ab1_exprstat_3 ON (a+b), a FROM ab1;
SELECT stxkind FROM pg_statistic_ext WHERE stxname = 'ab1_exprstat_3';
stxkind
-----------
{d,f,m,e}
(1 row)
-- date_trunc on timestamptz is not immutable, but that should not matter
CREATE STATISTICS ab1_exprstat_4 ON date_trunc('day', d) FROM ab1;
-- date_trunc on timestamp is immutable
CREATE STATISTICS ab1_exprstat_5 ON date_trunc('day', c) FROM ab1;
-- check use of a boolean-returning expression
CREATE STATISTICS ab1_exprstat_6 ON
(case a when 1 then true else false end), b FROM ab1;
-- insert some data and run analyze, to test that these cases build properly
INSERT INTO ab1
SELECT x / 10, x / 3,
'2020-10-01'::timestamp + x * interval '1 day',
'2020-10-01'::timestamptz + x * interval '1 day'
FROM generate_series(1, 100) x;
ANALYZE ab1;
-- apply some stats
SELECT * FROM check_estimated_rows('SELECT * FROM ab1 WHERE (case a when 1 then true else false end) AND b=2');
estimated | actual
-----------+--------
1 | 0
(1 row)
DROP TABLE ab1;
-- Verify supported object types for extended statistics
CREATE schema tststats;
CREATE TABLE tststats.t (a int, b int, c text);
CREATE INDEX ti ON tststats.t (a, b);
CREATE SEQUENCE tststats.s;
CREATE VIEW tststats.v AS SELECT * FROM tststats.t;
CREATE MATERIALIZED VIEW tststats.mv AS SELECT * FROM tststats.t;
CREATE TYPE tststats.ty AS (a int, b int, c text);
CREATE FOREIGN DATA WRAPPER extstats_dummy_fdw;
CREATE SERVER extstats_dummy_srv FOREIGN DATA WRAPPER extstats_dummy_fdw;
CREATE FOREIGN TABLE tststats.f (a int, b int, c text) SERVER extstats_dummy_srv;
CREATE TABLE tststats.pt (a int, b int, c text) PARTITION BY RANGE (a, b);
CREATE TABLE tststats.pt1 PARTITION OF tststats.pt FOR VALUES FROM (-10, -10) TO (10, 10);
CREATE STATISTICS tststats.s1 ON a, b FROM tststats.t;
CREATE STATISTICS tststats.s2 ON a, b FROM tststats.ti;
ERROR: cannot define statistics for relation "ti"
DETAIL: This operation is not supported for indexes.
CREATE STATISTICS tststats.s3 ON a, b FROM tststats.s;
ERROR: cannot define statistics for relation "s"
DETAIL: This operation is not supported for sequences.
CREATE STATISTICS tststats.s4 ON a, b FROM tststats.v;
ERROR: cannot define statistics for relation "v"
DETAIL: This operation is not supported for views.
CREATE STATISTICS tststats.s5 ON a, b FROM tststats.mv;
CREATE STATISTICS tststats.s6 ON a, b FROM tststats.ty;
ERROR: cannot define statistics for relation "ty"
DETAIL: This operation is not supported for composite types.
CREATE STATISTICS tststats.s7 ON a, b FROM tststats.f;
CREATE STATISTICS tststats.s8 ON a, b FROM tststats.pt;
CREATE STATISTICS tststats.s9 ON a, b FROM tststats.pt1;
DO $$
DECLARE
relname text := reltoastrelid::regclass FROM pg_class WHERE oid = 'tststats.t'::regclass;
BEGIN
EXECUTE 'CREATE STATISTICS tststats.s10 ON a, b FROM ' || relname;
EXCEPTION WHEN wrong_object_type THEN
RAISE NOTICE 'stats on toast table not created';
END;
$$;
NOTICE: stats on toast table not created
DROP SCHEMA tststats CASCADE;
NOTICE: drop cascades to 7 other objects
DETAIL: drop cascades to table tststats.t
drop cascades to sequence tststats.s
drop cascades to view tststats.v
drop cascades to materialized view tststats.mv
drop cascades to type tststats.ty
drop cascades to foreign table tststats.f
drop cascades to table tststats.pt
DROP FOREIGN DATA WRAPPER extstats_dummy_fdw CASCADE;
NOTICE: drop cascades to server extstats_dummy_srv
-- n-distinct tests
CREATE TABLE ndistinct (
filler1 TEXT,
filler2 NUMERIC,
a INT,
b INT,
filler3 DATE,
c INT,
d INT
)
WITH (autovacuum_enabled = off);
-- over-estimates when using only per-column statistics
INSERT INTO ndistinct (a, b, c, filler1)
SELECT i/100, i/100, i/100, cash_words((i/100)::money)
FROM generate_series(1,1000) s(i);
ANALYZE ndistinct;
-- Group Aggregate, due to over-estimate of the number of groups
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b');
estimated | actual
-----------+--------
100 | 11
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY b, c');
estimated | actual
-----------+--------
100 | 11
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b, c');
estimated | actual
-----------+--------
100 | 11
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b, c, d');
estimated | actual
-----------+--------
200 | 11
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY b, c, d');
estimated | actual
-----------+--------
200 | 11
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b, (a+1)');
estimated | actual
-----------+--------
100 | 11
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY (a+1), (b+100)');
estimated | actual
-----------+--------
100 | 11
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY (a+1), (b+100), (2*c)');
estimated | actual
-----------+--------
100 | 11
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, (a+1), (b+100)');
estimated | actual
-----------+--------
100 | 11
(1 row)
-- correct command
CREATE STATISTICS s10 ON a, b, c FROM ndistinct;
ANALYZE ndistinct;
SELECT s.stxkind, d.stxdndistinct
FROM pg_statistic_ext s, pg_statistic_ext_data d
WHERE s.stxrelid = 'ndistinct'::regclass
AND d.stxoid = s.oid;
stxkind | stxdndistinct
---------+-----------------------------------------------------
{d,f,m} | {"3, 4": 11, "3, 6": 11, "4, 6": 11, "3, 4, 6": 11}
(1 row)
-- minor improvement, make sure the ctid does not break the matching
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY ctid, a, b');
estimated | actual
-----------+--------
1000 | 1000
(1 row)
-- Hash Aggregate, thanks to estimates improved by the statistic
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b');
estimated | actual
-----------+--------
11 | 11
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY b, c');
estimated | actual
-----------+--------
11 | 11
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b, c');
estimated | actual
-----------+--------
11 | 11
(1 row)
-- partial improvement (match on attributes)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b, (a+1)');
estimated | actual
-----------+--------
11 | 11
(1 row)
-- expressions - no improvement
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY (a+1), (b+100)');
estimated | actual
-----------+--------
11 | 11
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY (a+1), (b+100), (2*c)');
estimated | actual
-----------+--------
11 | 11
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, (a+1), (b+100)');
estimated | actual
-----------+--------
11 | 11
(1 row)
-- last two plans keep using Group Aggregate, because 'd' is not covered
-- by the statistic and while it's NULL-only we assume 200 values for it
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b, c, d');
estimated | actual
-----------+--------
200 | 11
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY b, c, d');
estimated | actual
-----------+--------
200 | 11
(1 row)
TRUNCATE TABLE ndistinct;
-- under-estimates when using only per-column statistics
INSERT INTO ndistinct (a, b, c, filler1)
SELECT mod(i,13), mod(i,17), mod(i,19),
cash_words(mod(i,23)::int::money)
FROM generate_series(1,1000) s(i);
ANALYZE ndistinct;
SELECT s.stxkind, d.stxdndistinct
FROM pg_statistic_ext s, pg_statistic_ext_data d
WHERE s.stxrelid = 'ndistinct'::regclass
AND d.stxoid = s.oid;
stxkind | stxdndistinct
---------+----------------------------------------------------------
{d,f,m} | {"3, 4": 221, "3, 6": 247, "4, 6": 323, "3, 4, 6": 1000}
(1 row)
-- correct estimates
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b');
estimated | actual
-----------+--------
221 | 221
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b, c');
estimated | actual
-----------+--------
1000 | 1000
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b, c, d');
estimated | actual
-----------+--------
1000 | 1000
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY b, c, d');
estimated | actual
-----------+--------
323 | 323
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, d');
estimated | actual
-----------+--------
200 | 13
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b, (a+1)');
estimated | actual
-----------+--------
221 | 221
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY (a+1), (b+100)');
estimated | actual
-----------+--------
221 | 221
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY (a+1), (b+100), (2*c)');
estimated | actual
-----------+--------
1000 | 1000
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, (a+1), (b+100)');
estimated | actual
-----------+--------
221 | 221
(1 row)
DROP STATISTICS s10;
SELECT s.stxkind, d.stxdndistinct
FROM pg_statistic_ext s, pg_statistic_ext_data d
WHERE s.stxrelid = 'ndistinct'::regclass
AND d.stxoid = s.oid;
stxkind | stxdndistinct
---------+---------------
(0 rows)
-- dropping the statistics results in under-estimates
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b');
estimated | actual
-----------+--------
100 | 221
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b, c');
estimated | actual
-----------+--------
100 | 1000
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b, c, d');
estimated | actual
-----------+--------
200 | 1000
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY b, c, d');
estimated | actual
-----------+--------
200 | 323
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, d');
estimated | actual
-----------+--------
200 | 13
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b, (a+1)');
estimated | actual
-----------+--------
100 | 221
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY (a+1), (b+100)');
estimated | actual
-----------+--------
100 | 221
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY (a+1), (b+100), (2*c)');
estimated | actual
-----------+--------
100 | 1000
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, (a+1), (b+100)');
estimated | actual
-----------+--------
100 | 221
(1 row)
-- ndistinct estimates with statistics on expressions
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY (a+1), (b+100)');
estimated | actual
-----------+--------
100 | 221
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY (a+1), (b+100), (2*c)');
estimated | actual
-----------+--------
100 | 1000
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, (a+1), (b+100)');
estimated | actual
-----------+--------
100 | 221
(1 row)
CREATE STATISTICS s10 (ndistinct) ON (a+1), (b+100), (2*c) FROM ndistinct;
ANALYZE ndistinct;
SELECT s.stxkind, d.stxdndistinct
FROM pg_statistic_ext s, pg_statistic_ext_data d
WHERE s.stxrelid = 'ndistinct'::regclass
AND d.stxoid = s.oid;
stxkind | stxdndistinct
---------+-------------------------------------------------------------------
{d,e} | {"-1, -2": 221, "-1, -3": 247, "-2, -3": 323, "-1, -2, -3": 1000}
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY (a+1), (b+100)');
estimated | actual
-----------+--------
221 | 221
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY (a+1), (b+100), (2*c)');
estimated | actual
-----------+--------
1000 | 1000
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, (a+1), (b+100)');
estimated | actual
-----------+--------
221 | 221
(1 row)
DROP STATISTICS s10;
-- a mix of attributes and expressions
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b');
estimated | actual
-----------+--------
100 | 221
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, (2*c)');
estimated | actual
-----------+--------
100 | 247
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b, (2*c)');
estimated | actual
-----------+--------
100 | 1000
(1 row)
CREATE STATISTICS s10 (ndistinct) ON a, b, (2*c) FROM ndistinct;
ANALYZE ndistinct;
SELECT s.stxkind, d.stxdndistinct
FROM pg_statistic_ext s, pg_statistic_ext_data d
WHERE s.stxrelid = 'ndistinct'::regclass
AND d.stxoid = s.oid;
stxkind | stxdndistinct
---------+-------------------------------------------------------------
{d,e} | {"3, 4": 221, "3, -1": 247, "4, -1": 323, "3, 4, -1": 1000}
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b');
estimated | actual
-----------+--------
221 | 221
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, (2*c)');
estimated | actual
-----------+--------
247 | 247
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b, (2*c)');
estimated | actual
-----------+--------
1000 | 1000
(1 row)
DROP STATISTICS s10;
-- combination of multiple ndistinct statistics, with/without expressions
TRUNCATE ndistinct;
-- two mostly independent groups of columns
INSERT INTO ndistinct (a, b, c, d)
SELECT mod(i,3), mod(i,9), mod(i,5), mod(i,20)
FROM generate_series(1,1000) s(i);
ANALYZE ndistinct;
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b');
estimated | actual
-----------+--------
27 | 9
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, (b+1)');
estimated | actual
-----------+--------
27 | 9
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY (a*5), b');
estimated | actual
-----------+--------
27 | 9
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY (a*5), (b+1)');
estimated | actual
-----------+--------
27 | 9
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY (a*5), (b+1), c');
estimated | actual
-----------+--------
100 | 45
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b, (c*10)');
estimated | actual
-----------+--------
100 | 45
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, (b+1), c, (d - 1)');
estimated | actual
-----------+--------
100 | 180
(1 row)
-- basic statistics on both attributes (no expressions)
CREATE STATISTICS s11 (ndistinct) ON a, b FROM ndistinct;
CREATE STATISTICS s12 (ndistinct) ON c, d FROM ndistinct;
ANALYZE ndistinct;
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b');
estimated | actual
-----------+--------
9 | 9
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, (b+1)');
estimated | actual
-----------+--------
9 | 9
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY (a*5), b');
estimated | actual
-----------+--------
9 | 9
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY (a*5), (b+1)');
estimated | actual
-----------+--------
9 | 9
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY (a*5), (b+1), c');
estimated | actual
-----------+--------
45 | 45
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b, (c*10)');
estimated | actual
-----------+--------
45 | 45
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, (b+1), c, (d - 1)');
estimated | actual
-----------+--------
100 | 180
(1 row)
-- replace the second statistics by statistics on expressions
DROP STATISTICS s12;
CREATE STATISTICS s12 (ndistinct) ON (c * 10), (d - 1) FROM ndistinct;
ANALYZE ndistinct;
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b');
estimated | actual
-----------+--------
9 | 9
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, (b+1)');
estimated | actual
-----------+--------
9 | 9
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY (a*5), b');
estimated | actual
-----------+--------
9 | 9
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY (a*5), (b+1)');
estimated | actual
-----------+--------
9 | 9
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY (a*5), (b+1), c');
estimated | actual
-----------+--------
45 | 45
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b, (c*10)');
estimated | actual
-----------+--------
45 | 45
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, (b+1), c, (d - 1)');
estimated | actual
-----------+--------
100 | 180
(1 row)
-- replace the second statistics by statistics on both attributes and expressions
DROP STATISTICS s12;
CREATE STATISTICS s12 (ndistinct) ON c, d, (c * 10), (d - 1) FROM ndistinct;
ANALYZE ndistinct;
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b');
estimated | actual
-----------+--------
9 | 9
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, (b+1)');
estimated | actual
-----------+--------
9 | 9
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY (a*5), b');
estimated | actual
-----------+--------
9 | 9
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY (a*5), (b+1)');
estimated | actual
-----------+--------
9 | 9
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY (a*5), (b+1), c');
estimated | actual
-----------+--------
45 | 45
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b, (c*10)');
estimated | actual
-----------+--------
45 | 45
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, (b+1), c, (d - 1)');
estimated | actual
-----------+--------
100 | 180
(1 row)
-- replace the other statistics by statistics on both attributes and expressions
DROP STATISTICS s11;
CREATE STATISTICS s11 (ndistinct) ON a, b, (a*5), (b+1) FROM ndistinct;
ANALYZE ndistinct;
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b');
estimated | actual
-----------+--------
9 | 9
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, (b+1)');
estimated | actual
-----------+--------
9 | 9
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY (a*5), b');
estimated | actual
-----------+--------
9 | 9
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY (a*5), (b+1)');
estimated | actual
-----------+--------
9 | 9
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY (a*5), (b+1), c');
estimated | actual
-----------+--------
45 | 45
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b, (c*10)');
estimated | actual
-----------+--------
45 | 45
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, (b+1), c, (d - 1)');
estimated | actual
-----------+--------
100 | 180
(1 row)
-- replace statistics by somewhat overlapping ones (this expected to get worse estimate
-- because the first statistics shall be applied to 3 columns, and the second one can't
-- be really applied)
DROP STATISTICS s11;
DROP STATISTICS s12;
CREATE STATISTICS s11 (ndistinct) ON a, b, (a*5), (b+1) FROM ndistinct;
CREATE STATISTICS s12 (ndistinct) ON a, (b+1), (c * 10) FROM ndistinct;
ANALYZE ndistinct;
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b');
estimated | actual
-----------+--------
9 | 9
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, (b+1)');
estimated | actual
-----------+--------
9 | 9
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY (a*5), b');
estimated | actual
-----------+--------
9 | 9
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY (a*5), (b+1)');
estimated | actual
-----------+--------
9 | 9
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY (a*5), (b+1), c');
estimated | actual
-----------+--------
45 | 45
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b, (c*10)');
estimated | actual
-----------+--------
100 | 45
(1 row)
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, (b+1), c, (d - 1)');
estimated | actual
-----------+--------
100 | 180
(1 row)
DROP STATISTICS s11;
DROP STATISTICS s12;
-- functional dependencies tests
CREATE TABLE functional_dependencies (
filler1 TEXT,
filler2 NUMERIC,
a INT,
b TEXT,
filler3 DATE,
c INT,
d TEXT
)
WITH (autovacuum_enabled = off);
CREATE INDEX fdeps_ab_idx ON functional_dependencies (a, b);
CREATE INDEX fdeps_abc_idx ON functional_dependencies (a, b, c);
-- random data (no functional dependencies)
INSERT INTO functional_dependencies (a, b, c, filler1)
SELECT mod(i, 5), mod(i, 7), mod(i, 11), i FROM generate_series(1,1000) s(i);
ANALYZE functional_dependencies;
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = 1 AND b = ''1''');
estimated | actual
-----------+--------
29 | 29
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = 1 AND b = ''1'' AND c = 1');
estimated | actual
-----------+--------
3 | 3
(1 row)
-- create statistics
CREATE STATISTICS func_deps_stat (dependencies) ON a, b, c FROM functional_dependencies;
ANALYZE functional_dependencies;
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = 1 AND b = ''1''');
estimated | actual
-----------+--------
29 | 29
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = 1 AND b = ''1'' AND c = 1');
estimated | actual
-----------+--------
3 | 3
(1 row)
-- a => b, a => c, b => c
TRUNCATE functional_dependencies;
DROP STATISTICS func_deps_stat;
-- now do the same thing, but with expressions
INSERT INTO functional_dependencies (a, b, c, filler1)
SELECT i, i, i, i FROM generate_series(1,5000) s(i);
ANALYZE functional_dependencies;
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE mod(a, 11) = 1 AND mod(b::int, 13) = 1');
estimated | actual
-----------+--------
1 | 35
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE mod(a, 11) = 1 AND mod(b::int, 13) = 1 AND mod(c, 7) = 1');
estimated | actual
-----------+--------
1 | 5
(1 row)
-- create statistics
CREATE STATISTICS func_deps_stat (dependencies) ON (mod(a,11)), (mod(b::int, 13)), (mod(c, 7)) FROM functional_dependencies;
ANALYZE functional_dependencies;
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE mod(a, 11) = 1 AND mod(b::int, 13) = 1');
estimated | actual
-----------+--------
35 | 35
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE mod(a, 11) = 1 AND mod(b::int, 13) = 1 AND mod(c, 7) = 1');
estimated | actual
-----------+--------
5 | 5
(1 row)
-- a => b, a => c, b => c
TRUNCATE functional_dependencies;
DROP STATISTICS func_deps_stat;
INSERT INTO functional_dependencies (a, b, c, filler1)
SELECT mod(i,100), mod(i,50), mod(i,25), i FROM generate_series(1,5000) s(i);
ANALYZE functional_dependencies;
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = 1 AND b = ''1''');
estimated | actual
-----------+--------
1 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = 1 AND b = ''1'' AND c = 1');
estimated | actual
-----------+--------
1 | 50
(1 row)
-- IN
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a IN (1, 51) AND b = ''1''');
estimated | actual
-----------+--------
2 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a IN (1, 51) AND b IN (''1'', ''2'')');
estimated | actual
-----------+--------
4 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a IN (1, 2, 51, 52) AND b IN (''1'', ''2'')');
estimated | actual
-----------+--------
8 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a IN (1, 2, 51, 52) AND b = ''1''');
estimated | actual
-----------+--------
4 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a IN (1, 26, 51, 76) AND b IN (''1'', ''26'') AND c = 1');
estimated | actual
-----------+--------
1 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a IN (1, 26, 51, 76) AND b IN (''1'', ''26'') AND c IN (1)');
estimated | actual
-----------+--------
1 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a IN (1, 2, 26, 27, 51, 52, 76, 77) AND b IN (''1'', ''2'', ''26'', ''27'') AND c IN (1, 2)');
estimated | actual
-----------+--------
3 | 400
(1 row)
-- OR clauses referencing the same attribute
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a = 1 OR a = 51) AND b = ''1''');
estimated | actual
-----------+--------
2 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a = 1 OR a = 51) AND (b = ''1'' OR b = ''2'')');
estimated | actual
-----------+--------
4 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a = 1 OR a = 2 OR a = 51 OR a = 52) AND (b = ''1'' OR b = ''2'')');
estimated | actual
-----------+--------
8 | 200
(1 row)
-- OR clauses referencing different attributes
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a = 1 OR b = ''1'') AND b = ''1''');
estimated | actual
-----------+--------
3 | 100
(1 row)
-- ANY
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = ANY (ARRAY[1, 51]) AND b = ''1''');
estimated | actual
-----------+--------
2 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = ANY (ARRAY[1, 51]) AND b = ANY (ARRAY[''1'', ''2''])');
estimated | actual
-----------+--------
4 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = ANY (ARRAY[1, 2, 51, 52]) AND b = ANY (ARRAY[''1'', ''2''])');
estimated | actual
-----------+--------
8 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = ANY (ARRAY[1, 26, 51, 76]) AND b = ANY (ARRAY[''1'', ''26'']) AND c = 1');
estimated | actual
-----------+--------
1 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = ANY (ARRAY[1, 26, 51, 76]) AND b = ANY (ARRAY[''1'', ''26'']) AND c = ANY (ARRAY[1])');
estimated | actual
-----------+--------
1 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = ANY (ARRAY[1, 2, 26, 27, 51, 52, 76, 77]) AND b = ANY (ARRAY[''1'', ''2'', ''26'', ''27'']) AND c = ANY (ARRAY[1, 2])');
estimated | actual
-----------+--------
3 | 400
(1 row)
-- ANY with inequalities should not benefit from functional dependencies
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a < ANY (ARRAY[1, 51]) AND b > ''1''');
estimated | actual
-----------+--------
2472 | 2400
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a >= ANY (ARRAY[1, 51]) AND b <= ANY (ARRAY[''1'', ''2''])');
estimated | actual
-----------+--------
1441 | 1250
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a <= ANY (ARRAY[1, 2, 51, 52]) AND b >= ANY (ARRAY[''1'', ''2''])');
estimated | actual
-----------+--------
3909 | 2550
(1 row)
-- ALL (should not benefit from functional dependencies)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a IN (1, 51) AND b = ALL (ARRAY[''1''])');
estimated | actual
-----------+--------
2 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a IN (1, 51) AND b = ALL (ARRAY[''1'', ''2''])');
estimated | actual
-----------+--------
1 | 0
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a IN (1, 2, 51, 52) AND b = ALL (ARRAY[''1'', ''2''])');
estimated | actual
-----------+--------
1 | 0
(1 row)
-- create statistics
CREATE STATISTICS func_deps_stat (dependencies) ON a, b, c FROM functional_dependencies;
ANALYZE functional_dependencies;
-- print the detected dependencies
SELECT dependencies FROM pg_stats_ext WHERE statistics_name = 'func_deps_stat';
dependencies
------------------------------------------------------------------------------------------------------------
{"3 => 4": 1.000000, "3 => 6": 1.000000, "4 => 6": 1.000000, "3, 4 => 6": 1.000000, "3, 6 => 4": 1.000000}
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = 1 AND b = ''1''');
estimated | actual
-----------+--------
50 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = 1 AND b = ''1'' AND c = 1');
estimated | actual
-----------+--------
50 | 50
(1 row)
-- IN
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a IN (1, 51) AND b = ''1''');
estimated | actual
-----------+--------
100 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a IN (1, 51) AND b IN (''1'', ''2'')');
estimated | actual
-----------+--------
100 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a IN (1, 2, 51, 52) AND b IN (''1'', ''2'')');
estimated | actual
-----------+--------
200 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a IN (1, 2, 51, 52) AND b = ''1''');
estimated | actual
-----------+--------
100 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a IN (1, 26, 51, 76) AND b IN (''1'', ''26'') AND c = 1');
estimated | actual
-----------+--------
200 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a IN (1, 26, 51, 76) AND b IN (''1'', ''26'') AND c IN (1)');
estimated | actual
-----------+--------
200 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a IN (1, 2, 26, 27, 51, 52, 76, 77) AND b IN (''1'', ''2'', ''26'', ''27'') AND c IN (1, 2)');
estimated | actual
-----------+--------
400 | 400
(1 row)
-- OR clauses referencing the same attribute
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a = 1 OR a = 51) AND b = ''1''');
estimated | actual
-----------+--------
99 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a = 1 OR a = 51) AND (b = ''1'' OR b = ''2'')');
estimated | actual
-----------+--------
99 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a = 1 OR a = 2 OR a = 51 OR a = 52) AND (b = ''1'' OR b = ''2'')');
estimated | actual
-----------+--------
197 | 200
(1 row)
-- OR clauses referencing different attributes are incompatible
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a = 1 OR b = ''1'') AND b = ''1''');
estimated | actual
-----------+--------
3 | 100
(1 row)
-- ANY
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = ANY (ARRAY[1, 51]) AND b = ''1''');
estimated | actual
-----------+--------
100 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = ANY (ARRAY[1, 51]) AND b = ANY (ARRAY[''1'', ''2''])');
estimated | actual
-----------+--------
100 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = ANY (ARRAY[1, 2, 51, 52]) AND b = ANY (ARRAY[''1'', ''2''])');
estimated | actual
-----------+--------
200 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = ANY (ARRAY[1, 26, 51, 76]) AND b = ANY (ARRAY[''1'', ''26'']) AND c = 1');
estimated | actual
-----------+--------
200 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = ANY (ARRAY[1, 26, 51, 76]) AND b = ANY (ARRAY[''1'', ''26'']) AND c = ANY (ARRAY[1])');
estimated | actual
-----------+--------
200 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = ANY (ARRAY[1, 2, 26, 27, 51, 52, 76, 77]) AND b = ANY (ARRAY[''1'', ''2'', ''26'', ''27'']) AND c = ANY (ARRAY[1, 2])');
estimated | actual
-----------+--------
400 | 400
(1 row)
-- ANY with inequalities should not benefit from functional dependencies
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a < ANY (ARRAY[1, 51]) AND b > ''1''');
estimated | actual
-----------+--------
2472 | 2400
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a >= ANY (ARRAY[1, 51]) AND b <= ANY (ARRAY[''1'', ''2''])');
estimated | actual
-----------+--------
1441 | 1250
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a <= ANY (ARRAY[1, 2, 51, 52]) AND b >= ANY (ARRAY[''1'', ''2''])');
estimated | actual
-----------+--------
3909 | 2550
(1 row)
-- ALL (should not benefit from functional dependencies)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a IN (1, 51) AND b = ALL (ARRAY[''1''])');
estimated | actual
-----------+--------
2 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a IN (1, 51) AND b = ALL (ARRAY[''1'', ''2''])');
estimated | actual
-----------+--------
1 | 0
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a IN (1, 2, 51, 52) AND b = ALL (ARRAY[''1'', ''2''])');
estimated | actual
-----------+--------
1 | 0
(1 row)
-- changing the type of column c causes all its stats to be dropped, reverting
-- to default estimates without any statistics, i.e. 0.5% selectivity for each
-- condition
ALTER TABLE functional_dependencies ALTER COLUMN c TYPE numeric;
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = 1 AND b = ''1'' AND c = 1');
estimated | actual
-----------+--------
1 | 50
(1 row)
ANALYZE functional_dependencies;
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = 1 AND b = ''1'' AND c = 1');
estimated | actual
-----------+--------
50 | 50
(1 row)
DROP STATISTICS func_deps_stat;
-- now try functional dependencies with expressions
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) = 2 AND upper(b) = ''1''');
estimated | actual
-----------+--------
1 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) = 2 AND upper(b) = ''1'' AND (c + 1) = 2');
estimated | actual
-----------+--------
1 | 50
(1 row)
-- IN
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) IN (2, 102) AND upper(b) = ''1''');
estimated | actual
-----------+--------
1 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) IN (2, 102) AND upper(b) IN (''1'', ''2'')');
estimated | actual
-----------+--------
1 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) IN (2, 4, 102, 104) AND upper(b) IN (''1'', ''2'')');
estimated | actual
-----------+--------
1 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) IN (2, 4, 102, 104) AND upper(b) = ''1''');
estimated | actual
-----------+--------
1 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) IN (2, 52, 102, 152) AND upper(b) IN (''1'', ''26'') AND (c + 1) = 2');
estimated | actual
-----------+--------
1 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) IN (2, 52, 102, 152) AND upper(b) IN (''1'', ''26'') AND (c + 1) IN (2)');
estimated | actual
-----------+--------
1 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) IN (2, 4, 52, 54, 102, 104, 152, 154) AND upper(b) IN (''1'', ''2'', ''26'', ''27'') AND (c + 1) IN (2, 3)');
estimated | actual
-----------+--------
1 | 400
(1 row)
-- OR clauses referencing the same attribute
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE ((a * 2) = 2 OR (a * 2) = 102) AND upper(b) = ''1''');
estimated | actual
-----------+--------
1 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE ((a * 2) = 2 OR (a * 2) = 102) AND (upper(b) = ''1'' OR upper(b) = ''2'')');
estimated | actual
-----------+--------
1 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE ((a * 2) = 2 OR (a * 2) = 4 OR (a * 2) = 102 OR (a * 2) = 104) AND (upper(b) = ''1'' OR upper(b) = ''2'')');
estimated | actual
-----------+--------
1 | 200
(1 row)
-- OR clauses referencing different attributes
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE ((a * 2) = 2 OR upper(b) = ''1'') AND upper(b) = ''1''');
estimated | actual
-----------+--------
1 | 100
(1 row)
-- ANY
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) = ANY (ARRAY[2, 102]) AND upper(b) = ''1''');
estimated | actual
-----------+--------
1 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) = ANY (ARRAY[2, 102]) AND upper(b) = ANY (ARRAY[''1'', ''2''])');
estimated | actual
-----------+--------
1 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) = ANY (ARRAY[2, 4, 102, 104]) AND upper(b) = ANY (ARRAY[''1'', ''2''])');
estimated | actual
-----------+--------
1 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) = ANY (ARRAY[2, 52, 102, 152]) AND upper(b) = ANY (ARRAY[''1'', ''26'']) AND (c + 1) = 2');
estimated | actual
-----------+--------
1 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) = ANY (ARRAY[2, 52, 102, 152]) AND upper(b) = ANY (ARRAY[''1'', ''26'']) AND (c + 1) = ANY (ARRAY[2])');
estimated | actual
-----------+--------
1 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) = ANY (ARRAY[2, 4, 52, 54, 102, 104, 152, 154]) AND upper(b) = ANY (ARRAY[''1'', ''2'', ''26'', ''27'']) AND (c + 1) = ANY (ARRAY[2, 3])');
estimated | actual
-----------+--------
1 | 400
(1 row)
-- ANY with inequalities should not benefit from functional dependencies
-- the estimates however improve thanks to having expression statistics
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) < ANY (ARRAY[2, 102]) AND upper(b) > ''1''');
estimated | actual
-----------+--------
926 | 2400
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) >= ANY (ARRAY[2, 102]) AND upper(b) <= ANY (ARRAY[''1'', ''2''])');
estimated | actual
-----------+--------
1543 | 1250
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) <= ANY (ARRAY[2, 4, 102, 104]) AND upper(b) >= ANY (ARRAY[''1'', ''2''])');
estimated | actual
-----------+--------
2229 | 2550
(1 row)
-- ALL (should not benefit from functional dependencies)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) IN (2, 102) AND upper(b) = ALL (ARRAY[''1''])');
estimated | actual
-----------+--------
1 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) IN (2, 102) AND upper(b) = ALL (ARRAY[''1'', ''2''])');
estimated | actual
-----------+--------
1 | 0
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) IN (2, 4, 102, 104) AND upper(b) = ALL (ARRAY[''1'', ''2''])');
estimated | actual
-----------+--------
1 | 0
(1 row)
-- create statistics on expressions
CREATE STATISTICS func_deps_stat (dependencies) ON (a * 2), upper(b), (c + 1) FROM functional_dependencies;
ANALYZE functional_dependencies;
-- print the detected dependencies
SELECT dependencies FROM pg_stats_ext WHERE statistics_name = 'func_deps_stat';
dependencies
------------------------------------------------------------------------------------------------------------------------
{"-1 => -2": 1.000000, "-1 => -3": 1.000000, "-2 => -3": 1.000000, "-1, -2 => -3": 1.000000, "-1, -3 => -2": 1.000000}
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) = 2 AND upper(b) = ''1''');
estimated | actual
-----------+--------
50 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) = 2 AND upper(b) = ''1'' AND (c + 1) = 2');
estimated | actual
-----------+--------
50 | 50
(1 row)
-- IN
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) IN (2, 102) AND upper(b) = ''1''');
estimated | actual
-----------+--------
100 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) IN (2, 102) AND upper(b) IN (''1'', ''2'')');
estimated | actual
-----------+--------
100 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) IN (2, 4, 102, 104) AND upper(b) IN (''1'', ''2'')');
estimated | actual
-----------+--------
200 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) IN (2, 4, 102, 104) AND upper(b) = ''1''');
estimated | actual
-----------+--------
100 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) IN (2, 52, 102, 152) AND upper(b) IN (''1'', ''26'') AND (c + 1) = 2');
estimated | actual
-----------+--------
200 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) IN (2, 52, 102, 152) AND upper(b) IN (''1'', ''26'') AND (c + 1) IN (2)');
estimated | actual
-----------+--------
200 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) IN (2, 4, 52, 54, 102, 104, 152, 154) AND upper(b) IN (''1'', ''2'', ''26'', ''27'') AND (c + 1) IN (2, 3)');
estimated | actual
-----------+--------
400 | 400
(1 row)
-- OR clauses referencing the same attribute
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE ((a * 2) = 2 OR (a * 2) = 102) AND upper(b) = ''1''');
estimated | actual
-----------+--------
99 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE ((a * 2) = 2 OR (a * 2) = 102) AND (upper(b) = ''1'' OR upper(b) = ''2'')');
estimated | actual
-----------+--------
99 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE ((a * 2) = 2 OR (a * 2) = 4 OR (a * 2) = 102 OR (a * 2) = 104) AND (upper(b) = ''1'' OR upper(b) = ''2'')');
estimated | actual
-----------+--------
197 | 200
(1 row)
-- OR clauses referencing different attributes
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE ((a * 2) = 2 OR upper(b) = ''1'') AND upper(b) = ''1''');
estimated | actual
-----------+--------
3 | 100
(1 row)
-- ANY
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) = ANY (ARRAY[2, 102]) AND upper(b) = ''1''');
estimated | actual
-----------+--------
100 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) = ANY (ARRAY[2, 102]) AND upper(b) = ANY (ARRAY[''1'', ''2''])');
estimated | actual
-----------+--------
100 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) = ANY (ARRAY[2, 4, 102, 104]) AND upper(b) = ANY (ARRAY[''1'', ''2''])');
estimated | actual
-----------+--------
200 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) = ANY (ARRAY[2, 52, 102, 152]) AND upper(b) = ANY (ARRAY[''1'', ''26'']) AND (c + 1) = 2');
estimated | actual
-----------+--------
200 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) = ANY (ARRAY[2, 52, 102, 152]) AND upper(b) = ANY (ARRAY[''1'', ''26'']) AND (c + 1) = ANY (ARRAY[2])');
estimated | actual
-----------+--------
200 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) = ANY (ARRAY[2, 4, 52, 54, 102, 104, 152, 154]) AND upper(b) = ANY (ARRAY[''1'', ''2'', ''26'', ''27'']) AND (c + 1) = ANY (ARRAY[2, 3])');
estimated | actual
-----------+--------
400 | 400
(1 row)
-- ANY with inequalities should not benefit from functional dependencies
-- the estimates however improve thanks to having expression statistics
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) < ANY (ARRAY[2, 102]) AND upper(b) > ''1''');
estimated | actual
-----------+--------
2472 | 2400
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) >= ANY (ARRAY[2, 102]) AND upper(b) <= ANY (ARRAY[''1'', ''2''])');
estimated | actual
-----------+--------
1441 | 1250
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) <= ANY (ARRAY[2, 4, 102, 104]) AND upper(b) >= ANY (ARRAY[''1'', ''2''])');
estimated | actual
-----------+--------
3909 | 2550
(1 row)
-- ALL (should not benefit from functional dependencies)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) IN (2, 102) AND upper(b) = ALL (ARRAY[''1''])');
estimated | actual
-----------+--------
2 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) IN (2, 102) AND upper(b) = ALL (ARRAY[''1'', ''2''])');
estimated | actual
-----------+--------
1 | 0
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE (a * 2) IN (2, 4, 102, 104) AND upper(b) = ALL (ARRAY[''1'', ''2''])');
estimated | actual
-----------+--------
1 | 0
(1 row)
-- check the ability to use multiple functional dependencies
CREATE TABLE functional_dependencies_multi (
a INTEGER,
b INTEGER,
c INTEGER,
d INTEGER
)
WITH (autovacuum_enabled = off);
INSERT INTO functional_dependencies_multi (a, b, c, d)
SELECT
mod(i,7),
mod(i,7),
mod(i,11),
mod(i,11)
FROM generate_series(1,5000) s(i);
ANALYZE functional_dependencies_multi;
-- estimates without any functional dependencies
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies_multi WHERE a = 0 AND b = 0');
estimated | actual
-----------+--------
102 | 714
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies_multi WHERE 0 = a AND 0 = b');
estimated | actual
-----------+--------
102 | 714
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies_multi WHERE c = 0 AND d = 0');
estimated | actual
-----------+--------
41 | 454
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies_multi WHERE a = 0 AND b = 0 AND c = 0 AND d = 0');
estimated | actual
-----------+--------
1 | 64
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies_multi WHERE 0 = a AND b = 0 AND 0 = c AND d = 0');
estimated | actual
-----------+--------
1 | 64
(1 row)
-- create separate functional dependencies
CREATE STATISTICS functional_dependencies_multi_1 (dependencies) ON a, b FROM functional_dependencies_multi;
CREATE STATISTICS functional_dependencies_multi_2 (dependencies) ON c, d FROM functional_dependencies_multi;
ANALYZE functional_dependencies_multi;
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies_multi WHERE a = 0 AND b = 0');
estimated | actual
-----------+--------
714 | 714
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies_multi WHERE 0 = a AND 0 = b');
estimated | actual
-----------+--------
714 | 714
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies_multi WHERE c = 0 AND d = 0');
estimated | actual
-----------+--------
454 | 454
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies_multi WHERE a = 0 AND b = 0 AND c = 0 AND d = 0');
estimated | actual
-----------+--------
65 | 64
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies_multi WHERE 0 = a AND b = 0 AND 0 = c AND d = 0');
estimated | actual
-----------+--------
65 | 64
(1 row)
DROP TABLE functional_dependencies_multi;
-- MCV lists
CREATE TABLE mcv_lists (
filler1 TEXT,
filler2 NUMERIC,
a INT,
b VARCHAR,
filler3 DATE,
c INT,
d TEXT,
ia INT[]
)
WITH (autovacuum_enabled = off);
-- random data (no MCV list)
INSERT INTO mcv_lists (a, b, c, filler1)
SELECT mod(i,37), mod(i,41), mod(i,43), mod(i,47) FROM generate_series(1,5000) s(i);
ANALYZE mcv_lists;
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b = ''1''');
estimated | actual
-----------+--------
3 | 4
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b = ''1'' AND c = 1');
estimated | actual
-----------+--------
1 | 1
(1 row)
-- create statistics
CREATE STATISTICS mcv_lists_stats (mcv) ON a, b, c FROM mcv_lists;
ANALYZE mcv_lists;
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b = ''1''');
estimated | actual
-----------+--------
3 | 4
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b = ''1'' AND c = 1');
estimated | actual
-----------+--------
1 | 1
(1 row)
TRUNCATE mcv_lists;
DROP STATISTICS mcv_lists_stats;
-- random data (no MCV list), but with expression
INSERT INTO mcv_lists (a, b, c, filler1)
SELECT i, i, i, i FROM generate_series(1,1000) s(i);
ANALYZE mcv_lists;
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,7) = 1 AND mod(b::int,11) = 1');
estimated | actual
-----------+--------
1 | 13
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,7) = 1 AND mod(b::int,11) = 1 AND mod(c,13) = 1');
estimated | actual
-----------+--------
1 | 1
(1 row)
-- create statistics
CREATE STATISTICS mcv_lists_stats (mcv) ON (mod(a,7)), (mod(b::int,11)), (mod(c,13)) FROM mcv_lists;
ANALYZE mcv_lists;
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,7) = 1 AND mod(b::int,11) = 1');
estimated | actual
-----------+--------
13 | 13
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,7) = 1 AND mod(b::int,11) = 1 AND mod(c,13) = 1');
estimated | actual
-----------+--------
1 | 1
(1 row)
-- 100 distinct combinations, all in the MCV list
TRUNCATE mcv_lists;
DROP STATISTICS mcv_lists_stats;
INSERT INTO mcv_lists (a, b, c, ia, filler1)
SELECT mod(i,100), mod(i,50), mod(i,25), array[mod(i,25)], i
FROM generate_series(1,5000) s(i);
ANALYZE mcv_lists;
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b = ''1''');
estimated | actual
-----------+--------
1 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 = a AND ''1'' = b');
estimated | actual
-----------+--------
1 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < 1 AND b < ''1''');
estimated | actual
-----------+--------
1 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 > a AND ''1'' > b');
estimated | actual
-----------+--------
1 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a <= 0 AND b <= ''0''');
estimated | actual
-----------+--------
1 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 0 >= a AND ''0'' >= b');
estimated | actual
-----------+--------
1 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b = ''1'' AND c = 1');
estimated | actual
-----------+--------
1 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < 5 AND b < ''1'' AND c < 5');
estimated | actual
-----------+--------
1 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < 5 AND ''1'' > b AND 5 > c');
estimated | actual
-----------+--------
1 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a <= 4 AND b <= ''0'' AND c <= 4');
estimated | actual
-----------+--------
1 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 4 >= a AND ''0'' >= b AND 4 >= c');
estimated | actual
-----------+--------
1 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ''1'' OR c = 1');
estimated | actual
-----------+--------
343 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ''1'' OR c = 1 OR d IS NOT NULL');
estimated | actual
-----------+--------
343 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IN (1, 2, 51, 52) AND b IN ( ''1'', ''2'')');
estimated | actual
-----------+--------
8 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IN (1, 2, 51, 52, NULL) AND b IN ( ''1'', ''2'', NULL)');
estimated | actual
-----------+--------
8 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = ANY (ARRAY[1, 2, 51, 52]) AND b = ANY (ARRAY[''1'', ''2''])');
estimated | actual
-----------+--------
8 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = ANY (ARRAY[NULL, 1, 2, 51, 52]) AND b = ANY (ARRAY[''1'', ''2'', NULL])');
estimated | actual
-----------+--------
8 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a <= ANY (ARRAY[1, 2, 3]) AND b IN (''1'', ''2'', ''3'')');
estimated | actual
-----------+--------
26 | 150
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a <= ANY (ARRAY[1, NULL, 2, 3]) AND b IN (''1'', ''2'', NULL, ''3'')');
estimated | actual
-----------+--------
26 | 150
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < ALL (ARRAY[4, 5]) AND c > ANY (ARRAY[1, 2, 3])');
estimated | actual
-----------+--------
10 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < ALL (ARRAY[4, 5]) AND c > ANY (ARRAY[1, 2, 3, NULL])');
estimated | actual
-----------+--------
10 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < ALL (ARRAY[4, 5]) AND b IN (''1'', ''2'', ''3'') AND c > ANY (ARRAY[1, 2, 3])');
estimated | actual
-----------+--------
1 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < ALL (ARRAY[4, 5]) AND b IN (''1'', ''2'', NULL, ''3'') AND c > ANY (ARRAY[1, 2, NULL, 3])');
estimated | actual
-----------+--------
1 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = ANY (ARRAY[4,5]) AND 4 = ANY(ia)');
estimated | actual
-----------+--------
4 | 50
(1 row)
-- create statistics
CREATE STATISTICS mcv_lists_stats (mcv) ON a, b, c, ia FROM mcv_lists;
ANALYZE mcv_lists;
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b = ''1''');
estimated | actual
-----------+--------
50 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 = a AND ''1'' = b');
estimated | actual
-----------+--------
50 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < 1 AND b < ''1''');
estimated | actual
-----------+--------
50 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 > a AND ''1'' > b');
estimated | actual
-----------+--------
50 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a <= 0 AND b <= ''0''');
estimated | actual
-----------+--------
50 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 0 >= a AND ''0'' >= b');
estimated | actual
-----------+--------
50 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b = ''1'' AND c = 1');
estimated | actual
-----------+--------
50 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < 5 AND b < ''1'' AND c < 5');
estimated | actual
-----------+--------
50 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < 5 AND ''1'' > b AND 5 > c');
estimated | actual
-----------+--------
50 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a <= 4 AND b <= ''0'' AND c <= 4');
estimated | actual
-----------+--------
50 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 4 >= a AND ''0'' >= b AND 4 >= c');
estimated | actual
-----------+--------
50 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ''1'' OR c = 1');
estimated | actual
-----------+--------
200 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ''1'' OR c = 1 OR d IS NOT NULL');
estimated | actual
-----------+--------
200 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ''1'' OR c = 1 OR d IS NOT NULL');
estimated | actual
-----------+--------
200 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IN (1, 2, 51, 52) AND b IN ( ''1'', ''2'')');
estimated | actual
-----------+--------
200 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IN (1, 2, 51, 52, NULL) AND b IN ( ''1'', ''2'', NULL)');
estimated | actual
-----------+--------
200 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = ANY (ARRAY[1, 2, 51, 52]) AND b = ANY (ARRAY[''1'', ''2''])');
estimated | actual
-----------+--------
200 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = ANY (ARRAY[NULL, 1, 2, 51, 52]) AND b = ANY (ARRAY[''1'', ''2'', NULL])');
estimated | actual
-----------+--------
200 | 200
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a <= ANY (ARRAY[1, 2, 3]) AND b IN (''1'', ''2'', ''3'')');
estimated | actual
-----------+--------
150 | 150
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a <= ANY (ARRAY[1, NULL, 2, 3]) AND b IN (''1'', ''2'', NULL, ''3'')');
estimated | actual
-----------+--------
150 | 150
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < ALL (ARRAY[4, 5]) AND c > ANY (ARRAY[1, 2, 3])');
estimated | actual
-----------+--------
100 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < ALL (ARRAY[4, 5]) AND c > ANY (ARRAY[1, 2, 3, NULL])');
estimated | actual
-----------+--------
100 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < ALL (ARRAY[4, 5]) AND b IN (''1'', ''2'', ''3'') AND c > ANY (ARRAY[1, 2, 3])');
estimated | actual
-----------+--------
100 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < ALL (ARRAY[4, 5]) AND b IN (''1'', ''2'', NULL, ''3'') AND c > ANY (ARRAY[1, 2, NULL, 3])');
estimated | actual
-----------+--------
100 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = ANY (ARRAY[4,5]) AND 4 = ANY(ia)');
estimated | actual
-----------+--------
4 | 50
(1 row)
-- check change of unrelated column type does not reset the MCV statistics
ALTER TABLE mcv_lists ALTER COLUMN d TYPE VARCHAR(64);
SELECT d.stxdmcv IS NOT NULL
FROM pg_statistic_ext s, pg_statistic_ext_data d
WHERE s.stxname = 'mcv_lists_stats'
AND d.stxoid = s.oid;
?column?
----------
t
(1 row)
-- check change of column type resets the MCV statistics
ALTER TABLE mcv_lists ALTER COLUMN c TYPE numeric;
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b = ''1''');
estimated | actual
-----------+--------
1 | 50
(1 row)
ANALYZE mcv_lists;
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b = ''1''');
estimated | actual
-----------+--------
50 | 50
(1 row)
-- 100 distinct combinations, all in the MCV list, but with expressions
TRUNCATE mcv_lists;
DROP STATISTICS mcv_lists_stats;
INSERT INTO mcv_lists (a, b, c, filler1)
SELECT i, i, i, i FROM generate_series(1,1000) s(i);
ANALYZE mcv_lists;
-- without any stats on the expressions, we have to use default selectivities, which
-- is why the estimates here are different from the pre-computed case above
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,20) = 1 AND mod(b::int,10) = 1');
estimated | actual
-----------+--------
1 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 = mod(a,20) AND 1 = mod(b::int,10)');
estimated | actual
-----------+--------
1 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,20) < 1 AND mod(b::int,10) < 1');
estimated | actual
-----------+--------
111 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 > mod(a,20) AND 1 > mod(b::int,10)');
estimated | actual
-----------+--------
111 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,20) = 1 AND mod(b::int,10) = 1 AND mod(c,5) = 1');
estimated | actual
-----------+--------
1 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,20) = 1 OR mod(b::int,10) = 1 OR mod(c,25) = 1 OR d IS NOT NULL');
estimated | actual
-----------+--------
15 | 120
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,20) IN (1, 2, 51, 52, NULL) AND mod(b::int,10) IN ( 1, 2, NULL)');
estimated | actual
-----------+--------
1 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,20) = ANY (ARRAY[1, 2, 51, 52]) AND mod(b::int,10) = ANY (ARRAY[1, 2])');
estimated | actual
-----------+--------
1 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,20) <= ANY (ARRAY[1, NULL, 2, 3]) AND mod(b::int,10) IN (1, 2, NULL, 3)');
estimated | actual
-----------+--------
11 | 150
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,20) < ALL (ARRAY[4, 5]) AND mod(b::int,10) IN (1, 2, 3) AND mod(c,5) > ANY (ARRAY[1, 2, 3])');
estimated | actual
-----------+--------
1 | 100
(1 row)
-- create statistics with expressions only (we create three separate stats, in order not to build more complex extended stats)
CREATE STATISTICS mcv_lists_stats_1 ON (mod(a,20)) FROM mcv_lists;
CREATE STATISTICS mcv_lists_stats_2 ON (mod(b::int,10)) FROM mcv_lists;
CREATE STATISTICS mcv_lists_stats_3 ON (mod(c,5)) FROM mcv_lists;
ANALYZE mcv_lists;
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,20) = 1 AND mod(b::int,10) = 1');
estimated | actual
-----------+--------
5 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 = mod(a,20) AND 1 = mod(b::int,10)');
estimated | actual
-----------+--------
5 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,20) < 1 AND mod(b::int,10) < 1');
estimated | actual
-----------+--------
5 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 > mod(a,20) AND 1 > mod(b::int,10)');
estimated | actual
-----------+--------
5 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,20) = 1 AND mod(b::int,10) = 1 AND mod(c,5) = 1');
estimated | actual
-----------+--------
1 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,20) = 1 OR mod(b::int,10) = 1 OR mod(c,25) = 1 OR d IS NOT NULL');
estimated | actual
-----------+--------
149 | 120
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,20) IN (1, 2, 51, 52, NULL) AND mod(b::int,10) IN ( 1, 2, NULL)');
estimated | actual
-----------+--------
20 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,20) = ANY (ARRAY[1, 2, 51, 52]) AND mod(b::int,10) = ANY (ARRAY[1, 2])');
estimated | actual
-----------+--------
20 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,20) <= ANY (ARRAY[1, NULL, 2, 3]) AND mod(b::int,10) IN (1, 2, NULL, 3)');
estimated | actual
-----------+--------
116 | 150
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,20) < ALL (ARRAY[4, 5]) AND mod(b::int,10) IN (1, 2, 3) AND mod(c,5) > ANY (ARRAY[1, 2, 3])');
estimated | actual
-----------+--------
12 | 100
(1 row)
DROP STATISTICS mcv_lists_stats_1;
DROP STATISTICS mcv_lists_stats_2;
DROP STATISTICS mcv_lists_stats_3;
-- create statistics with both MCV and expressions
CREATE STATISTICS mcv_lists_stats (mcv) ON (mod(a,20)), (mod(b::int,10)), (mod(c,5)) FROM mcv_lists;
ANALYZE mcv_lists;
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,20) = 1 AND mod(b::int,10) = 1');
estimated | actual
-----------+--------
50 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 = mod(a,20) AND 1 = mod(b::int,10)');
estimated | actual
-----------+--------
50 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,20) < 1 AND mod(b::int,10) < 1');
estimated | actual
-----------+--------
50 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 > mod(a,20) AND 1 > mod(b::int,10)');
estimated | actual
-----------+--------
50 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,20) = 1 AND mod(b::int,10) = 1 AND mod(c,5) = 1');
estimated | actual
-----------+--------
50 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,20) = 1 OR mod(b::int,10) = 1 OR mod(c,25) = 1 OR d IS NOT NULL');
estimated | actual
-----------+--------
105 | 120
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,20) IN (1, 2, 51, 52, NULL) AND mod(b::int,10) IN ( 1, 2, NULL)');
estimated | actual
-----------+--------
100 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,20) = ANY (ARRAY[1, 2, 51, 52]) AND mod(b::int,10) = ANY (ARRAY[1, 2])');
estimated | actual
-----------+--------
100 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,20) <= ANY (ARRAY[1, NULL, 2, 3]) AND mod(b::int,10) IN (1, 2, NULL, 3)');
estimated | actual
-----------+--------
150 | 150
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,20) < ALL (ARRAY[4, 5]) AND mod(b::int,10) IN (1, 2, 3) AND mod(c,5) > ANY (ARRAY[1, 2, 3])');
estimated | actual
-----------+--------
100 | 100
(1 row)
-- we can't use the statistic for OR clauses that are not fully covered (missing 'd' attribute)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,20) = 1 OR mod(b::int,10) = 1 OR mod(c,5) = 1 OR d IS NOT NULL');
estimated | actual
-----------+--------
200 | 200
(1 row)
-- 100 distinct combinations with NULL values, all in the MCV list
TRUNCATE mcv_lists;
DROP STATISTICS mcv_lists_stats;
INSERT INTO mcv_lists (a, b, c, filler1)
SELECT
(CASE WHEN mod(i,100) = 1 THEN NULL ELSE mod(i,100) END),
(CASE WHEN mod(i,50) = 1 THEN NULL ELSE mod(i,50) END),
(CASE WHEN mod(i,25) = 1 THEN NULL ELSE mod(i,25) END),
i
FROM generate_series(1,5000) s(i);
ANALYZE mcv_lists;
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IS NULL AND b IS NULL');
estimated | actual
-----------+--------
1 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IS NULL AND b IS NULL AND c IS NULL');
estimated | actual
-----------+--------
1 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IS NULL AND b IS NOT NULL');
estimated | actual
-----------+--------
49 | 0
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IS NOT NULL AND b IS NULL AND c IS NOT NULL');
estimated | actual
-----------+--------
95 | 0
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IN (0, 1) AND b IN (''0'', ''1'')');
estimated | actual
-----------+--------
1 | 50
(1 row)
-- create statistics
CREATE STATISTICS mcv_lists_stats (mcv) ON a, b, c FROM mcv_lists;
ANALYZE mcv_lists;
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IS NULL AND b IS NULL');
estimated | actual
-----------+--------
50 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IS NULL AND b IS NULL AND c IS NULL');
estimated | actual
-----------+--------
50 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IS NULL AND b IS NOT NULL');
estimated | actual
-----------+--------
1 | 0
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IS NOT NULL AND b IS NULL AND c IS NOT NULL');
estimated | actual
-----------+--------
1 | 0
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IN (0, 1) AND b IN (''0'', ''1'')');
estimated | actual
-----------+--------
50 | 50
(1 row)
-- test pg_mcv_list_items with a very simple (single item) MCV list
TRUNCATE mcv_lists;
INSERT INTO mcv_lists (a, b, c) SELECT 1, 2, 3 FROM generate_series(1,1000) s(i);
ANALYZE mcv_lists;
SELECT m.*
FROM pg_statistic_ext s, pg_statistic_ext_data d,
pg_mcv_list_items(d.stxdmcv) m
WHERE s.stxname = 'mcv_lists_stats'
AND d.stxoid = s.oid;
index | values | nulls | frequency | base_frequency
-------+---------+---------+-----------+----------------
0 | {1,2,3} | {f,f,f} | 1 | 1
(1 row)
-- 2 distinct combinations with NULL values, all in the MCV list
TRUNCATE mcv_lists;
DROP STATISTICS mcv_lists_stats;
INSERT INTO mcv_lists (a, b, c, d)
SELECT
NULL, -- always NULL
(CASE WHEN mod(i,2) = 0 THEN NULL ELSE 'x' END),
(CASE WHEN mod(i,2) = 0 THEN NULL ELSE 0 END),
(CASE WHEN mod(i,2) = 0 THEN NULL ELSE 'x' END)
FROM generate_series(1,5000) s(i);
ANALYZE mcv_lists;
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = ''x'' OR d = ''x''');
estimated | actual
-----------+--------
3750 | 2500
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ''x'' OR d = ''x''');
estimated | actual
-----------+--------
3750 | 2500
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IS NULL AND (b = ''x'' OR d = ''x'')');
estimated | actual
-----------+--------
3750 | 2500
(1 row)
-- create statistics
CREATE STATISTICS mcv_lists_stats (mcv) ON a, b, d FROM mcv_lists;
ANALYZE mcv_lists;
-- test pg_mcv_list_items with MCV list containing variable-length data and NULLs
SELECT m.*
FROM pg_statistic_ext s, pg_statistic_ext_data d,
pg_mcv_list_items(d.stxdmcv) m
WHERE s.stxname = 'mcv_lists_stats'
AND d.stxoid = s.oid;
index | values | nulls | frequency | base_frequency
-------+------------------+---------+-----------+----------------
0 | {NULL,x,x} | {t,f,f} | 0.5 | 0.25
1 | {NULL,NULL,NULL} | {t,t,t} | 0.5 | 0.25
(2 rows)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = ''x'' OR d = ''x''');
estimated | actual
-----------+--------
2500 | 2500
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ''x'' OR d = ''x''');
estimated | actual
-----------+--------
2500 | 2500
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IS NULL AND (b = ''x'' OR d = ''x'')');
estimated | actual
-----------+--------
2500 | 2500
(1 row)
-- mcv with pass-by-ref fixlen types, e.g. uuid
CREATE TABLE mcv_lists_uuid (
a UUID,
b UUID,
c UUID
)
WITH (autovacuum_enabled = off);
INSERT INTO mcv_lists_uuid (a, b, c)
SELECT
fipshash(mod(i,100)::text)::uuid,
fipshash(mod(i,50)::text)::uuid,
fipshash(mod(i,25)::text)::uuid
FROM generate_series(1,5000) s(i);
ANALYZE mcv_lists_uuid;
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_uuid WHERE a = ''e7f6c011-776e-8db7-cd33-0b54174fd76f'' AND b = ''e7f6c011-776e-8db7-cd33-0b54174fd76f''');
estimated | actual
-----------+--------
1 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_uuid WHERE a = ''e7f6c011-776e-8db7-cd33-0b54174fd76f'' AND b = ''e7f6c011-776e-8db7-cd33-0b54174fd76f'' AND c = ''e7f6c011-776e-8db7-cd33-0b54174fd76f''');
estimated | actual
-----------+--------
1 | 50
(1 row)
CREATE STATISTICS mcv_lists_uuid_stats (mcv) ON a, b, c
FROM mcv_lists_uuid;
ANALYZE mcv_lists_uuid;
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_uuid WHERE a = ''e7f6c011-776e-8db7-cd33-0b54174fd76f'' AND b = ''e7f6c011-776e-8db7-cd33-0b54174fd76f''');
estimated | actual
-----------+--------
50 | 50
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_uuid WHERE a = ''e7f6c011-776e-8db7-cd33-0b54174fd76f'' AND b = ''e7f6c011-776e-8db7-cd33-0b54174fd76f'' AND c = ''e7f6c011-776e-8db7-cd33-0b54174fd76f''');
estimated | actual
-----------+--------
50 | 50
(1 row)
DROP TABLE mcv_lists_uuid;
-- mcv with arrays
CREATE TABLE mcv_lists_arrays (
a TEXT[],
b NUMERIC[],
c INT[]
)
WITH (autovacuum_enabled = off);
INSERT INTO mcv_lists_arrays (a, b, c)
SELECT
ARRAY[fipshash((i/100)::text), fipshash((i/100-1)::text), fipshash((i/100+1)::text)],
ARRAY[(i/100-1)::numeric/1000, (i/100)::numeric/1000, (i/100+1)::numeric/1000],
ARRAY[(i/100-1), i/100, (i/100+1)]
FROM generate_series(1,5000) s(i);
CREATE STATISTICS mcv_lists_arrays_stats (mcv) ON a, b, c
FROM mcv_lists_arrays;
ANALYZE mcv_lists_arrays;
-- mcv with bool
CREATE TABLE mcv_lists_bool (
a BOOL,
b BOOL,
c BOOL
)
WITH (autovacuum_enabled = off);
INSERT INTO mcv_lists_bool (a, b, c)
SELECT
(mod(i,2) = 0), (mod(i,4) = 0), (mod(i,8) = 0)
FROM generate_series(1,10000) s(i);
ANALYZE mcv_lists_bool;
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE a AND b AND c');
estimated | actual
-----------+--------
156 | 1250
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND b AND c');
estimated | actual
-----------+--------
156 | 0
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND NOT b AND c');
estimated | actual
-----------+--------
469 | 0
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND b AND NOT c');
estimated | actual
-----------+--------
1094 | 0
(1 row)
CREATE STATISTICS mcv_lists_bool_stats (mcv) ON a, b, c
FROM mcv_lists_bool;
ANALYZE mcv_lists_bool;
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE a AND b AND c');
estimated | actual
-----------+--------
1250 | 1250
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND b AND c');
estimated | actual
-----------+--------
1 | 0
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND NOT b AND c');
estimated | actual
-----------+--------
1 | 0
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND b AND NOT c');
estimated | actual
-----------+--------
1 | 0
(1 row)
-- mcv covering just a small fraction of data
CREATE TABLE mcv_lists_partial (
a INT,
b INT,
c INT
);
-- 10 frequent groups, each with 100 elements
INSERT INTO mcv_lists_partial (a, b, c)
SELECT
mod(i,10),
mod(i,10),
mod(i,10)
FROM generate_series(0,999) s(i);
-- 100 groups that will make it to the MCV list (includes the 10 frequent ones)
INSERT INTO mcv_lists_partial (a, b, c)
SELECT
i,
i,
i
FROM generate_series(0,99) s(i);
-- 4000 groups in total, most of which won't make it (just a single item)
INSERT INTO mcv_lists_partial (a, b, c)
SELECT
i,
i,
i
FROM generate_series(0,3999) s(i);
ANALYZE mcv_lists_partial;
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 0 AND b = 0 AND c = 0');
estimated | actual
-----------+--------
1 | 102
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 0 OR b = 0 OR c = 0');
estimated | actual
-----------+--------
300 | 102
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 10 AND b = 10 AND c = 10');
estimated | actual
-----------+--------
1 | 2
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 10 OR b = 10 OR c = 10');
estimated | actual
-----------+--------
6 | 2
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 0 AND b = 0 AND c = 10');
estimated | actual
-----------+--------
1 | 0
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 0 OR b = 0 OR c = 10');
estimated | actual
-----------+--------
204 | 104
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE (a = 0 AND b = 0 AND c = 0) OR (a = 1 AND b = 1 AND c = 1) OR (a = 2 AND b = 2 AND c = 2)');
estimated | actual
-----------+--------
1 | 306
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE (a = 0 AND b = 0) OR (a = 0 AND c = 0) OR (b = 0 AND c = 0)');
estimated | actual
-----------+--------
6 | 102
(1 row)
CREATE STATISTICS mcv_lists_partial_stats (mcv) ON a, b, c
FROM mcv_lists_partial;
ANALYZE mcv_lists_partial;
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 0 AND b = 0 AND c = 0');
estimated | actual
-----------+--------
102 | 102
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 0 OR b = 0 OR c = 0');
estimated | actual
-----------+--------
96 | 102
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 10 AND b = 10 AND c = 10');
estimated | actual
-----------+--------
2 | 2
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 10 OR b = 10 OR c = 10');
estimated | actual
-----------+--------
2 | 2
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 0 AND b = 0 AND c = 10');
estimated | actual
-----------+--------
1 | 0
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 0 OR b = 0 OR c = 10');
estimated | actual
-----------+--------
102 | 104
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE (a = 0 AND b = 0 AND c = 0) OR (a = 1 AND b = 1 AND c = 1) OR (a = 2 AND b = 2 AND c = 2)');
estimated | actual
-----------+--------
306 | 306
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE (a = 0 AND b = 0) OR (a = 0 AND c = 0) OR (b = 0 AND c = 0)');
estimated | actual
-----------+--------
108 | 102
(1 row)
DROP TABLE mcv_lists_partial;
-- check the ability to use multiple MCV lists
CREATE TABLE mcv_lists_multi (
a INTEGER,
b INTEGER,
c INTEGER,
d INTEGER
)
WITH (autovacuum_enabled = off);
INSERT INTO mcv_lists_multi (a, b, c, d)
SELECT
mod(i,5),
mod(i,5),
mod(i,7),
mod(i,7)
FROM generate_series(1,5000) s(i);
ANALYZE mcv_lists_multi;
-- estimates without any mcv statistics
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AND b = 0');
estimated | actual
-----------+--------
200 | 1000
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE c = 0 AND d = 0');
estimated | actual
-----------+--------
102 | 714
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE b = 0 AND c = 0');
estimated | actual
-----------+--------
143 | 142
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE b = 0 OR c = 0');
estimated | actual
-----------+--------
1571 | 1572
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AND b = 0 AND c = 0 AND d = 0');
estimated | actual
-----------+--------
4 | 142
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE (a = 0 AND b = 0) OR (c = 0 AND d = 0)');
estimated | actual
-----------+--------
298 | 1572
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 OR b = 0 OR c = 0 OR d = 0');
estimated | actual
-----------+--------
2649 | 1572
(1 row)
-- create separate MCV statistics
CREATE STATISTICS mcv_lists_multi_1 (mcv) ON a, b FROM mcv_lists_multi;
CREATE STATISTICS mcv_lists_multi_2 (mcv) ON c, d FROM mcv_lists_multi;
ANALYZE mcv_lists_multi;
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AND b = 0');
estimated | actual
-----------+--------
1000 | 1000
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE c = 0 AND d = 0');
estimated | actual
-----------+--------
714 | 714
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE b = 0 AND c = 0');
estimated | actual
-----------+--------
143 | 142
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE b = 0 OR c = 0');
estimated | actual
-----------+--------
1571 | 1572
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AND b = 0 AND c = 0 AND d = 0');
estimated | actual
-----------+--------
143 | 142
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE (a = 0 AND b = 0) OR (c = 0 AND d = 0)');
estimated | actual
-----------+--------
1571 | 1572
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 OR b = 0 OR c = 0 OR d = 0');
estimated | actual
-----------+--------
1571 | 1572
(1 row)
DROP TABLE mcv_lists_multi;
-- statistics on integer expressions
CREATE TABLE expr_stats (a int, b int, c int);
INSERT INTO expr_stats SELECT mod(i,10), mod(i,10), mod(i,10) FROM generate_series(1,1000) s(i);
ANALYZE expr_stats;
SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE (2*a) = 0 AND (3*b) = 0');
estimated | actual
-----------+--------
1 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE (a+b) = 0 AND (a-b) = 0');
estimated | actual
-----------+--------
1 | 100
(1 row)
CREATE STATISTICS expr_stats_1 (mcv) ON (a+b), (a-b), (2*a), (3*b) FROM expr_stats;
ANALYZE expr_stats;
SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE (2*a) = 0 AND (3*b) = 0');
estimated | actual
-----------+--------
100 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE (a+b) = 0 AND (a-b) = 0');
estimated | actual
-----------+--------
100 | 100
(1 row)
DROP STATISTICS expr_stats_1;
DROP TABLE expr_stats;
-- statistics on a mix columns and expressions
CREATE TABLE expr_stats (a int, b int, c int);
INSERT INTO expr_stats SELECT mod(i,10), mod(i,10), mod(i,10) FROM generate_series(1,1000) s(i);
ANALYZE expr_stats;
SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 0 AND (2*a) = 0 AND (3*b) = 0');
estimated | actual
-----------+--------
1 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 3 AND b = 3 AND (a-b) = 0');
estimated | actual
-----------+--------
1 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 0 AND b = 1 AND (a-b) = 0');
estimated | actual
-----------+--------
1 | 0
(1 row)
CREATE STATISTICS expr_stats_1 (mcv) ON a, b, (2*a), (3*b), (a+b), (a-b) FROM expr_stats;
ANALYZE expr_stats;
SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 0 AND (2*a) = 0 AND (3*b) = 0');
estimated | actual
-----------+--------
100 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 3 AND b = 3 AND (a-b) = 0');
estimated | actual
-----------+--------
100 | 100
(1 row)
SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 0 AND b = 1 AND (a-b) = 0');
estimated | actual
-----------+--------
1 | 0
(1 row)
DROP TABLE expr_stats;
-- statistics on expressions with different data types
CREATE TABLE expr_stats (a int, b name, c text);
INSERT INTO expr_stats SELECT mod(i,10), fipshash(mod(i,10)::text), fipshash(mod(i,10)::text) FROM generate_series(1,1000) s(i);
ANALYZE expr_stats;
SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 0 AND (b || c) <= ''z'' AND (c || b) >= ''0''');
estimated | actual
-----------+--------
11 | 100
(1 row)
CREATE STATISTICS expr_stats_1 (mcv) ON a, b, (b || c), (c || b) FROM expr_stats;
ANALYZE expr_stats;
SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 0 AND (b || c) <= ''z'' AND (c || b) >= ''0''');
estimated | actual
-----------+--------
100 | 100
(1 row)
DROP TABLE expr_stats;
-- test handling of a mix of compatible and incompatible expressions
CREATE TABLE expr_stats_incompatible_test (
c0 double precision,
c1 boolean NOT NULL
);
CREATE STATISTICS expr_stat_comp_1 ON c0, c1 FROM expr_stats_incompatible_test;
INSERT INTO expr_stats_incompatible_test VALUES (1234,false), (5678,true);
ANALYZE expr_stats_incompatible_test;
SELECT c0 FROM ONLY expr_stats_incompatible_test WHERE
(
upper('x') LIKE ('x'||('[0,1]'::int4range))
AND
(c0 IN (0, 1) OR c1)
);
c0
----
(0 rows)
DROP TABLE expr_stats_incompatible_test;
-- Permission tests. Users should not be able to see specific data values in
-- the extended statistics, if they lack permission to see those values in
-- the underlying table.
--
-- Currently this is only relevant for MCV stats.
CREATE SCHEMA tststats;
CREATE TABLE tststats.priv_test_tbl (
a int,
b int
);
INSERT INTO tststats.priv_test_tbl
SELECT mod(i,5), mod(i,10) FROM generate_series(1,100) s(i);
CREATE STATISTICS tststats.priv_test_stats (mcv) ON a, b
FROM tststats.priv_test_tbl;
ANALYZE tststats.priv_test_tbl;
-- Check printing info about extended statistics by \dX
create table stts_t1 (a int, b int);
create statistics (ndistinct) on a, b from stts_t1;
create statistics (ndistinct, dependencies) on a, b from stts_t1;
create statistics (ndistinct, dependencies, mcv) on a, b from stts_t1;
create table stts_t2 (a int, b int, c int);
create statistics on b, c from stts_t2;
create table stts_t3 (col1 int, col2 int, col3 int);
create statistics stts_hoge on col1, col2, col3 from stts_t3;
create schema stts_s1;
create schema stts_s2;
create statistics stts_s1.stts_foo on col1, col2 from stts_t3;
create statistics stts_s2.stts_yama (dependencies, mcv) on col1, col3 from stts_t3;
insert into stts_t1 select i,i from generate_series(1,100) i;
analyze stts_t1;
set search_path to public, stts_s1, stts_s2, tststats;
\dX
List of extended statistics
Schema | Name | Definition | Ndistinct | Dependencies | MCV
----------+------------------------+------------------------------------------------------------------+-----------+--------------+---------
public | func_deps_stat | (a * 2), upper(b), (c + 1::numeric) FROM functional_dependencies | | defined |
public | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays | | | defined
public | mcv_lists_bool_stats | a, b, c FROM mcv_lists_bool | | | defined
public | mcv_lists_stats | a, b, d FROM mcv_lists | | | defined
public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined | defined | defined
public | stts_t1_a_b_stat | a, b FROM stts_t1 | defined | |
public | stts_t1_a_b_stat1 | a, b FROM stts_t1 | defined | defined |
public | stts_t1_a_b_stat2 | a, b FROM stts_t1 | defined | defined | defined
public | stts_t2_b_c_stat | b, c FROM stts_t2 | defined | defined | defined
stts_s1 | stts_foo | col1, col2 FROM stts_t3 | defined | defined | defined
stts_s2 | stts_yama | col1, col3 FROM stts_t3 | | defined | defined
tststats | priv_test_stats | a, b FROM priv_test_tbl | | | defined
(12 rows)
\dX stts_t*
List of extended statistics
Schema | Name | Definition | Ndistinct | Dependencies | MCV
--------+-------------------+-------------------+-----------+--------------+---------
public | stts_t1_a_b_stat | a, b FROM stts_t1 | defined | |
public | stts_t1_a_b_stat1 | a, b FROM stts_t1 | defined | defined |
public | stts_t1_a_b_stat2 | a, b FROM stts_t1 | defined | defined | defined
public | stts_t2_b_c_stat | b, c FROM stts_t2 | defined | defined | defined
(4 rows)
\dX *stts_hoge
List of extended statistics
Schema | Name | Definition | Ndistinct | Dependencies | MCV
--------+-----------+-------------------------------+-----------+--------------+---------
public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined | defined | defined
(1 row)
\dX+
List of extended statistics
Schema | Name | Definition | Ndistinct | Dependencies | MCV
----------+------------------------+------------------------------------------------------------------+-----------+--------------+---------
public | func_deps_stat | (a * 2), upper(b), (c + 1::numeric) FROM functional_dependencies | | defined |
public | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays | | | defined
public | mcv_lists_bool_stats | a, b, c FROM mcv_lists_bool | | | defined
public | mcv_lists_stats | a, b, d FROM mcv_lists | | | defined
public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined | defined | defined
public | stts_t1_a_b_stat | a, b FROM stts_t1 | defined | |
public | stts_t1_a_b_stat1 | a, b FROM stts_t1 | defined | defined |
public | stts_t1_a_b_stat2 | a, b FROM stts_t1 | defined | defined | defined
public | stts_t2_b_c_stat | b, c FROM stts_t2 | defined | defined | defined
stts_s1 | stts_foo | col1, col2 FROM stts_t3 | defined | defined | defined
stts_s2 | stts_yama | col1, col3 FROM stts_t3 | | defined | defined
tststats | priv_test_stats | a, b FROM priv_test_tbl | | | defined
(12 rows)
\dX+ stts_t*
List of extended statistics
Schema | Name | Definition | Ndistinct | Dependencies | MCV
--------+-------------------+-------------------+-----------+--------------+---------
public | stts_t1_a_b_stat | a, b FROM stts_t1 | defined | |
public | stts_t1_a_b_stat1 | a, b FROM stts_t1 | defined | defined |
public | stts_t1_a_b_stat2 | a, b FROM stts_t1 | defined | defined | defined
public | stts_t2_b_c_stat | b, c FROM stts_t2 | defined | defined | defined
(4 rows)
\dX+ *stts_hoge
List of extended statistics
Schema | Name | Definition | Ndistinct | Dependencies | MCV
--------+-----------+-------------------------------+-----------+--------------+---------
public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined | defined | defined
(1 row)
\dX+ stts_s2.stts_yama
List of extended statistics
Schema | Name | Definition | Ndistinct | Dependencies | MCV
---------+-----------+-------------------------+-----------+--------------+---------
stts_s2 | stts_yama | col1, col3 FROM stts_t3 | | defined | defined
(1 row)
create statistics (mcv) ON a, b, (a+b), (a-b) FROM stts_t1;
create statistics (mcv) ON a, b, (a+b), (a-b) FROM stts_t1;
create statistics (mcv) ON (a+b), (a-b) FROM stts_t1;
\dX stts_t*expr*
List of extended statistics
Schema | Name | Definition | Ndistinct | Dependencies | MCV
--------+-----------------------------+-------------------------------------+-----------+--------------+---------
public | stts_t1_a_b_expr_expr_stat | a, b, (a + b), (a - b) FROM stts_t1 | | | defined
public | stts_t1_a_b_expr_expr_stat1 | a, b, (a + b), (a - b) FROM stts_t1 | | | defined
public | stts_t1_expr_expr_stat | (a + b), (a - b) FROM stts_t1 | | | defined
(3 rows)
drop statistics stts_t1_a_b_expr_expr_stat;
drop statistics stts_t1_a_b_expr_expr_stat1;
drop statistics stts_t1_expr_expr_stat;
set search_path to public, stts_s1;
\dX
List of extended statistics
Schema | Name | Definition | Ndistinct | Dependencies | MCV
---------+------------------------+------------------------------------------------------------------+-----------+--------------+---------
public | func_deps_stat | (a * 2), upper(b), (c + 1::numeric) FROM functional_dependencies | | defined |
public | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays | | | defined
public | mcv_lists_bool_stats | a, b, c FROM mcv_lists_bool | | | defined
public | mcv_lists_stats | a, b, d FROM mcv_lists | | | defined
public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined | defined | defined
public | stts_t1_a_b_stat | a, b FROM stts_t1 | defined | |
public | stts_t1_a_b_stat1 | a, b FROM stts_t1 | defined | defined |
public | stts_t1_a_b_stat2 | a, b FROM stts_t1 | defined | defined | defined
public | stts_t2_b_c_stat | b, c FROM stts_t2 | defined | defined | defined
stts_s1 | stts_foo | col1, col2 FROM stts_t3 | defined | defined | defined
(10 rows)
create role regress_stats_ext nosuperuser;
set role regress_stats_ext;
\dX
List of extended statistics
Schema | Name | Definition | Ndistinct | Dependencies | MCV
--------+------------------------+------------------------------------------------------------------+-----------+--------------+---------
public | func_deps_stat | (a * 2), upper(b), (c + 1::numeric) FROM functional_dependencies | | defined |
public | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays | | | defined
public | mcv_lists_bool_stats | a, b, c FROM mcv_lists_bool | | | defined
public | mcv_lists_stats | a, b, d FROM mcv_lists | | | defined
public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined | defined | defined
public | stts_t1_a_b_stat | a, b FROM stts_t1 | defined | |
public | stts_t1_a_b_stat1 | a, b FROM stts_t1 | defined | defined |
public | stts_t1_a_b_stat2 | a, b FROM stts_t1 | defined | defined | defined
public | stts_t2_b_c_stat | b, c FROM stts_t2 | defined | defined | defined
(9 rows)
reset role;
drop table stts_t1, stts_t2, stts_t3;
drop schema stts_s1, stts_s2 cascade;
drop user regress_stats_ext;
reset search_path;
-- User with no access
CREATE USER regress_stats_user1;
GRANT USAGE ON SCHEMA tststats TO regress_stats_user1;
SET SESSION AUTHORIZATION regress_stats_user1;
SELECT * FROM tststats.priv_test_tbl; -- Permission denied
ERROR: permission denied for table priv_test_tbl
-- Check individual columns if we don't have table privilege
SELECT * FROM tststats.priv_test_tbl
WHERE a = 1 and tststats.priv_test_tbl.* > (1, 1) is not null;
ERROR: permission denied for table priv_test_tbl
-- Attempt to gain access using a leaky operator
CREATE FUNCTION op_leak(int, int) RETURNS bool
AS 'BEGIN RAISE NOTICE ''op_leak => %, %'', $1, $2; RETURN $1 < $2; END'
LANGUAGE plpgsql;
CREATE OPERATOR <<< (procedure = op_leak, leftarg = int, rightarg = int,
restrict = scalarltsel);
SELECT * FROM tststats.priv_test_tbl WHERE a <<< 0 AND b <<< 0; -- Permission denied
ERROR: permission denied for table priv_test_tbl
DELETE FROM tststats.priv_test_tbl WHERE a <<< 0 AND b <<< 0; -- Permission denied
ERROR: permission denied for table priv_test_tbl
-- Grant access via a security barrier view, but hide all data
RESET SESSION AUTHORIZATION;
CREATE VIEW tststats.priv_test_view WITH (security_barrier=true)
AS SELECT * FROM tststats.priv_test_tbl WHERE false;
GRANT SELECT, DELETE ON tststats.priv_test_view TO regress_stats_user1;
-- Should now have access via the view, but see nothing and leak nothing
SET SESSION AUTHORIZATION regress_stats_user1;
SELECT * FROM tststats.priv_test_view WHERE a <<< 0 AND b <<< 0; -- Should not leak
a | b
---+---
(0 rows)
DELETE FROM tststats.priv_test_view WHERE a <<< 0 AND b <<< 0; -- Should not leak
-- Grant table access, but hide all data with RLS
RESET SESSION AUTHORIZATION;
ALTER TABLE tststats.priv_test_tbl ENABLE ROW LEVEL SECURITY;
GRANT SELECT, DELETE ON tststats.priv_test_tbl TO regress_stats_user1;
-- Should now have direct table access, but see nothing and leak nothing
SET SESSION AUTHORIZATION regress_stats_user1;
SELECT * FROM tststats.priv_test_tbl WHERE a <<< 0 AND b <<< 0; -- Should not leak
a | b
---+---
(0 rows)
DELETE FROM tststats.priv_test_tbl WHERE a <<< 0 AND b <<< 0; -- Should not leak
-- Tidy up
DROP OPERATOR <<< (int, int);
DROP FUNCTION op_leak(int, int);
RESET SESSION AUTHORIZATION;
DROP SCHEMA tststats CASCADE;
NOTICE: drop cascades to 2 other objects
DETAIL: drop cascades to table tststats.priv_test_tbl
drop cascades to view tststats.priv_test_view
DROP USER regress_stats_user1;
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