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

-- Generic extended statistics support
-- Ensure stats are dropped sanely
CREATE TABLE ab1 (a INTEGER, b INTEGER, c INTEGER);
CREATE STATISTICS ab1_a_b_stats ON (a, b) FROM ab1;
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;
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_a_b_stats ON (a, b) FROM ab1;
ALTER TABLE ab1 DROP COLUMN a;
\d ab1
                Table "public.ab1"
 Column |  Type   | Collation | Nullable | Default 
--------+---------+-----------+----------+---------
 b      | integer |           |          | 
 c      | integer |           |          | 
Statistics:
    "public.ab1_b_c_stats" WITH (ndistinct) ON (b, c)

DROP TABLE ab1;
-- 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;
ERROR:  extended statistics could not be collected for column "a" of relation public.ab1
HINT:  Consider ALTER TABLE "public"."ab1" ALTER "a" SET STATISTICS -1
ALTER TABLE ab1 ALTER a SET STATISTICS -1;
ANALYZE ab1;
DROP TABLE ab1;
-- n-distinct tests
CREATE TABLE ndistinct (
    filler1 TEXT,
    filler2 NUMERIC,
    a INT,
    b INT,
    filler3 DATE,
    c INT,
    d INT
);
-- unknown column
CREATE STATISTICS s10 ON (unknown_column) FROM ndistinct;
ERROR:  column "unknown_column" referenced in statistics does not exist
-- single column
CREATE STATISTICS s10 ON (a) FROM ndistinct;
ERROR:  statistics require at least 2 columns
-- single column, duplicated
CREATE STATISTICS s10 ON (a,a) FROM ndistinct;
ERROR:  duplicate column name in statistics definition
-- two columns, one duplicated
CREATE STATISTICS s10 ON (a, a, b) FROM ndistinct;
ERROR:  duplicate column name in statistics definition
-- correct command
CREATE STATISTICS s10 ON (a, b, c) FROM ndistinct;
-- perfectly correlated groups
INSERT INTO ndistinct (a, b, c, filler1)
     SELECT i/100, i/100, i/100, cash_words(i::money)
       FROM generate_series(1,10000) s(i);
ANALYZE ndistinct;
SELECT staenabled, standistinct
  FROM pg_statistic_ext WHERE starelid = 'ndistinct'::regclass;
 staenabled |                                          standistinct                                          
------------+------------------------------------------------------------------------------------------------
 {d}        | [{(b 3 4), 101.000000}, {(b 3 6), 101.000000}, {(b 4 6), 101.000000}, {(b 3 4 6), 101.000000}]
(1 row)

EXPLAIN (COSTS off)
 SELECT COUNT(*) FROM ndistinct GROUP BY a, b;
         QUERY PLAN          
-----------------------------
 HashAggregate
   Group Key: a, b
   ->  Seq Scan on ndistinct
(3 rows)

EXPLAIN (COSTS off)
 SELECT COUNT(*) FROM ndistinct GROUP BY a, b, c;
         QUERY PLAN          
-----------------------------
 HashAggregate
   Group Key: a, b, c
   ->  Seq Scan on ndistinct
(3 rows)

EXPLAIN (COSTS off)
 SELECT COUNT(*) FROM ndistinct GROUP BY a, b, c, d;
         QUERY PLAN          
-----------------------------
 HashAggregate
   Group Key: a, b, c, d
   ->  Seq Scan on ndistinct
(3 rows)

TRUNCATE TABLE ndistinct;
-- partially correlated groups
INSERT INTO ndistinct (a, b, c)
     SELECT i/50, i/100, i/200 FROM generate_series(1,10000) s(i);
ANALYZE ndistinct;
SELECT staenabled, standistinct
  FROM pg_statistic_ext WHERE starelid = 'ndistinct'::regclass;
 staenabled |                                          standistinct                                          
------------+------------------------------------------------------------------------------------------------
 {d}        | [{(b 3 4), 201.000000}, {(b 3 6), 201.000000}, {(b 4 6), 101.000000}, {(b 3 4 6), 201.000000}]
(1 row)

EXPLAIN
 SELECT COUNT(*) FROM ndistinct GROUP BY a, b;
                             QUERY PLAN                              
---------------------------------------------------------------------
 HashAggregate  (cost=230.00..232.01 rows=201 width=16)
   Group Key: a, b
   ->  Seq Scan on ndistinct  (cost=0.00..155.00 rows=10000 width=8)
(3 rows)

EXPLAIN
 SELECT COUNT(*) FROM ndistinct GROUP BY a, b, c;
                              QUERY PLAN                              
----------------------------------------------------------------------
 HashAggregate  (cost=255.00..257.01 rows=201 width=20)
   Group Key: a, b, c
   ->  Seq Scan on ndistinct  (cost=0.00..155.00 rows=10000 width=12)
(3 rows)

EXPLAIN
 SELECT COUNT(*) FROM ndistinct GROUP BY a, b, c, d;
                              QUERY PLAN                              
----------------------------------------------------------------------
 HashAggregate  (cost=280.00..290.00 rows=1000 width=24)
   Group Key: a, b, c, d
   ->  Seq Scan on ndistinct  (cost=0.00..155.00 rows=10000 width=16)
(3 rows)

EXPLAIN
 SELECT COUNT(*) FROM ndistinct GROUP BY b, c, d;
                              QUERY PLAN                              
----------------------------------------------------------------------
 HashAggregate  (cost=255.00..265.00 rows=1000 width=20)
   Group Key: b, c, d
   ->  Seq Scan on ndistinct  (cost=0.00..155.00 rows=10000 width=12)
(3 rows)

EXPLAIN
 SELECT COUNT(*) FROM ndistinct GROUP BY a, d;
                             QUERY PLAN                              
---------------------------------------------------------------------
 HashAggregate  (cost=230.00..240.00 rows=1000 width=16)
   Group Key: a, d
   ->  Seq Scan on ndistinct  (cost=0.00..155.00 rows=10000 width=8)
(3 rows)

DROP TABLE ndistinct;