961 lines
31 KiB
Plaintext
961 lines
31 KiB
Plaintext
-- Generic extended statistics support
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-- We will be checking execution plans without/with statistics, so
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-- let's make sure we get simple non-parallel plans. Also set the
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-- work_mem low so that we can use small amounts of data.
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-- check the number of estimated/actual rows in the top node
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create function check_estimated_rows(text) returns table (estimated int, actual int)
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language plpgsql as
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$$
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declare
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ln text;
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tmp text[];
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first_row bool := true;
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begin
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for ln in
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execute format('explain analyze %s', $1)
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loop
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if first_row then
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first_row := false;
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tmp := regexp_match(ln, 'rows=(\d*) .* rows=(\d*)');
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return query select tmp[1]::int, tmp[2]::int;
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end if;
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end loop;
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end;
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$$;
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-- Verify failures
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CREATE STATISTICS tst;
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ERROR: syntax error at or near ";"
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LINE 1: CREATE STATISTICS tst;
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^
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CREATE STATISTICS tst ON a, b;
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ERROR: syntax error at or near ";"
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LINE 1: CREATE STATISTICS tst ON a, b;
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^
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CREATE STATISTICS tst FROM sometab;
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ERROR: syntax error at or near "FROM"
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LINE 1: CREATE STATISTICS tst FROM sometab;
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^
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CREATE STATISTICS tst ON a, b FROM nonexistent;
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ERROR: relation "nonexistent" does not exist
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CREATE STATISTICS tst ON a, b FROM pg_class;
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ERROR: column "a" does not exist
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CREATE STATISTICS tst ON relname, relname, relnatts FROM pg_class;
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ERROR: duplicate column name in statistics definition
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CREATE STATISTICS tst ON relnatts + relpages FROM pg_class;
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ERROR: only simple column references are allowed in CREATE STATISTICS
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CREATE STATISTICS tst ON (relpages, reltuples) FROM pg_class;
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ERROR: only simple column references are allowed in CREATE STATISTICS
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CREATE STATISTICS tst (unrecognized) ON relname, relnatts FROM pg_class;
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ERROR: unrecognized statistics kind "unrecognized"
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-- Ensure stats are dropped sanely, and test IF NOT EXISTS while at it
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CREATE TABLE ab1 (a INTEGER, b INTEGER, c INTEGER);
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CREATE STATISTICS IF NOT EXISTS ab1_a_b_stats ON a, b FROM ab1;
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CREATE STATISTICS IF NOT EXISTS ab1_a_b_stats ON a, b FROM ab1;
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NOTICE: statistics object "ab1_a_b_stats" already exists, skipping
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DROP STATISTICS ab1_a_b_stats;
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CREATE SCHEMA regress_schema_2;
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CREATE STATISTICS regress_schema_2.ab1_a_b_stats ON a, b FROM ab1;
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-- Let's also verify the pg_get_statisticsobjdef output looks sane.
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SELECT pg_get_statisticsobjdef(oid) FROM pg_statistic_ext WHERE stxname = 'ab1_a_b_stats';
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pg_get_statisticsobjdef
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-------------------------------------------------------------------
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CREATE STATISTICS regress_schema_2.ab1_a_b_stats ON a, b FROM ab1
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(1 row)
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DROP STATISTICS regress_schema_2.ab1_a_b_stats;
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-- Ensure statistics are dropped when columns are
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CREATE STATISTICS ab1_b_c_stats ON b, c FROM ab1;
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CREATE STATISTICS ab1_a_b_c_stats ON a, b, c FROM ab1;
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CREATE STATISTICS ab1_b_a_stats ON b, a FROM ab1;
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ALTER TABLE ab1 DROP COLUMN a;
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\d ab1
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Table "public.ab1"
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Column | Type | Collation | Nullable | Default
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--------+---------+-----------+----------+---------
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b | integer | | |
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c | integer | | |
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Statistics objects:
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"public"."ab1_b_c_stats" (ndistinct, dependencies, mcv) ON b, c FROM ab1
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-- Ensure statistics are dropped when table is
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SELECT stxname FROM pg_statistic_ext WHERE stxname LIKE 'ab1%';
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stxname
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---------------
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ab1_b_c_stats
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(1 row)
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DROP TABLE ab1;
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SELECT stxname FROM pg_statistic_ext WHERE stxname LIKE 'ab1%';
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stxname
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---------
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(0 rows)
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-- Ensure things work sanely with SET STATISTICS 0
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CREATE TABLE ab1 (a INTEGER, b INTEGER);
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ALTER TABLE ab1 ALTER a SET STATISTICS 0;
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INSERT INTO ab1 SELECT a, a%23 FROM generate_series(1, 1000) a;
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CREATE STATISTICS ab1_a_b_stats ON a, b FROM ab1;
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ANALYZE ab1;
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WARNING: statistics object "public.ab1_a_b_stats" could not be computed for relation "public.ab1"
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ALTER TABLE ab1 ALTER a SET STATISTICS -1;
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-- setting statistics target 0 skips the statistics, without printing any message, so check catalog
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ALTER STATISTICS ab1_a_b_stats SET STATISTICS 0;
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ANALYZE ab1;
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SELECT stxname, stxdndistinct, stxddependencies, stxdmcv
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FROM pg_statistic_ext s, pg_statistic_ext_data d
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WHERE s.stxname = 'ab1_a_b_stats'
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AND d.stxoid = s.oid;
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stxname | stxdndistinct | stxddependencies | stxdmcv
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---------------+---------------+------------------+---------
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ab1_a_b_stats | | |
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(1 row)
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ALTER STATISTICS ab1_a_b_stats SET STATISTICS -1;
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-- partial analyze doesn't build stats either
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ANALYZE ab1 (a);
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WARNING: statistics object "public.ab1_a_b_stats" could not be computed for relation "public.ab1"
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ANALYZE ab1;
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DROP TABLE ab1;
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ALTER STATISTICS ab1_a_b_stats SET STATISTICS 0;
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ERROR: statistics object "ab1_a_b_stats" does not exist
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ALTER STATISTICS IF EXISTS ab1_a_b_stats SET STATISTICS 0;
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NOTICE: statistics object "ab1_a_b_stats" does not exist, skipping
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-- Ensure we can build statistics for tables with inheritance.
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CREATE TABLE ab1 (a INTEGER, b INTEGER);
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CREATE TABLE ab1c () INHERITS (ab1);
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INSERT INTO ab1 VALUES (1,1);
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CREATE STATISTICS ab1_a_b_stats ON a, b FROM ab1;
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ANALYZE ab1;
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DROP TABLE ab1 CASCADE;
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NOTICE: drop cascades to table ab1c
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-- Verify supported object types for extended statistics
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CREATE schema tststats;
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CREATE TABLE tststats.t (a int, b int, c text);
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CREATE INDEX ti ON tststats.t (a, b);
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CREATE SEQUENCE tststats.s;
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CREATE VIEW tststats.v AS SELECT * FROM tststats.t;
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CREATE MATERIALIZED VIEW tststats.mv AS SELECT * FROM tststats.t;
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CREATE TYPE tststats.ty AS (a int, b int, c text);
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CREATE FOREIGN DATA WRAPPER extstats_dummy_fdw;
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CREATE SERVER extstats_dummy_srv FOREIGN DATA WRAPPER extstats_dummy_fdw;
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CREATE FOREIGN TABLE tststats.f (a int, b int, c text) SERVER extstats_dummy_srv;
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CREATE TABLE tststats.pt (a int, b int, c text) PARTITION BY RANGE (a, b);
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CREATE TABLE tststats.pt1 PARTITION OF tststats.pt FOR VALUES FROM (-10, -10) TO (10, 10);
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CREATE STATISTICS tststats.s1 ON a, b FROM tststats.t;
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CREATE STATISTICS tststats.s2 ON a, b FROM tststats.ti;
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ERROR: relation "ti" is not a table, foreign table, or materialized view
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CREATE STATISTICS tststats.s3 ON a, b FROM tststats.s;
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ERROR: relation "s" is not a table, foreign table, or materialized view
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CREATE STATISTICS tststats.s4 ON a, b FROM tststats.v;
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ERROR: relation "v" is not a table, foreign table, or materialized view
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CREATE STATISTICS tststats.s5 ON a, b FROM tststats.mv;
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CREATE STATISTICS tststats.s6 ON a, b FROM tststats.ty;
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ERROR: relation "ty" is not a table, foreign table, or materialized view
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CREATE STATISTICS tststats.s7 ON a, b FROM tststats.f;
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CREATE STATISTICS tststats.s8 ON a, b FROM tststats.pt;
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CREATE STATISTICS tststats.s9 ON a, b FROM tststats.pt1;
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DO $$
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DECLARE
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relname text := reltoastrelid::regclass FROM pg_class WHERE oid = 'tststats.t'::regclass;
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BEGIN
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EXECUTE 'CREATE STATISTICS tststats.s10 ON a, b FROM ' || relname;
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EXCEPTION WHEN wrong_object_type THEN
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RAISE NOTICE 'stats on toast table not created';
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END;
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$$;
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NOTICE: stats on toast table not created
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DROP SCHEMA tststats CASCADE;
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NOTICE: drop cascades to 7 other objects
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DETAIL: drop cascades to table tststats.t
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drop cascades to sequence tststats.s
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drop cascades to view tststats.v
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drop cascades to materialized view tststats.mv
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drop cascades to type tststats.ty
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drop cascades to foreign table tststats.f
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drop cascades to table tststats.pt
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DROP FOREIGN DATA WRAPPER extstats_dummy_fdw CASCADE;
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NOTICE: drop cascades to server extstats_dummy_srv
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-- n-distinct tests
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CREATE TABLE ndistinct (
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filler1 TEXT,
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filler2 NUMERIC,
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a INT,
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b INT,
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filler3 DATE,
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c INT,
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d INT
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);
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-- over-estimates when using only per-column statistics
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INSERT INTO ndistinct (a, b, c, filler1)
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SELECT i/100, i/100, i/100, cash_words((i/100)::money)
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FROM generate_series(1,1000) s(i);
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ANALYZE ndistinct;
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-- Group Aggregate, due to over-estimate of the number of groups
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SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b');
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estimated | actual
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-----------+--------
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100 | 11
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(1 row)
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SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY b, c');
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estimated | actual
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-----------+--------
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100 | 11
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(1 row)
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SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b, c');
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estimated | actual
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-----------+--------
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100 | 11
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(1 row)
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SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b, c, d');
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estimated | actual
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-----------+--------
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200 | 11
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(1 row)
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SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY b, c, d');
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estimated | actual
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-----------+--------
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200 | 11
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(1 row)
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-- correct command
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CREATE STATISTICS s10 ON a, b, c FROM ndistinct;
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ANALYZE ndistinct;
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SELECT s.stxkind, d.stxdndistinct
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FROM pg_statistic_ext s, pg_statistic_ext_data d
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WHERE s.stxrelid = 'ndistinct'::regclass
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AND d.stxoid = s.oid;
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stxkind | stxdndistinct
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---------+-----------------------------------------------------
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{d,f,m} | {"3, 4": 11, "3, 6": 11, "4, 6": 11, "3, 4, 6": 11}
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(1 row)
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-- minor improvement, make sure the ctid does not break the matching
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SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY ctid, a, b');
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estimated | actual
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-----------+--------
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11 | 1000
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(1 row)
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-- Hash Aggregate, thanks to estimates improved by the statistic
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SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b');
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estimated | actual
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-----------+--------
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11 | 11
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(1 row)
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SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY b, c');
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estimated | actual
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-----------+--------
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11 | 11
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(1 row)
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SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b, c');
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estimated | actual
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-----------+--------
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11 | 11
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(1 row)
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-- last two plans keep using Group Aggregate, because 'd' is not covered
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-- by the statistic and while it's NULL-only we assume 200 values for it
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SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b, c, d');
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estimated | actual
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-----------+--------
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200 | 11
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(1 row)
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SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY b, c, d');
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estimated | actual
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-----------+--------
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200 | 11
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(1 row)
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TRUNCATE TABLE ndistinct;
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-- under-estimates when using only per-column statistics
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INSERT INTO ndistinct (a, b, c, filler1)
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SELECT mod(i,50), mod(i,51), mod(i,32),
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cash_words(mod(i,33)::int::money)
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FROM generate_series(1,5000) s(i);
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ANALYZE ndistinct;
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SELECT s.stxkind, d.stxdndistinct
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FROM pg_statistic_ext s, pg_statistic_ext_data d
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WHERE s.stxrelid = 'ndistinct'::regclass
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AND d.stxoid = s.oid;
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stxkind | stxdndistinct
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---------+------------------------------------------------------------
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{d,f,m} | {"3, 4": 2550, "3, 6": 800, "4, 6": 1632, "3, 4, 6": 5000}
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(1 row)
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-- correct esimates
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SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b');
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estimated | actual
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-----------+--------
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2550 | 2550
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(1 row)
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SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b, c');
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estimated | actual
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-----------+--------
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5000 | 5000
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(1 row)
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SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b, c, d');
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estimated | actual
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-----------+--------
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5000 | 5000
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(1 row)
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SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY b, c, d');
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estimated | actual
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-----------+--------
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1632 | 1632
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(1 row)
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SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, d');
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estimated | actual
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-----------+--------
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500 | 50
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(1 row)
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DROP STATISTICS s10;
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SELECT s.stxkind, d.stxdndistinct
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FROM pg_statistic_ext s, pg_statistic_ext_data d
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WHERE s.stxrelid = 'ndistinct'::regclass
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AND d.stxoid = s.oid;
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stxkind | stxdndistinct
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---------+---------------
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(0 rows)
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-- dropping the statistics results in under-estimates
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SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b');
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estimated | actual
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-----------+--------
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500 | 2550
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(1 row)
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SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b, c');
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estimated | actual
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-----------+--------
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500 | 5000
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(1 row)
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SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b, c, d');
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estimated | actual
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-----------+--------
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500 | 5000
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(1 row)
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SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY b, c, d');
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estimated | actual
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-----------+--------
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500 | 1632
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(1 row)
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SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, d');
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estimated | actual
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-----------+--------
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500 | 50
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(1 row)
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-- functional dependencies tests
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CREATE TABLE functional_dependencies (
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filler1 TEXT,
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filler2 NUMERIC,
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a INT,
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b TEXT,
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filler3 DATE,
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c INT,
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d TEXT
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);
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CREATE INDEX fdeps_ab_idx ON functional_dependencies (a, b);
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CREATE INDEX fdeps_abc_idx ON functional_dependencies (a, b, c);
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-- random data (no functional dependencies)
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INSERT INTO functional_dependencies (a, b, c, filler1)
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SELECT mod(i, 23), mod(i, 29), mod(i, 31), i FROM generate_series(1,5000) s(i);
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ANALYZE functional_dependencies;
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SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = 1 AND b = ''1''');
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estimated | actual
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-----------+--------
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8 | 8
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(1 row)
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SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = 1 AND b = ''1'' AND c = 1');
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estimated | actual
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-----------+--------
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1 | 1
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(1 row)
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-- create statistics
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CREATE STATISTICS func_deps_stat (dependencies) ON a, b, c FROM functional_dependencies;
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ANALYZE functional_dependencies;
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SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = 1 AND b = ''1''');
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estimated | actual
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|
-----------+--------
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8 | 8
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(1 row)
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SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = 1 AND b = ''1'' AND c = 1');
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estimated | actual
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-----------+--------
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1 | 1
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(1 row)
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-- a => b, a => c, b => c
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TRUNCATE functional_dependencies;
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DROP STATISTICS func_deps_stat;
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INSERT INTO functional_dependencies (a, b, c, filler1)
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SELECT mod(i,100), mod(i,50), mod(i,25), i FROM generate_series(1,5000) s(i);
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ANALYZE functional_dependencies;
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SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = 1 AND b = ''1''');
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estimated | actual
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-----------+--------
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1 | 50
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(1 row)
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SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = 1 AND b = ''1'' AND c = 1');
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estimated | actual
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-----------+--------
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1 | 50
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(1 row)
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-- create statistics
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CREATE STATISTICS func_deps_stat (dependencies) ON a, b, c FROM functional_dependencies;
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ANALYZE functional_dependencies;
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SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = 1 AND b = ''1''');
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estimated | actual
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-----------+--------
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50 | 50
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|
(1 row)
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SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = 1 AND b = ''1'' AND c = 1');
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estimated | actual
|
|
-----------+--------
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|
50 | 50
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|
(1 row)
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|
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-- check change of column type doesn't break it
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ALTER TABLE functional_dependencies ALTER COLUMN c TYPE numeric;
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SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = 1 AND b = ''1'' AND c = 1');
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estimated | actual
|
|
-----------+--------
|
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50 | 50
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|
(1 row)
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ANALYZE functional_dependencies;
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SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = 1 AND b = ''1'' AND c = 1');
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estimated | actual
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|
-----------+--------
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50 | 50
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(1 row)
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|
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-- check the ability to use multiple functional dependencies
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CREATE TABLE functional_dependencies_multi (
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a INTEGER,
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b INTEGER,
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c INTEGER,
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d INTEGER
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);
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INSERT INTO functional_dependencies_multi (a, b, c, d)
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SELECT
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mod(i,7),
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mod(i,7),
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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 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)
|
|
|
|
-- 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 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)
|
|
|
|
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
|
|
);
|
|
-- 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)
|
|
|
|
-- 100 distinct combinations, all in the MCV list
|
|
TRUNCATE mcv_lists;
|
|
DROP STATISTICS mcv_lists_stats;
|
|
INSERT INTO mcv_lists (a, b, c, filler1)
|
|
SELECT mod(i,100), mod(i,50), 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 a < 1 AND b < ''1''');
|
|
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 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 <= 4 AND b <= ''0'' AND c <= 4');
|
|
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)
|
|
|
|
-- 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
|
|
-----------+--------
|
|
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 a <= 0 AND b <= ''0''');
|
|
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 <= 4 AND b <= ''0'' AND c <= 4');
|
|
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)
|
|
|
|
-- 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 a = 1 OR b = ''1'' OR c = 1 OR d IS NOT NULL');
|
|
estimated | actual
|
|
-----------+--------
|
|
343 | 200
|
|
(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 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)
|
|
|
|
-- 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)
|
|
|
|
-- 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
|
|
(CASE WHEN mod(i,2) = 0 THEN NULL ELSE 0 END),
|
|
(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)
|
|
|
|
-- create statistics
|
|
CREATE STATISTICS mcv_lists_stats (mcv) ON b, d FROM mcv_lists;
|
|
ANALYZE mcv_lists;
|
|
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = ''x'' OR d = ''x''');
|
|
estimated | actual
|
|
-----------+--------
|
|
2500 | 2500
|
|
(1 row)
|
|
|
|
-- mcv with arrays
|
|
CREATE TABLE mcv_lists_arrays (
|
|
a TEXT[],
|
|
b NUMERIC[],
|
|
c INT[]
|
|
);
|
|
INSERT INTO mcv_lists_arrays (a, b, c)
|
|
SELECT
|
|
ARRAY[md5((i/100)::text), md5((i/100-1)::text), md5((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
|
|
);
|
|
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)
|
|
|
|
-- check the ability to use multiple MCV lists
|
|
CREATE TABLE mcv_lists_multi (
|
|
a INTEGER,
|
|
b INTEGER,
|
|
c INTEGER,
|
|
d INTEGER
|
|
);
|
|
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 a = 0 AND b = 0 AND c = 0 AND d = 0');
|
|
estimated | actual
|
|
-----------+--------
|
|
4 | 142
|
|
(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 a = 0 AND b = 0 AND c = 0 AND d = 0');
|
|
estimated | actual
|
|
-----------+--------
|
|
143 | 142
|
|
(1 row)
|
|
|
|
DROP TABLE mcv_lists_multi;
|
|
-- 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;
|
|
-- 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
|
|
-- 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
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-- Tidy up
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DROP OPERATOR <<< (int, int);
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DROP FUNCTION op_leak(int, int);
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RESET SESSION AUTHORIZATION;
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DROP SCHEMA tststats CASCADE;
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NOTICE: drop cascades to 2 other objects
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DETAIL: drop cascades to table tststats.priv_test_tbl
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drop cascades to view tststats.priv_test_view
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DROP USER regress_stats_user1;
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