One more step towards improving the AQO regression tests stability.

Move GUCs, which can be changed in runtime, from global regression tests conf
to first executed test 'aqo_disabled.sql'. There we set these values by ALTER
SYSTEM/pg_reload_conf() and use them during the test.
Also, we call aqo_reset() at the start of each test.

And a bit more:
1. Avoid to show a number of records in AQO ML storage - it can
depend on optimizer settings and quite unstable (in progress).
2. Use aliases query in output to avoid unstability of naming of anonymous
columns.

Author: danolivo

Makefile

@@ -16,6 +16,12 @@ TAP_TESTS = 1
 REGRESS = aqo_dummy_test
 REGRESS_OPTS = --schedule=$(srcdir)/regress_schedule
 
+# Set default values of some gucs to be stable on custom settings during
+# a kind of installcheck
+PGOPTIONS = --aqo.force_collect_stat=off --max_parallel_maintenance_workers=1 \
+	--aqo.join_threshold=0 --max_parallel_workers_per_gather=1
+export PGOPTIONS
+
 fdw_srcdir = $(top_srcdir)/contrib/postgres_fdw
 stat_srcdir = $(top_srcdir)/contrib/pg_stat_statements
 PG_CPPFLAGS += -I$(libpq_srcdir) -I$(fdw_srcdir) -I$(stat_srcdir)

aqo.conf

@@ -1,5 +1,3 @@
 autovacuum = off
 shared_preload_libraries = 'postgres_fdw, aqo'
-max_parallel_maintenance_workers = 1 # switch off parallel workers because of unsteadiness
-aqo.wide_search = 'on'
 compute_query_id = 'regress'

expected/aqo_controlled.out

@@ -1,3 +1,10 @@
+CREATE EXTENSION IF NOT EXISTS aqo;
+SELECT true AS success FROM aqo_reset();
+ success 
+---------
+ t
+(1 row)
+
 CREATE TABLE aqo_test0(a int, b int, c int, d int);
 WITH RECURSIVE t(a, b, c, d)
 AS (
@@ -25,8 +32,6 @@ AS (
 ) INSERT INTO aqo_test2 (SELECT * FROM t);
 CREATE INDEX aqo_test2_idx_a ON aqo_test2 (a);
 ANALYZE aqo_test2;
-CREATE EXTENSION aqo;
-SET aqo.join_threshold = 0;
 SET aqo.mode = 'controlled';
 EXPLAIN (COSTS FALSE)
 SELECT * FROM aqo_test0
@@ -199,11 +204,12 @@ WHERE t1.a = t2.b AND t2.a = t3.b;
 
 SELECT count(*) FROM
 	(SELECT queryid AS id FROM aqo_queries) AS q1,
-	LATERAL aqo_queries_update(q1.id, NULL, NULL, true, NULL)
+	LATERAL aqo_queries_update(q1.id, NULL, NULL, true, NULL) AS ret
+WHERE NOT ret
 ; -- set use = true
  count 
 -------
-    12
+     1
 (1 row)
 
 EXPLAIN (COSTS FALSE)
@@ -311,11 +317,4 @@ DROP INDEX aqo_test1_idx_a;
 DROP TABLE aqo_test1;
 DROP INDEX aqo_test2_idx_a;
 DROP TABLE aqo_test2;
--- XXX: extension dropping doesn't clear file storage. Do it manually.
-SELECT 1 FROM aqo_reset();
- ?column? 
-----------
-        1
-(1 row)
-
 DROP EXTENSION aqo;

expected/aqo_disabled.out

@@ -1,3 +1,12 @@
+-- Create the extension. Drop all lumps which could survive from
+-- previous pass (repeated installcheck as an example).
+CREATE EXTENSION IF NOT EXISTS aqo;
+SELECT true AS success FROM aqo_reset();
+ success 
+---------
+ t
+(1 row)
+
 CREATE TABLE aqo_test0(a int, b int, c int, d int);
 WITH RECURSIVE t(a, b, c, d)
 AS (
@@ -16,8 +25,6 @@ AS (
 ) INSERT INTO aqo_test1 (SELECT * FROM t);
 CREATE INDEX aqo_test1_idx_a ON aqo_test1 (a);
 ANALYZE aqo_test1;
-CREATE EXTENSION aqo;
-SET aqo.join_threshold = 0;
 SET aqo.mode = 'controlled';
 CREATE TABLE tmp1 AS SELECT * FROM aqo_test0
 WHERE a < 3 AND b < 3 AND c < 3 AND d < 3;
@@ -151,11 +158,12 @@ SELECT count(*) FROM aqo_queries WHERE queryid <> fs; -- Should be zero
 SET aqo.mode = 'controlled';
 SELECT count(*) FROM
 	(SELECT queryid AS id FROM aqo_queries) AS q1,
-	LATERAL aqo_queries_update(q1.id, NULL, true, true, false)
+	LATERAL aqo_queries_update(q1.id, NULL, true, true, false) AS ret
+WHERE NOT ret
 ; -- Enable all disabled query classes
  count 
 -------
-     5
+     1
 (1 row)
 
 EXPLAIN SELECT * FROM aqo_test0
@@ -223,15 +231,8 @@ SELECT count(*) FROM aqo_queries WHERE queryid <> fs; -- Should be zero
      0
 (1 row)
 
--- XXX: extension dropping doesn't clear file storage. Do it manually.
-SELECT 1 FROM aqo_reset();
- ?column? 
-----------
-        1
-(1 row)
-
-DROP EXTENSION aqo;
 DROP INDEX aqo_test0_idx_a;
 DROP TABLE aqo_test0;
 DROP INDEX aqo_test1_idx_a;
 DROP TABLE aqo_test1;
+DROP EXTENSION aqo;

expected/aqo_fdw.out

@@ -3,12 +3,17 @@
 -- JOIN push-down (check push of baserestrictinfo and joininfo)
 -- Aggregate push-down
 -- Push-down of groupings with HAVING clause.
-CREATE EXTENSION aqo;
-CREATE EXTENSION postgres_fdw;
+CREATE EXTENSION IF NOT EXISTS aqo;
+CREATE EXTENSION IF NOT EXISTS postgres_fdw;
+SELECT true AS success FROM aqo_reset();
+ success 
+---------
+ t
+(1 row)
+
 SET aqo.mode = 'learn';
 SET aqo.show_details = 'true'; -- show AQO info for each node and entire query.
 SET aqo.show_hash = 'false'; -- a hash value is system-depended. Ignore it.
-SET aqo.join_threshold = 0;
 DO $d$
     BEGIN
         EXECUTE $$CREATE SERVER loopback FOREIGN DATA WRAPPER postgres_fdw
@@ -100,15 +105,23 @@ SELECT str FROM expln('
   EXPLAIN (ANALYZE, COSTS OFF, SUMMARY OFF, TIMING OFF)
   SELECT * FROM frgn AS a, frgn AS b WHERE a.x=b.x;
 ') AS str WHERE str NOT LIKE '%Sort Method%';
-                    str                    
--------------------------------------------
- Foreign Scan (actual rows=1 loops=1)
+                            str                             
+------------------------------------------------------------
+ Merge Join (actual rows=1 loops=1)
    AQO not used
-   Relations: (frgn a) INNER JOIN (frgn b)
+   Merge Cond: (a.x = b.x)
+   ->  Sort (actual rows=1 loops=1)
+         Sort Key: a.x
+         ->  Foreign Scan on frgn a (actual rows=1 loops=1)
+               AQO not used
+   ->  Sort (actual rows=1 loops=1)
+         Sort Key: b.x
+         ->  Foreign Scan on frgn b (actual rows=1 loops=1)
+               AQO not used
  Using aqo: true
  AQO mode: LEARN
  JOINS: 0
-(6 rows)
+(14 rows)
 
 -- Should learn on postgres_fdw nodes
 SELECT str FROM expln('

expected/aqo_forced.out

@@ -1,3 +1,11 @@
+-- Preliminaries
+CREATE EXTENSION IF NOT EXISTS aqo;
+SELECT true AS success FROM aqo_reset();
+ success 
+---------
+ t
+(1 row)
+
 CREATE TABLE aqo_test0(a int, b int, c int, d int);
 WITH RECURSIVE t(a, b, c, d)
 AS (
@@ -16,8 +24,6 @@ AS (
 ) INSERT INTO aqo_test1 (SELECT * FROM t);
 CREATE INDEX aqo_test1_idx_a ON aqo_test1 (a);
 ANALYZE aqo_test1;
-CREATE EXTENSION aqo;
-SET aqo.join_threshold = 0;
 SET aqo.mode = 'controlled';
 EXPLAIN (COSTS FALSE)
 SELECT * FROM aqo_test0
@@ -82,11 +88,4 @@ DROP INDEX aqo_test0_idx_a;
 DROP TABLE aqo_test0;
 DROP INDEX aqo_test1_idx_a;
 DROP TABLE aqo_test1;
--- XXX: extension dropping doesn't clear file storage. Do it manually.
-SELECT 1 FROM aqo_reset();
- ?column? 
-----------
-        1
-(1 row)
-
 DROP EXTENSION aqo;

expected/aqo_intelligent.out

@@ -1,3 +1,10 @@
+CREATE EXTENSION IF NOT EXISTS aqo;
+SELECT true AS success FROM aqo_reset();
+ success 
+---------
+ t
+(1 row)
+
 CREATE TABLE aqo_test0(a int, b int, c int, d int);
 WITH RECURSIVE t(a, b, c, d)
 AS (
@@ -16,8 +23,6 @@ AS (
 ) INSERT INTO aqo_test1 (SELECT * FROM t);
 CREATE INDEX aqo_test1_idx_a ON aqo_test1 (a);
 ANALYZE aqo_test1;
-CREATE EXTENSION aqo;
-SET aqo.join_threshold = 0;
 SET aqo.mode = 'intelligent';
 EXPLAIN SELECT * FROM aqo_test0
 WHERE a < 3 AND b < 3 AND c < 3 AND d < 3;
@@ -519,11 +524,4 @@ DROP INDEX aqo_test0_idx_a;
 DROP TABLE aqo_test0;
 DROP INDEX aqo_test1_idx_a;
 DROP TABLE aqo_test1;
--- XXX: extension dropping doesn't clear file storage. Do it manually.
-SELECT 1 FROM aqo_reset();
- ?column? 
-----------
-        1
-(1 row)
-
 DROP EXTENSION aqo;

expected/aqo_learn.out

@@ -1,3 +1,10 @@
+CREATE EXTENSION IF NOT EXISTS aqo;
+SELECT true AS success FROM aqo_reset();
+ success 
+---------
+ t
+(1 row)
+
 -- The function just copied from stats_ext.sql
 create function check_estimated_rows(text) returns table (estimated int, actual int)
 language plpgsql as
@@ -36,8 +43,6 @@ AS (
 ) INSERT INTO aqo_test1 (SELECT * FROM t);
 CREATE INDEX aqo_test1_idx_a ON aqo_test1 (a);
 ANALYZE aqo_test1;
-CREATE EXTENSION aqo;
-SET aqo.join_threshold = 0;
 SET aqo.mode = 'intelligent';
 EXPLAIN SELECT * FROM aqo_test0
 WHERE a < 3 AND b < 3 AND c < 3 AND d < 3;
@@ -236,10 +241,10 @@ SELECT count(*) FROM tmp1;
 (1 row)
 
 -- Remove data on some unneeded instances of tmp1 table.
-SELECT * FROM aqo_cleanup();
- nfs | nfss 
------+------
-   9 |   18
+SELECT true AS success FROM aqo_cleanup();
+ success 
+---------
+ t
 (1 row)
 
 -- Result of the query below should be empty
@@ -563,7 +568,7 @@ SELECT * FROM check_estimated_rows(
   'SELECT * FROM aqo_test1 AS t1, aqo_test1 AS t2 WHERE t1.a = t2.b');
  estimated | actual 
 -----------+--------
-        19 |     19
+        20 |     19
 (1 row)
 
 SELECT count(*) FROM
@@ -716,11 +721,4 @@ DROP INDEX aqo_test0_idx_a;
 DROP TABLE aqo_test0;
 DROP INDEX aqo_test1_idx_a;
 DROP TABLE aqo_test1;
--- XXX: extension dropping doesn't clear file storage. Do it manually.
-SELECT 1 FROM aqo_reset();
- ?column? 
-----------
-        1
-(1 row)
-
 DROP EXTENSION aqo;

expected/clean_aqo_data.out

@@ -1,5 +1,10 @@
-CREATE EXTENSION aqo;
-SET aqo.join_threshold = 0;
+CREATE EXTENSION IF NOT EXISTS aqo;
+SELECT true AS success FROM aqo_reset();
+ success 
+---------
+ t
+(1 row)
+
 SET aqo.mode = 'learn';
 DROP TABLE IF EXISTS a;
 NOTICE:  table "a" does not exist, skipping
@@ -11,9 +16,9 @@ SELECT * FROM a;
 (0 rows)
 
 SELECT 'a'::regclass::oid AS a_oid \gset
-SELECT true FROM aqo_cleanup();
- ?column? 
-----------
+SELECT true AS success FROM aqo_cleanup();
+ success 
+---------
  t
 (1 row)
 
@@ -54,9 +59,9 @@ SELECT count(*) FROM aqo_query_stat WHERE
 (1 row)
 
 DROP TABLE a;
-SELECT true FROM aqo_cleanup();
- ?column? 
-----------
+SELECT true AS success FROM aqo_cleanup();
+ success 
+---------
  t
 (1 row)
 
@@ -119,7 +124,7 @@ SELECT 'b'::regclass::oid AS b_oid \gset
 SELECT count(*) FROM aqo_data WHERE :a_oid=ANY(oids);
  count 
 -------
-     2
+     3
 (1 row)
 
 SELECT count(*) FROM aqo_queries WHERE
@@ -175,9 +180,9 @@ SELECT count(*) FROM aqo_query_stat WHERE
 (1 row)
 
 DROP TABLE a;
-SELECT true FROM aqo_cleanup();
- ?column? 
-----------
+SELECT true AS success FROM aqo_cleanup();
+ success 
+---------
  t
 (1 row)
 
@@ -253,9 +258,9 @@ SELECT count(*) FROM aqo_query_stat WHERE
 (1 row)
 
 DROP TABLE b;
-SELECT true FROM aqo_cleanup();
- ?column? 
-----------
+SELECT true AS success FROM aqo_cleanup();
+ success 
+---------
  t
 (1 row)