Handles EXPLAIN output diffs in PG15: enable_group_by_reordering

Relevant PG commit
db0d67db2401eb6238ccc04c6407a4fd4f985832

src/test/regress/expected/cte_inline.out

@@ -449,6 +449,29 @@ DEBUG:  Creating router plan
 (5 rows)
 
 \set VERBOSITY default
+-- enable_group_by_reordering is a new GUC introduced in PG15
+-- it does some optimization of the order of group by keys which results
+-- in a different explain output plan between PG13/14 and PG15
+-- Hence we set that GUC to off.
+SHOW server_version \gset
+SELECT substring(:'server_version', '\d+')::int > 14 AS server_version_above_fourteen
+\gset
+\if :server_version_above_fourteen
+SET enable_group_by_reordering TO off;
+\endif
+SELECT DISTINCT 1 FROM run_command_on_workers($$ALTER SYSTEM SET enable_group_by_reordering TO off;$$);
+ ?column?
+---------------------------------------------------------------------
+        1
+(1 row)
+
+SELECT run_command_on_workers($$SELECT pg_reload_conf()$$);
+ run_command_on_workers
+---------------------------------------------------------------------
+ (localhost,57637,t,t)
+ (localhost,57638,t,t)
+(2 rows)
+
 EXPLAIN (COSTS OFF) WITH cte_1 AS NOT MATERIALIZED (SELECT * FROM test_table)
 SELECT
 	count(*)
@@ -487,6 +510,22 @@ DEBUG:  join prunable for intervals [1073741824,2147483647] and [0,1073741823]
                                  ->  Seq Scan on test_table_1960000 test_table_1
 (12 rows)
 
+\if :server_version_above_fourteen
+RESET enable_group_by_reordering;
+\endif
+SELECT DISTINCT 1 FROM run_command_on_workers($$ALTER SYSTEM RESET enable_group_by_reordering;$$);
+ ?column?
+---------------------------------------------------------------------
+        1
+(1 row)
+
+SELECT run_command_on_workers($$SELECT pg_reload_conf()$$);
+ run_command_on_workers
+---------------------------------------------------------------------
+ (localhost,57637,t,t)
+ (localhost,57638,t,t)
+(2 rows)
+
 -- ctes with volatile functions are not
 -- inlined
 WITH cte_1 AS (SELECT *, random() FROM test_table)

src/test/regress/sql/cte_inline.sql

@@ -236,6 +236,19 @@ $Q$);
 
 \set VERBOSITY default
 
+-- enable_group_by_reordering is a new GUC introduced in PG15
+-- it does some optimization of the order of group by keys which results
+-- in a different explain output plan between PG13/14 and PG15
+-- Hence we set that GUC to off.
+SHOW server_version \gset
+SELECT substring(:'server_version', '\d+')::int > 14 AS server_version_above_fourteen
+\gset
+\if :server_version_above_fourteen
+SET enable_group_by_reordering TO off;
+\endif
+SELECT DISTINCT 1 FROM run_command_on_workers($$ALTER SYSTEM SET enable_group_by_reordering TO off;$$);
+SELECT run_command_on_workers($$SELECT pg_reload_conf()$$);
+
 EXPLAIN (COSTS OFF) WITH cte_1 AS NOT MATERIALIZED (SELECT * FROM test_table)
 SELECT
 	count(*)
@@ -245,6 +258,11 @@ FROM
 	cte_1 as second_entry
 		USING (key);
 
+\if :server_version_above_fourteen
+RESET enable_group_by_reordering;
+\endif
+SELECT DISTINCT 1 FROM run_command_on_workers($$ALTER SYSTEM RESET enable_group_by_reordering;$$);
+SELECT run_command_on_workers($$SELECT pg_reload_conf()$$);
 
 
 -- ctes with volatile functions are not