Parsed test spec with 3 sessions

starting permutation: s3_prep s2_delete s1_group s3_parked s3_vacuum s2_wakeup s1_plain s3_stats s3_vacuum2 s3_stats2 s3_verify
injection_points_attach
-----------------------
                       
(1 row)

step s3_prep: VACUUM (FREEZE, ANALYZE) vgd;
step s2_delete: DELETE FROM vgd WHERE k % 2 = 0;
step s1_group: 
	SELECT count(*) AS groups, count(DISTINCT k) AS distinct_groups,
		   sum(c) AS rows_counted, min(c) AS min_rows, max(c) AS max_rows
	  FROM (SELECT k, count(*) AS c FROM vgd GROUP BY k) g;
 <waiting ...>
step s3_parked: SELECT count(*) = 1 AS parked FROM pg_stat_activity WHERE wait_event_type = 'InjectionPoint' AND wait_event = 'lion-entry-scan-resumed';
parked
------
t     
(1 row)

step s3_vacuum: VACUUM vgd;
step s2_wakeup: 
	/*
	 * Detach first, so that nothing can park at the point again, then
	 * release whoever is parked now.  How MANY times the point is reached is
	 * not fixed - the two-column driver runs more than one entry scan, and a
	 * scan fires the point once per leaf it consumes an entry from -
	 * but after this step nobody is waiting on it, which is all the
	 * permutation needs.  injection_points_wakeup() searches the WAITERS, so
	 * it still works after the detach.
	 */
	SELECT injection_points_detach('lion-entry-scan-resumed');
	DO $$
	DECLARE n int; zero int := 0;
	BEGIN
		FOR i IN 1 .. 6000 LOOP
			SELECT count(*) INTO n FROM pg_stat_activity
			 WHERE wait_event = 'lion-entry-scan-resumed';
			IF n = 0 THEN
				zero := zero + 1;
				EXIT WHEN zero >= 10;
			ELSE
				zero := 0;
				/*
				 * The waiter clears its slot itself once it notices the
				 * counter, so it can be gone between the poll above and
				 * this call; that is a success, not a failure.
				 */
				BEGIN
					PERFORM injection_points_wakeup('lion-entry-scan-resumed');
				EXCEPTION WHEN OTHERS THEN NULL;
				END;
			END IF;
			PERFORM pg_sleep(0.01);
		END LOOP;
	END $$;

injection_points_detach
-----------------------
                       
(1 row)

step s1_group: <... completed>
groups|distinct_groups|rows_counted|min_rows|max_rows
------+---------------+------------+--------+--------
    20|             20|        6000|     300|     300
(1 row)

step s1_plain: 
	SET pg_lion.enable_count_pushdown = off;
	SELECT count(*) AS groups, count(DISTINCT k) AS distinct_groups,
		   sum(c) AS rows_counted
	  FROM (SELECT k, count(*) AS c FROM vgd GROUP BY k) g;
	SELECT count(*) AS groups2, count(DISTINCT (k, g)) AS distinct_groups2,
		   sum(c) AS rows_counted2
	  FROM (SELECT k, g, count(*) AS c FROM vgd GROUP BY k, g) x;
	SET pg_lion.enable_count_pushdown = on;

groups|distinct_groups|rows_counted
------+---------------+------------
    20|             20|        6000
(1 row)

groups2|distinct_groups2|rows_counted2
-------+----------------+-------------
     60|              60|         6000
(1 row)

step s3_stats: 
	SELECT entries BETWEEN 20 AND 40 AS entries_in_range,
		   ntids BETWEEN 6000 AND 6020 AS ntids_in_range,
		   deleted_pages > 0 AS chains_were_freed
	  FROM lion_index_stats('vgd_k');

entries_in_range|ntids_in_range|chains_were_freed
----------------+--------------+-----------------
t               |t             |t                
(1 row)

step s3_vacuum2: VACUUM (INDEX_CLEANUP ON) vgd;
step s3_stats2: SELECT entries, ntids FROM lion_index_stats('vgd_k');
entries|ntids
-------+-----
     20| 6000
(1 row)

step s3_verify: SELECT lion_index_verify('vgd_k', true);
				  SELECT lion_index_verify('vgd_g', true);
lion_index_verify
-----------------
                 
(1 row)

lion_index_verify
-----------------
                 
(1 row)


starting permutation: s3_prep s2_delete s1_group2 s3_parked s3_vacuum s2_wakeup s1_plain s3_stats s3_vacuum2 s3_stats2 s3_verify
injection_points_attach
-----------------------
                       
(1 row)

step s3_prep: VACUUM (FREEZE, ANALYZE) vgd;
step s2_delete: DELETE FROM vgd WHERE k % 2 = 0;
step s1_group2: 
	SELECT count(*) AS groups, count(DISTINCT (k, g)) AS distinct_groups,
		   sum(c) AS rows_counted
	  FROM (SELECT k, g, count(*) AS c FROM vgd GROUP BY k, g) x;
 <waiting ...>
step s3_parked: SELECT count(*) = 1 AS parked FROM pg_stat_activity WHERE wait_event_type = 'InjectionPoint' AND wait_event = 'lion-entry-scan-resumed';
parked
------
t     
(1 row)

step s3_vacuum: VACUUM vgd;
step s2_wakeup: 
	/*
	 * Detach first, so that nothing can park at the point again, then
	 * release whoever is parked now.  How MANY times the point is reached is
	 * not fixed - the two-column driver runs more than one entry scan, and a
	 * scan fires the point once per leaf it consumes an entry from -
	 * but after this step nobody is waiting on it, which is all the
	 * permutation needs.  injection_points_wakeup() searches the WAITERS, so
	 * it still works after the detach.
	 */
	SELECT injection_points_detach('lion-entry-scan-resumed');
	DO $$
	DECLARE n int; zero int := 0;
	BEGIN
		FOR i IN 1 .. 6000 LOOP
			SELECT count(*) INTO n FROM pg_stat_activity
			 WHERE wait_event = 'lion-entry-scan-resumed';
			IF n = 0 THEN
				zero := zero + 1;
				EXIT WHEN zero >= 10;
			ELSE
				zero := 0;
				/*
				 * The waiter clears its slot itself once it notices the
				 * counter, so it can be gone between the poll above and
				 * this call; that is a success, not a failure.
				 */
				BEGIN
					PERFORM injection_points_wakeup('lion-entry-scan-resumed');
				EXCEPTION WHEN OTHERS THEN NULL;
				END;
			END IF;
			PERFORM pg_sleep(0.01);
		END LOOP;
	END $$;

injection_points_detach
-----------------------
                       
(1 row)

step s1_group2: <... completed>
groups|distinct_groups|rows_counted
------+---------------+------------
    60|             60|        6000
(1 row)

step s1_plain: 
	SET pg_lion.enable_count_pushdown = off;
	SELECT count(*) AS groups, count(DISTINCT k) AS distinct_groups,
		   sum(c) AS rows_counted
	  FROM (SELECT k, count(*) AS c FROM vgd GROUP BY k) g;
	SELECT count(*) AS groups2, count(DISTINCT (k, g)) AS distinct_groups2,
		   sum(c) AS rows_counted2
	  FROM (SELECT k, g, count(*) AS c FROM vgd GROUP BY k, g) x;
	SET pg_lion.enable_count_pushdown = on;

groups|distinct_groups|rows_counted
------+---------------+------------
    20|             20|        6000
(1 row)

groups2|distinct_groups2|rows_counted2
-------+----------------+-------------
     60|              60|         6000
(1 row)

step s3_stats: 
	SELECT entries BETWEEN 20 AND 40 AS entries_in_range,
		   ntids BETWEEN 6000 AND 6020 AS ntids_in_range,
		   deleted_pages > 0 AS chains_were_freed
	  FROM lion_index_stats('vgd_k');

entries_in_range|ntids_in_range|chains_were_freed
----------------+--------------+-----------------
t               |t             |t                
(1 row)

step s3_vacuum2: VACUUM (INDEX_CLEANUP ON) vgd;
step s3_stats2: SELECT entries, ntids FROM lion_index_stats('vgd_k');
entries|ntids
-------+-----
     20| 6000
(1 row)

step s3_verify: SELECT lion_index_verify('vgd_k', true);
				  SELECT lion_index_verify('vgd_g', true);
lion_index_verify
-----------------
                 
(1 row)

lion_index_verify
-----------------
                 
(1 row)