Improve coverage of nodeAppend runtime partition prune

coverage report indicated that mark_invalid_subplans_as_finished() and
nearby code was not getting exercised by any tests.  Add a new one which
has execution-time Params rather than only external Params to fix this.

In passing, David noticed that ab_q6 tests were not actually required to
have a generic plan. The tests were testing exec Params not external
Params, so there was no need for the PREPARE.  Remove the PREPARE,
making these plain queries.  (The new queries are called from
explain_parallel_append, which may be unnecessary since they don't
actually have a Parallel Append node, just an Append.  But it doesn't
seem to hurt anything, either.)

Author: David Rowley
Discussion: https://postgr.es/m/CAKJS1f--hopb6JBSDY4wiXTS3ZcDp-wparXjTQ1nzNdBa04Fog@mail.gmail.com

Author: alvherre

src/test/regress/expected/partition_prune.out

@@ -1751,16 +1751,15 @@ explain (analyze, costs off, summary off, timing off) execute ab_q3 (2, 2);
 -- Suppress the number of loops each parallel node runs for.  This is because
 -- more than one worker may run the same parallel node if timing conditions
 -- are just right, which destabilizes the test.
-create function explain_parallel_append(text, int[]) returns setof text
+create function explain_parallel_append(text) returns setof text
 language plpgsql as
 $$
 declare
     ln text;
-    args text := string_agg(u::text, ', ') from unnest($2) u;
 begin
     for ln in
-        execute format('explain (analyze, costs off, summary off, timing off) execute %s(%s)',
-            $1, args)
+        execute format('explain (analyze, costs off, summary off, timing off) %s',
+            $1)
     loop
         if ln like '%Parallel%' then
             ln := regexp_replace(ln, 'loops=\d*',  'loops=N');
@@ -1808,7 +1807,7 @@ execute ab_q4 (1, 8);
 
 (1 row)
 
-select explain_parallel_append('ab_q4', '{2, 2}');
+select explain_parallel_append('execute ab_q4 (2, 2)');
                             explain_parallel_append                            
 -------------------------------------------------------------------------------
  Finalize Aggregate (actual rows=1 loops=1)
@@ -1861,7 +1860,7 @@ execute ab_q5 (1, 2, 3);
 
 (1 row)
 
-select explain_parallel_append('ab_q5', '{1, 1, 1}');
+select explain_parallel_append('execute ab_q5 (1, 1, 1)');
                             explain_parallel_append                            
 -------------------------------------------------------------------------------
  Finalize Aggregate (actual rows=1 loops=1)
@@ -1879,7 +1878,7 @@ select explain_parallel_append('ab_q5', '{1, 1, 1}');
                            Filter: ((b < 4) AND (a = ANY (ARRAY[$1, $2, $3])))
 (13 rows)
 
-select explain_parallel_append('ab_q5', '{2, 3, 3}');
+select explain_parallel_append('execute ab_q5 (2, 3, 3)');
                             explain_parallel_append                            
 -------------------------------------------------------------------------------
  Finalize Aggregate (actual rows=1 loops=1)
@@ -1905,7 +1904,7 @@ select explain_parallel_append('ab_q5', '{2, 3, 3}');
 
 -- Try some params whose values do not belong to any partition.
 -- We'll still get a single subplan in this case, but it should not be scanned.
-select explain_parallel_append('ab_q5', '{33, 44, 55}');
+select explain_parallel_append('execute ab_q5 (33, 44, 55)');
                             explain_parallel_append                            
 -------------------------------------------------------------------------------
  Finalize Aggregate (actual rows=1 loops=1)
@@ -1919,7 +1918,29 @@ select explain_parallel_append('ab_q5', '{33, 44, 55}');
                            Filter: ((b < 4) AND (a = ANY (ARRAY[$1, $2, $3])))
 (9 rows)
 
--- Test parallel Append with IN list and parameterized nested loops
+-- Test Parallel Append with exec params
+select explain_parallel_append('select count(*) from ab where (a = (select 1) or a = (select 3)) and b = 2');
+                         explain_parallel_append                         
+-------------------------------------------------------------------------
+ Aggregate (actual rows=1 loops=1)
+   InitPlan 1 (returns $0)
+     ->  Result (actual rows=1 loops=1)
+   InitPlan 2 (returns $1)
+     ->  Result (actual rows=1 loops=1)
+   ->  Gather (actual rows=0 loops=1)
+         Workers Planned: 2
+         Params Evaluated: $0, $1
+         Workers Launched: 2
+         ->  Parallel Append (actual rows=0 loops=N)
+               ->  Parallel Seq Scan on ab_a1_b2 (actual rows=0 loops=N)
+                     Filter: ((b = 2) AND ((a = $0) OR (a = $1)))
+               ->  Parallel Seq Scan on ab_a2_b2 (never executed)
+                     Filter: ((b = 2) AND ((a = $0) OR (a = $1)))
+               ->  Parallel Seq Scan on ab_a3_b2 (actual rows=0 loops=N)
+                     Filter: ((b = 2) AND ((a = $0) OR (a = $1)))
+(16 rows)
+
+-- Test pruning during parallel nested loop query
 create table lprt_a (a int not null);
 -- Insert some values we won't find in ab
 insert into lprt_a select 0 from generate_series(1,100);
@@ -1937,39 +1958,7 @@ create index ab_a3_b2_a_idx on ab_a3_b2 (a);
 create index ab_a3_b3_a_idx on ab_a3_b3 (a);
 set enable_hashjoin = 0;
 set enable_mergejoin = 0;
-prepare ab_q6 (int, int, int) as
-select avg(ab.a) from ab inner join lprt_a a on ab.a = a.a where a.a in($1,$2,$3);
-execute ab_q6 (1, 2, 3);
- avg 
------
-    
-(1 row)
-
-execute ab_q6 (1, 2, 3);
- avg 
------
-    
-(1 row)
-
-execute ab_q6 (1, 2, 3);
- avg 
------
-    
-(1 row)
-
-execute ab_q6 (1, 2, 3);
- avg 
------
-    
-(1 row)
-
-execute ab_q6 (1, 2, 3);
- avg 
------
-    
-(1 row)
-
-select explain_parallel_append('ab_q6', '{0, 0, 1}');
+select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on ab.a = a.a where a.a in(0, 0, 1)');
                                       explain_parallel_append                                      
 ---------------------------------------------------------------------------------------------------
  Finalize Aggregate (actual rows=1 loops=1)
@@ -2002,16 +1991,16 @@ select explain_parallel_append('ab_q6', '{0, 0, 1}');
 (27 rows)
 
 insert into lprt_a values(3),(3);
-explain (analyze, costs off, summary off, timing off) execute ab_q6 (1, 0, 3);
-                                            QUERY PLAN                                             
+select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on ab.a = a.a where a.a in(1, 0, 3)');
+                                      explain_parallel_append                                      
 ---------------------------------------------------------------------------------------------------
  Finalize Aggregate (actual rows=1 loops=1)
    ->  Gather (actual rows=2 loops=1)
          Workers Planned: 1
          Workers Launched: 1
          ->  Partial Aggregate (actual rows=1 loops=2)
                ->  Nested Loop (actual rows=0 loops=2)
-                     ->  Parallel Seq Scan on lprt_a a (actual rows=52 loops=2)
+                     ->  Parallel Seq Scan on lprt_a a (actual rows=52 loops=N)
                            Filter: (a = ANY ('{1,0,3}'::integer[]))
                      ->  Append (actual rows=0 loops=104)
                            ->  Index Scan using ab_a1_b1_a_idx on ab_a1_b1 (actual rows=0 loops=2)
@@ -2034,16 +2023,16 @@ explain (analyze, costs off, summary off, timing off) execute ab_q6 (1, 0, 3);
                                  Index Cond: (a = a.a)
 (27 rows)
 
-explain (analyze, costs off, summary off, timing off) execute ab_q6 (1, 0, 0);
-                                            QUERY PLAN                                             
+select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on ab.a = a.a where a.a in(1, 0, 0)');
+                                      explain_parallel_append                                      
 ---------------------------------------------------------------------------------------------------
  Finalize Aggregate (actual rows=1 loops=1)
    ->  Gather (actual rows=2 loops=1)
          Workers Planned: 1
          Workers Launched: 1
          ->  Partial Aggregate (actual rows=1 loops=2)
                ->  Nested Loop (actual rows=0 loops=2)
-                     ->  Parallel Seq Scan on lprt_a a (actual rows=51 loops=2)
+                     ->  Parallel Seq Scan on lprt_a a (actual rows=51 loops=N)
                            Filter: (a = ANY ('{1,0,0}'::integer[]))
                            Rows Removed by Filter: 1
                      ->  Append (actual rows=0 loops=102)
@@ -2068,16 +2057,16 @@ explain (analyze, costs off, summary off, timing off) execute ab_q6 (1, 0, 0);
 (28 rows)
 
 delete from lprt_a where a = 1;
-explain (analyze, costs off, summary off, timing off) execute ab_q6 (1, 0, 0);
-                                         QUERY PLAN                                         
+select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on ab.a = a.a where a.a in(1, 0, 0)');
+                                  explain_parallel_append                                   
 --------------------------------------------------------------------------------------------
  Finalize Aggregate (actual rows=1 loops=1)
    ->  Gather (actual rows=2 loops=1)
          Workers Planned: 1
          Workers Launched: 1
          ->  Partial Aggregate (actual rows=1 loops=2)
                ->  Nested Loop (actual rows=0 loops=2)
-                     ->  Parallel Seq Scan on lprt_a a (actual rows=50 loops=2)
+                     ->  Parallel Seq Scan on lprt_a a (actual rows=50 loops=N)
                            Filter: (a = ANY ('{1,0,0}'::integer[]))
                            Rows Removed by Filter: 1
                      ->  Append (actual rows=0 loops=100)
@@ -2171,7 +2160,6 @@ deallocate ab_q2;
 deallocate ab_q3;
 deallocate ab_q4;
 deallocate ab_q5;
-deallocate ab_q6;
 drop table ab, lprt_a;
 -- Join
 create table tbl1(col1 int);

src/test/regress/sql/partition_prune.sql

@@ -364,16 +364,15 @@ explain (analyze, costs off, summary off, timing off) execute ab_q3 (2, 2);
 -- Suppress the number of loops each parallel node runs for.  This is because
 -- more than one worker may run the same parallel node if timing conditions
 -- are just right, which destabilizes the test.
-create function explain_parallel_append(text, int[]) returns setof text
+create function explain_parallel_append(text) returns setof text
 language plpgsql as
 $$
 declare
     ln text;
-    args text := string_agg(u::text, ', ') from unnest($2) u;
 begin
     for ln in
-        execute format('explain (analyze, costs off, summary off, timing off) execute %s(%s)',
-            $1, args)
+        execute format('explain (analyze, costs off, summary off, timing off) %s',
+            $1)
     loop
         if ln like '%Parallel%' then
             ln := regexp_replace(ln, 'loops=\d*',  'loops=N');
@@ -399,7 +398,7 @@ execute ab_q4 (1, 8);
 execute ab_q4 (1, 8);
 execute ab_q4 (1, 8);
 execute ab_q4 (1, 8);
-select explain_parallel_append('ab_q4', '{2, 2}');
+select explain_parallel_append('execute ab_q4 (2, 2)');
 
 -- Test run-time pruning with IN lists.
 prepare ab_q5 (int, int, int) as
@@ -413,14 +412,17 @@ execute ab_q5 (1, 2, 3);
 execute ab_q5 (1, 2, 3);
 execute ab_q5 (1, 2, 3);
 
-select explain_parallel_append('ab_q5', '{1, 1, 1}');
-select explain_parallel_append('ab_q5', '{2, 3, 3}');
+select explain_parallel_append('execute ab_q5 (1, 1, 1)');
+select explain_parallel_append('execute ab_q5 (2, 3, 3)');
 
 -- Try some params whose values do not belong to any partition.
 -- We'll still get a single subplan in this case, but it should not be scanned.
-select explain_parallel_append('ab_q5', '{33, 44, 55}');
+select explain_parallel_append('execute ab_q5 (33, 44, 55)');
 
--- Test parallel Append with IN list and parameterized nested loops
+-- Test Parallel Append with exec params
+select explain_parallel_append('select count(*) from ab where (a = (select 1) or a = (select 3)) and b = 2');
+
+-- Test pruning during parallel nested loop query
 create table lprt_a (a int not null);
 -- Insert some values we won't find in ab
 insert into lprt_a select 0 from generate_series(1,100);
@@ -443,24 +445,16 @@ create index ab_a3_b3_a_idx on ab_a3_b3 (a);
 set enable_hashjoin = 0;
 set enable_mergejoin = 0;
 
-prepare ab_q6 (int, int, int) as
-select avg(ab.a) from ab inner join lprt_a a on ab.a = a.a where a.a in($1,$2,$3);
-execute ab_q6 (1, 2, 3);
-execute ab_q6 (1, 2, 3);
-execute ab_q6 (1, 2, 3);
-execute ab_q6 (1, 2, 3);
-execute ab_q6 (1, 2, 3);
-
-select explain_parallel_append('ab_q6', '{0, 0, 1}');
+select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on ab.a = a.a where a.a in(0, 0, 1)');
 
 insert into lprt_a values(3),(3);
 
-explain (analyze, costs off, summary off, timing off) execute ab_q6 (1, 0, 3);
-explain (analyze, costs off, summary off, timing off) execute ab_q6 (1, 0, 0);
+select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on ab.a = a.a where a.a in(1, 0, 3)');
+select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on ab.a = a.a where a.a in(1, 0, 0)');
 
 delete from lprt_a where a = 1;
 
-explain (analyze, costs off, summary off, timing off) execute ab_q6 (1, 0, 0);
+select explain_parallel_append('select avg(ab.a) from ab inner join lprt_a a on ab.a = a.a where a.a in(1, 0, 0)');
 
 reset enable_hashjoin;
 reset enable_mergejoin;
@@ -478,7 +472,6 @@ deallocate ab_q2;
 deallocate ab_q3;
 deallocate ab_q4;
 deallocate ab_q5;
-deallocate ab_q6;
 
 drop table ab, lprt_a;