Rely on plan_cache_mode to force generic plans in partition_prune test.

This file had a very weird mix of tests that did "set plan_cache_mode =
force_generic_plan" to get a generic plan, and tests that relied on
using five dummy executions of a prepared statement.  Converting them
all to rely on plan_cache_mode is more consistent and shaves off a
noticeable fraction of the test script's runtime.

Discussion: https://postgr.es/m/11952.1569536725@sss.pgh.pa.us

src/test/regress/expected/partition_prune.out

 --
 -- Test partitioning planner code
 --
+-- Force generic plans to be used for all prepared statements in this file.
+set plan_cache_mode = force_generic_plan;
 create table lp (a char) partition by list (a);
 create table lp_default partition of lp default;
 create table lp_ef partition of lp for values in ('e', 'f');
@@ -1715,33 +1717,6 @@ create table ab_a3_b3 partition of ab_a3 for values in (3);
 set enable_indexonlyscan = off;
 prepare ab_q1 (int, int, int) as
 select * from ab where a between $1 and $2 and b <= $3;
--- Execute query 5 times to allow choose_custom_plan
--- to start considering a generic plan.
-execute ab_q1 (1, 8, 3);
- a | b 
----+---
-(0 rows)
-
-execute ab_q1 (1, 8, 3);
- a | b 
----+---
-(0 rows)
-
-execute ab_q1 (1, 8, 3);
- a | b 
----+---
-(0 rows)
-
-execute ab_q1 (1, 8, 3);
- a | b 
----+---
-(0 rows)
-
-execute ab_q1 (1, 8, 3);
- a | b 
----+---
-(0 rows)
-
 explain (analyze, costs off, summary off, timing off) execute ab_q1 (2, 2, 3);
                        QUERY PLAN                        
 ---------------------------------------------------------
@@ -1778,33 +1753,6 @@ deallocate ab_q1;
 -- Runtime pruning after optimizer pruning
 prepare ab_q1 (int, int) as
 select a from ab where a between $1 and $2 and b < 3;
--- Execute query 5 times to allow choose_custom_plan
--- to start considering a generic plan.
-execute ab_q1 (1, 8);
- a 
----
-(0 rows)
-
-execute ab_q1 (1, 8);
- a 
----
-(0 rows)
-
-execute ab_q1 (1, 8);
- a 
----
-(0 rows)
-
-execute ab_q1 (1, 8);
- a 
----
-(0 rows)
-
-execute ab_q1 (1, 8);
- a 
----
-(0 rows)
-
 explain (analyze, costs off, summary off, timing off) execute ab_q1 (2, 2);
                       QUERY PLAN                       
 -------------------------------------------------------
@@ -1835,31 +1783,6 @@ explain (analyze, costs off, summary off, timing off) execute ab_q1 (2, 4);
 -- different levels of partitioning.
 prepare ab_q2 (int, int) as
 select a from ab where a between $1 and $2 and b < (select 3);
-execute ab_q2 (1, 8);
- a 
----
-(0 rows)
-
-execute ab_q2 (1, 8);
- a 
----
-(0 rows)
-
-execute ab_q2 (1, 8);
- a 
----
-(0 rows)
-
-execute ab_q2 (1, 8);
- a 
----
-(0 rows)
-
-execute ab_q2 (1, 8);
- a 
----
-(0 rows)
-
 explain (analyze, costs off, summary off, timing off) execute ab_q2 (2, 2);
                        QUERY PLAN                       
 --------------------------------------------------------
@@ -1878,31 +1801,6 @@ explain (analyze, costs off, summary off, timing off) execute ab_q2 (2, 2);
 -- As above, but swap the PARAM_EXEC Param to the first partition level
 prepare ab_q3 (int, int) as
 select a from ab where b between $1 and $2 and a < (select 3);
-execute ab_q3 (1, 8);
- a 
----
-(0 rows)
-
-execute ab_q3 (1, 8);
- a 
----
-(0 rows)
-
-execute ab_q3 (1, 8);
- a 
----
-(0 rows)
-
-execute ab_q3 (1, 8);
- a 
----
-(0 rows)
-
-execute ab_q3 (1, 8);
- a 
----
-(0 rows)
-
 explain (analyze, costs off, summary off, timing off) execute ab_q3 (2, 2);
                        QUERY PLAN                       
 --------------------------------------------------------
@@ -2021,38 +1919,6 @@ set parallel_setup_cost = 0;
 set parallel_tuple_cost = 0;
 set min_parallel_table_scan_size = 0;
 set max_parallel_workers_per_gather = 2;
--- Execute query 5 times to allow choose_custom_plan
--- to start considering a generic plan.
-execute ab_q4 (1, 8);
- avg 
------
-    
-(1 row)
-
-execute ab_q4 (1, 8);
- avg 
------
-    
-(1 row)
-
-execute ab_q4 (1, 8);
- avg 
------
-    
-(1 row)
-
-execute ab_q4 (1, 8);
- avg 
------
-    
-(1 row)
-
-execute ab_q4 (1, 8);
- avg 
------
-    
-(1 row)
-
 select explain_parallel_append('execute ab_q4 (2, 2)');
                             explain_parallel_append                            
 -------------------------------------------------------------------------------
@@ -2074,38 +1940,6 @@ select explain_parallel_append('execute ab_q4 (2, 2)');
 -- Test run-time pruning with IN lists.
 prepare ab_q5 (int, int, int) as
 select avg(a) from ab where a in($1,$2,$3) and b < 4;
--- Execute query 5 times to allow choose_custom_plan
--- to start considering a generic plan.
-execute ab_q5 (1, 2, 3);
- avg 
------
-    
-(1 row)
-
-execute ab_q5 (1, 2, 3);
- avg 
------
-    
-(1 row)
-
-execute ab_q5 (1, 2, 3);
- avg 
------
-    
-(1 row)
-
-execute ab_q5 (1, 2, 3);
- avg 
------
-    
-(1 row)
-
-execute ab_q5 (1, 2, 3);
- avg 
------
-    
-(1 row)
-
 select explain_parallel_append('execute ab_q5 (1, 1, 1)');
                             explain_parallel_append                            
 -------------------------------------------------------------------------------
@@ -2530,7 +2364,6 @@ create table xy_1 (x int, y int);
 insert into xy_1 values(100,-10);
 set enable_bitmapscan = 0;
 set enable_indexscan = 0;
-set plan_cache_mode = 'force_generic_plan';
 prepare ab_q6 as
 select * from (
 	select tableoid::regclass,a,b from ab
@@ -2573,7 +2406,6 @@ execute ab_q6(100);
 
 reset enable_bitmapscan;
 reset enable_indexscan;
-reset plan_cache_mode;
 deallocate ab_q1;
 deallocate ab_q2;
 deallocate ab_q3;
@@ -2956,33 +2788,6 @@ alter table part_bac attach partition part_cab for values in(2);
 alter table part_cab attach partition part_abc_p1 for values in(3);
 prepare part_abc_q1 (int, int, int) as
 select * from part_abc where a = $1 and b = $2 and c = $3;
--- Execute query 5 times to allow choose_custom_plan
--- to start considering a generic plan.
-execute part_abc_q1 (1, 2, 3);
- a | b | c 
----+---+---
-(0 rows)
-
-execute part_abc_q1 (1, 2, 3);
- a | b | c 
----+---+---
-(0 rows)
-
-execute part_abc_q1 (1, 2, 3);
- a | b | c 
----+---+---
-(0 rows)
-
-execute part_abc_q1 (1, 2, 3);
- a | b | c 
----+---+---
-(0 rows)
-
-execute part_abc_q1 (1, 2, 3);
- a | b | c 
----+---+---
-(0 rows)
-
 -- Single partition should be scanned.
 explain (analyze, costs off, summary off, timing off) execute part_abc_q1 (1, 2, 3);
                    QUERY PLAN                    
@@ -3009,31 +2814,6 @@ select * from listp where b = 1;
 -- partitions before finally detecting the correct set of 2nd level partitions
 -- which match the given parameter.
 prepare q1 (int,int) as select * from listp where b in ($1,$2);
-execute q1 (1,2);
- a | b 
----+---
-(0 rows)
-
-execute q1 (1,2);
- a | b 
----+---
-(0 rows)
-
-execute q1 (1,2);
- a | b 
----+---
-(0 rows)
-
-execute q1 (1,2);
- a | b 
----+---
-(0 rows)
-
-execute q1 (1,2);
- a | b 
----+---
-(0 rows)
-
 explain (analyze, costs off, summary off, timing off)  execute q1 (1,1);
                      QUERY PLAN                      
 -----------------------------------------------------
@@ -3066,31 +2846,6 @@ explain (analyze, costs off, summary off, timing off)  execute q1 (0,0);
 deallocate q1;
 -- Test more complex cases where a not-equal condition further eliminates partitions.
 prepare q1 (int,int,int,int) as select * from listp where b in($1,$2) and $3 <> b and $4 <> b;
-execute q1 (1,2,3,4);
- a | b 
----+---
-(0 rows)
-
-execute q1 (1,2,3,4);
- a | b 
----+---
-(0 rows)
-
-execute q1 (1,2,3,4);
- a | b 
----+---
-(0 rows)
-
-execute q1 (1,2,3,4);
- a | b 
----+---
-(0 rows)
-
-execute q1 (1,2,3,4);
- a | b 
----+---
-(0 rows)
-
 -- Both partitions allowed by IN clause, but one disallowed by <> clause
 explain (analyze, costs off, summary off, timing off)  execute q1 (1,2,2,0);
                                QUERY PLAN                                
@@ -3259,7 +3014,6 @@ select * from mc3p where a < 3 and abs(b) = 1;
 -- a combination of runtime parameters is specified, not all of whose values
 -- are available at the same time
 --
-set plan_cache_mode = force_generic_plan;
 prepare ps1 as
   select * from mc3p where a = $1 and abs(b) < (select 3);
 explain (analyze, costs off, summary off, timing off)
@@ -3292,7 +3046,6 @@ execute ps2(1);
 (8 rows)
 
 deallocate ps2;
-reset plan_cache_mode;
 drop table mc3p;
 -- Ensure runtime pruning works with initplans params with boolean types
 create table boolvalues (value bool not null);
@@ -3344,48 +3097,6 @@ insert into ma_test select x,x from generate_series(0,29) t(x);
 create index on ma_test (b);
 analyze ma_test;
 prepare mt_q1 (int) as select a from ma_test where a >= $1 and a % 10 = 5 order by b;
--- Execute query 5 times to allow choose_custom_plan
--- to start considering a generic plan.
-execute mt_q1(0);
- a  
-----
-  5
- 15
- 25
-(3 rows)
-
-execute mt_q1(0);
- a  
-----
-  5
- 15
- 25
-(3 rows)
-
-execute mt_q1(0);
- a  
-----
-  5
- 15
- 25
-(3 rows)
-
-execute mt_q1(0);
- a  
-----
-  5
- 15
- 25
-(3 rows)
-
-execute mt_q1(0);
- a  
-----
-  5
- 15
- 25
-(3 rows)
-
 explain (analyze, costs off, summary off, timing off) execute mt_q1(15);
                                   QUERY PLAN                                   
 -------------------------------------------------------------------------------
@@ -3857,7 +3568,6 @@ from (
       select 1, 1, 1
      ) s(a, b, c)
 where s.a = $1 and s.b = $2 and s.c = (select 1);
-set plan_cache_mode to force_generic_plan;
 explain (costs off) execute q (1, 1);
                           QUERY PLAN                           
 ---------------------------------------------------------------
@@ -3879,7 +3589,6 @@ execute q (1, 1);
  1 | 1 | 1
 (1 row)
 
-reset plan_cache_mode;
 drop table p, q;
 -- Ensure run-time pruning works correctly when we match a partitioned table
 -- on the first level but find no matching partitions on the second level.

src/test/regress/sql/partition_prune.sql

 --
 -- Test partitioning planner code
 --
+
+-- Force generic plans to be used for all prepared statements in this file.
+set plan_cache_mode = force_generic_plan;
+
 create table lp (a char) partition by list (a);
 create table lp_default partition of lp default;
 create table lp_ef partition of lp for values in ('e', 'f');
@@ -355,14 +359,6 @@ set enable_indexonlyscan = off;
 prepare ab_q1 (int, int, int) as
 select * from ab where a between $1 and $2 and b <= $3;
 
--- Execute query 5 times to allow choose_custom_plan
--- to start considering a generic plan.
-execute ab_q1 (1, 8, 3);
-execute ab_q1 (1, 8, 3);
-execute ab_q1 (1, 8, 3);
-execute ab_q1 (1, 8, 3);
-execute ab_q1 (1, 8, 3);
-
 explain (analyze, costs off, summary off, timing off) execute ab_q1 (2, 2, 3);
 explain (analyze, costs off, summary off, timing off) execute ab_q1 (1, 2, 3);
 
@@ -372,14 +368,6 @@ deallocate ab_q1;
 prepare ab_q1 (int, int) as
 select a from ab where a between $1 and $2 and b < 3;
 
--- Execute query 5 times to allow choose_custom_plan
--- to start considering a generic plan.
-execute ab_q1 (1, 8);
-execute ab_q1 (1, 8);
-execute ab_q1 (1, 8);
-execute ab_q1 (1, 8);
-execute ab_q1 (1, 8);
-
 explain (analyze, costs off, summary off, timing off) execute ab_q1 (2, 2);
 explain (analyze, costs off, summary off, timing off) execute ab_q1 (2, 4);
 
@@ -388,24 +376,12 @@ explain (analyze, costs off, summary off, timing off) execute ab_q1 (2, 4);
 prepare ab_q2 (int, int) as
 select a from ab where a between $1 and $2 and b < (select 3);
 
-execute ab_q2 (1, 8);
-execute ab_q2 (1, 8);
-execute ab_q2 (1, 8);
-execute ab_q2 (1, 8);
-execute ab_q2 (1, 8);
-
 explain (analyze, costs off, summary off, timing off) execute ab_q2 (2, 2);
 
 -- As above, but swap the PARAM_EXEC Param to the first partition level
 prepare ab_q3 (int, int) as
 select a from ab where b between $1 and $2 and a < (select 3);
 
-execute ab_q3 (1, 8);
-execute ab_q3 (1, 8);
-execute ab_q3 (1, 8);
-execute ab_q3 (1, 8);
-execute ab_q3 (1, 8);
-
 explain (analyze, costs off, summary off, timing off) execute ab_q3 (2, 2);
 
 -- Test a backwards Append scan
@@ -485,27 +461,12 @@ set parallel_tuple_cost = 0;
 set min_parallel_table_scan_size = 0;
 set max_parallel_workers_per_gather = 2;
 
--- Execute query 5 times to allow choose_custom_plan
--- to start considering a generic plan.
-execute ab_q4 (1, 8);
-execute ab_q4 (1, 8);
-execute ab_q4 (1, 8);
-execute ab_q4 (1, 8);
-execute ab_q4 (1, 8);
 select explain_parallel_append('execute ab_q4 (2, 2)');
 
 -- Test run-time pruning with IN lists.
 prepare ab_q5 (int, int, int) as
 select avg(a) from ab where a in($1,$2,$3) and b < 4;
 
--- Execute query 5 times to allow choose_custom_plan
--- to start considering a generic plan.
-execute ab_q5 (1, 2, 3);
-execute ab_q5 (1, 2, 3);
-execute ab_q5 (1, 2, 3);
-execute ab_q5 (1, 2, 3);
-execute ab_q5 (1, 2, 3);
-
 select explain_parallel_append('execute ab_q5 (1, 1, 1)');
 select explain_parallel_append('execute ab_q5 (2, 3, 3)');
 
@@ -579,7 +540,6 @@ insert into xy_1 values(100,-10);
 
 set enable_bitmapscan = 0;
 set enable_indexscan = 0;
-set plan_cache_mode = 'force_generic_plan';
 
 prepare ab_q6 as
 select * from (
@@ -598,7 +558,6 @@ execute ab_q6(100);
 
 reset enable_bitmapscan;
 reset enable_indexscan;
-reset plan_cache_mode;
 
 deallocate ab_q1;
 deallocate ab_q2;
@@ -712,14 +671,6 @@ alter table part_cab attach partition part_abc_p1 for values in(3);
 prepare part_abc_q1 (int, int, int) as
 select * from part_abc where a = $1 and b = $2 and c = $3;
 
--- Execute query 5 times to allow choose_custom_plan
--- to start considering a generic plan.
-execute part_abc_q1 (1, 2, 3);
-execute part_abc_q1 (1, 2, 3);
-execute part_abc_q1 (1, 2, 3);
-execute part_abc_q1 (1, 2, 3);
-execute part_abc_q1 (1, 2, 3);
-
 -- Single partition should be scanned.
 explain (analyze, costs off, summary off, timing off) execute part_abc_q1 (1, 2, 3);
 
@@ -741,12 +692,6 @@ select * from listp where b = 1;
 -- which match the given parameter.
 prepare q1 (int,int) as select * from listp where b in ($1,$2);
 
-execute q1 (1,2);
-execute q1 (1,2);
-execute q1 (1,2);
-execute q1 (1,2);
-execute q1 (1,2);
-
 explain (analyze, costs off, summary off, timing off)  execute q1 (1,1);
 
 explain (analyze, costs off, summary off, timing off)  execute q1 (2,2);
@@ -760,12 +705,6 @@ deallocate q1;
 -- Test more complex cases where a not-equal condition further eliminates partitions.
 prepare q1 (int,int,int,int) as select * from listp where b in($1,$2) and $3 <> b and $4 <> b;
 
-execute q1 (1,2,3,4);
-execute q1 (1,2,3,4);
-execute q1 (1,2,3,4);
-execute q1 (1,2,3,4);
-execute q1 (1,2,3,4);
-
 -- Both partitions allowed by IN clause, but one disallowed by <> clause
 explain (analyze, costs off, summary off, timing off)  execute q1 (1,2,2,0);
 
@@ -842,7 +781,6 @@ select * from mc3p where a < 3 and abs(b) = 1;
 -- a combination of runtime parameters is specified, not all of whose values
 -- are available at the same time
 --
-set plan_cache_mode = force_generic_plan;
 prepare ps1 as
   select * from mc3p where a = $1 and abs(b) < (select 3);
 explain (analyze, costs off, summary off, timing off)
@@ -853,7 +791,6 @@ prepare ps2 as
 explain (analyze, costs off, summary off, timing off)
 execute ps2(1);
 deallocate ps2;
-reset plan_cache_mode;
 
 drop table mc3p;
 
@@ -888,14 +825,6 @@ create index on ma_test (b);
 analyze ma_test;
 prepare mt_q1 (int) as select a from ma_test where a >= $1 and a % 10 = 5 order by b;
 
--- Execute query 5 times to allow choose_custom_plan
--- to start considering a generic plan.
-execute mt_q1(0);
-execute mt_q1(0);
-execute mt_q1(0);
-execute mt_q1(0);
-execute mt_q1(0);
-
 explain (analyze, costs off, summary off, timing off) execute mt_q1(15);
 execute mt_q1(15);
 explain (analyze, costs off, summary off, timing off) execute mt_q1(25);
@@ -1075,12 +1004,9 @@ from (
      ) s(a, b, c)
 where s.a = $1 and s.b = $2 and s.c = (select 1);
 
-set plan_cache_mode to force_generic_plan;
-
 explain (costs off) execute q (1, 1);
 execute q (1, 1);
 
-reset plan_cache_mode;
 drop table p, q;
 
 -- Ensure run-time pruning works correctly when we match a partitioned table