Remove have_gather_plan_node.

src/gausskernel/optimizer/path/allpaths.cpp

@@ -68,7 +68,6 @@ static void set_plain_rel_size(PlannerInfo* root, RelOptInfo* rel, RangeTblEntry
 static void create_plain_partial_paths(PlannerInfo* root, RelOptInfo* rel);
 static void set_tablesample_rel_size(PlannerInfo* root, RelOptInfo* rel, RangeTblEntry* rte);
 static void set_plain_rel_pathlist(PlannerInfo* root, RelOptInfo* rel, RangeTblEntry* rte);
-static void have_gather_plan_node(Plan* plan, void* context, const char* query_string);
 static void set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte);
 static void set_foreign_size(PlannerInfo* root, RelOptInfo* rel, RangeTblEntry* rte);
 static void set_foreign_pathlist(PlannerInfo* root, RelOptInfo* rel, RangeTblEntry* rte);
@@ -281,16 +280,6 @@ static void set_base_rel_sizes(PlannerInfo* root)
             set_rel_consider_parallel(root, rel, root->simple_rte_array[rti]);
 
         set_rel_size(root, rel, (Index)rti, root->simple_rte_array[rti]);
-
-        /* we have not merge the commit that change plan generation,
-         * so we temporarily use this function to avoid gather-nesting problem. */
-        if (root->simple_rte_array[rti]->rtekind == RTE_SUBQUERY && rel->subplan != NULL) {
-            bool have_gather = false;
-            have_gather_plan_node(rel->subplan, (void*)&have_gather, NULL);
-            if (have_gather)
-                rel->consider_parallel = false;
-        }
-
         /* Try inlist2join optimization */
         inlist2join_qrw_optimization(root, rti);
     }
@@ -1002,20 +991,6 @@ static void set_plain_rel_pathlist(PlannerInfo* root, RelOptInfo* rel, RangeTblE
     }
 }
 
-/*
- * we have not merge the commit that change plan generation,
- * so we temporarily use this function to avoid gather-nesting problem.
- */
-static void have_gather_plan_node(Plan* plan, void* context, const char* query_string)
-{
-    if (IsA(plan, Gather)) {
-        bool* result = (bool*)context;
-        *result = true;
-    } else {
-        PlanTreeWalker(plan, have_gather_plan_node, context, query_string);
-    }
-}
-
 /*
  * If this relation could possibly be scanned from within a worker, then set
  * its consider_parallel flag.
@@ -1036,9 +1011,10 @@ static void set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel, RangeT
 
     /* Assorted checks based on rtekind. */
     switch (rte->rtekind) {
-        case RTE_RELATION:
+        case RTE_RELATION: {
             /*
-             * Currently, parallel workers can't access the leader's temporary
+             * Don't support parallel query in next cases:
+             * 1. Currently, parallel workers can't access the leader's temporary
              * tables.  We could possibly relax this if the wrote all of its
              * local buffers at the start of the query and made no changes
              * thereafter (maybe we could allow hint bit changes), and if we
@@ -1046,14 +1022,14 @@ static void set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel, RangeT
              * temporary buffers could be expensive, though, and we don't have
              * the rest of the necessary infrastructure right now anyway.  So
              * for now, bail out if we see a temporary table.
-             *
-             * Don't support parallel query for foreign table.
+             * 2. Global temp table.
+             * 3. Foreign table.
+             * 4. partitioned table.
+             * 5. non row-oriented table.
              */
-            if (get_rel_persistence(rte->relid) == RELPERSISTENCE_TEMP || rte->relkind == RELKIND_FOREIGN_TABLE) {
-                return;
-            }
-            /* Don't support parallel for partitioned table. */
-            if (rte->ispartrel) {
+            char persistence = get_rel_persistence(rte->relid);
+            if (persistence == RELPERSISTENCE_TEMP || persistence == RELPERSISTENCE_GLOBAL_TEMP ||
+                rte->relkind == RELKIND_FOREIGN_TABLE || rte->ispartrel || rel->orientation != REL_ROW_ORIENTED) {
                 return;
             }
 
@@ -1072,7 +1048,7 @@ static void set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel, RangeT
                 return;
             }
             break;
-
+        }
         case RTE_SUBQUERY:
             /*
              * Subplans currently aren't passed to workers.  Even if they
@@ -1082,14 +1058,6 @@ static void set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel, RangeT
              * involves any parallel-restricted operations.  It would be
              * nice to relax this restriction some day, but it's going to
              * take a fair amount of work.
-             *
-             * we have not merge the commit that change plan generation,
-             * so the problem mentioned above have not been solved very well.
-             * but if rte->kind is RTE_SUBQUERY, it means rel will have subplan
-             * so we temporarily use function have_gather_plan_node to find out
-             * if there is a Gather plan node in rel->subplan, if yes, do not
-             * consider parallel about this rel to avoid gather-nesting problem.
-             * see have_gather_plan_node, and it is not a good idea.
              */
             break;
 

src/gausskernel/runtime/executor/execMain.cpp

@@ -2029,7 +2029,7 @@ static void ExecutePlan(EState *estate, PlanState *planstate, bool use_parallel_
             slot = NULL;
         }
         /******************************* MOT LLVM *************************************/
-        else if (!IS_PGXC_COORDINATOR && JitExec::IsMotCodegenEnabled() && mot_jit_context) {
+        else if (mot_jit_context && !IS_PGXC_COORDINATOR && JitExec::IsMotCodegenEnabled()) {
             int scan_ended = 0;
             if (!mot_finished_execution) {
                 // previous iteration has not signaled end of scan

src/test/regress/expected/parallel_append.out

@@ -233,6 +233,76 @@ select d.d1, sum(d.d2), sum(t.a2) from (select * from a union all select * from
   5 |  26 |  20
 (5 rows)
 
+-- set parallel_workers of table a to 0, subplan of seqscan on a should not be paralleled
+alter table a set (parallel_workers=0);
+explain (costs off) select * from d left outer join (select * from a union all select * from b) as t on d.d1=t.a1 order by 1,2,3,4,5,6;
+                   QUERY PLAN                   
+------------------------------------------------
+ Sort
+   Sort Key: d.d1, d.d2, d.d3, a.a1, a.a2, a.a3
+   ->  Hash Right Join
+         Hash Cond: (a.a1 = d.d1)
+         ->  Gather
+               Number of Workers: 2
+               ->  Parallel Append
+                     ->  Seq Scan on a
+                     ->  Parallel Seq Scan on b
+         ->  Hash
+               ->  Gather
+                     Number of Workers: 1
+                     ->  Parallel Seq Scan on d
+(13 rows)
+
+explain (costs off) select d.d1, sum(d.d2), sum(t.a2) from (select * from a union all select * from b) t, d where t.a1=d1 group by d.d1 order by 1,2;
+                      QUERY PLAN                      
+------------------------------------------------------
+ Sort
+   Sort Key: d.d1, (sum(d.d2))
+   ->  HashAggregate
+         Group By Key: d.d1
+         ->  Hash Join
+               Hash Cond: (a.a1 = d.d1)
+               ->  Gather
+                     Number of Workers: 2
+                     ->  Parallel Append
+                           ->  Seq Scan on a
+                           ->  Parallel Seq Scan on b
+               ->  Hash
+                     ->  Gather
+                           Number of Workers: 1
+                           ->  Parallel Seq Scan on d
+(15 rows)
+
+select * from d left outer join (select * from a union all select * from b) as t on d.d1=t.a1 order by 1,2,3,4,5,6;
+ d1 | d2 | d3 | a1 | a2 | a3 
+----+----+----+----+----+----
+  1 |  2 |  3 |  1 |  1 |  1
+  1 |  3 |  2 |  1 |  1 |  1
+  2 |  3 |  4 |  2 |  2 |  2
+  2 |  4 |  4 |  2 |  2 |  2
+  3 |  4 |  5 |  3 |  3 |  3
+  3 |  5 |  6 |  3 |  3 |  3
+  4 |  5 |  6 |  4 |  4 |  4
+  4 |  5 |  6 |  4 |  4 |  4
+  4 |  6 |  8 |  4 |  4 |  4
+  4 |  6 |  8 |  4 |  4 |  4
+  5 |  6 |  7 |  5 |  5 |  5
+  5 |  6 |  7 |  5 |  5 |  5
+  5 |  7 | 10 |  5 |  5 |  5
+  5 |  7 | 10 |  5 |  5 |  5
+(14 rows)
+
+select d.d1, sum(d.d2), sum(t.a2) from (select * from a union all select * from b) t, d where t.a1=d1 group by d.d1 order by 1,2;
+ d1 | sum | sum 
+----+-----+-----
+  1 |   5 |   2
+  2 |   7 |   4
+  3 |   9 |   6
+  4 |  22 |  16
+  5 |  26 |  20
+(5 rows)
+
+alter table a reset (parallel_workers);
 ---------------------------------------
 -- 2. except && except all
 ---------------------------------------

src/test/regress/expected/parallel_hashjoin.out

@@ -31,6 +31,7 @@ select * from parallel_hashjoin_test_a left outer join parallel_hashjoin_test_b
   9 |  9
 (9 rows)
 
+set force_parallel_mode=on;
 set parallel_setup_cost = 1;
 set min_parallel_table_scan_size=0;
 set parallel_tuple_cost = 0.01;
@@ -96,3 +97,4 @@ reset parallel_setup_cost;
 reset min_parallel_table_scan_size;
 reset parallel_tuple_cost;
 reset enable_nestloop;
+reset force_parallel_mode;

src/test/regress/expected/parallel_nested_loop.out

@@ -25,6 +25,7 @@ select * from parallel_nested_loop_test_a left outer join parallel_nested_loop_t
 
 set parallel_setup_cost = 0;
 set min_parallel_table_scan_size=0;
+set force_parallel_mode=on;
 explain (costs off) select * from parallel_nested_loop_test_a left outer join parallel_nested_loop_test_b on parallel_nested_loop_test_a.id = 1;
                           QUERY PLAN                          
 --------------------------------------------------------------
@@ -51,3 +52,4 @@ drop table parallel_nested_loop_test_a;
 drop table parallel_nested_loop_test_b;
 reset parallel_setup_cost;
 reset min_parallel_table_scan_size;
+reset force_parallel_mode;

src/test/regress/sql/parallel_append.sql

@@ -49,6 +49,13 @@ select * from (select * from a union all select * from b) as ta, c where ta.a1 =
 select * from d left outer join (select * from a union all select * from b) as t on d.d1=t.a1;
 select d.d1, sum(d.d2), sum(t.a2) from (select * from a union all select * from b) t, d where t.a1=d1 group by d.d1 order by 1,2;
 
+-- set parallel_workers of table a to 0, subplan of seqscan on a should not be paralleled
+alter table a set (parallel_workers=0);
+explain (costs off) select * from d left outer join (select * from a union all select * from b) as t on d.d1=t.a1 order by 1,2,3,4,5,6;
+explain (costs off) select d.d1, sum(d.d2), sum(t.a2) from (select * from a union all select * from b) t, d where t.a1=d1 group by d.d1 order by 1,2;
+select * from d left outer join (select * from a union all select * from b) as t on d.d1=t.a1 order by 1,2,3,4,5,6;
+select d.d1, sum(d.d2), sum(t.a2) from (select * from a union all select * from b) t, d where t.a1=d1 group by d.d1 order by 1,2;
+alter table a reset (parallel_workers);
 
 ---------------------------------------
 -- 2. except && except all

src/test/regress/sql/parallel_hashjoin.sql

@@ -7,6 +7,7 @@ analyse parallel_hashjoin_test_b;
 explain (costs off) select * from parallel_hashjoin_test_a left outer join parallel_hashjoin_test_b on parallel_hashjoin_test_a.id = parallel_hashjoin_test_b.id where parallel_hashjoin_test_a.id < 10 order by parallel_hashjoin_test_a.id;
 select * from parallel_hashjoin_test_a left outer join parallel_hashjoin_test_b on parallel_hashjoin_test_a.id = parallel_hashjoin_test_b.id where parallel_hashjoin_test_a.id < 10 order by parallel_hashjoin_test_a.id;
 
+set force_parallel_mode=on;
 set parallel_setup_cost = 1;
 set min_parallel_table_scan_size=0;
 set parallel_tuple_cost = 0.01;
@@ -22,4 +23,4 @@ reset parallel_setup_cost;
 reset min_parallel_table_scan_size;
 reset parallel_tuple_cost;
 reset enable_nestloop;
-
+reset force_parallel_mode;

src/test/regress/sql/parallel_nested_loop.sql

@@ -9,6 +9,7 @@ select * from parallel_nested_loop_test_a left outer join parallel_nested_loop_t
 
 set parallel_setup_cost = 0;
 set min_parallel_table_scan_size=0;
+set force_parallel_mode=on;
 
 explain (costs off) select * from parallel_nested_loop_test_a left outer join parallel_nested_loop_test_b on parallel_nested_loop_test_a.id = 1;
 select * from parallel_nested_loop_test_a left outer join parallel_nested_loop_test_b on parallel_nested_loop_test_a.id = 1;
@@ -17,4 +18,5 @@ drop table parallel_nested_loop_test_a;
 drop table parallel_nested_loop_test_b;
 
 reset parallel_setup_cost;
-reset min_parallel_table_scan_size;
+reset min_parallel_table_scan_size;
+reset force_parallel_mode;