diff -U3 /tmp/cirrus-ci-build/contrib/pg_overexplain/expected/pg_overexplain.out /tmp/cirrus-ci-build/build/testrun/pg_overexplain/regress/results/pg_overexplain.out
--- /tmp/cirrus-ci-build/contrib/pg_overexplain/expected/pg_overexplain.out	2025-05-15 22:51:07.510084831 +0000
+++ /tmp/cirrus-ci-build/build/testrun/pg_overexplain/regress/results/pg_overexplain.out	2025-05-15 22:54:54.362204522 +0000
@@ -91,26 +91,26 @@
  GroupAggregate
    Group Key: vegetables.genus
    Disabled Nodes: 0
-   Parallel Safe: true
+   Parallel Safe: false
    Plan Node ID: 0
    ->  Sort
          Sort Key: vegetables.genus, vegetables.name
          Disabled Nodes: 0
-         Parallel Safe: true
+         Parallel Safe: false
          Plan Node ID: 1
          ->  Append
                Disabled Nodes: 0
-               Parallel Safe: true
+               Parallel Safe: false
                Plan Node ID: 2
                Append RTIs: 1
                ->  Seq Scan on brassica vegetables_1
                      Disabled Nodes: 0
-                     Parallel Safe: true
+                     Parallel Safe: false
                      Plan Node ID: 3
                      Scan RTI: 3
                ->  Seq Scan on daucus vegetables_2
                      Disabled Nodes: 0
-                     Parallel Safe: true
+                     Parallel Safe: false
                      Plan Node ID: 4
                      Scan RTI: 4
  PlannedStmt:
@@ -163,7 +163,7 @@
          <Item>vegetables.genus</Item>                              +
        </Group-Key>                                                 +
        <Disabled-Nodes>0</Disabled-Nodes>                           +
-       <Parallel-Safe>true</Parallel-Safe>                          +
+       <Parallel-Safe>false</Parallel-Safe>                         +
        <Plan-Node-ID>0</Plan-Node-ID>                               +
        <extParam>none</extParam>                                    +
        <allParam>none</allParam>                                    +
@@ -179,7 +179,7 @@
              <Item>vegetables.name</Item>                           +
            </Sort-Key>                                              +
            <Disabled-Nodes>0</Disabled-Nodes>                       +
-           <Parallel-Safe>true</Parallel-Safe>                      +
+           <Parallel-Safe>false</Parallel-Safe>                     +
            <Plan-Node-ID>1</Plan-Node-ID>                           +
            <extParam>none</extParam>                                +
            <allParam>none</allParam>                                +
@@ -191,7 +191,7 @@
                <Async-Capable>false</Async-Capable>                 +
                <Disabled>false</Disabled>                           +
                <Disabled-Nodes>0</Disabled-Nodes>                   +
-               <Parallel-Safe>true</Parallel-Safe>                  +
+               <Parallel-Safe>false</Parallel-Safe>                 +
                <Plan-Node-ID>2</Plan-Node-ID>                       +
                <extParam>none</extParam>                            +
                <allParam>none</allParam>                            +
@@ -207,7 +207,7 @@
                    <Alias>vegetables_1</Alias>                      +
                    <Disabled>false</Disabled>                       +
                    <Disabled-Nodes>0</Disabled-Nodes>               +
-                   <Parallel-Safe>true</Parallel-Safe>              +
+                   <Parallel-Safe>false</Parallel-Safe>             +
                    <Plan-Node-ID>3</Plan-Node-ID>                   +
                    <extParam>none</extParam>                        +
                    <allParam>none</allParam>                        +
@@ -222,7 +222,7 @@
                    <Alias>vegetables_2</Alias>                      +
                    <Disabled>false</Disabled>                       +
                    <Disabled-Nodes>0</Disabled-Nodes>               +
-                   <Parallel-Safe>true</Parallel-Safe>              +
+                   <Parallel-Safe>false</Parallel-Safe>             +
                    <Plan-Node-ID>4</Plan-Node-ID>                   +
                    <extParam>none</extParam>                        +
                    <allParam>none</allParam>                        +
@@ -306,46 +306,40 @@
 EXPLAIN (DEBUG, COSTS OFF)
 SELECT genus, array_agg(name ORDER BY name) FROM vegetables GROUP BY genus
 $$);
-                      explain_filter                       
------------------------------------------------------------
- Gather
-   Workers Planned: 1
-   Single Copy: true
-   Disabled Nodes: 0
+                   explain_filter                    
+-----------------------------------------------------
+ GroupAggregate
+   Group Key: vegetables.genus
+   Disabled Nodes: 2
    Parallel Safe: false
    Plan Node ID: 0
-   ->  GroupAggregate
-         Group Key: vegetables.genus
+   ->  Sort
+         Sort Key: vegetables.genus, vegetables.name
          Disabled Nodes: 2
-         Parallel Safe: true
+         Parallel Safe: false
          Plan Node ID: 1
-         ->  Sort
-               Sort Key: vegetables.genus, vegetables.name
+         ->  Append
                Disabled Nodes: 2
-               Parallel Safe: true
+               Parallel Safe: false
                Plan Node ID: 2
-               ->  Append
-                     Disabled Nodes: 2
-                     Parallel Safe: true
+               ->  Seq Scan on brassica vegetables_1
+                     Disabled: true
+                     Disabled Nodes: 1
+                     Parallel Safe: false
                      Plan Node ID: 3
-                     ->  Seq Scan on brassica vegetables_1
-                           Disabled: true
-                           Disabled Nodes: 1
-                           Parallel Safe: true
-                           Plan Node ID: 4
-                     ->  Seq Scan on daucus vegetables_2
-                           Disabled: true
-                           Disabled Nodes: 1
-                           Parallel Safe: true
-                           Plan Node ID: 5
+               ->  Seq Scan on daucus vegetables_2
+                     Disabled: true
+                     Disabled Nodes: 1
+                     Parallel Safe: false
+                     Plan Node ID: 4
  PlannedStmt:
    Command Type: select
-   Flags: canSetTag, parallelModeNeeded
+   Flags: canSetTag
    Subplans Needing Rewind: none
    Relation OIDs: NNN...
    Executor Parameter Types: none
    Parse Location: 0 to end
-(37 rows)
+(31 rows)
 
 SET debug_parallel_query = false;
 RESET enable_seqscan;
@@ -392,25 +386,25 @@
 ------------------------------------------------------------------------------------------
  Nested Loop (actual rows=N.NN loops=1)
    Disabled Nodes: 0
-   Parallel Safe: true
+   Parallel Safe: false
    Plan Node ID: 0
    ->  Append (actual rows=N.NN loops=1)
          Disabled Nodes: 0
-         Parallel Safe: true
+         Parallel Safe: false
          Plan Node ID: 1
          ->  Index Scan using brassica_id_idx on brassica v1_1 (actual rows=N.NN loops=1)
                Index Searches: 1
                Disabled Nodes: 0
-               Parallel Safe: true
+               Parallel Safe: false
                Plan Node ID: 2
          ->  Index Scan using daucus_id_idx on daucus v1_2 (actual rows=N.NN loops=1)
                Index Searches: 1
                Disabled Nodes: 0
-               Parallel Safe: true
+               Parallel Safe: false
                Plan Node ID: 3
    ->  Append (actual rows=N.NN loops=8)
          Disabled Nodes: 0
-         Parallel Safe: true
+         Parallel Safe: false
          Plan Node ID: 4
          extParam: 0
          allParam: 0
@@ -418,7 +412,7 @@
                Index Cond: (id = v1.id)
                Index Searches: 8
                Disabled Nodes: 0
-               Parallel Safe: true
+               Parallel Safe: false
                Plan Node ID: 5
                extParam: 0
                allParam: 0
@@ -426,7 +420,7 @@
                Index Cond: (id = v1.id)
                Index Searches: 8
                Disabled Nodes: 0
-               Parallel Safe: true
+               Parallel Safe: false
                Plan Node ID: 6
                extParam: 0
                allParam: 0