Remove some unnecessary fields from Plan trees.

In the wake of commit f2343653f, we no longer need some fields that
were used before to control executor lock acquisitions:

* PlannedStmt.nonleafResultRelations can go away entirely.

* partitioned_rels can go away from Append, MergeAppend, and ModifyTable.
However, ModifyTable still needs to know the RT index of the partition
root table if any, which was formerly kept in the first entry of that
list.  Add a new field "rootRelation" to remember that.  rootRelation is
partly redundant with nominalRelation, in that if it's set it will have
the same value as nominalRelation.  However, the latter field has a
different purpose so it seems best to keep them distinct.

Amit Langote, reviewed by David Rowley and Jesper Pedersen,
and whacked around a bit more by me

Discussion: https://postgr.es/m/468c85d9-540e-66a2-1dde-fec2b741e688@lab.ntt.co.jp

3 files changed, 4 insertions, 14 deletions

diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index 3b690b55b3..e47641d572 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -91,7 +91,6 @@ _copyPlannedStmt(const PlannedStmt *from)
 	COPY_NODE_FIELD(planTree);
 	COPY_NODE_FIELD(rtable);
 	COPY_NODE_FIELD(resultRelations);
-	COPY_NODE_FIELD(nonleafResultRelations);
 	COPY_NODE_FIELD(rootResultRelations);
 	COPY_NODE_FIELD(subplans);
 	COPY_BITMAPSET_FIELD(rewindPlanIDs);
@@ -204,7 +203,7 @@ _copyModifyTable(const ModifyTable *from)
 	COPY_SCALAR_FIELD(operation);
 	COPY_SCALAR_FIELD(canSetTag);
 	COPY_SCALAR_FIELD(nominalRelation);
-	COPY_NODE_FIELD(partitioned_rels);
+	COPY_SCALAR_FIELD(rootRelation);
 	COPY_SCALAR_FIELD(partColsUpdated);
 	COPY_NODE_FIELD(resultRelations);
 	COPY_SCALAR_FIELD(resultRelIndex);
@@ -244,7 +243,6 @@ _copyAppend(const Append *from)
 	 */
 	COPY_NODE_FIELD(appendplans);
 	COPY_SCALAR_FIELD(first_partial_plan);
-	COPY_NODE_FIELD(partitioned_rels);
 	COPY_NODE_FIELD(part_prune_info);
 
 	return newnode;
@@ -266,7 +264,6 @@ _copyMergeAppend(const MergeAppend *from)
 	/*
 	 * copy remainder of node
 	 */
-	COPY_NODE_FIELD(partitioned_rels);
 	COPY_NODE_FIELD(mergeplans);
 	COPY_SCALAR_FIELD(numCols);
 	COPY_POINTER_FIELD(sortColIdx, from->numCols * sizeof(AttrNumber));
diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index 863d29cc57..9f4ffac91e 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -280,7 +280,6 @@ _outPlannedStmt(StringInfo str, const PlannedStmt *node)
 	WRITE_NODE_FIELD(planTree);
 	WRITE_NODE_FIELD(rtable);
 	WRITE_NODE_FIELD(resultRelations);
-	WRITE_NODE_FIELD(nonleafResultRelations);
 	WRITE_NODE_FIELD(rootResultRelations);
 	WRITE_NODE_FIELD(subplans);
 	WRITE_BITMAPSET_FIELD(rewindPlanIDs);
@@ -376,7 +375,7 @@ _outModifyTable(StringInfo str, const ModifyTable *node)
 	WRITE_ENUM_FIELD(operation, CmdType);
 	WRITE_BOOL_FIELD(canSetTag);
 	WRITE_UINT_FIELD(nominalRelation);
-	WRITE_NODE_FIELD(partitioned_rels);
+	WRITE_UINT_FIELD(rootRelation);
 	WRITE_BOOL_FIELD(partColsUpdated);
 	WRITE_NODE_FIELD(resultRelations);
 	WRITE_INT_FIELD(resultRelIndex);
@@ -405,7 +404,6 @@ _outAppend(StringInfo str, const Append *node)
 
 	WRITE_NODE_FIELD(appendplans);
 	WRITE_INT_FIELD(first_partial_plan);
-	WRITE_NODE_FIELD(partitioned_rels);
 	WRITE_NODE_FIELD(part_prune_info);
 }
 
@@ -418,7 +416,6 @@ _outMergeAppend(StringInfo str, const MergeAppend *node)
 
 	_outPlanInfo(str, (const Plan *) node);
 
-	WRITE_NODE_FIELD(partitioned_rels);
 	WRITE_NODE_FIELD(mergeplans);
 
 	WRITE_INT_FIELD(numCols);
@@ -2179,7 +2176,7 @@ _outModifyTablePath(StringInfo str, const ModifyTablePath *node)
 	WRITE_ENUM_FIELD(operation, CmdType);
 	WRITE_BOOL_FIELD(canSetTag);
 	WRITE_UINT_FIELD(nominalRelation);
-	WRITE_NODE_FIELD(partitioned_rels);
+	WRITE_UINT_FIELD(rootRelation);
 	WRITE_BOOL_FIELD(partColsUpdated);
 	WRITE_NODE_FIELD(resultRelations);
 	WRITE_NODE_FIELD(subpaths);
@@ -2259,7 +2256,6 @@ _outPlannerGlobal(StringInfo str, const PlannerGlobal *node)
 	WRITE_NODE_FIELD(finalrtable);
 	WRITE_NODE_FIELD(finalrowmarks);
 	WRITE_NODE_FIELD(resultRelations);
-	WRITE_NODE_FIELD(nonleafResultRelations);
 	WRITE_NODE_FIELD(rootResultRelations);
 	WRITE_NODE_FIELD(relationOids);
 	WRITE_NODE_FIELD(invalItems);
diff --git a/src/backend/nodes/readfuncs.c b/src/backend/nodes/readfuncs.c
index 73ffa9714c..e117867de5 100644
--- a/src/backend/nodes/readfuncs.c
+++ b/src/backend/nodes/readfuncs.c
@@ -1504,7 +1504,6 @@ _readPlannedStmt(void)
 	READ_NODE_FIELD(planTree);
 	READ_NODE_FIELD(rtable);
 	READ_NODE_FIELD(resultRelations);
-	READ_NODE_FIELD(nonleafResultRelations);
 	READ_NODE_FIELD(rootResultRelations);
 	READ_NODE_FIELD(subplans);
 	READ_BITMAPSET_FIELD(rewindPlanIDs);
@@ -1598,7 +1597,7 @@ _readModifyTable(void)
 	READ_ENUM_FIELD(operation, CmdType);
 	READ_BOOL_FIELD(canSetTag);
 	READ_UINT_FIELD(nominalRelation);
-	READ_NODE_FIELD(partitioned_rels);
+	READ_UINT_FIELD(rootRelation);
 	READ_BOOL_FIELD(partColsUpdated);
 	READ_NODE_FIELD(resultRelations);
 	READ_INT_FIELD(resultRelIndex);
@@ -1632,7 +1631,6 @@ _readAppend(void)
 
 	READ_NODE_FIELD(appendplans);
 	READ_INT_FIELD(first_partial_plan);
-	READ_NODE_FIELD(partitioned_rels);
 	READ_NODE_FIELD(part_prune_info);
 
 	READ_DONE();
@@ -1648,7 +1646,6 @@ _readMergeAppend(void)
 
 	ReadCommonPlan(&local_node->plan);
 
-	READ_NODE_FIELD(partitioned_rels);
 	READ_NODE_FIELD(mergeplans);
 	READ_INT_FIELD(numCols);
 	READ_ATTRNUMBER_ARRAY(sortColIdx, local_node->numCols);