Redesign initialization of partition routing structures

This speeds up write operations (INSERT, UPDATE, DELETE, COPY, as well
as the future MERGE) on partitioned tables.

This changes the setup for tuple routing so that it does far less work
during the initial setup and pushes more work out to when partitions
receive tuples.  PartitionDispatchData structs for sub-partitioned
tables are only created when a tuple gets routed through it.  The
possibly large arrays in the PartitionTupleRouting struct have largely
been removed.  The partitions[] array remains but now never contains any
NULL gaps.  Previously the NULLs had to be skipped during
ExecCleanupTupleRouting(), which could add a large overhead to the
cleanup when the number of partitions was large.  The partitions[] array
is allocated small to start with and only enlarged when we route tuples
to enough partitions that it runs out of space. This allows us to keep
simple single-row partition INSERTs running quickly.  Redesign

The arrays in PartitionTupleRouting which stored the tuple translation maps
have now been removed.  These have been moved out into a
PartitionRoutingInfo struct which is an additional field in ResultRelInfo.

The find_all_inheritors() call still remains by far the slowest part of
ExecSetupPartitionTupleRouting(). This commit just removes the other slow
parts.

In passing also rename the tuple translation maps from being ParentToChild
and ChildToParent to being RootToPartition and PartitionToRoot. The old
names mislead you into thinking that a partition of some sub-partitioned
table would translate to the rowtype of the sub-partitioned table rather
than the root partitioned table.

Authors: David Rowley and Amit Langote, heavily revised by Álvaro Herrera
Testing help from Jesper Pedersen and Kato Sho.
Discussion: https://postgr.es/m/CAKJS1f_1RJyFquuCKRFHTdcXqoPX-PYqAd7nz=GVBwvGh4a6xA@mail.gmail.com

1 files changed, 522 insertions, 435 deletions

diff --git a/src/backend/executor/execPartition.c b/src/backend/executor/execPartition.c
index e11fe687121..e3cb4fb1bee 100644
--- a/src/backend/executor/execPartition.c
+++ b/src/backend/executor/execPartition.c
@@ -33,21 +33,98 @@
 
 
 /*-----------------------
+ * PartitionTupleRouting - Encapsulates all information required to
+ * route a tuple inserted into a partitioned table to one of its leaf
+ * partitions.
+ *
+ * partition_root
+ *		The partitioned table that's the target of the command.
+ *
+ * partition_dispatch_info
+ *		Array of 'max_dispatch' elements containing a pointer to a
+ *		PartitionDispatch object for every partitioned table touched by tuple
+ *		routing.  The entry for the target partitioned table is *always*
+ *		present in the 0th element of this array.  See comment for
+ *		PartitionDispatchData->indexes for details on how this array is
+ *		indexed.
+ *
+ * num_dispatch
+ *		The current number of items stored in the 'partition_dispatch_info'
+ *		array.  Also serves as the index of the next free array element for
+ *		new PartitionDispatch objects that need to be stored.
+ *
+ * max_dispatch
+ *		The current allocated size of the 'partition_dispatch_info' array.
+ *
+ * partitions
+ *		Array of 'max_partitions' elements containing a pointer to a
+ *		ResultRelInfo for every leaf partitions touched by tuple routing.
+ *		Some of these are pointers to ResultRelInfos which are borrowed out of
+ *		'subplan_resultrel_htab'.  The remainder have been built especially
+ *		for tuple routing.  See comment for PartitionDispatchData->indexes for
+ *		details on how this array is indexed.
+ *
+ * num_partitions
+ *		The current number of items stored in the 'partitions' array.  Also
+ *		serves as the index of the next free array element for new
+ *		ResultRelInfo objects that need to be stored.
+ *
+ * max_partitions
+ *		The current allocated size of the 'partitions' array.
+ *
+ * subplan_resultrel_htab
+ *		Hash table to store subplan ResultRelInfos by Oid.  This is used to
+ *		cache ResultRelInfos from subplans of an UPDATE ModifyTable node;
+ *		NULL in other cases.  Some of these may be useful for tuple routing
+ *		to save having to build duplicates.
+ *
+ * memcxt
+ *		Memory context used to allocate subsidiary structs.
+ *-----------------------
+ */
+typedef struct PartitionTupleRouting
+{
+	Relation	partition_root;
+	PartitionDispatch *partition_dispatch_info;
+	int			num_dispatch;
+	int			max_dispatch;
+	ResultRelInfo **partitions;
+	int			num_partitions;
+	int			max_partitions;
+	HTAB	   *subplan_resultrel_htab;
+	MemoryContext memcxt;
+} PartitionTupleRouting;
+
+/*-----------------------
  * PartitionDispatch - information about one partitioned table in a partition
- * hierarchy required to route a tuple to one of its partitions
+ * hierarchy required to route a tuple to any of its partitions.  A
+ * PartitionDispatch is always encapsulated inside a PartitionTupleRouting
+ * struct and stored inside its 'partition_dispatch_info' array.
  *
- *	reldesc		Relation descriptor of the table
- *	key			Partition key information of the table
- *	keystate	Execution state required for expressions in the partition key
- *	partdesc	Partition descriptor of the table
- *	tupslot		A standalone TupleTableSlot initialized with this table's tuple
- *				descriptor
- *	tupmap		TupleConversionMap to convert from the parent's rowtype to
- *				this table's rowtype (when extracting the partition key of a
- *				tuple just before routing it through this table)
- *	indexes		Array with partdesc->nparts members (for details on what
- *				individual members represent, see how they are set in
- *				get_partition_dispatch_recurse())
+ * reldesc
+ *		Relation descriptor of the table
+ * key
+ *		Partition key information of the table
+ * keystate
+ *		Execution state required for expressions in the partition key
+ * partdesc
+ *		Partition descriptor of the table
+ * tupslot
+ *		A standalone TupleTableSlot initialized with this table's tuple
+ *		descriptor, or NULL if no tuple conversion between the parent is
+ *		required.
+ * tupmap
+ *		TupleConversionMap to convert from the parent's rowtype to this table's
+ *		rowtype  (when extracting the partition key of a tuple just before
+ *		routing it through this table). A NULL value is stored if no tuple
+ *		conversion is required.
+ * indexes
+ *		Array of partdesc->nparts elements.  For leaf partitions the index
+ *		corresponds to the partition's ResultRelInfo in the encapsulating
+ *		PartitionTupleRouting's partitions array.  For partitioned partitions,
+ *		the index corresponds to the PartitionDispatch for it in its
+ *		partition_dispatch_info array.  -1 indicates we've not yet allocated
+ *		anything in PartitionTupleRouting for the partition.
  *-----------------------
  */
 typedef struct PartitionDispatchData
@@ -58,14 +135,32 @@ typedef struct PartitionDispatchData
 	PartitionDesc partdesc;
 	TupleTableSlot *tupslot;
 	AttrNumber *tupmap;
-	int		   *indexes;
+	int			indexes[FLEXIBLE_ARRAY_MEMBER];
 } PartitionDispatchData;
 
-
-static PartitionDispatch *RelationGetPartitionDispatchInfo(Relation rel,
-								 int *num_parted, List **leaf_part_oids);
-static void get_partition_dispatch_recurse(Relation rel, Relation parent,
-							   List **pds, List **leaf_part_oids);
+/* struct to hold result relations coming from UPDATE subplans */
+typedef struct SubplanResultRelHashElem
+{
+	Oid		relid;		/* hash key -- must be first */
+	ResultRelInfo *rri;
+} SubplanResultRelHashElem;
+
+
+static void ExecHashSubPlanResultRelsByOid(ModifyTableState *mtstate,
+							   PartitionTupleRouting *proute);
+static ResultRelInfo *ExecInitPartitionInfo(ModifyTableState *mtstate,
+					  EState *estate, PartitionTupleRouting *proute,
+					  PartitionDispatch dispatch,
+					  ResultRelInfo *rootResultRelInfo,
+					  int partidx);
+static void ExecInitRoutingInfo(ModifyTableState *mtstate,
+					EState *estate,
+					PartitionTupleRouting *proute,
+					PartitionDispatch dispatch,
+					ResultRelInfo *partRelInfo,
+					int partidx);
+static PartitionDispatch ExecInitPartitionDispatchInfo(PartitionTupleRouting *proute,
+							  Oid partoid, PartitionDispatch parent_pd, int partidx);
 static void FormPartitionKeyDatum(PartitionDispatch pd,
 					  TupleTableSlot *slot,
 					  EState *estate,
@@ -92,131 +187,87 @@ static void find_matching_subplans_recurse(PartitionPruningData *prunedata,
  * Note that all the relations in the partition tree are locked using the
  * RowExclusiveLock mode upon return from this function.
  *
- * While we allocate the arrays of pointers of ResultRelInfo and
- * TupleConversionMap for all partitions here, actual objects themselves are
- * lazily allocated for a given partition if a tuple is actually routed to it;
- * see ExecInitPartitionInfo.  However, if the function is invoked for update
- * tuple routing, caller would already have initialized ResultRelInfo's for
- * some of the partitions, which are reused and assigned to their respective
- * slot in the aforementioned array.  For such partitions, we delay setting
- * up objects such as TupleConversionMap until those are actually chosen as
- * the partitions to route tuples to.  See ExecPrepareTupleRouting.
+ * Callers must use the returned PartitionTupleRouting during calls to
+ * ExecFindPartition().  The actual ResultRelInfo for a partition is only
+ * allocated when the partition is found for the first time.
+ *
+ * The current memory context is used to allocate this struct and all
+ * subsidiary structs that will be allocated from it later on.  Typically
+ * it should be estate->es_query_cxt.
  */
 PartitionTupleRouting *
 ExecSetupPartitionTupleRouting(ModifyTableState *mtstate, Relation rel)
 {
-	List	   *leaf_parts;
-	ListCell   *cell;
-	int			i;
-	ResultRelInfo *update_rri = NULL;
-	int			num_update_rri = 0,
-				update_rri_index = 0;
 	PartitionTupleRouting *proute;
-	int			nparts;
 	ModifyTable *node = mtstate ? (ModifyTable *) mtstate->ps.plan : NULL;
 
+	/* Lock all the partitions. */
+	(void) find_all_inheritors(RelationGetRelid(rel), RowExclusiveLock, NULL);
+
 	/*
-	 * Get the information about the partition tree after locking all the
-	 * partitions.
+	 * Here we attempt to expend as little effort as possible in setting up
+	 * the PartitionTupleRouting.  Each partition's ResultRelInfo is built on
+	 * demand, only when we actually need to route a tuple to that partition.
+	 * The reason for this is that a common case is for INSERT to insert a
+	 * single tuple into a partitioned table and this must be fast.
 	 */
-	(void) find_all_inheritors(RelationGetRelid(rel), RowExclusiveLock, NULL);
 	proute = (PartitionTupleRouting *) palloc0(sizeof(PartitionTupleRouting));
-	proute->partition_dispatch_info =
-		RelationGetPartitionDispatchInfo(rel, &proute->num_dispatch,
-										 &leaf_parts);
-	proute->num_partitions = nparts = list_length(leaf_parts);
-	proute->partitions =
-		(ResultRelInfo **) palloc(nparts * sizeof(ResultRelInfo *));
-	proute->parent_child_tupconv_maps =
-		(TupleConversionMap **) palloc0(nparts * sizeof(TupleConversionMap *));
-	proute->partition_oids = (Oid *) palloc(nparts * sizeof(Oid));
-
-	/* Set up details specific to the type of tuple routing we are doing. */
-	if (node && node->operation == CMD_UPDATE)
-	{
-		update_rri = mtstate->resultRelInfo;
-		num_update_rri = list_length(node->plans);
-		proute->subplan_partition_offsets =
-			palloc(num_update_rri * sizeof(int));
-		proute->num_subplan_partition_offsets = num_update_rri;
-
-		/*
-		 * We need an additional tuple slot for storing transient tuples that
-		 * are converted to the root table descriptor.
-		 */
-		proute->root_tuple_slot = MakeTupleTableSlot(RelationGetDescr(rel),
-													 &TTSOpsHeapTuple);
-	}
-
-	i = 0;
-	foreach(cell, leaf_parts)
-	{
-		ResultRelInfo *leaf_part_rri = NULL;
-		Oid			leaf_oid = lfirst_oid(cell);
-
-		proute->partition_oids[i] = leaf_oid;
-
-		/*
-		 * If the leaf partition is already present in the per-subplan result
-		 * rels, we re-use that rather than initialize a new result rel. The
-		 * per-subplan resultrels and the resultrels of the leaf partitions
-		 * are both in the same canonical order. So while going through the
-		 * leaf partition oids, we need to keep track of the next per-subplan
-		 * result rel to be looked for in the leaf partition resultrels.
-		 */
-		if (update_rri_index < num_update_rri &&
-			RelationGetRelid(update_rri[update_rri_index].ri_RelationDesc) == leaf_oid)
-		{
-			leaf_part_rri = &update_rri[update_rri_index];
-
-			/*
-			 * This is required in order to convert the partition's tuple to
-			 * be compatible with the root partitioned table's tuple
-			 * descriptor.  When generating the per-subplan result rels, this
-			 * was not set.
-			 */
-			leaf_part_rri->ri_PartitionRoot = rel;
-
-			/* Remember the subplan offset for this ResultRelInfo */
-			proute->subplan_partition_offsets[update_rri_index] = i;
+	proute->partition_root = rel;
+	proute->memcxt = CurrentMemoryContext;
+	/* Rest of members initialized by zeroing */
 
-			update_rri_index++;
-		}
-
-		proute->partitions[i] = leaf_part_rri;
-		i++;
-	}
+	/*
+	 * Initialize this table's PartitionDispatch object.  Here we pass in the
+	 * parent as NULL as we don't need to care about any parent of the target
+	 * partitioned table.
+	 */
+	ExecInitPartitionDispatchInfo(proute, RelationGetRelid(rel), NULL, 0);
 
 	/*
-	 * For UPDATE, we should have found all the per-subplan resultrels in the
-	 * leaf partitions.  (If this is an INSERT, both values will be zero.)
+	 * If performing an UPDATE with tuple routing, we can reuse partition
+	 * sub-plan result rels.  We build a hash table to map the OIDs of
+	 * partitions present in mtstate->resultRelInfo to their ResultRelInfos.
+	 * Every time a tuple is routed to a partition that we've yet to set the
+	 * ResultRelInfo for, before we go to the trouble of making one, we check
+	 * for a pre-made one in the hash table.
 	 */
-	Assert(update_rri_index == num_update_rri);
+	if (node && node->operation == CMD_UPDATE)
+		ExecHashSubPlanResultRelsByOid(mtstate, proute);
 
 	return proute;
 }
 
 /*
- * ExecFindPartition -- Find a leaf partition in the partition tree rooted
- * at parent, for the heap tuple contained in *slot
+ * ExecFindPartition -- Return the ResultRelInfo for the leaf partition that
+ * the tuple contained in *slot should belong to.
+ *
+ * If the partition's ResultRelInfo does not yet exist in 'proute' then we set
+ * one up or reuse one from mtstate's resultRelInfo array.  When reusing a
+ * ResultRelInfo from the mtstate we verify that the relation is a valid
+ * target for INSERTs and then set up a PartitionRoutingInfo for it.
+ *
+ * rootResultRelInfo is the relation named in the query.
  *
  * estate must be non-NULL; we'll need it to compute any expressions in the
- * partition key(s)
+ * partition keys.  Also, its per-tuple contexts are used as evaluation
+ * scratch space.
  *
  * If no leaf partition is found, this routine errors out with the appropriate
- * error message, else it returns the leaf partition sequence number
- * as an index into the array of (ResultRelInfos of) all leaf partitions in
- * the partition tree.
+ * error message.  An error may also raised if the found target partition is
+ * not a valid target for an INSERT.
  */
-int
-ExecFindPartition(ResultRelInfo *resultRelInfo, PartitionDispatch *pd,
+ResultRelInfo *
+ExecFindPartition(ModifyTableState *mtstate,
+				  ResultRelInfo *rootResultRelInfo,
+				  PartitionTupleRouting *proute,
 				  TupleTableSlot *slot, EState *estate)
 {
-	int			result;
+	PartitionDispatch *pd = proute->partition_dispatch_info;
 	Datum		values[PARTITION_MAX_KEYS];
 	bool		isnull[PARTITION_MAX_KEYS];
 	Relation	rel;
 	PartitionDispatch dispatch;
+	PartitionDesc partdesc;
 	ExprContext *ecxt = GetPerTupleExprContext(estate);
 	TupleTableSlot *ecxt_scantuple_old = ecxt->ecxt_scantuple;
 	TupleTableSlot *myslot = NULL;
@@ -229,25 +280,31 @@ ExecFindPartition(ResultRelInfo *resultRelInfo, PartitionDispatch *pd,
 	 * First check the root table's partition constraint, if any.  No point in
 	 * routing the tuple if it doesn't belong in the root table itself.
 	 */
-	if (resultRelInfo->ri_PartitionCheck)
-		ExecPartitionCheck(resultRelInfo, slot, estate, true);
+	if (rootResultRelInfo->ri_PartitionCheck)
+		ExecPartitionCheck(rootResultRelInfo, slot, estate, true);
 
 	/* start with the root partitioned table */
 	dispatch = pd[0];
 	while (true)
 	{
 		AttrNumber *map = dispatch->tupmap;
-		int			cur_index = -1;
+		int			partidx = -1;
+
+		CHECK_FOR_INTERRUPTS();
 
 		rel = dispatch->reldesc;
+		partdesc = dispatch->partdesc;
 
 		/*
 		 * Convert the tuple to this parent's layout, if different from the
 		 * current relation.
 		 */
 		myslot = dispatch->tupslot;
-		if (myslot != NULL && map != NULL)
+		if (myslot != NULL)
+		{
+			Assert(map != NULL);
 			slot = execute_attr_map_slot(map, slot, myslot);
+		}
 
 		/*
 		 * Extract partition key from tuple. Expression evaluation machinery
@@ -261,97 +318,196 @@ ExecFindPartition(ResultRelInfo *resultRelInfo, PartitionDispatch *pd,
 		FormPartitionKeyDatum(dispatch, slot, estate, values, isnull);
 
 		/*
-		 * Nothing for get_partition_for_tuple() to do if there are no
-		 * partitions to begin with.
+		 * If this partitioned table has no partitions or no partition for
+		 * these values, error out.
 		 */
-		if (dispatch->partdesc->nparts == 0)
+		if (partdesc->nparts == 0 ||
+			(partidx = get_partition_for_tuple(dispatch, values, isnull)) < 0)
 		{
-			result = -1;
-			break;
+			char	   *val_desc;
+
+			val_desc = ExecBuildSlotPartitionKeyDescription(rel,
+															values, isnull, 64);
+			Assert(OidIsValid(RelationGetRelid(rel)));
+			ereport(ERROR,
+					(errcode(ERRCODE_CHECK_VIOLATION),
+					 errmsg("no partition of relation \"%s\" found for row",
+							RelationGetRelationName(rel)),
+					 val_desc ?
+					 errdetail("Partition key of the failing row contains %s.",
+							   val_desc) : 0));
 		}
 
-		cur_index = get_partition_for_tuple(dispatch, values, isnull);
-
-		/*
-		 * cur_index < 0 means we failed to find a partition of this parent.
-		 * cur_index >= 0 means we either found the leaf partition, or the
-		 * next parent to find a partition of.
-		 */
-		if (cur_index < 0)
+		if (partdesc->is_leaf[partidx])
 		{
-			result = -1;
-			break;
-		}
-		else if (dispatch->indexes[cur_index] >= 0)
-		{
-			result = dispatch->indexes[cur_index];
-			/* success! */
-			break;
+			ResultRelInfo *rri;
+
+			/*
+			 * Look to see if we've already got a ResultRelInfo for this
+			 * partition.
+			 */
+			if (likely(dispatch->indexes[partidx] >= 0))
+			{
+				/* ResultRelInfo already built */
+				Assert(dispatch->indexes[partidx] < proute->num_partitions);
+				rri = proute->partitions[dispatch->indexes[partidx]];
+			}
+			else
+			{
+				bool		found = false;
+
+				/*
+				 * We have not yet set up a ResultRelInfo for this partition,
+				 * but if we have a subplan hash table, we might have one
+				 * there.  If not, we'll have to create one.
+				 */
+				if (proute->subplan_resultrel_htab)
+				{
+					Oid			partoid = partdesc->oids[partidx];
+					SubplanResultRelHashElem   *elem;
+
+					elem = hash_search(proute->subplan_resultrel_htab,
+									   &partoid, HASH_FIND, NULL);
+					if (elem)
+					{
+						found = true;
+						rri = elem->rri;
+
+						/* Verify this ResultRelInfo allows INSERTs */
+						CheckValidResultRel(rri, CMD_INSERT);
+
+						/* Set up the PartitionRoutingInfo for it */
+						ExecInitRoutingInfo(mtstate, estate, proute, dispatch,
+											rri, partidx);
+					}
+				}
+
+				/* We need to create a new one. */
+				if (!found)
+					rri = ExecInitPartitionInfo(mtstate, estate, proute,
+												dispatch,
+												rootResultRelInfo, partidx);
+			}
+
+			/* Release the tuple in the lowest parent's dedicated slot. */
+			if (slot == myslot)
+				ExecClearTuple(myslot);
+
+			MemoryContextSwitchTo(oldcxt);
+			ecxt->ecxt_scantuple = ecxt_scantuple_old;
+			return rri;
 		}
 		else
 		{
-			/* move down one level */
-			dispatch = pd[-dispatch->indexes[cur_index]];
+			/*
+			 * Partition is a sub-partitioned table; get the PartitionDispatch
+			 */
+			if (likely(dispatch->indexes[partidx] >= 0))
+			{
+				/* Already built. */
+				Assert(dispatch->indexes[partidx] < proute->num_dispatch);
+
+				/*
+				 * Move down to the next partition level and search again
+				 * until we find a leaf partition that matches this tuple
+				 */
+				dispatch = pd[dispatch->indexes[partidx]];
+			}
+			else
+			{
+				/* Not yet built. Do that now. */
+				PartitionDispatch subdispatch;
+
+				/*
+				 * Create the new PartitionDispatch.  We pass the current one
+				 * in as the parent PartitionDispatch
+				 */
+				subdispatch = ExecInitPartitionDispatchInfo(proute,
+															partdesc->oids[partidx],
+															dispatch, partidx);
+				Assert(dispatch->indexes[partidx] >= 0 &&
+					   dispatch->indexes[partidx] < proute->num_dispatch);
+				dispatch = subdispatch;
+			}
 		}
 	}
+}
+
+/*
+ * ExecHashSubPlanResultRelsByOid
+ *		Build a hash table to allow fast lookups of subplan ResultRelInfos by
+ *		partition Oid.  We also populate the subplan ResultRelInfo with an
+ *		ri_PartitionRoot.
+ */
+static void
+ExecHashSubPlanResultRelsByOid(ModifyTableState *mtstate,
+							   PartitionTupleRouting *proute)
+{
+	HASHCTL		ctl;
+	HTAB	   *htab;
+	int			i;
+
+	memset(&ctl, 0, sizeof(ctl));
+	ctl.keysize = sizeof(Oid);
+	ctl.entrysize = sizeof(SubplanResultRelHashElem);
+	ctl.hcxt = CurrentMemoryContext;
 
-	/* Release the tuple in the lowest parent's dedicated slot. */
-	if (slot == myslot)
-		ExecClearTuple(myslot);
+	htab = hash_create("PartitionTupleRouting table", mtstate->mt_nplans,
+					   &ctl, HASH_ELEM | HASH_BLOBS | HASH_CONTEXT);
+	proute->subplan_resultrel_htab = htab;
 
-	/* A partition was not found. */
-	if (result < 0)
+	/* Hash all subplans by their Oid */
+	for (i = 0; i < mtstate->mt_nplans; i++)
 	{
-		char	   *val_desc;
-
-		val_desc = ExecBuildSlotPartitionKeyDescription(rel,
-														values, isnull, 64);
-		Assert(OidIsValid(RelationGetRelid(rel)));
-		ereport(ERROR,
-				(errcode(ERRCODE_CHECK_VIOLATION),
-				 errmsg("no partition of relation \"%s\" found for row",
-						RelationGetRelationName(rel)),
-				 val_desc ? errdetail("Partition key of the failing row contains %s.", val_desc) : 0));
-	}
+		ResultRelInfo *rri = &mtstate->resultRelInfo[i];
+		bool		found;
+		Oid			partoid = RelationGetRelid(rri->ri_RelationDesc);
+		SubplanResultRelHashElem   *elem;
 
-	MemoryContextSwitchTo(oldcxt);
-	ecxt->ecxt_scantuple = ecxt_scantuple_old;
+		elem = (SubplanResultRelHashElem *)
+			hash_search(htab, &partoid, HASH_ENTER, &found);
+		Assert(!found);
+		elem->rri = rri;
 
-	return result;
+		/*
+		 * This is required in order to convert the partition's tuple to be
+		 * compatible with the root partitioned table's tuple descriptor. When
+		 * generating the per-subplan result rels, this was not set.
+		 */
+		rri->ri_PartitionRoot = proute->partition_root;
+	}
 }
 
 /*
  * ExecInitPartitionInfo
  *		Initialize ResultRelInfo and other information for a partition
+ *		and store it in the next empty slot in the proute->partitions array.
  *
  * Returns the ResultRelInfo
  */
-ResultRelInfo *
-ExecInitPartitionInfo(ModifyTableState *mtstate,
-					  ResultRelInfo *resultRelInfo,
+static ResultRelInfo *
+ExecInitPartitionInfo(ModifyTableState *mtstate, EState *estate,
 					  PartitionTupleRouting *proute,
-					  EState *estate, int partidx)
+					  PartitionDispatch dispatch,
+					  ResultRelInfo *rootResultRelInfo,
+					  int partidx)
 {
 	ModifyTable *node = (ModifyTable *) mtstate->ps.plan;
-	Relation	rootrel = resultRelInfo->ri_RelationDesc,
+	Relation	rootrel = rootResultRelInfo->ri_RelationDesc,
 				partrel;
 	Relation	firstResultRel = mtstate->resultRelInfo[0].ri_RelationDesc;
 	ResultRelInfo *leaf_part_rri;
-	MemoryContext oldContext;
+	MemoryContext oldcxt;
 	AttrNumber *part_attnos = NULL;
 	bool		found_whole_row;
 
+	oldcxt = MemoryContextSwitchTo(proute->memcxt);
+
 	/*
 	 * We locked all the partitions in ExecSetupPartitionTupleRouting
 	 * including the leaf partitions.
 	 */
-	partrel = heap_open(proute->partition_oids[partidx], NoLock);
-
-	/*
-	 * Keep ResultRelInfo and other information for this partition in the
-	 * per-query memory context so they'll survive throughout the query.
-	 */
-	oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
+	partrel = heap_open(dispatch->partdesc->oids[partidx], NoLock);
 
 	leaf_part_rri = makeNode(ResultRelInfo);
 	InitResultRelInfo(leaf_part_rri,
@@ -368,18 +524,6 @@ ExecInitPartitionInfo(ModifyTableState *mtstate,
 	CheckValidResultRel(leaf_part_rri, CMD_INSERT);
 
 	/*
-	 * Since we've just initialized this ResultRelInfo, it's not in any list
-	 * attached to the estate as yet.  Add it, so that it can be found later.
-	 *
-	 * Note that the entries in this list appear in no predetermined order,
-	 * because partition result rels are initialized as and when they're
-	 * needed.
-	 */
-	estate->es_tuple_routing_result_relations =
-		lappend(estate->es_tuple_routing_result_relations,
-				leaf_part_rri);
-
-	/*
 	 * Open partition indices.  The user may have asked to check for conflicts
 	 * within this leaf partition and do "nothing" instead of throwing an
 	 * error.  Be prepared in that case by initializing the index information
@@ -522,14 +666,14 @@ ExecInitPartitionInfo(ModifyTableState *mtstate,
 	}
 
 	/* Set up information needed for routing tuples to the partition. */
-	ExecInitRoutingInfo(mtstate, estate, proute, leaf_part_rri, partidx);
+	ExecInitRoutingInfo(mtstate, estate, proute, dispatch,
+						leaf_part_rri, partidx);
 
 	/*
 	 * If there is an ON CONFLICT clause, initialize state for it.
 	 */
 	if (node && node->onConflictAction != ONCONFLICT_NONE)
 	{
-		TupleConversionMap *map = proute->parent_child_tupconv_maps[partidx];
 		int			firstVarno = mtstate->resultRelInfo[0].ri_RangeTableIndex;
 		TupleDesc	partrelDesc = RelationGetDescr(partrel);
 		ExprContext *econtext = mtstate->ps.ps_ExprContext;
@@ -542,7 +686,7 @@ ExecInitPartitionInfo(ModifyTableState *mtstate,
 		 * list and searching for ancestry relationships to each index in the
 		 * ancestor table.
 		 */
-		if (list_length(resultRelInfo->ri_onConflictArbiterIndexes) > 0)
+		if (list_length(rootResultRelInfo->ri_onConflictArbiterIndexes) > 0)
 		{
 			List	   *childIdxs;
 
@@ -555,7 +699,7 @@ ExecInitPartitionInfo(ModifyTableState *mtstate,
 				ListCell   *lc2;
 
 				ancestors = get_partition_ancestors(childIdx);
-				foreach(lc2, resultRelInfo->ri_onConflictArbiterIndexes)
+				foreach(lc2, rootResultRelInfo->ri_onConflictArbiterIndexes)
 				{
 					if (list_member_oid(ancestors, lfirst_oid(lc2)))
 						arbiterIndexes = lappend_oid(arbiterIndexes, childIdx);
@@ -569,7 +713,7 @@ ExecInitPartitionInfo(ModifyTableState *mtstate,
 		 * (This shouldn't happen, since arbiter index selection should not
 		 * pick up an invalid index.)
 		 */
-		if (list_length(resultRelInfo->ri_onConflictArbiterIndexes) !=
+		if (list_length(rootResultRelInfo->ri_onConflictArbiterIndexes) !=
 			list_length(arbiterIndexes))
 			elog(ERROR, "invalid arbiter index list");
 		leaf_part_rri->ri_onConflictArbiterIndexes = arbiterIndexes;
@@ -579,8 +723,12 @@ ExecInitPartitionInfo(ModifyTableState *mtstate,
 		 */
 		if (node->onConflictAction == ONCONFLICT_UPDATE)
 		{
+			TupleConversionMap *map;
+
+			map = leaf_part_rri->ri_PartitionInfo->pi_RootToPartitionMap;
+
 			Assert(node->onConflictSet != NIL);
-			Assert(resultRelInfo->ri_onConflict != NULL);
+			Assert(rootResultRelInfo->ri_onConflict != NULL);
 
 			/*
 			 * If the partition's tuple descriptor matches exactly the root
@@ -589,7 +737,7 @@ ExecInitPartitionInfo(ModifyTableState *mtstate,
 			 * need to create state specific to this partition.
 			 */
 			if (map == NULL)
-				leaf_part_rri->ri_onConflict = resultRelInfo->ri_onConflict;
+				leaf_part_rri->ri_onConflict = rootResultRelInfo->ri_onConflict;
 			else
 			{
 				List	   *onconflset;
@@ -680,37 +828,51 @@ ExecInitPartitionInfo(ModifyTableState *mtstate,
 		}
 	}
 
-	Assert(proute->partitions[partidx] == NULL);
-	proute->partitions[partidx] = leaf_part_rri;
+	/*
+	 * Since we've just initialized this ResultRelInfo, it's not in any list
+	 * attached to the estate as yet.  Add it, so that it can be found later.
+	 *
+	 * Note that the entries in this list appear in no predetermined order,
+	 * because partition result rels are initialized as and when they're
+	 * needed.
+	 */
+	MemoryContextSwitchTo(estate->es_query_cxt);
+	estate->es_tuple_routing_result_relations =
+		lappend(estate->es_tuple_routing_result_relations,
+				leaf_part_rri);
 
-	MemoryContextSwitchTo(oldContext);
+	MemoryContextSwitchTo(oldcxt);
 
 	return leaf_part_rri;
 }
 
 /*
  * ExecInitRoutingInfo
- *		Set up information needed for routing tuples to a leaf partition
+ *		Set up information needed for translating tuples between root
+ *		partitioned table format and partition format, and keep track of it
+ *		in PartitionTupleRouting.
  */
-void
+static void
 ExecInitRoutingInfo(ModifyTableState *mtstate,
 					EState *estate,
 					PartitionTupleRouting *proute,
+					PartitionDispatch dispatch,
 					ResultRelInfo *partRelInfo,
 					int partidx)
 {
-	MemoryContext oldContext;
+	MemoryContext oldcxt;
+	PartitionRoutingInfo *partrouteinfo;
+	int		rri_index;
 
-	/*
-	 * Switch into per-query memory context.
-	 */
-	oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
+	oldcxt = MemoryContextSwitchTo(proute->memcxt);
+
+	partrouteinfo = palloc(sizeof(PartitionRoutingInfo));
 
 	/*
 	 * Set up a tuple conversion map to convert a tuple routed to the
 	 * partition from the parent's type to the partition's.
 	 */
-	proute->parent_child_tupconv_maps[partidx] =
+	partrouteinfo->pi_RootToPartitionMap =
 		convert_tuples_by_name(RelationGetDescr(partRelInfo->ri_PartitionRoot),
 							   RelationGetDescr(partRelInfo->ri_RelationDesc),
 							   gettext_noop("could not convert row type"));
@@ -721,29 +883,36 @@ ExecInitRoutingInfo(ModifyTableState *mtstate,
 	 * for various operations that are applied to tuples after routing, such
 	 * as checking constraints.
 	 */
-	if (proute->parent_child_tupconv_maps[partidx] != NULL)
+	if (partrouteinfo->pi_RootToPartitionMap != NULL)
 	{
 		Relation	partrel = partRelInfo->ri_RelationDesc;
 
 		/*
-		 * Initialize the array in proute where these slots are stored, if not
-		 * already done.
-		 */
-		if (proute->partition_tuple_slots == NULL)
-			proute->partition_tuple_slots = (TupleTableSlot **)
-				palloc0(proute->num_partitions *
-						sizeof(TupleTableSlot *));
-
-		/*
 		 * Initialize the slot itself setting its descriptor to this
 		 * partition's TupleDesc; TupleDesc reference will be released at the
 		 * end of the command.
 		 */
-		proute->partition_tuple_slots[partidx] =
-			ExecInitExtraTupleSlot(estate,
-								   RelationGetDescr(partrel),
+		partrouteinfo->pi_PartitionTupleSlot =
+			ExecInitExtraTupleSlot(estate, RelationGetDescr(partrel),
 								   &TTSOpsHeapTuple);
 	}
+	else
+		partrouteinfo->pi_PartitionTupleSlot = NULL;
+
+	/*
+	 * Also, if transition capture is required, store a map to convert tuples
+	 * from partition's rowtype to the root partition table's.
+	 */
+	if (mtstate &&
+		(mtstate->mt_transition_capture || mtstate->mt_oc_transition_capture))
+	{
+		partrouteinfo->pi_PartitionToRootMap =
+			convert_tuples_by_name(RelationGetDescr(partRelInfo->ri_RelationDesc),
+								   RelationGetDescr(partRelInfo->ri_PartitionRoot),
+								   gettext_noop("could not convert row type"));
+	}
+	else
+		partrouteinfo->pi_PartitionToRootMap = NULL;
 
 	/*
 	 * If the partition is a foreign table, let the FDW init itself for
@@ -753,73 +922,138 @@ ExecInitRoutingInfo(ModifyTableState *mtstate,
 		partRelInfo->ri_FdwRoutine->BeginForeignInsert != NULL)
 		partRelInfo->ri_FdwRoutine->BeginForeignInsert(mtstate, partRelInfo);
 
-	MemoryContextSwitchTo(oldContext);
-
-	partRelInfo->ri_PartitionReadyForRouting = true;
-}
-
-/*
- * ExecSetupChildParentMapForLeaf -- Initialize the per-leaf-partition
- * child-to-root tuple conversion map array.
- *
- * This map is required for capturing transition tuples when the target table
- * is a partitioned table. For a tuple that is routed by an INSERT or UPDATE,
- * we need to convert it from the leaf partition to the target table
- * descriptor.
- */
-void
-ExecSetupChildParentMapForLeaf(PartitionTupleRouting *proute)
-{
-	Assert(proute != NULL);
+	partRelInfo->ri_PartitionInfo = partrouteinfo;
 
 	/*
-	 * These array elements get filled up with maps on an on-demand basis.
-	 * Initially just set all of them to NULL.
+	 * Keep track of it in the PartitionTupleRouting->partitions array.
 	 */
-	proute->child_parent_tupconv_maps =
-		(TupleConversionMap **) palloc0(sizeof(TupleConversionMap *) *
-										proute->num_partitions);
+	Assert(dispatch->indexes[partidx] == -1);
+
+	rri_index = proute->num_partitions++;
+
+	/* Allocate or enlarge the array, as needed */
+	if (proute->num_partitions >= proute->max_partitions)
+	{
+		if (proute->max_partitions == 0)
+		{
+			proute->max_partitions = 8;
+			proute->partitions = (ResultRelInfo **)
+				palloc(sizeof(ResultRelInfo *) * proute->max_partitions);
+		}
+		else
+		{
+			proute->max_partitions *= 2;
+			proute->partitions = (ResultRelInfo **)
+				repalloc(proute->partitions, sizeof(ResultRelInfo *) *
+						 proute->max_partitions);
+		}
+	}
 
-	/* Same is the case for this array. All the values are set to false */
-	proute->child_parent_map_not_required =
-		(bool *) palloc0(sizeof(bool) * proute->num_partitions);
+	proute->partitions[rri_index] = partRelInfo;
+	dispatch->indexes[partidx] = rri_index;
+
+	MemoryContextSwitchTo(oldcxt);
 }
 
 /*
- * TupConvMapForLeaf -- Get the tuple conversion map for a given leaf partition
- * index.
+ * ExecInitPartitionDispatchInfo
+ *		Initialize PartitionDispatch for a partitioned table and store it in
+ *		the next available slot in the proute->partition_dispatch_info array.
+ *		Also, record the index into this array in the parent_pd->indexes[]
+ *		array in the partidx element so that we can properly retrieve the
+ *		newly created PartitionDispatch later.
  */
-TupleConversionMap *
-TupConvMapForLeaf(PartitionTupleRouting *proute,
-				  ResultRelInfo *rootRelInfo, int leaf_index)
+static PartitionDispatch
+ExecInitPartitionDispatchInfo(PartitionTupleRouting *proute, Oid partoid,
+							  PartitionDispatch parent_pd, int partidx)
 {
-	ResultRelInfo **resultRelInfos = proute->partitions;
-	TupleConversionMap **map;
-	TupleDesc	tupdesc;
+	Relation	rel;
+	PartitionDesc partdesc;
+	PartitionDispatch pd;
+	int			dispatchidx;
+	MemoryContext oldcxt;
 
-	/* Don't call this if we're not supposed to be using this type of map. */
-	Assert(proute->child_parent_tupconv_maps != NULL);
+	oldcxt = MemoryContextSwitchTo(proute->memcxt);
 
-	/* If it's already known that we don't need a map, return NULL. */
-	if (proute->child_parent_map_not_required[leaf_index])
-		return NULL;
+	if (partoid != RelationGetRelid(proute->partition_root))
+		rel = heap_open(partoid, NoLock);
+	else
+		rel = proute->partition_root;
+	partdesc = RelationGetPartitionDesc(rel);
 
-	/* If we've already got a map, return it. */
-	map = &proute->child_parent_tupconv_maps[leaf_index];
-	if (*map != NULL)
-		return *map;
+	pd = (PartitionDispatch) palloc(offsetof(PartitionDispatchData, indexes) +
+									partdesc->nparts * sizeof(int));
+	pd->reldesc = rel;
+	pd->key = RelationGetPartitionKey(rel);
+	pd->keystate = NIL;
+	pd->partdesc = partdesc;
+	if (parent_pd != NULL)
+	{
+		TupleDesc	tupdesc = RelationGetDescr(rel);
 
-	/* No map yet; try to create one. */
-	tupdesc = RelationGetDescr(resultRelInfos[leaf_index]->ri_RelationDesc);
-	*map =
-		convert_tuples_by_name(tupdesc,
-							   RelationGetDescr(rootRelInfo->ri_RelationDesc),
-							   gettext_noop("could not convert row type"));
+		/*
+		 * For sub-partitioned tables where the column order differs from its
+		 * direct parent partitioned table, we must store a tuple table slot
+		 * initialized with its tuple descriptor and a tuple conversion map to
+		 * convert a tuple from its parent's rowtype to its own.  This is to
+		 * make sure that we are looking at the correct row using the correct
+		 * tuple descriptor when computing its partition key for tuple
+		 * routing.
+		 */
+		pd->tupmap = convert_tuples_by_name_map_if_req(RelationGetDescr(parent_pd->reldesc),
+													   tupdesc,
+													   gettext_noop("could not convert row type"));
+		pd->tupslot = pd->tupmap ?
+			MakeSingleTupleTableSlot(tupdesc, &TTSOpsHeapTuple) : NULL;
+	}
+	else
+	{
+		/* Not required for the root partitioned table */
+		pd->tupmap = NULL;
+		pd->tupslot = NULL;
+	}
 
-	/* If it turns out no map is needed, remember for next time. */
-	proute->child_parent_map_not_required[leaf_index] = (*map == NULL);
+	/*
+	 * Initialize with -1 to signify that the corresponding partition's
+	 * ResultRelInfo or PartitionDispatch has not been created yet.
+	 */
+	memset(pd->indexes, -1, sizeof(int) * partdesc->nparts);
+
+	/* Track in PartitionTupleRouting for later use */
+	dispatchidx = proute->num_dispatch++;
+
+	/* Allocate or enlarge the array, as needed */
+	if (proute->num_dispatch >= proute->max_dispatch)
+	{
+		if (proute->max_dispatch == 0)
+		{
+			proute->max_dispatch = 4;
+			proute->partition_dispatch_info = (PartitionDispatch *)
+				palloc(sizeof(PartitionDispatch) * proute->max_dispatch);
+		}
+		else
+		{
+			proute->max_dispatch *= 2;
+			proute->partition_dispatch_info = (PartitionDispatch *)
+				repalloc(proute->partition_dispatch_info,
+						 sizeof(PartitionDispatch) * proute->max_dispatch);
+		}
+	}
+	proute->partition_dispatch_info[dispatchidx] = pd;
 
-	return *map;
+	/*
+	 * Finally, if setting up a PartitionDispatch for a sub-partitioned table,
+	 * install a downlink in the parent to allow quick descent.
+	 */
+	if (parent_pd)
+	{
+		Assert(parent_pd->indexes[partidx] == -1);
+		parent_pd->indexes[partidx] = dispatchidx;
+	}
+
+	MemoryContextSwitchTo(oldcxt);
+
+	return pd;
 }
 
 /*
@@ -832,8 +1066,8 @@ void
 ExecCleanupTupleRouting(ModifyTableState *mtstate,
 						PartitionTupleRouting *proute)
 {
+	HTAB	   *htab = proute->subplan_resultrel_htab;
 	int			i;
-	int			subplan_index = 0;
 
 	/*
 	 * Remember, proute->partition_dispatch_info[0] corresponds to the root
@@ -847,187 +1081,40 @@ ExecCleanupTupleRouting(ModifyTableState *mtstate,
 		PartitionDispatch pd = proute->partition_dispatch_info[i];
 
 		heap_close(pd->reldesc, NoLock);
-		ExecDropSingleTupleTableSlot(pd->tupslot);
+
+		if (pd->tupslot)
+			ExecDropSingleTupleTableSlot(pd->tupslot);
 	}
 
 	for (i = 0; i < proute->num_partitions; i++)
 	{
 		ResultRelInfo *resultRelInfo = proute->partitions[i];
 
-		/* skip further processing for uninitialized partitions */
-		if (resultRelInfo == NULL)
-			continue;
+		/*
+		 * Check if this result rel is one belonging to the node's subplans,
+		 * if so, let ExecEndPlan() clean it up.
+		 */
+		if (htab)
+		{
+			Oid			partoid;
+			bool		found;
+
+			partoid = RelationGetRelid(resultRelInfo->ri_RelationDesc);
+
+			(void) hash_search(htab, &partoid, HASH_FIND, &found);
+			if (found)
+				continue;
+		}
 
 		/* Allow any FDWs to shut down if they've been exercised */
-		if (resultRelInfo->ri_PartitionReadyForRouting &&
-			resultRelInfo->ri_FdwRoutine != NULL &&
+		if (resultRelInfo->ri_FdwRoutine != NULL &&
 			resultRelInfo->ri_FdwRoutine->EndForeignInsert != NULL)
 			resultRelInfo->ri_FdwRoutine->EndForeignInsert(mtstate->ps.state,
 														   resultRelInfo);
 
-		/*
-		 * If this result rel is one of the UPDATE subplan result rels, let
-		 * ExecEndPlan() close it. For INSERT or COPY,
-		 * proute->subplan_partition_offsets will always be NULL. Note that
-		 * the subplan_partition_offsets array and the partitions array have
-		 * the partitions in the same order. So, while we iterate over
-		 * partitions array, we also iterate over the
-		 * subplan_partition_offsets array in order to figure out which of the
-		 * result rels are present in the UPDATE subplans.
-		 */
-		if (proute->subplan_partition_offsets &&
-			subplan_index < proute->num_subplan_partition_offsets &&
-			proute->subplan_partition_offsets[subplan_index] == i)
-		{
-			subplan_index++;
-			continue;
-		}
-
 		ExecCloseIndices(resultRelInfo);
 		heap_close(resultRelInfo->ri_RelationDesc, NoLock);
 	}
-
-	/* Release the standalone partition tuple descriptors, if any */
-	if (proute->root_tuple_slot)
-		ExecDropSingleTupleTableSlot(proute->root_tuple_slot);
-}
-
-/*
- * RelationGetPartitionDispatchInfo
- *		Returns information necessary to route tuples down a partition tree
- *
- * The number of elements in the returned array (that is, the number of
- * PartitionDispatch objects for the partitioned tables in the partition tree)
- * is returned in *num_parted and a list of the OIDs of all the leaf
- * partitions of rel is returned in *leaf_part_oids.
- *
- * All the relations in the partition tree (including 'rel') must have been
- * locked (using at least the AccessShareLock) by the caller.
- */
-static PartitionDispatch *
-RelationGetPartitionDispatchInfo(Relation rel,
-								 int *num_parted, List **leaf_part_oids)
-{
-	List	   *pdlist = NIL;
-	PartitionDispatchData **pd;
-	ListCell   *lc;
-	int			i;
-
-	Assert(rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE);
-
-	*num_parted = 0;
-	*leaf_part_oids = NIL;
-
-	get_partition_dispatch_recurse(rel, NULL, &pdlist, leaf_part_oids);
-	*num_parted = list_length(pdlist);
-	pd = (PartitionDispatchData **) palloc(*num_parted *
-										   sizeof(PartitionDispatchData *));
-	i = 0;
-	foreach(lc, pdlist)
-	{
-		pd[i++] = lfirst(lc);
-	}
-
-	return pd;
-}
-
-/*
- * get_partition_dispatch_recurse
- *		Recursively expand partition tree rooted at rel
- *
- * As the partition tree is expanded in a depth-first manner, we maintain two
- * global lists: of PartitionDispatch objects corresponding to partitioned
- * tables in *pds and of the leaf partition OIDs in *leaf_part_oids.
- *
- * Note that the order of OIDs of leaf partitions in leaf_part_oids matches
- * the order in which the planner's expand_partitioned_rtentry() processes
- * them.  It's not necessarily the case that the offsets match up exactly,
- * because constraint exclusion might prune away some partitions on the
- * planner side, whereas we'll always have the complete list; but unpruned
- * partitions will appear in the same order in the plan as they are returned
- * here.
- */
-static void
-get_partition_dispatch_recurse(Relation rel, Relation parent,
-							   List **pds, List **leaf_part_oids)
-{
-	TupleDesc	tupdesc = RelationGetDescr(rel);
-	PartitionDesc partdesc = RelationGetPartitionDesc(rel);
-	PartitionKey partkey = RelationGetPartitionKey(rel);
-	PartitionDispatch pd;
-	int			i;
-
-	check_stack_depth();
-
-	/* Build a PartitionDispatch for this table and add it to *pds. */
-	pd = (PartitionDispatch) palloc(sizeof(PartitionDispatchData));
-	*pds = lappend(*pds, pd);
-	pd->reldesc = rel;
-	pd->key = partkey;
-	pd->keystate = NIL;
-	pd->partdesc = partdesc;
-	if (parent != NULL)
-	{
-		/*
-		 * For every partitioned table other than the root, we must store a
-		 * tuple table slot initialized with its tuple descriptor and a tuple
-		 * conversion map to convert a tuple from its parent's rowtype to its
-		 * own. That is to make sure that we are looking at the correct row
-		 * using the correct tuple descriptor when computing its partition key
-		 * for tuple routing.
-		 */
-		pd->tupslot = MakeSingleTupleTableSlot(tupdesc, &TTSOpsHeapTuple);
-		pd->tupmap = convert_tuples_by_name_map_if_req(RelationGetDescr(parent),
-													   tupdesc,
-													   gettext_noop("could not convert row type"));
-	}
-	else
-	{
-		/* Not required for the root partitioned table */
-		pd->tupslot = NULL;
-		pd->tupmap = NULL;
-	}
-
-	/*
-	 * Go look at each partition of this table.  If it's a leaf partition,
-	 * simply add its OID to *leaf_part_oids.  If it's a partitioned table,
-	 * recursively call get_partition_dispatch_recurse(), so that its
-	 * partitions are processed as well and a corresponding PartitionDispatch
-	 * object gets added to *pds.
-	 *
-	 * The 'indexes' array is used when searching for a partition matching a
-	 * given tuple.  The actual value we store here depends on whether the
-	 * array element belongs to a leaf partition or a subpartitioned table.
-	 * For leaf partitions we store the index into *leaf_part_oids, and for
-	 * sub-partitioned tables we store a negative version of the index into
-	 * the *pds list.  Both indexes are 0-based, but the first element of the
-	 * *pds list is the root partition, so 0 always means the first leaf. When
-	 * searching, if we see a negative value, the search must continue in the
-	 * corresponding sub-partition; otherwise, we've identified the correct
-	 * partition.
-	 */
-	pd->indexes = (int *) palloc(partdesc->nparts * sizeof(int));
-	for (i = 0; i < partdesc->nparts; i++)
-	{
-		Oid			partrelid = partdesc->oids[i];
-
-		if (get_rel_relkind(partrelid) != RELKIND_PARTITIONED_TABLE)
-		{
-			*leaf_part_oids = lappend_oid(*leaf_part_oids, partrelid);
-			pd->indexes[i] = list_length(*leaf_part_oids) - 1;
-		}
-		else
-		{
-			/*
-			 * We assume all tables in the partition tree were already locked
-			 * by the caller.
-			 */
-			Relation	partrel = heap_open(partrelid, NoLock);
-
-			pd->indexes[i] = -list_length(*pds);
-			get_partition_dispatch_recurse(partrel, rel, pds, leaf_part_oids);
-		}
-	}
 }
 
 /* ----------------