Clean up code, comments, and formatting for table partitioning.

Amit Langote, plus pgindent-ing by me.  Inspired in part by review
comments from Tomas Vondra.

src/backend/catalog/heap.c

@@ -1887,6 +1887,10 @@ heap_drop_with_catalog(Oid relid)
 
 	if (parent)
 	{
+		/*
+		 * Invalidate the parent's relcache so that the partition is no longer
+		 * included in its partition descriptor.
+		 */
 		CacheInvalidateRelcache(parent);
 		heap_close(parent, NoLock);		/* keep the lock */
 	}

src/backend/catalog/partition.c

@@ -1492,7 +1492,7 @@ generate_partition_qual(Relation rel, bool recurse)
  *			Construct values[] and isnull[] arrays for the partition key
  *			of a tuple.
  *
- *	pkinfo			partition key execution info
+ *	pd				Partition dispatch object of the partitioned table
  *	slot			Heap tuple from which to extract partition key
  *	estate			executor state for evaluating any partition key
  *					expressions (must be non-NULL)
@@ -1565,7 +1565,7 @@ FormPartitionKeyDatum(PartitionDispatch pd,
  * the latter case.
  */
 int
-get_partition_for_tuple(PartitionDispatch * pd,
+get_partition_for_tuple(PartitionDispatch *pd,
 						TupleTableSlot *slot,
 						EState *estate,
 						Oid *failed_at)

src/backend/commands/copy.c

@@ -1403,31 +1403,28 @@ BeginCopy(ParseState *pstate,
 					 errmsg("table \"%s\" does not have OIDs",
 							RelationGetRelationName(cstate->rel))));
 
-		/*
-		 * Initialize state for CopyFrom tuple routing.  Watch out for
-		 * any foreign partitions.
-		 */
+		/* Initialize state for CopyFrom tuple routing. */
 		if (is_from && rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
 		{
-			PartitionDispatch *pd;
 			List	   *leaf_parts;
 			ListCell   *cell;
 			int			i,
-							num_parted,
-							num_leaf_parts;
+						num_parted;
 			ResultRelInfo *leaf_part_rri;
 
 			/* Get the tuple-routing information and lock partitions */
-			pd = RelationGetPartitionDispatchInfo(rel, RowExclusiveLock,
-												  &num_parted, &leaf_parts);
-			num_leaf_parts = list_length(leaf_parts);
-			cstate->partition_dispatch_info = pd;
+			cstate->partition_dispatch_info =
+				RelationGetPartitionDispatchInfo(rel, RowExclusiveLock,
+												 &num_parted,
+												 &leaf_parts);
 			cstate->num_dispatch = num_parted;
-			cstate->num_partitions = num_leaf_parts;
-			cstate->partitions = (ResultRelInfo *) palloc(num_leaf_parts *
+			cstate->num_partitions = list_length(leaf_parts);
+			cstate->partitions = (ResultRelInfo *)
+				palloc(cstate->num_partitions *
 					   sizeof(ResultRelInfo));
 			cstate->partition_tupconv_maps = (TupleConversionMap **)
-						palloc0(num_leaf_parts * sizeof(TupleConversionMap *));
+				palloc0(cstate->num_partitions *
+						sizeof(TupleConversionMap *));
 
 			leaf_part_rri = cstate->partitions;
 			i = 0;
@@ -1438,8 +1435,8 @@ BeginCopy(ParseState *pstate,
 				/*
 				 * We locked all the partitions above including the leaf
 				 * partitions.  Note that each of the relations in
-				 * cstate->partitions will be closed by CopyFrom() after
-				 * it's finished with its processing.
+				 * cstate->partitions will be closed by CopyFrom() after it's
+				 * finished with its processing.
 				 */
 				partrel = heap_open(lfirst_oid(cell), NoLock);
 
@@ -1452,7 +1449,8 @@ BeginCopy(ParseState *pstate,
 				InitResultRelInfo(leaf_part_rri,
 								  partrel,
 								  1,	/* dummy */
-								  false, /* no partition constraint check */
+								  false,		/* no partition constraint
+												 * check */
 								  0);
 
 				/* Open partition indices */
@@ -2486,8 +2484,8 @@ CopyFrom(CopyState cstate)
 	 * BEFORE/INSTEAD OF triggers, or we need to evaluate volatile default
 	 * expressions. Such triggers or expressions might query the table we're
 	 * inserting to, and act differently if the tuples that have already been
-	 * processed and prepared for insertion are not there.  We also can't
-	 * do it if the table is partitioned.
+	 * processed and prepared for insertion are not there.  We also can't do
+	 * it if the table is partitioned.
 	 */
 	if ((resultRelInfo->ri_TrigDesc != NULL &&
 		 (resultRelInfo->ri_TrigDesc->trig_insert_before_row ||

src/backend/executor/nodeModifyTable.c

@@ -1718,26 +1718,26 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
 	if (operation == CMD_INSERT &&
 		rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
 	{
-		PartitionDispatch  *pd;
 		int					i,
 							j,
-							num_parted,
-							num_leaf_parts;
+							num_parted;
 		List			   *leaf_parts;
 		ListCell		   *cell;
 		ResultRelInfo	   *leaf_part_rri;
 
-		/* Form the partition node tree and lock partitions */
-		pd = RelationGetPartitionDispatchInfo(rel, RowExclusiveLock,
-											  &num_parted, &leaf_parts);
-		mtstate->mt_partition_dispatch_info = pd;
+		/* Get the tuple-routing information and lock partitions */
+		mtstate->mt_partition_dispatch_info =
+					RelationGetPartitionDispatchInfo(rel, RowExclusiveLock,
+													 &num_parted,
+													 &leaf_parts);
 		mtstate->mt_num_dispatch = num_parted;
-		num_leaf_parts = list_length(leaf_parts);
-		mtstate->mt_num_partitions = num_leaf_parts;
+		mtstate->mt_num_partitions = list_length(leaf_parts);
 		mtstate->mt_partitions = (ResultRelInfo *)
-						palloc0(num_leaf_parts * sizeof(ResultRelInfo));
+						palloc0(mtstate->mt_num_partitions *
+												sizeof(ResultRelInfo));
 		mtstate->mt_partition_tupconv_maps = (TupleConversionMap **)
-					palloc0(num_leaf_parts * sizeof(TupleConversionMap *));
+						palloc0(mtstate->mt_num_partitions *
+												sizeof(TupleConversionMap *));
 
 		leaf_part_rri = mtstate->mt_partitions;
 		i = j = 0;

src/include/catalog/pg_partitioned_table.h

@@ -7,7 +7,7 @@
  *
  * Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group
  *
- * $PostgreSQL: pgsql/src/include/catalog/pg_partitioned_table.h $
+ * src/include/catalog/pg_partitioned_table.h
  *
  * NOTES
  *	  the genbki.sh script reads this file and generates .bki
@@ -39,17 +39,15 @@ CATALOG(pg_partitioned_table,3350) BKI_WITHOUT_OIDS
 	 * field of a heap tuple can be reliably accessed using its C struct
 	 * offset, as previous fields are all non-nullable fixed-length fields.
 	 */
-	int2vector		partattrs;		/* each member of the array is the
-									 * attribute number of a partition key
-									 * column, or 0 if the column is actually
-									 * an expression */
+	int2vector	partattrs;		/* each member of the array is the attribute
+								 * number of a partition key column, or 0 if
+								 * the column is actually an expression */
 
 #ifdef CATALOG_VARLEN
 	oidvector	partclass;		/* operator class to compare keys */
 	oidvector	partcollation;	/* user-specified collation for keys */
-	pg_node_tree	partexprs;		/* list of expressions in the partitioning
-									 * key; one item for each zero entry in
-									 * partattrs[] */
+	pg_node_tree partexprs;		/* list of expressions in the partition key;
+								 * one item for each zero entry in partattrs[] */
 #endif
 } FormData_pg_partitioned_table;