intorel_startup(DestReceiver *self, int operation, TupleDesc typeinfo)
{
	DR_intorel *myState = (DR_intorel *) self;
	IntoClause *into = myState->into;
	bool		is_matview;
	char		relkind;
	CreateStmt *create;
	Oid			intoRelationId;
	Relation	intoRelationDesc;
	RangeTblEntry *rte;
	Datum		toast_options;
	ListCell   *lc;
	int			attnum;
	static char *validnsps[] = HEAP_RELOPT_NAMESPACES;

	Assert(into != NULL);		/* else somebody forgot to set it */

	/* This code supports both CREATE TABLE AS and CREATE MATERIALIZED VIEW */
	is_matview = (into->viewQuery != NULL);
	relkind = is_matview ? RELKIND_MATVIEW : RELKIND_RELATION;

	/*
	 * Create the target relation by faking up a CREATE TABLE parsetree and
	 * passing it to DefineRelation.
	 */
	create = makeNode(CreateStmt);
	create->relation = into->rel;
	create->tableElts = NIL;	/* will fill below */
	create->inhRelations = NIL;
	create->ofTypename = NULL;
	create->constraints = NIL;
	create->options = into->options;
	create->oncommit = into->onCommit;
	create->tablespacename = into->tableSpaceName;
	create->if_not_exists = false;

	/*
	 * Build column definitions using "pre-cooked" type and collation info. If
	 * a column name list was specified in CREATE TABLE AS, override the
	 * column names derived from the query.  (Too few column names are OK, too
	 * many are not.)
	 */
	lc = list_head(into->colNames);
	for (attnum = 0; attnum < typeinfo->natts; attnum++)
	{
		Form_pg_attribute attribute = typeinfo->attrs[attnum];
		ColumnDef  *col = makeNode(ColumnDef);
		TypeName   *coltype = makeNode(TypeName);

		if (lc)
		{
			col->colname = strVal(lfirst(lc));
			lc = lnext(lc);
		}
		else
			col->colname = NameStr(attribute->attname);
		col->typeName = coltype;
		col->inhcount = 0;
		col->is_local = true;
		col->is_not_null = false;
		col->is_from_type = false;
		col->storage = 0;
		col->raw_default = NULL;
		col->cooked_default = NULL;
		col->collClause = NULL;
		col->collOid = attribute->attcollation;
		col->constraints = NIL;
		col->fdwoptions = NIL;
		col->location = -1;

		coltype->names = NIL;
		coltype->typeOid = attribute->atttypid;
		coltype->setof = false;
		coltype->pct_type = false;
		coltype->typmods = NIL;
		coltype->typemod = attribute->atttypmod;
		coltype->arrayBounds = NIL;
		coltype->location = -1;

		/*
		 * It's possible that the column is of a collatable type but the
		 * collation could not be resolved, so double-check.  (We must check
		 * this here because DefineRelation would adopt the type's default
		 * collation rather than complaining.)
		 */
		if (!OidIsValid(col->collOid) &&
			type_is_collatable(coltype->typeOid))
			ereport(ERROR,
					(errcode(ERRCODE_INDETERMINATE_COLLATION),
					 errmsg("no collation was derived for column \"%s\" with collatable type %s",
							col->colname, format_type_be(coltype->typeOid)),
					 errhint("Use the COLLATE clause to set the collation explicitly.")));

		create->tableElts = lappend(create->tableElts, col);
	}

	if (lc != NULL)
		ereport(ERROR,
				(errcode(ERRCODE_SYNTAX_ERROR),
				 errmsg("too many column names were specified")));

	/*
	 * Actually create the target table
	 */
	intoRelationId = DefineRelation(create, relkind, InvalidOid);

	/*
	 * If necessary, create a TOAST table for the target table.  Note that
	 * NewRelationCreateToastTable ends with CommandCounterIncrement(), so
	 * that the TOAST table will be visible for insertion.
	 */
	CommandCounterIncrement();

	/* parse and validate reloptions for the toast table */
	toast_options = transformRelOptions((Datum) 0,
										create->options,
										"toast",
										validnsps,
										true, false);

	(void) heap_reloptions(RELKIND_TOASTVALUE, toast_options, true);

	NewRelationCreateToastTable(intoRelationId, toast_options);

	/* Create the "view" part of a materialized view. */
	if (is_matview)
	{
		/* StoreViewQuery scribbles on tree, so make a copy */
		Query	   *query = (Query *) copyObject(into->viewQuery);

		StoreViewQuery(intoRelationId, query, false);
		CommandCounterIncrement();
	}

	/*
	 * Finally we can open the target table
	 */
	intoRelationDesc = heap_open(intoRelationId, AccessExclusiveLock);

	/*
	 * Check INSERT permission on the constructed table.
	 *
	 * XXX: It would arguably make sense to skip this check if into->skipData
	 * is true.
	 */
	rte = makeNode(RangeTblEntry);
	rte->rtekind = RTE_RELATION;
	rte->relid = intoRelationId;
	rte->relkind = relkind;
	rte->requiredPerms = ACL_INSERT;

	for (attnum = 1; attnum <= intoRelationDesc->rd_att->natts; attnum++)
		rte->modifiedCols = bms_add_member(rte->modifiedCols,
								attnum - FirstLowInvalidHeapAttributeNumber);

	ExecCheckRTPerms(list_make1(rte), true);

	/*
	 * Make sure the constructed table does not have RLS enabled.
	 *
	 * check_enable_rls() will ereport(ERROR) itself if the user has requested
	 * something invalid, and otherwise will return RLS_ENABLED if RLS should
	 * be enabled here.  We don't actually support that currently, so throw
	 * our own ereport(ERROR) if that happens.
	 */
	if (check_enable_rls(intoRelationId, InvalidOid) == RLS_ENABLED)
		ereport(ERROR,
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
				 (errmsg("policies not yet implemented for this command"))));

	/*
	 * Tentatively mark the target as populated, if it's a matview and we're
	 * going to fill it; otherwise, no change needed.
	 */
	if (is_matview && !into->skipData)
		SetMatViewPopulatedState(intoRelationDesc, true);

	/*
	 * Fill private fields of myState for use by later routines
	 */
	myState->rel = intoRelationDesc;
	myState->output_cid = GetCurrentCommandId(true);

	/* and remember the new relation's OID for ExecCreateTableAs */
	CreateAsRelid = RelationGetRelid(myState->rel);

	/*
	 * We can skip WAL-logging the insertions, unless PITR or streaming
	 * replication is in use. We can skip the FSM in any case.
	 */
	myState->hi_options = HEAP_INSERT_SKIP_FSM |
		(XLogIsNeeded() ? 0 : HEAP_INSERT_SKIP_WAL);
	myState->bistate = GetBulkInsertState();

	/* Not using WAL requires smgr_targblock be initially invalid */
	Assert(RelationGetTargetBlock(intoRelationDesc) == InvalidBlockNumber);
}