Function ExecInitForeignScanForPartition

src/backend/executor/nodeForeignscan.c:157–302

}

ForeignScanState *
ExecInitForeignScanForPartition(ForeignScan *node, EState *estate, int eflags, Relation currentRelation)
{
	ForeignScanState *scanstate;
	Index		scanrelid = node->scan.scanrelid;
	Index		tlistvarno;
	FdwRoutine *fdwroutine;

	/* check for unsupported flags */
	Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)));

	/*
	 * create state structure
	 */
	scanstate = makeNode(ForeignScanState);
	scanstate->ss.ps.plan = (Plan *) node;
	scanstate->ss.ps.state = estate;
	scanstate->ss.ps.ExecProcNode = ExecForeignScan;

	/*
	 * Miscellaneous initialization
	 *
	 * create expression context for node
	 */
	ExecAssignExprContext(estate, &scanstate->ss.ps);

	/*
	 * open the scan relation, if any; also acquire function pointers from the
	 * FDW's handler
	 */
	if (scanrelid > 0)
	{
		scanstate->ss.ss_currentRelation = currentRelation;
		fdwroutine = GetFdwRoutineForRelation(currentRelation, true);
	}
	else
	{
		/* We can't use the relcache, so get fdwroutine the hard way */
		fdwroutine = GetFdwRoutineByServerId(node->fs_server);
	}

	/*
	 * Determine the scan tuple type.  If the FDW provided a targetlist
	 * describing the scan tuples, use that; else use base relation's rowtype.
	 */
	if (node->fdw_scan_tlist != NIL || currentRelation == NULL)
	{
		TupleDesc	scan_tupdesc;

		scan_tupdesc = ExecTypeFromTL(node->fdw_scan_tlist);
		ExecInitScanTupleSlot(estate, &scanstate->ss, scan_tupdesc,
							  &TTSOpsHeapTuple);
		/* Node's targetlist will contain Vars with varno = INDEX_VAR */
		tlistvarno = INDEX_VAR;
	}
	else
	{
		TupleDesc	scan_tupdesc;