code: @Override
  	public Scan open() {
  		Scan s = p1.open();
  		// throws an exception if p2 is not a tableplan
  		TableScan ts = (TableScan) tp2.open();
  		Index idx = ii.open(tx);
  		return new IndexJoinScan(s, idx, joinFields, ts);
  	}
docs: Opens an index-join scan for this query
  
  @see Plan#open()