private HashMap<String, Expression> _compNamesAndExprs = new HashMap<String, Expression>();
private HashMap<Set<String>, Expression> _compNamesOrExprs = new HashMap<Set<String>, Expression>();
public CostParallelismAssignerTest() {
String parserConfPath = "../test/squall/unit_tests/confs/0_1G_tpch7_ncl";
ParserMain pm = new ParserMain();
Map map = pm.createConfig(parserConfPath);
_parsedQuery = ParserUtil.parseQuery(map);
Schema schema = new Schema(map);
ProjGlobalCollect globalProject = new ProjGlobalCollect(_parsedQuery.getSelectItems(), _parsedQuery.getWhereExpr());