void derivedTableOptimization(SCSEP& csep) { // @bug5634. replace the unused column with ConstantColumn from derived table column list, // ExeMgr will not project ConstantColumn. Only count for local derived column. // subquery may carry main query derived table list for column reference, those // derived tables are not checked for optimization in this scope. CalpontSelectExecutionPlan::SelectList derivedTbList = csep->derivedTableList(); // @bug6156. Skip horizontal optimization for no table union. bool horizontalOptimization = true; for (uint i = 0; i < derivedTbList.size(); i++) { CalpontSelectExecutionPlan* plan = dynamic_cast<CalpontSelectExecutionPlan*>(derivedTbList[i].get()); CalpontSelectExecutionPlan::ReturnedColumnList cols = plan->returnedCols(); vector<CalpontSelectExecutionPlan::ReturnedColumnList> unionColVec; // only do vertical optimization for union all // @bug6134. Also skip the vertical optimization for select distinct // because all columns need to be projected to check the distinctness. bool verticalOptimization = false; if (plan->distinctUnionNum() == 0 && !plan->distinct()) { verticalOptimization = true; for (uint j = 0; j < plan->unionVec().size(); j++) { unionColVec.push_back( dynamic_cast<CalpontSelectExecutionPlan*>(plan->unionVec()[j].get())->returnedCols()); } } if (plan->tableList().empty()) horizontalOptimization = false; for (uint j = 0; j < plan->unionVec().size(); j++) { if (dynamic_cast<CalpontSelectExecutionPlan*>(plan->unionVec()[j].get())->tableList().empty()) { horizontalOptimization = false; break; } } if (verticalOptimization) { int64_t val = 1; for (uint i = 0; i < cols.size(); i++) { //if (cols[i]->derivedTable().empty()) if (cols[i]->refCount() == 0) { if (cols[i]->derivedRefCol()) cols[i]->derivedRefCol()->decRefCount(); cols[i].reset(new ConstantColumn(val)); for (uint j = 0; j < unionColVec.size(); j++) unionColVec[j][i].reset(new ConstantColumn(val)); } } // set back plan->returnedCols(cols); for (uint j = 0; j < unionColVec.size(); j++) dynamic_cast<CalpontSelectExecutionPlan*>(plan->unionVec()[j].get())->returnedCols(unionColVec[j]); } } /* * @bug5635. Move filters that only belongs to a derived table to inside the derived table. * 1. parse tree walk to populate derivedTableFilterMap and set null candidate on the tree. * 2. remove the null filters * 3. and the filters of derivedTableFilterMap and append to the WHERE filter of the derived table * * Note: * 1. Subquery filters is ignored because derived table can not be in subquery * 2. While walking tree, whenever a single derive simplefilter is encountered, * this filter is pushed to the corresponding stack * 2. Whenever an OR operator is encountered, all the filter stack of * that OR involving derived table are emptied and null candidate of each * stacked filter needs to be reset (not null) */ ParseTree* pt = csep->filters(); map<string, ParseTree*> derivedTbFilterMap; if (horizontalOptimization && pt) { pt->walk(setDerivedTable); setDerivedFilter(pt, derivedTbFilterMap, derivedTbList); csep->filters(pt); } // AND the filters of individual stack to the derived table filter tree // @todo union filters. // @todo outer join complication map<string, ParseTree*>::iterator mapIt; for (uint i = 0; i < derivedTbList.size(); i++) { CalpontSelectExecutionPlan* plan = dynamic_cast<CalpontSelectExecutionPlan*>(derivedTbList[i].get()); CalpontSelectExecutionPlan::ReturnedColumnList derivedColList = plan->returnedCols(); mapIt = derivedTbFilterMap.find(plan->derivedTbAlias()); if (mapIt != derivedTbFilterMap.end()) { // replace all derived column of this filter with real column from // derived table projection list. ParseTree* mainFilter = new ParseTree(); mainFilter->copyTree(*(mapIt->second)); replaceRefCol(mainFilter, derivedColList); ParseTree* derivedFilter = plan->filters(); if (derivedFilter) { LogicOperator* op = new LogicOperator("and"); ParseTree* filter = new ParseTree(op); filter->left(derivedFilter); filter->right(mainFilter); plan->filters(filter); } else { plan->filters(mainFilter); } // union filter handling for (uint j = 0; j < plan->unionVec().size(); j++) { CalpontSelectExecutionPlan* unionPlan = dynamic_cast<CalpontSelectExecutionPlan*>(plan->unionVec()[j].get()); CalpontSelectExecutionPlan::ReturnedColumnList unionColList = unionPlan->returnedCols(); ParseTree* mainFilterForUnion = new ParseTree(); mainFilterForUnion->copyTree(*(mapIt->second)); replaceRefCol(mainFilterForUnion, unionColList); ParseTree* unionFilter = unionPlan->filters(); if (unionFilter) { LogicOperator* op = new LogicOperator("and"); ParseTree* filter = new ParseTree(op); filter->left(unionFilter); filter->right(mainFilterForUnion); unionPlan->filters(filter); } else { unionPlan->filters(mainFilterForUnion); } } } } // clean derivedTbFilterMap because all the filters are copied for ( mapIt = derivedTbFilterMap.begin(); mapIt != derivedTbFilterMap.end(); ++mapIt ) delete (*mapIt).second; // recursively process the nested derived table for (uint i = 0; i < csep->subSelectList().size(); i++) { SCSEP subselect(boost::dynamic_pointer_cast<CalpontSelectExecutionPlan>(csep->subSelectList()[i])); derivedTableOptimization(subselect); } }
ParseTree* setDerivedFilter(ParseTree*& n, map<string, ParseTree*>& filterMap, CalpontSelectExecutionPlan::SelectList& derivedTbList) { if (!(n->derivedTable().empty())) { // @todo replace virtual column of n to real column // all simple columns should belong to the same derived table CalpontSelectExecutionPlan* csep = NULL; for (uint i = 0; i < derivedTbList.size(); i++) { CalpontSelectExecutionPlan* plan = dynamic_cast<CalpontSelectExecutionPlan*>(derivedTbList[i].get()); if (plan->derivedTbAlias() == n->derivedTable()) { csep = plan; break; } } // should never be null; if null then give up optimization. if (!csep) return n; // 2. push the filter to the derived table filter stack, or 'and' with // the filters in the stack map<string, ParseTree*>::iterator mapIter = filterMap.find(n->derivedTable()); if ( mapIter == filterMap.end()) { filterMap.insert(pair<string, ParseTree*>(n->derivedTable(), n)); } else { ParseTree* pt = new ParseTree(new LogicOperator("and")); pt->left(mapIter->second); pt->right(n); mapIter->second = pt; } int64_t val = 1; n = new ParseTree(new ConstantColumn(val)); } else { Operator* op = dynamic_cast<Operator*>(n->data()); if (op && (op->op() == OP_OR || op->op() == OP_XOR)) { return n; } else { ParseTree* lhs = n->left(); ParseTree* rhs = n->right(); if (lhs) n->left(setDerivedFilter(lhs, filterMap, derivedTbList)); if (rhs) n->right(setDerivedFilter(rhs, filterMap, derivedTbList)); } } return n; }