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arangodb/arangod/Aql/ExecutionPlan.cpp

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////////////////////////////////////////////////////////////////////////////////
/// @brief Aql, execution plan
///
/// @file
///
/// DISCLAIMER
///
/// Copyright 2014 ArangoDB GmbH, Cologne, Germany
/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
///
/// Licensed under the Apache License, Version 2.0 (the "License");
/// you may not use this file except in compliance with the License.
/// You may obtain a copy of the License at
///
/// http://www.apache.org/licenses/LICENSE-2.0
///
/// Unless required by applicable law or agreed to in writing, software
/// distributed under the License is distributed on an "AS IS" BASIS,
/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
/// See the License for the specific language governing permissions and
/// limitations under the License.
///
/// Copyright holder is ArangoDB GmbH, Cologne, Germany
///
/// @author Jan Steemann
/// @author Copyright 2014, ArangoDB GmbH, Cologne, Germany
/// @author Copyright 2012-2013, triAGENS GmbH, Cologne, Germany
////////////////////////////////////////////////////////////////////////////////
#include "Aql/ExecutionPlan.h"
#include "Aql/Ast.h"
#include "Aql/AstNode.h"
#include "Aql/ExecutionNode.h"
#include "Aql/Expression.h"
#include "Aql/Query.h"
#include "Aql/Variable.h"
#include "Utils/Exception.h"
using namespace triagens::aql;
// -----------------------------------------------------------------------------
// --SECTION-- constructors / destructors
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @brief create the plan
////////////////////////////////////////////////////////////////////////////////
ExecutionPlan::ExecutionPlan ()
: _nodes(),
_root(nullptr) {
_nodes.reserve(8);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief destroy the plan, frees all assigned nodes
////////////////////////////////////////////////////////////////////////////////
ExecutionPlan::~ExecutionPlan () {
for (auto it = _nodes.begin(); it != _nodes.end(); ++it) {
delete (*it);
}
}
// -----------------------------------------------------------------------------
// --SECTION-- public functions
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @brief create an execution plan from an AST
////////////////////////////////////////////////////////////////////////////////
ExecutionPlan* ExecutionPlan::instanciateFromAst (Ast const* ast) {
TRI_ASSERT(ast != nullptr);
auto root = ast->root();
TRI_ASSERT(root != nullptr);
TRI_ASSERT(root->type == NODE_TYPE_ROOT);
auto plan = new ExecutionPlan();
try {
plan->_root = plan->fromNode(ast, root);
std::cout << plan->_root->toJson().toString() << "\n";
return plan;
}
catch (...) {
delete plan;
throw;
}
}
// -----------------------------------------------------------------------------
// --SECTION-- private functions
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @brief add a node to the plan, will delete node if addition fails
////////////////////////////////////////////////////////////////////////////////
ExecutionNode* ExecutionPlan::addNode (ExecutionNode* node) {
TRI_ASSERT(node != nullptr);
try {
_nodes.push_back(node);
return node;
}
catch (...) {
delete node;
throw;
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief creates a calculation node for an arbitrary expression
////////////////////////////////////////////////////////////////////////////////
CalculationNode* ExecutionPlan::createTemporaryCalculation (Ast const* ast,
AstNode const* expression) {
// generate a temporary variable
auto out = ast->variables()->createTemporaryVariable();
TRI_ASSERT(out != nullptr);
// generate a temporary calculation node
auto expr = new Expression(ast->query()->executor(), const_cast<AstNode*>(expression));
try {
auto en = new CalculationNode(expr, out);
addNode(reinterpret_cast<ExecutionNode*>(en));
return en;
}
catch (...) {
// prevent memleak
delete expr;
throw;
// no need to delete "out" as this is automatically freed by the variables management
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief adds "previous" as dependency to "plan", returns "plan"
////////////////////////////////////////////////////////////////////////////////
ExecutionNode* ExecutionPlan::addDependency (ExecutionNode* previous,
ExecutionNode* plan) {
TRI_ASSERT(previous != nullptr);
TRI_ASSERT(plan != nullptr);
try {
plan->addDependency(previous);
return plan;
}
catch (...) {
// prevent memleak
delete plan;
throw;
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief create an execution plan element from an AST FOR node
////////////////////////////////////////////////////////////////////////////////
ExecutionNode* ExecutionPlan::fromNodeFor (Ast const* ast,
ExecutionNode* previous,
AstNode const* node) {
TRI_ASSERT(node != nullptr && node->type == NODE_TYPE_FOR);
TRI_ASSERT(node->numMembers() == 2);
auto variable = node->getMember(0);
auto expression = node->getMember(1);
// fetch 1st operand (out variable name)
TRI_ASSERT(variable->type == NODE_TYPE_VARIABLE);
auto v = static_cast<Variable*>(variable->getData());
TRI_ASSERT(v != nullptr);
ExecutionNode* en = nullptr;
// peek at second operand
if (expression->type == NODE_TYPE_COLLECTION) {
// second operand is a collection
char const* collectionName = expression->getStringValue();
en = addNode(new EnumerateCollectionNode(ast->query()->vocbase(), std::string(collectionName), v));
}
else if (expression->type == NODE_TYPE_REFERENCE) {
// second operand is already a variable
auto inVariable = static_cast<Variable*>(variable->getData());
TRI_ASSERT(inVariable != nullptr);
en = addNode(new EnumerateListNode(inVariable, v));
}
else {
// second operand is some misc. expression
auto calc = createTemporaryCalculation(ast, expression);
calc->addDependency(previous);
en = addNode(new EnumerateListNode(calc->outVariable(), v));
previous = calc;
}
TRI_ASSERT(en != nullptr);
return addDependency(previous, en);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief create an execution plan element from an AST FILTER node
////////////////////////////////////////////////////////////////////////////////
ExecutionNode* ExecutionPlan::fromNodeFilter (Ast const* ast,
ExecutionNode* previous,
AstNode const* node) {
TRI_ASSERT(node != nullptr && node->type == NODE_TYPE_FILTER);
TRI_ASSERT(node->numMembers() == 1);
auto expression = node->getMember(0);
ExecutionNode* en = nullptr;
if (expression->type == NODE_TYPE_REFERENCE) {
// operand is already a variable
auto v = static_cast<Variable*>(expression->getData());
TRI_ASSERT(v != nullptr);
en = addNode(new FilterNode(v));
}
else {
// operand is some misc expression
auto calc = createTemporaryCalculation(ast, expression);
calc->addDependency(previous);
en = addNode(new FilterNode(calc->outVariable()));
previous = calc;
}
return addDependency(previous, en);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief create an execution plan element from an AST LET node
/// this also includes handling of subqueries (as subqueries can only occur
/// inside LET nodes)
////////////////////////////////////////////////////////////////////////////////
ExecutionNode* ExecutionPlan::fromNodeLet (Ast const* ast,
ExecutionNode* previous,
AstNode const* node) {
TRI_ASSERT(node != nullptr && node->type == NODE_TYPE_LET);
TRI_ASSERT(node->numMembers() == 2);
AstNode const* variable = node->getMember(0);
AstNode const* expression = node->getMember(1);
auto v = static_cast<Variable*>(variable->getData());
ExecutionNode* en = nullptr;
if (expression->type == NODE_TYPE_SUBQUERY) {
// operand is a subquery...
auto subquery = fromNode(ast, expression);
if (subquery == nullptr) {
THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY);
}
en = addNode(new SubqueryNode(subquery, v));
}
else {
// operand is some misc expression, including references to other variables
auto expr = new Expression(ast->query()->executor(), const_cast<AstNode*>(expression));
try {
en = addNode(new CalculationNode(expr, v));
}
catch (...) {
// prevent memleak
delete expr;
throw;
}
}
return addDependency(previous, en);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief create an execution plan element from an AST SORT node
////////////////////////////////////////////////////////////////////////////////
ExecutionNode* ExecutionPlan::fromNodeSort (Ast const* ast,
ExecutionNode* previous,
AstNode const* node) {
TRI_ASSERT(node != nullptr && node->type == NODE_TYPE_SORT);
TRI_ASSERT(node->numMembers() == 1);
auto list = node->getMember(0);
TRI_ASSERT(list->type == NODE_TYPE_LIST);
std::vector<std::pair<Variable const*, bool>> elements;
std::vector<CalculationNode*> temp;
try {
size_t const n = list->numMembers();
for (size_t i = 0; i < n; ++i) {
auto element = list->getMember(i);
TRI_ASSERT(element != nullptr);
TRI_ASSERT(element->type == NODE_TYPE_SORT_ELEMENT);
TRI_ASSERT(element->numMembers() == 1);
auto expression = element->getMember(0);
if (expression->type == NODE_TYPE_REFERENCE) {
// sort operand is a variable
auto v = static_cast<Variable*>(expression->getData());
TRI_ASSERT(v != nullptr);
elements.push_back(std::make_pair(v, element->getBoolValue()));
}
else {
// sort operand is some misc expression
auto calc = createTemporaryCalculation(ast, expression);
temp.push_back(calc);
elements.push_back(std::make_pair(calc->outVariable(), element->getBoolValue()));
}
}
}
catch (...) {
// prevent memleak
for (auto it = temp.begin(); it != temp.end(); ++it) {
delete (*it);
}
throw;
}
TRI_ASSERT(! elements.empty());
// properly link the temporary calculations in the plan
for (auto it = temp.begin(); it != temp.end(); ++it) {
(*it)->addDependency(previous);
previous = (*it);
}
auto en = addNode(new SortNode(elements));
return addDependency(previous, en);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief create an execution plan element from an AST COLLECT node
/// note that also a sort plan node will be added in front of the collect plan
/// node
////////////////////////////////////////////////////////////////////////////////
ExecutionNode* ExecutionPlan::fromNodeCollect (Ast const* ast,
ExecutionNode* previous,
AstNode const* node) {
TRI_ASSERT(node != nullptr && node->type == NODE_TYPE_COLLECT);
size_t const n = node->numMembers();
TRI_ASSERT(n >= 1);
auto list = node->getMember(0);
size_t const numVars = list->numMembers();
std::vector<std::pair<Variable const*, bool>> sortElements;
std::vector<std::pair<Variable const*, Variable const*>> aggregateVariables;
aggregateVariables.reserve(numVars);
for (size_t i = 0; i < numVars; ++i) {
auto assigner = list->getMember(i);
if (assigner == nullptr) {
continue;
}
TRI_ASSERT(assigner->type == NODE_TYPE_ASSIGN);
auto out = assigner->getMember(0);
TRI_ASSERT(out != nullptr);
auto v = static_cast<Variable*>(out->getData());
TRI_ASSERT(v != nullptr);
auto expression = assigner->getMember(1);
if (expression->type == NODE_TYPE_REFERENCE) {
// operand is a variable
auto e = static_cast<Variable*>(expression->getData());
aggregateVariables.push_back(std::make_pair(v, e));
sortElements.push_back(std::make_pair(e, true));
}
else {
// operand is some misc expression
auto calc = createTemporaryCalculation(ast, expression);
calc->addDependency(previous);
previous = calc;
aggregateVariables.push_back(std::make_pair(v, calc->outVariable()));
sortElements.push_back(std::make_pair(calc->outVariable(), true));
}
}
// inject a sort node for all expressions / variables that we just picked up...
auto sort = addNode(new SortNode(sortElements));
sort->addDependency(previous);
previous = sort;
// handle out variable
Variable* outVariable = nullptr;
if (n == 2) {
// collect with an output variable!
auto v = node->getMember(1);
outVariable = static_cast<Variable*>(v->getData());
}
auto en = addNode(new AggregateNode(aggregateVariables, outVariable));
return addDependency(previous, en);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief create an execution plan element from an AST LIMIT node
////////////////////////////////////////////////////////////////////////////////
ExecutionNode* ExecutionPlan::fromNodeLimit (Ast const* ast,
ExecutionNode* previous,
AstNode const* node) {
TRI_ASSERT(node != nullptr && node->type == NODE_TYPE_LIMIT);
TRI_ASSERT(node->numMembers() == 2);
auto offset = node->getMember(0);
auto count = node->getMember(1);
TRI_ASSERT(offset->type == NODE_TYPE_VALUE);
TRI_ASSERT(count->type == NODE_TYPE_VALUE);
auto en = addNode(new LimitNode(static_cast<size_t>(offset->getIntValue()), static_cast<size_t>(count->getIntValue())));
return addDependency(previous, en);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief create an execution plan element from an AST RETURN node
////////////////////////////////////////////////////////////////////////////////
ExecutionNode* ExecutionPlan::fromNodeReturn (Ast const* ast,
ExecutionNode* previous,
AstNode const* node) {
TRI_ASSERT(node != nullptr && node->type == NODE_TYPE_RETURN);
TRI_ASSERT(node->numMembers() == 1);
auto expression = node->getMember(0);
ExecutionNode* en = nullptr;
if (expression->type == NODE_TYPE_REFERENCE) {
// operand is already a variable
auto v = static_cast<Variable*>(expression->getData());
TRI_ASSERT(v != nullptr);
en = addNode(new ReturnNode(v));
}
else {
// operand is some misc expression
auto calc = createTemporaryCalculation(ast, expression);
calc->addDependency(previous);
en = addNode(new ReturnNode(calc->outVariable()));
previous = calc;
}
return addDependency(previous, en);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief create an execution plan element from an AST REMOVE node
////////////////////////////////////////////////////////////////////////////////
ExecutionNode* ExecutionPlan::fromNodeRemove (Ast const* ast,
ExecutionNode* previous,
AstNode const* node) {
TRI_ASSERT(node != nullptr && node->type == NODE_TYPE_REMOVE);
// TODO
THROW_ARANGO_EXCEPTION(TRI_ERROR_NOT_IMPLEMENTED);
return nullptr;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief create an execution plan element from an AST INSERT node
////////////////////////////////////////////////////////////////////////////////
ExecutionNode* ExecutionPlan::fromNodeInsert (Ast const* ast,
ExecutionNode* previous,
AstNode const* node) {
TRI_ASSERT(node != nullptr && node->type == NODE_TYPE_INSERT);
// TODO
THROW_ARANGO_EXCEPTION(TRI_ERROR_NOT_IMPLEMENTED);
return nullptr;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief create an execution plan element from an AST UPDATE node
////////////////////////////////////////////////////////////////////////////////
ExecutionNode* ExecutionPlan::fromNodeUpdate (Ast const* ast,
ExecutionNode* previous,
AstNode const* node) {
TRI_ASSERT(node != nullptr && node->type == NODE_TYPE_UPDATE);
// TODO
THROW_ARANGO_EXCEPTION(TRI_ERROR_NOT_IMPLEMENTED);
return nullptr;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief create an execution plan element from an AST REPLACE node
////////////////////////////////////////////////////////////////////////////////
ExecutionNode* ExecutionPlan::fromNodeReplace (Ast const* ast,
ExecutionNode* previous,
AstNode const* node) {
TRI_ASSERT(node != nullptr && node->type == NODE_TYPE_REPLACE);
// TODO
THROW_ARANGO_EXCEPTION(TRI_ERROR_NOT_IMPLEMENTED);
return nullptr;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief create an execution plan from an abstract syntax tree node
////////////////////////////////////////////////////////////////////////////////
ExecutionNode* ExecutionPlan::fromNode (Ast const* ast,
AstNode const* node) {
TRI_ASSERT(node != nullptr);
ExecutionNode* en = addNode(new SingletonNode());
size_t const n = node->numMembers();
for (size_t i = 0; i < n; ++i) {
auto member = node->getMember(i);
if (member == nullptr || member->type == NODE_TYPE_NOP) {
continue;
}
switch (member->type) {
case NODE_TYPE_FOR: {
en = fromNodeFor(ast, en, member);
break;
}
case NODE_TYPE_FILTER: {
en = fromNodeFilter(ast, en, member);
break;
}
case NODE_TYPE_LET: {
en = fromNodeLet(ast, en, member);
break;
}
case NODE_TYPE_SORT: {
en = fromNodeSort(ast, en, member);
break;
}
case NODE_TYPE_COLLECT: {
en = fromNodeCollect(ast, en, member);
break;
}
case NODE_TYPE_LIMIT: {
en = fromNodeLimit(ast, en, member);
break;
}
case NODE_TYPE_RETURN: {
en = fromNodeReturn(ast, en, member);
break;
}
case NODE_TYPE_REMOVE: {
en = fromNodeRemove(ast, en, member);
break;
}
case NODE_TYPE_INSERT: {
en = fromNodeInsert(ast, en, member);
break;
}
case NODE_TYPE_UPDATE: {
en = fromNodeUpdate(ast, en, member);
break;
}
case NODE_TYPE_REPLACE: {
en = fromNodeReplace(ast, en, member);
break;
}
default: {
// node type not implemented
en = nullptr;
break;
}
}
if (en == nullptr) {
THROW_ARANGO_EXCEPTION(TRI_ERROR_INTERNAL);
}
}
return en;
}
// -----------------------------------------------------------------------------
// --SECTION-- END-OF-FILE
// -----------------------------------------------------------------------------
// Local Variables:
// mode: outline-minor
// outline-regexp: "/// @brief\\|/// {@inheritDoc}\\|/// @page\\|// --SECTION--\\|/// @\\}"
// End:
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