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arangodb/arangod/Indexes/HashIndex.cpp

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////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2014-2016 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 Dr. Frank Celler
////////////////////////////////////////////////////////////////////////////////
#include "HashIndex.h"
#include "Aql/Ast.h"
#include "Aql/AstNode.h"
#include "Aql/SortCondition.h"
#include "Basics/Exceptions.h"
#include "Indexes/SimpleAttributeEqualityMatcher.h"
#include "VocBase/transaction.h"
#include "VocBase/VocShaper.h"
using namespace arangodb;
////////////////////////////////////////////////////////////////////////////////
/// @brief Frees an index element
////////////////////////////////////////////////////////////////////////////////
static void FreeElement(TRI_index_element_t* element) {
TRI_index_element_t::freeElement(element);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief determines if two elements are equal
////////////////////////////////////////////////////////////////////////////////
static bool IsEqualElementElement(void* userData,
TRI_index_element_t const* left,
TRI_index_element_t const* right) {
return left->document() == right->document();
}
////////////////////////////////////////////////////////////////////////////////
/// @brief given a key generates a hash integer
////////////////////////////////////////////////////////////////////////////////
static uint64_t HashKey(void* userData,
TRI_hash_index_search_value_t const* key) {
uint64_t hash = 0x0123456789abcdef;
for (size_t j = 0; j < key->_length; ++j) {
// ignore the sid for hashing
hash = fasthash64(key->_values[j]._data.data, key->_values[j]._data.length,
hash);
}
return hash;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief determines if a key corresponds to an element
////////////////////////////////////////////////////////////////////////////////
static bool IsEqualKeyElement(void* userData,
TRI_hash_index_search_value_t const* left,
TRI_index_element_t const* right) {
TRI_ASSERT(right->document() != nullptr);
for (size_t j = 0; j < left->_length; ++j) {
TRI_shaped_json_t* leftJson = &left->_values[j];
TRI_shaped_sub_t* rightSub = &right->subObjects()[j];
if (leftJson->_sid != rightSub->_sid) {
return false;
}
auto length = leftJson->_data.length;
char const* rightData;
size_t rightLength;
TRI_InspectShapedSub(rightSub, right->document(), rightData, rightLength);
if (length != rightLength) {
return false;
}
if (length > 0 && memcmp(leftJson->_data.data, rightData, length) != 0) {
return false;
}
}
return true;
}
static bool IsEqualKeyElementHash(
void* userData, TRI_hash_index_search_value_t const* left,
uint64_t const hash, // Has been computed but is not used here
TRI_index_element_t const* right) {
return IsEqualKeyElement(userData, left, right);
}
TRI_doc_mptr_t* HashIndexIterator::next() {
while (true) {
if (_posInBuffer >= _buffer.size()) {
if (_position >= _keys.size()) {
// we're at the end of the lookup values
return nullptr;
}
// We have to refill the buffer
_buffer.clear();
_posInBuffer = 0;
int res = _index->lookup(_trx, _keys[_position++], _buffer);
if (res != TRI_ERROR_NO_ERROR) {
THROW_ARANGO_EXCEPTION(res);
}
}
if (!_buffer.empty()) {
// found something
return _buffer.at(_posInBuffer++);
}
}
}
void HashIndexIterator::reset() {
_buffer.clear();
_position = 0;
_posInBuffer = 0;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief create the unique array
////////////////////////////////////////////////////////////////////////////////
HashIndex::UniqueArray::UniqueArray(
TRI_HashArray_t* hashArray, HashElementFunc* hashElement,
IsEqualElementElementByKey* isEqualElElByKey)
: _hashArray(hashArray),
_hashElement(hashElement),
_isEqualElElByKey(isEqualElElByKey) {
TRI_ASSERT(_hashArray != nullptr);
TRI_ASSERT(_hashElement != nullptr);
TRI_ASSERT(_isEqualElElByKey != nullptr);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief destroy the unique array
////////////////////////////////////////////////////////////////////////////////
HashIndex::UniqueArray::~UniqueArray() {
if (_hashArray != nullptr) {
_hashArray->invokeOnAllElements(FreeElement);
}
delete _hashArray;
delete _hashElement;
delete _isEqualElElByKey;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief create the multi array
////////////////////////////////////////////////////////////////////////////////
HashIndex::MultiArray::MultiArray(TRI_HashArrayMulti_t* hashArray,
HashElementFunc* hashElement,
IsEqualElementElementByKey* isEqualElElByKey)
: _hashArray(hashArray),
_hashElement(hashElement),
_isEqualElElByKey(isEqualElElByKey) {
TRI_ASSERT(_hashArray != nullptr);
TRI_ASSERT(_hashElement != nullptr);
TRI_ASSERT(_isEqualElElByKey != nullptr);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief destroy the multi array
////////////////////////////////////////////////////////////////////////////////
HashIndex::MultiArray::~MultiArray() {
if (_hashArray != nullptr) {
_hashArray->invokeOnAllElements(FreeElement);
}
delete _hashArray;
delete _hashElement;
delete _isEqualElElByKey;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief create an index search value
////////////////////////////////////////////////////////////////////////////////
TRI_hash_index_search_value_t::TRI_hash_index_search_value_t()
: _length(0), _values(nullptr) {}
TRI_hash_index_search_value_t::~TRI_hash_index_search_value_t() { destroy(); }
void TRI_hash_index_search_value_t::reserve(size_t n) {
TRI_ASSERT(_values == nullptr);
_values = static_cast<TRI_shaped_json_t*>(
TRI_Allocate(TRI_UNKNOWN_MEM_ZONE, n * sizeof(TRI_shaped_json_t), true));
if (_values == nullptr) {
THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY);
}
_length = n;
}
void TRI_hash_index_search_value_t::destroy() {
if (_values != nullptr) {
for (size_t i = 0; i < _length; ++i) {
TRI_DestroyShapedJson(TRI_UNKNOWN_MEM_ZONE, &_values[i]);
}
TRI_Free(TRI_UNKNOWN_MEM_ZONE, _values);
_values = nullptr;
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief create the index
////////////////////////////////////////////////////////////////////////////////
HashIndex::HashIndex(
TRI_idx_iid_t iid, TRI_document_collection_t* collection,
std::vector<std::vector<arangodb::basics::AttributeName>> const& fields,
bool unique, bool sparse)
: PathBasedIndex(iid, collection, fields, unique, sparse, false),
_uniqueArray(nullptr) {
uint32_t indexBuckets = 1;
if (collection != nullptr) {
// document is a nullptr in the coordinator case
indexBuckets = collection->_info.indexBuckets();
}
auto func = std::make_unique<HashElementFunc>(_paths.size());
auto compare = std::make_unique<IsEqualElementElementByKey>(_paths.size());
if (unique) {
auto array = std::make_unique<TRI_HashArray_t>(
HashKey, *(func.get()), IsEqualKeyElementHash, IsEqualElementElement,
*(compare.get()), indexBuckets,
[]() -> std::string { return "unique hash-array"; });
_uniqueArray =
new HashIndex::UniqueArray(array.get(), func.get(), compare.get());
array.release();
} else {
_multiArray = nullptr;
auto array = std::make_unique<TRI_HashArrayMulti_t>(
HashKey, *(func.get()), IsEqualKeyElement, IsEqualElementElement,
*(compare.get()), indexBuckets, 64,
[]() -> std::string { return "multi hash-array"; });
_multiArray =
new HashIndex::MultiArray(array.get(), func.get(), compare.get());
array.release();
}
compare.release();
func.release();
}
////////////////////////////////////////////////////////////////////////////////
/// @brief create an index stub with a hard-coded selectivity estimate
/// this is used in the cluster coordinator case
////////////////////////////////////////////////////////////////////////////////
HashIndex::HashIndex(VPackSlice const& slice)
: PathBasedIndex(slice, false), _uniqueArray(nullptr) {}
////////////////////////////////////////////////////////////////////////////////
/// @brief destroys the index
////////////////////////////////////////////////////////////////////////////////
HashIndex::~HashIndex() {
if (_unique) {
delete _uniqueArray;
} else {
delete _multiArray;
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief returns a selectivity estimate for the index
////////////////////////////////////////////////////////////////////////////////
double HashIndex::selectivityEstimate() const {
if (_unique) {
return 1.0;
}
if (_multiArray == nullptr) {
// use hard-coded selectivity estimate in case of cluster coordinator
return _selectivityEstimate;
}
double estimate = _multiArray->_hashArray->selectivity();
TRI_ASSERT(estimate >= 0.0 &&
estimate <= 1.00001); // floating-point tolerance
return estimate;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief returns the index memory usage
////////////////////////////////////////////////////////////////////////////////
size_t HashIndex::memory() const {
if (_unique) {
return static_cast<size_t>(elementSize() *
_uniqueArray->_hashArray->size() +
_uniqueArray->_hashArray->memoryUsage());
}
return static_cast<size_t>(elementSize() * _multiArray->_hashArray->size() +
_multiArray->_hashArray->memoryUsage());
}
////////////////////////////////////////////////////////////////////////////////
/// @brief return a velocypack representation of the index
////////////////////////////////////////////////////////////////////////////////
void HashIndex::toVelocyPack(VPackBuilder& builder, bool withFigures) const {
Index::toVelocyPack(builder, withFigures);
builder.add("unique", VPackValue(_unique));
builder.add("sparse", VPackValue(_sparse));
}
////////////////////////////////////////////////////////////////////////////////
/// @brief return a velocypack representation of the index figures
////////////////////////////////////////////////////////////////////////////////
void HashIndex::toVelocyPackFigures(VPackBuilder& builder) const {
TRI_ASSERT(builder.isOpenObject());
builder.add("memory", VPackValue(memory()));
if (_unique) {
_uniqueArray->_hashArray->appendToVelocyPack(builder);
} else {
_multiArray->_hashArray->appendToVelocyPack(builder);
}
}
int HashIndex::insert(arangodb::Transaction* trx, TRI_doc_mptr_t const* doc,
bool isRollback) {
if (_unique) {
return insertUnique(trx, doc, isRollback);
}
return insertMulti(trx, doc, isRollback);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief removes an entry from the hash array part of the hash index
////////////////////////////////////////////////////////////////////////////////
int HashIndex::remove(arangodb::Transaction* trx, TRI_doc_mptr_t const* doc,
bool isRollback) {
if (_unique) {
return removeUnique(trx, doc, isRollback);
}
return removeMulti(trx, doc, isRollback);
}
int HashIndex::batchInsert(arangodb::Transaction* trx,
std::vector<TRI_doc_mptr_t const*> const* documents,
size_t numThreads) {
if (_unique) {
return batchInsertUnique(trx, documents, numThreads);
}
return batchInsertMulti(trx, documents, numThreads);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief provides a size hint for the hash index
////////////////////////////////////////////////////////////////////////////////
int HashIndex::sizeHint(arangodb::Transaction* trx, size_t size) {
if (_sparse) {
// for sparse indexes, we assume that we will have less index entries
// than if the index would be fully populated
size /= 5;
}
if (_unique) {
return _uniqueArray->_hashArray->resize(trx, size);
}
return _multiArray->_hashArray->resize(trx, size);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief locates entries in the hash index given shaped json objects
////////////////////////////////////////////////////////////////////////////////
int HashIndex::lookup(arangodb::Transaction* trx,
TRI_hash_index_search_value_t* searchValue,
std::vector<TRI_doc_mptr_t*>& documents) const {
if (_unique) {
TRI_index_element_t* found =
_uniqueArray->_hashArray->findByKey(trx, searchValue);
if (found != nullptr) {
// unique hash index: maximum number is 1
documents.emplace_back(found->document());
}
return TRI_ERROR_NO_ERROR;
}
std::vector<TRI_index_element_t*>* results = nullptr;
try {
results = _multiArray->_hashArray->lookupByKey(trx, searchValue);
} catch (...) {
return TRI_ERROR_OUT_OF_MEMORY;
}
if (results != nullptr) {
try {
for (size_t i = 0; i < results->size(); i++) {
documents.emplace_back((*results)[i]->document());
}
delete results;
} catch (...) {
delete results;
return TRI_ERROR_OUT_OF_MEMORY;
}
}
return TRI_ERROR_NO_ERROR;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief locates entries in the hash index given shaped json objects
////////////////////////////////////////////////////////////////////////////////
int HashIndex::lookup(arangodb::Transaction* trx,
TRI_hash_index_search_value_t* searchValue,
std::vector<TRI_doc_mptr_copy_t>& documents,
TRI_index_element_t*& next, size_t batchSize) const {
if (_unique) {
next = nullptr;
TRI_index_element_t* found =
_uniqueArray->_hashArray->findByKey(trx, searchValue);
if (found != nullptr) {
// unique hash index: maximum number is 1
documents.emplace_back(*(found->document()));
}
return TRI_ERROR_NO_ERROR;
}
std::vector<TRI_index_element_t*>* results = nullptr;
if (next == nullptr) {
try {
results =
_multiArray->_hashArray->lookupByKey(trx, searchValue, batchSize);
} catch (...) {
return TRI_ERROR_OUT_OF_MEMORY;
}
} else {
try {
results =
_multiArray->_hashArray->lookupByKeyContinue(trx, next, batchSize);
} catch (...) {
return TRI_ERROR_OUT_OF_MEMORY;
}
}
if (results != nullptr) {
if (results->size() > 0) {
next = results->back(); // for continuation the next time
try {
for (size_t i = 0; i < results->size(); i++) {
documents.emplace_back(*((*results)[i]->document()));
}
} catch (...) {
delete results;
return TRI_ERROR_OUT_OF_MEMORY;
}
} else {
next = nullptr;
}
delete results;
} else {
next = nullptr;
}
return TRI_ERROR_NO_ERROR;
}
int HashIndex::insertUnique(arangodb::Transaction* trx,
TRI_doc_mptr_t const* doc, bool isRollback) {
std::vector<TRI_index_element_t*> elements;
int res = fillElement(elements, doc);
if (res != TRI_ERROR_NO_ERROR) {
for (auto& it : elements) {
// free all elements to prevent leak
FreeElement(it);
}
return res;
}
auto work =
[this, trx](TRI_index_element_t* element, bool isRollback) -> int {
TRI_IF_FAILURE("InsertHashIndex") { return TRI_ERROR_DEBUG; }
return _uniqueArray->_hashArray->insert(trx, element);
};
size_t const n = elements.size();
for (size_t i = 0; i < n; ++i) {
auto hashElement = elements[i];
res = work(hashElement, isRollback);
if (res != TRI_ERROR_NO_ERROR) {
for (size_t j = i; j < n; ++j) {
// Free all elements that are not yet in the index
FreeElement(elements[j]);
}
// Already indexed elements will be removed by the rollback
break;
}
}
return res;
}
int HashIndex::batchInsertUnique(
arangodb::Transaction* trx,
std::vector<TRI_doc_mptr_t const*> const* documents, size_t numThreads) {
std::vector<TRI_index_element_t*> elements;
elements.reserve(documents->size());
for (auto& doc : *documents) {
int res = fillElement(elements, doc);
if (res != TRI_ERROR_NO_ERROR) {
for (auto& it : elements) {
// free all elements to prevent leak
FreeElement(it);
}
return res;
}
}
int res = _uniqueArray->_hashArray->batchInsert(trx, &elements, numThreads);
if (res != TRI_ERROR_NO_ERROR) {
for (auto& it : elements) {
// free all elements to prevent leak
FreeElement(it);
}
}
return res;
}
int HashIndex::insertMulti(arangodb::Transaction* trx,
TRI_doc_mptr_t const* doc, bool isRollback) {
std::vector<TRI_index_element_t*> elements;
int res = fillElement(elements, doc);
if (res != TRI_ERROR_NO_ERROR) {
for (auto& hashElement : elements) {
FreeElement(hashElement);
}
return res;
}
auto work = [this, trx](TRI_index_element_t*& element, bool isRollback) {
TRI_IF_FAILURE("InsertHashIndex") {
THROW_ARANGO_EXCEPTION(TRI_ERROR_DEBUG);
}
TRI_index_element_t* found =
_multiArray->_hashArray->insert(trx, element, false, true);
if (found != nullptr) {
// already got the exact same index entry. now free our local element...
FreeElement(element);
// we're not responsible for this element anymore
element = nullptr;
}
};
size_t const n = elements.size();
for (size_t i = 0; i < n; ++i) {
auto hashElement = elements[i];
try {
work(hashElement, isRollback);
} catch (arangodb::basics::Exception const& ex) {
res = ex.code();
} catch (...) {
res = TRI_ERROR_OUT_OF_MEMORY;
}
if (res != TRI_ERROR_NO_ERROR) {
for (size_t j = i; j < n; ++j) {
// Free all elements that are not yet in the index
FreeElement(elements[j]);
}
for (size_t j = 0; j < i; ++j) {
// Remove all allready indexed elements and free them
if (elements[j] != nullptr) {
removeMultiElement(trx, elements[j], isRollback);
}
}
return res;
}
}
return TRI_ERROR_NO_ERROR;
}
int HashIndex::batchInsertMulti(
arangodb::Transaction* trx,
std::vector<TRI_doc_mptr_t const*> const* documents, size_t numThreads) {
std::vector<TRI_index_element_t*> elements;
for (auto& doc : *documents) {
int res = fillElement(elements, doc);
if (res != TRI_ERROR_NO_ERROR) {
// Filling the elements failed for some reason. Assume loading as failed
for (auto& el : elements) {
// Free all elements that are not yet in the index
FreeElement(el);
}
return res;
}
}
return _multiArray->_hashArray->batchInsert(trx, &elements, numThreads);
}
int HashIndex::removeUniqueElement(arangodb::Transaction* trx,
TRI_index_element_t* element,
bool isRollback) {
TRI_IF_FAILURE("RemoveHashIndex") { return TRI_ERROR_DEBUG; }
TRI_index_element_t* old = _uniqueArray->_hashArray->remove(trx, element);
// this might happen when rolling back
if (old == nullptr) {
if (isRollback) {
return TRI_ERROR_NO_ERROR;
}
return TRI_ERROR_INTERNAL;
}
FreeElement(old);
return TRI_ERROR_NO_ERROR;
}
int HashIndex::removeUnique(arangodb::Transaction* trx,
TRI_doc_mptr_t const* doc, bool isRollback) {
std::vector<TRI_index_element_t*> elements;
int res = fillElement(elements, doc);
if (res != TRI_ERROR_NO_ERROR) {
for (auto& hashElement : elements) {
FreeElement(hashElement);
}
return res;
}
for (auto& hashElement : elements) {
int result = removeUniqueElement(trx, hashElement, isRollback);
// we may be looping through this multiple times, and if an error
// occurs, we want to keep it
if (result != TRI_ERROR_NO_ERROR) {
res = result;
}
FreeElement(hashElement);
}
return res;
}
int HashIndex::removeMultiElement(arangodb::Transaction* trx,
TRI_index_element_t* element,
bool isRollback) {
TRI_IF_FAILURE("RemoveHashIndex") { return TRI_ERROR_DEBUG; }
TRI_index_element_t* old = _multiArray->_hashArray->remove(trx, element);
if (old == nullptr) {
// not found
if (isRollback) { // ignore in this case, because it can happen
return TRI_ERROR_NO_ERROR;
}
return TRI_ERROR_INTERNAL;
}
FreeElement(old);
return TRI_ERROR_NO_ERROR;
}
int HashIndex::removeMulti(arangodb::Transaction* trx,
TRI_doc_mptr_t const* doc, bool isRollback) {
std::vector<TRI_index_element_t*> elements;
int res = fillElement(elements, doc);
if (res != TRI_ERROR_NO_ERROR) {
for (auto& hashElement : elements) {
FreeElement(hashElement);
}
}
for (auto& hashElement : elements) {
int result = removeMultiElement(trx, hashElement, isRollback);
// we may be looping through this multiple times, and if an error
// occurs, we want to keep it
if (result != TRI_ERROR_NO_ERROR) {
res = result;
}
FreeElement(hashElement);
}
return res;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief checks whether the index supports the condition
////////////////////////////////////////////////////////////////////////////////
bool HashIndex::supportsFilterCondition(
arangodb::aql::AstNode const* node,
arangodb::aql::Variable const* reference, size_t itemsInIndex,
size_t& estimatedItems, double& estimatedCost) const {
SimpleAttributeEqualityMatcher matcher(fields());
return matcher.matchAll(this, node, reference, itemsInIndex, estimatedItems,
estimatedCost);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief creates an IndexIterator for the given Condition
////////////////////////////////////////////////////////////////////////////////
IndexIterator* HashIndex::iteratorForCondition(
arangodb::Transaction* trx, IndexIteratorContext* context,
arangodb::aql::Ast* ast, arangodb::aql::AstNode const* node,
arangodb::aql::Variable const* reference, bool reverse) const {
TRI_ASSERT(node->type == aql::NODE_TYPE_OPERATOR_NARY_AND);
SimpleAttributeEqualityMatcher matcher(fields());
size_t const n = _fields.size();
TRI_ASSERT(node->numMembers() == n);
// initialize permutations
std::vector<PermutationState> permutationStates;
permutationStates.reserve(n);
size_t maxPermutations = 1;
std::pair<arangodb::aql::Variable const*,
std::vector<arangodb::basics::AttributeName>> paramPair;
for (size_t i = 0; i < n; ++i) {
auto comp = node->getMemberUnchecked(i);
auto attrNode = comp->getMember(0);
auto valNode = comp->getMember(1);
paramPair.first = nullptr;
paramPair.second.clear();
if (!attrNode->isAttributeAccessForVariable(paramPair) ||
paramPair.first != reference) {
attrNode = comp->getMember(1);
valNode = comp->getMember(0);
if (!attrNode->isAttributeAccessForVariable(paramPair) ||
paramPair.first != reference) {
return nullptr;
}
}
size_t attributePosition = SIZE_MAX;
for (size_t j = 0; j < _fields.size(); ++j) {
if (arangodb::basics::AttributeName::isIdentical(
_fields[j], paramPair.second, true)) {
attributePosition = j;
break;
}
}
if (attributePosition == SIZE_MAX) {
// index attribute not found in condition. this is a severe error
THROW_ARANGO_EXCEPTION(TRI_ERROR_INTERNAL);
}
arangodb::aql::AstNodeType type = comp->type;
if (comp->type == aql::NODE_TYPE_OPERATOR_BINARY_EQ) {
permutationStates.emplace_back(
PermutationState(type, valNode, attributePosition, 1));
TRI_IF_FAILURE("HashIndex::permutationEQ") {
THROW_ARANGO_EXCEPTION(TRI_ERROR_DEBUG);
}
} else if (comp->type == aql::NODE_TYPE_OPERATOR_BINARY_IN) {
if (isAttributeExpanded(attributePosition)) {
type = aql::NODE_TYPE_OPERATOR_BINARY_EQ;
permutationStates.emplace_back(
PermutationState(type, valNode, attributePosition, 1));
TRI_IF_FAILURE("HashIndex::permutationArrayIN") {
THROW_ARANGO_EXCEPTION(TRI_ERROR_DEBUG);
}
} else {
if (valNode->numMembers() == 0) {
return nullptr;
}
permutationStates.emplace_back(PermutationState(
type, valNode, attributePosition, valNode->numMembers()));
TRI_IF_FAILURE("HashIndex::permutationIN") {
THROW_ARANGO_EXCEPTION(TRI_ERROR_DEBUG);
}
maxPermutations *= valNode->numMembers();
}
}
}
if (permutationStates.empty()) {
// can only be caused by empty IN lists
return nullptr;
}
std::vector<TRI_hash_index_search_value_t*> searchValues;
searchValues.reserve(maxPermutations);
try {
// create all permutations
auto shaper = _collection->getShaper();
size_t current = 0;
bool done = false;
while (!done) {
auto searchValue = std::make_unique<TRI_hash_index_search_value_t>();
searchValue->reserve(n);
bool valid = true;
for (size_t i = 0; i < n; ++i) {
auto& state = permutationStates[i];
std::shared_ptr<VPackBuilder> valBuilder =
state.getValue()->toVelocyPackValue();
if (valBuilder == nullptr) {
valid = false;
break;
}
auto shaped =
TRI_ShapedJsonVelocyPack(shaper, valBuilder->slice(), false);
if (shaped == nullptr) {
// no such shape exists. this means we won't find this value and can
// go on with the next permutation
valid = false;
break;
}
searchValue->_values[state.attributePosition] = *shaped;
TRI_Free(shaper->memoryZone(), shaped);
}
if (valid) {
searchValues.push_back(searchValue.get());
searchValue.release();
}
// now permute
while (true) {
if (++permutationStates[current].current <
permutationStates[current].n) {
current = 0;
// abort inner iteration
break;
}
permutationStates[current].current = 0;
if (++current >= n) {
done = true;
break;
}
// next inner iteration
}
}
TRI_ASSERT(searchValues.size() <= maxPermutations);
// Create the iterator
TRI_IF_FAILURE("HashIndex::noIterator") {
THROW_ARANGO_EXCEPTION(TRI_ERROR_DEBUG);
}
} catch (...) {
// prevent a leak here
for (auto& it : searchValues) {
delete it;
}
throw;
}
return new HashIndexIterator(trx, this, searchValues);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief specializes the condition for use with the index
////////////////////////////////////////////////////////////////////////////////
arangodb::aql::AstNode* HashIndex::specializeCondition(
arangodb::aql::AstNode* node,
arangodb::aql::Variable const* reference) const {
SimpleAttributeEqualityMatcher matcher(fields());
return matcher.specializeAll(this, node, reference);
}
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