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arangodb/arangod/Indexes/HashIndex.h

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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
////////////////////////////////////////////////////////////////////////////////
#ifndef ARANGOD_INDEXES_HASH_INDEX_H
#define ARANGOD_INDEXES_HASH_INDEX_H 1
#include "Basics/Common.h"
#include "Basics/AssocMulti.h"
#include "Basics/AssocUnique.h"
#include "Indexes/PathBasedIndex.h"
#include "Indexes/IndexIterator.h"
#include "VocBase/shaped-json.h"
#include "VocBase/vocbase.h"
#include "VocBase/voc-types.h"
#include "VocBase/document-collection.h"
#include "VocBase/VocShaper.h"
////////////////////////////////////////////////////////////////////////////////
/// @brief hash index query parameter
////////////////////////////////////////////////////////////////////////////////
struct TRI_hash_index_search_value_t {
TRI_hash_index_search_value_t();
~TRI_hash_index_search_value_t();
TRI_hash_index_search_value_t(TRI_hash_index_search_value_t const&) = delete;
TRI_hash_index_search_value_t& operator=(
TRI_hash_index_search_value_t const&) = delete;
void reserve(size_t);
void destroy();
size_t _length;
struct TRI_shaped_json_s* _values;
};
namespace arangodb {
class HashIndex;
class Transaction;
class HashIndexIterator final : public IndexIterator {
public:
HashIndexIterator(arangodb::Transaction* trx, HashIndex const* index,
std::vector<TRI_hash_index_search_value_t*>& keys)
: _trx(trx),
_index(index),
_keys(keys),
_position(0),
_buffer(),
_posInBuffer(0) {}
~HashIndexIterator() {
for (auto& it : _keys) {
delete it;
}
}
TRI_doc_mptr_t* next() override;
void reset() override;
private:
arangodb::Transaction* _trx;
HashIndex const* _index;
std::vector<TRI_hash_index_search_value_t*> _keys;
size_t _position;
std::vector<TRI_doc_mptr_t*> _buffer;
size_t _posInBuffer;
};
class HashIndex final : public PathBasedIndex {
public:
HashIndex() = delete;
HashIndex(TRI_idx_iid_t, struct TRI_document_collection_t*,
std::vector<std::vector<arangodb::basics::AttributeName>> const&,
bool, bool);
explicit HashIndex(VPackSlice const&);
~HashIndex();
public:
IndexType type() const override final {
return Index::TRI_IDX_TYPE_HASH_INDEX;
}
bool isSorted() const override final { return false; }
bool hasSelectivityEstimate() const override final { return true; }
double selectivityEstimate() const override final;
size_t memory() const override final;
void toVelocyPack(VPackBuilder&, bool) const override final;
void toVelocyPackFigures(VPackBuilder&) const override final;
int insert(arangodb::Transaction*, struct TRI_doc_mptr_t const*,
bool) override final;
int remove(arangodb::Transaction*, struct TRI_doc_mptr_t const*,
bool) override final;
int batchInsert(arangodb::Transaction*,
std::vector<TRI_doc_mptr_t const*> const*,
size_t) override final;
int sizeHint(arangodb::Transaction*, size_t) override final;
bool hasBatchInsert() const override final { return true; }
std::vector<std::vector<std::pair<TRI_shape_pid_t, bool>>> const& paths()
const {
return _paths;
}
//////////////////////////////////////////////////////////////////////////////
/// @brief locates entries in the hash index given shaped json objects
//////////////////////////////////////////////////////////////////////////////
int lookup(arangodb::Transaction*, TRI_hash_index_search_value_t*,
std::vector<TRI_doc_mptr_t*>&) const;
//////////////////////////////////////////////////////////////////////////////
/// @brief locates entries in the hash index given shaped json objects
//////////////////////////////////////////////////////////////////////////////
int lookup(arangodb::Transaction*, TRI_hash_index_search_value_t*,
std::vector<TRI_doc_mptr_copy_t>&, TRI_index_element_t*&,
size_t batchSize) const;
bool supportsFilterCondition(arangodb::aql::AstNode const*,
arangodb::aql::Variable const*, size_t, size_t&,
double&) const override;
IndexIterator* iteratorForCondition(arangodb::Transaction*,
IndexIteratorContext*,
arangodb::aql::Ast*,
arangodb::aql::AstNode const*,
arangodb::aql::Variable const*,
bool) const override;
arangodb::aql::AstNode* specializeCondition(
arangodb::aql::AstNode*, arangodb::aql::Variable const*) const override;
private:
int insertUnique(arangodb::Transaction*, struct TRI_doc_mptr_t const*, bool);
int batchInsertUnique(arangodb::Transaction*,
std::vector<TRI_doc_mptr_t const*> const*, size_t);
int insertMulti(arangodb::Transaction*, struct TRI_doc_mptr_t const*, bool);
int batchInsertMulti(arangodb::Transaction*,
std::vector<TRI_doc_mptr_t const*> const*, size_t);
int removeUniqueElement(arangodb::Transaction*, TRI_index_element_t*, bool);
int removeUnique(arangodb::Transaction*, struct TRI_doc_mptr_t const*, bool);
int removeMultiElement(arangodb::Transaction*, TRI_index_element_t*, bool);
int removeMulti(arangodb::Transaction*, struct TRI_doc_mptr_t const*, bool);
bool accessFitsIndex(arangodb::aql::AstNode const* access,
arangodb::aql::AstNode const* other,
arangodb::aql::Variable const* reference,
std::unordered_set<size_t>& found) const;
//////////////////////////////////////////////////////////////////////////////
/// @brief given an element generates a hash integer
//////////////////////////////////////////////////////////////////////////////
private:
class HashElementFunc {
size_t _numFields;
public:
explicit HashElementFunc(size_t n) : _numFields(n) {}
uint64_t operator()(void* userData, TRI_index_element_t const* element,
bool byKey = true) {
uint64_t hash = 0x0123456789abcdef;
for (size_t j = 0; j < _numFields; j++) {
char const* data;
size_t length;
TRI_InspectShapedSub(&element->subObjects()[j], element->document(),
data, length);
// ignore the sid for hashing
// only hash the data block
hash = fasthash64(data, length, hash);
}
if (byKey) {
return hash;
}
TRI_doc_mptr_t* ptr = element->document();
return fasthash64(&ptr, sizeof(TRI_doc_mptr_t*), hash);
}
};
//////////////////////////////////////////////////////////////////////////////
/// @brief determines if a key corresponds to an element
//////////////////////////////////////////////////////////////////////////////
class IsEqualElementElementByKey {
size_t _numFields;
public:
explicit IsEqualElementElementByKey(size_t n) : _numFields(n) {}
bool operator()(void* userData, TRI_index_element_t const* left,
TRI_index_element_t const* right) {
TRI_ASSERT(left->document() != nullptr);
TRI_ASSERT(right->document() != nullptr);
if (left->document() == right->document()) {
return true;
}
for (size_t j = 0; j < _numFields; ++j) {
TRI_shaped_sub_t* leftSub = &left->subObjects()[j];
TRI_shaped_sub_t* rightSub = &right->subObjects()[j];
if (leftSub->_sid != rightSub->_sid) {
return false;
}
char const* leftData;
size_t leftLength;
TRI_InspectShapedSub(leftSub, left->document(), leftData, leftLength);
char const* rightData;
size_t rightLength;
TRI_InspectShapedSub(rightSub, right->document(), rightData,
rightLength);
if (leftLength != rightLength) {
return false;
}
if (leftLength > 0 && memcmp(leftData, rightData, leftLength) != 0) {
return false;
}
}
return true;
}
};
private:
//////////////////////////////////////////////////////////////////////////////
/// @brief the actual hash index (unique type)
//////////////////////////////////////////////////////////////////////////////
typedef arangodb::basics::AssocUnique<TRI_hash_index_search_value_t,
TRI_index_element_t> TRI_HashArray_t;
struct UniqueArray {
UniqueArray() = delete;
UniqueArray(TRI_HashArray_t*, HashElementFunc*,
IsEqualElementElementByKey*);
~UniqueArray();
TRI_HashArray_t* _hashArray; // the hash array itself, unique values
HashElementFunc* _hashElement; // hash function for elements
IsEqualElementElementByKey* _isEqualElElByKey; // comparison func
};
//////////////////////////////////////////////////////////////////////////////
/// @brief the actual hash index (multi type)
//////////////////////////////////////////////////////////////////////////////
typedef arangodb::basics::AssocMulti<TRI_hash_index_search_value_t,
TRI_index_element_t, uint32_t,
true> TRI_HashArrayMulti_t;
struct MultiArray {
MultiArray() = delete;
MultiArray(TRI_HashArrayMulti_t*, HashElementFunc*,
IsEqualElementElementByKey*);
~MultiArray();
TRI_HashArrayMulti_t*
_hashArray; // the hash array itself, non-unique values
HashElementFunc* _hashElement; // hash function for elements
IsEqualElementElementByKey* _isEqualElElByKey; // comparison func
};
union {
UniqueArray* _uniqueArray;
MultiArray* _multiArray;
};
};
}
#endif
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