1
0
Fork 0
arangodb/arangod/Indexes/PrimaryIndex.cpp

400 lines
14 KiB
C++

////////////////////////////////////////////////////////////////////////////////
/// @brief primary index
///
/// @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 Dr. Frank Celler
/// @author Copyright 2014, ArangoDB GmbH, Cologne, Germany
/// @author Copyright 2011-2013, triAGENS GmbH, Cologne, Germany
////////////////////////////////////////////////////////////////////////////////
#include "PrimaryIndex.h"
#include "Basics/Exceptions.h"
#include "Basics/hashes.h"
#include "Basics/logging.h"
#include "VocBase/document-collection.h"
#include "VocBase/transaction.h"
using namespace triagens::arango;
// -----------------------------------------------------------------------------
// --SECTION-- private functions
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @brief comparison function, compares a master pointer to another
////////////////////////////////////////////////////////////////////////////////
static inline bool IsDifferentKeyElement (TRI_doc_mptr_t const* header,
void const* element) {
TRI_doc_mptr_t const* e = static_cast<TRI_doc_mptr_t const*>(element);
// only after that compare actual keys
return (header->_hash != e->_hash || strcmp(TRI_EXTRACT_MARKER_KEY(header), TRI_EXTRACT_MARKER_KEY(e)) != 0); // ONLY IN INDEX, PROTECTED by RUNTIME
}
////////////////////////////////////////////////////////////////////////////////
/// @brief comparison function, compares a hash/key to a master pointer
////////////////////////////////////////////////////////////////////////////////
static inline bool IsDifferentHashElement (char const* key, uint64_t hash, void const* element) {
TRI_doc_mptr_t const* e = static_cast<TRI_doc_mptr_t const*>(element);
return (hash != e->_hash || strcmp(key, TRI_EXTRACT_MARKER_KEY(e)) != 0); // ONLY IN INDEX, PROTECTED by RUNTIME
}
// -----------------------------------------------------------------------------
// --SECTION-- class PrimaryIndex
// -----------------------------------------------------------------------------
uint64_t const PrimaryIndex::InitialSize = 251;
// -----------------------------------------------------------------------------
// --SECTION-- constructors and destructors
// -----------------------------------------------------------------------------
PrimaryIndex::PrimaryIndex (TRI_document_collection_t* collection)
: Index(0, collection, std::vector<std::string>( { TRI_VOC_ATTRIBUTE_KEY } )) {
_primaryIndex._nrAlloc = 0;
_primaryIndex._nrUsed = 0;
_primaryIndex._table = static_cast<void**>(TRI_Allocate(TRI_UNKNOWN_MEM_ZONE, static_cast<size_t>(InitialSize * sizeof(void*)), true));
if (_primaryIndex._table == nullptr) {
THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY);
}
_primaryIndex._nrAlloc = InitialSize;
}
PrimaryIndex::~PrimaryIndex () {
if (_primaryIndex._table != nullptr) {
TRI_Free(TRI_UNKNOWN_MEM_ZONE, _primaryIndex._table);
}
}
// -----------------------------------------------------------------------------
// --SECTION-- public methods
// -----------------------------------------------------------------------------
size_t PrimaryIndex::memory () const {
return static_cast<size_t>(_primaryIndex._nrAlloc * sizeof(void*));
}
////////////////////////////////////////////////////////////////////////////////
/// @brief return a JSON representation of the index
////////////////////////////////////////////////////////////////////////////////
triagens::basics::Json PrimaryIndex::toJson (TRI_memory_zone_t* zone) const {
auto json = Index::toJson(zone);
// hard-coded
json("unique", triagens::basics::Json(true))
("sparse", triagens::basics::Json(false));
return json;
}
int PrimaryIndex::insert (TRI_doc_mptr_t const*,
bool) {
THROW_ARANGO_EXCEPTION(TRI_ERROR_NOT_IMPLEMENTED);
}
int PrimaryIndex::remove (TRI_doc_mptr_t const*,
bool) {
THROW_ARANGO_EXCEPTION(TRI_ERROR_NOT_IMPLEMENTED);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief looks up an element given a key
////////////////////////////////////////////////////////////////////////////////
void* PrimaryIndex::lookupKey (char const* key) const {
if (_primaryIndex._nrUsed == 0) {
return nullptr;
}
// compute the hash
uint64_t const hash = calculateHash(key);
uint64_t const n = _primaryIndex._nrAlloc;
uint64_t i, k;
i = k = hash % n;
TRI_ASSERT_EXPENSIVE(n > 0);
// search the table
for (; i < n && _primaryIndex._table[i] != nullptr && IsDifferentHashElement(key, hash, _primaryIndex._table[i]); ++i);
if (i == n) {
for (i = 0; i < k && _primaryIndex._table[i] != nullptr && IsDifferentHashElement(key, hash, _primaryIndex._table[i]); ++i);
}
TRI_ASSERT_EXPENSIVE(i < n);
// return whatever we found
return _primaryIndex._table[i];
}
////////////////////////////////////////////////////////////////////////////////
/// @brief adds a key/element to the index
/// returns a status code, and *found will contain a found element (if any)
////////////////////////////////////////////////////////////////////////////////
int PrimaryIndex::insertKey (TRI_doc_mptr_t const* header,
void const** found) {
*found = nullptr;
if (shouldResize()) {
// check for out-of-memory
if (! resize(static_cast<uint64_t>(2 * _primaryIndex._nrAlloc + 1), false)) {
return TRI_ERROR_OUT_OF_MEMORY;
}
}
uint64_t const n = _primaryIndex._nrAlloc;
uint64_t i, k;
TRI_ASSERT_EXPENSIVE(n > 0);
i = k = header->_hash % n;
for (; i < n && _primaryIndex._table[i] != nullptr && IsDifferentKeyElement(header, _primaryIndex._table[i]); ++i);
if (i == n) {
for (i = 0; i < k && _primaryIndex._table[i] != nullptr && IsDifferentKeyElement(header, _primaryIndex._table[i]); ++i);
}
TRI_ASSERT_EXPENSIVE(i < n);
void* old = _primaryIndex._table[i];
// if we found an element, return
if (old != nullptr) {
*found = old;
return TRI_ERROR_NO_ERROR;
}
// add a new element to the associative idx
_primaryIndex._table[i] = (void*) header;
++_primaryIndex._nrUsed;
return TRI_ERROR_NO_ERROR;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief adds a key/element to the index
/// this is a special, optimized (read: reduced) variant of the above insert
/// function
////////////////////////////////////////////////////////////////////////////////
void PrimaryIndex::insertKey (TRI_doc_mptr_t const* header) {
uint64_t const n = _primaryIndex._nrAlloc;
uint64_t i, k;
i = k = header->_hash % n;
for (; i < n && _primaryIndex._table[i] != nullptr && IsDifferentKeyElement(header, _primaryIndex._table[i]); ++i);
if (i == n) {
for (i = 0; i < k && _primaryIndex._table[i] != nullptr && IsDifferentKeyElement(header, _primaryIndex._table[i]); ++i);
}
TRI_ASSERT_EXPENSIVE(i < n);
TRI_ASSERT_EXPENSIVE(_primaryIndex._table[i] == nullptr);
_primaryIndex._table[i] = const_cast<void*>(static_cast<void const*>(header));
++_primaryIndex._nrUsed;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief removes an key/element from the index
////////////////////////////////////////////////////////////////////////////////
void* PrimaryIndex::removeKey (char const* key) {
uint64_t const hash = calculateHash(key);
uint64_t const n = _primaryIndex._nrAlloc;
uint64_t i, k;
i = k = hash % n;
// search the table
for (; i < n && _primaryIndex._table[i] != nullptr && IsDifferentHashElement(key, hash, _primaryIndex._table[i]); ++i);
if (i == n) {
for (i = 0; i < k && _primaryIndex._table[i] != nullptr && IsDifferentHashElement(key, hash, _primaryIndex._table[i]); ++i);
}
TRI_ASSERT_EXPENSIVE(i < n);
// if we did not find such an item return false
if (_primaryIndex._table[i] == nullptr) {
return nullptr;
}
// remove item
void* old = _primaryIndex._table[i];
_primaryIndex._table[i] = nullptr;
_primaryIndex._nrUsed--;
// and now check the following places for items to move here
k = TRI_IncModU64(i, n);
while (_primaryIndex._table[k] != nullptr) {
uint64_t j = (static_cast<TRI_doc_mptr_t const*>(_primaryIndex._table[k])->_hash) % n;
if ((i < k && ! (i < j && j <= k)) || (k < i && ! (i < j || j <= k))) {
_primaryIndex._table[i] = _primaryIndex._table[k];
_primaryIndex._table[k] = nullptr;
i = k;
}
k = TRI_IncModU64(k, n);
}
if (_primaryIndex._nrUsed == 0) {
resize(InitialSize, true);
}
// return success
return old;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief resizes the index
////////////////////////////////////////////////////////////////////////////////
int PrimaryIndex::resize (size_t targetSize) {
if (! resize(static_cast<uint64_t>(2 * targetSize + 1), false)) {
return TRI_ERROR_OUT_OF_MEMORY;
}
return TRI_ERROR_NO_ERROR;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief resize the index to a good size if too small
////////////////////////////////////////////////////////////////////////////////
int PrimaryIndex::resize () {
if (shouldResize() &&
! resize(static_cast<uint64_t>(2 * _primaryIndex._nrAlloc + 1), false)) {
return TRI_ERROR_OUT_OF_MEMORY;
}
return TRI_ERROR_NO_ERROR;
}
uint64_t PrimaryIndex::calculateHash (char const* key) {
return TRI_FnvHashString(key);
}
uint64_t PrimaryIndex::calculateHash (char const* key,
size_t length) {
return TRI_FnvHashPointer(static_cast<void const*>(key), length);
}
// -----------------------------------------------------------------------------
// --SECTION-- private methods
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @brief whether or not the index must be resized
////////////////////////////////////////////////////////////////////////////////
bool PrimaryIndex::shouldResize () const {
return _primaryIndex._nrAlloc < _primaryIndex._nrUsed + _primaryIndex._nrUsed;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief resizes the index
////////////////////////////////////////////////////////////////////////////////
bool PrimaryIndex::resize (uint64_t targetSize,
bool allowShrink) {
TRI_ASSERT(targetSize > 0);
if (_primaryIndex._nrAlloc >= targetSize && ! allowShrink) {
return true;
}
void** oldTable = _primaryIndex._table;
// only log performance infos for indexes with more than this number of entries
static uint64_t const NotificationSizeThreshold = 131072;
double start = TRI_microtime();
if (targetSize > NotificationSizeThreshold) {
LOG_ACTION("index-resize %s, target size: %llu",
context().c_str(),
(unsigned long long) targetSize);
}
_primaryIndex._table = static_cast<void**>(TRI_Allocate(TRI_UNKNOWN_MEM_ZONE, (size_t) (targetSize * sizeof(void*)), true));
if (_primaryIndex._table == nullptr) {
_primaryIndex._table = oldTable;
return false;
}
if (_primaryIndex._nrUsed > 0) {
uint64_t const oldAlloc = _primaryIndex._nrAlloc;
// table is already cleared by allocate, now copy old data
for (uint64_t j = 0; j < oldAlloc; j++) {
TRI_doc_mptr_t const* element = static_cast<TRI_doc_mptr_t const*>(oldTable[j]);
if (element != nullptr) {
uint64_t const hash = element->_hash;
uint64_t i, k;
i = k = hash % targetSize;
for (; i < targetSize && _primaryIndex._table[i] != nullptr; ++i);
if (i == targetSize) {
for (i = 0; i < k && _primaryIndex._table[i] != nullptr; ++i);
}
TRI_ASSERT_EXPENSIVE(i < targetSize);
_primaryIndex._table[i] = (void*) element;
}
}
}
TRI_Free(TRI_UNKNOWN_MEM_ZONE, oldTable);
_primaryIndex._nrAlloc = targetSize;
LOG_TIMER((TRI_microtime() - start),
"index-resize, %s, target size: %llu",
context().c_str(),
(unsigned long long) targetSize);
return true;
}
// -----------------------------------------------------------------------------
// --SECTION-- END-OF-FILE
// -----------------------------------------------------------------------------
// Local Variables:
// mode: outline-minor
// outline-regexp: "/// @brief\\|/// {@inheritDoc}\\|/// @page\\|// --SECTION--\\|/// @\\}"
// End: