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arangodb/arangod/MMFiles/MMFilesEdgeIndex.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 "MMFilesEdgeIndex.h"
#include "Aql/AstNode.h"
#include "Aql/SortCondition.h"
#include "Basics/Exceptions.h"
#include "Basics/LocalTaskQueue.h"
#include "Basics/StaticStrings.h"
#include "Basics/StringRef.h"
#include "Basics/fasthash.h"
#include "Basics/hashes.h"
#include "Indexes/IndexLookupContext.h"
#include "Indexes/SimpleAttributeEqualityMatcher.h"
#include "MMFiles/MMFilesToken.h"
#include "StorageEngine/TransactionState.h"
#include "Utils/CollectionNameResolver.h"
#include "Utils/TransactionMethods.h"
#include "Utils/TransactionContext.h"
#include "VocBase/LogicalCollection.h"
#include <velocypack/Iterator.h>
#include <velocypack/velocypack-aliases.h>
using namespace arangodb;
/// @brief hard-coded vector of the index attributes
/// note that the attribute names must be hard-coded here to avoid an init-order
/// fiasco with StaticStrings::FromString etc.
static std::vector<std::vector<arangodb::basics::AttributeName>> const
IndexAttributes{{arangodb::basics::AttributeName("_from", false)},
{arangodb::basics::AttributeName("_to", false)}};
/// @brief hashes an edge key
static uint64_t HashElementKey(void*, VPackSlice const* key) {
TRI_ASSERT(key != nullptr);
// we can get away with the fast hash function here, as edge
// index values are restricted to strings
return MMFilesSimpleIndexElement::hash(*key);
}
/// @brief hashes an edge
static uint64_t HashElementEdge(void*, MMFilesSimpleIndexElement const& element, bool byKey) {
if (byKey) {
return element.hash();
}
TRI_voc_rid_t revisionId = element.revisionId();
return fasthash64_uint64(revisionId, 0x56781234);
}
/// @brief checks if key and element match
static bool IsEqualKeyEdge(void* userData, VPackSlice const* left, MMFilesSimpleIndexElement const& right) {
TRI_ASSERT(left != nullptr);
IndexLookupContext* context = static_cast<IndexLookupContext*>(userData);
TRI_ASSERT(context != nullptr);
try {
VPackSlice tmp = right.slice(context);
TRI_ASSERT(tmp.isString());
return left->equals(tmp);
} catch (...) {
return false;
}
}
/// @brief checks for elements are equal
static bool IsEqualElementEdge(void*, MMFilesSimpleIndexElement const& left, MMFilesSimpleIndexElement const& right) {
return left.revisionId() == right.revisionId();
}
/// @brief checks for elements are equal
static bool IsEqualElementEdgeByKey(void* userData, MMFilesSimpleIndexElement const& left, MMFilesSimpleIndexElement const& right) {
IndexLookupContext* context = static_cast<IndexLookupContext*>(userData);
try {
VPackSlice lSlice = left.slice(context);
VPackSlice rSlice = right.slice(context);
TRI_ASSERT(lSlice.isString());
TRI_ASSERT(rSlice.isString());
return lSlice.equals(rSlice);
} catch (...) {
return false;
}
}
MMFilesEdgeIndexIterator::MMFilesEdgeIndexIterator(LogicalCollection* collection, TransactionMethods* trx,
ManagedDocumentResult* mmdr,
arangodb::MMFilesEdgeIndex const* index,
TRI_MMFilesEdgeIndexHash_t const* indexImpl,
std::unique_ptr<VPackBuilder>& keys)
: IndexIterator(collection, trx, mmdr, index),
_index(indexImpl),
_keys(keys.get()),
_iterator(_keys->slice()),
_posInBuffer(0),
_batchSize(1000),
_lastElement() {
keys.release(); // now we have ownership for _keys
}
MMFilesEdgeIndexIterator::~MMFilesEdgeIndexIterator() {
if (_keys != nullptr) {
// return the VPackBuilder to the transaction context
_trx->transactionContextPtr()->returnBuilder(_keys.release());
}
}
bool MMFilesEdgeIndexIterator::next(TokenCallback const& cb, size_t limit) {
if (limit == 0 || (_buffer.empty() && !_iterator.valid())) {
// No limit no data, or we are actually done. The last call should have returned false
TRI_ASSERT(limit > 0); // Someone called with limit == 0. Api broken
return false;
}
while (limit > 0) {
if (_buffer.empty()) {
// We start a new lookup
_posInBuffer = 0;
VPackSlice tmp = _iterator.value();
if (tmp.isObject()) {
tmp = tmp.get(StaticStrings::IndexEq);
}
_index->lookupByKey(&_context, &tmp, _buffer, _batchSize);
} else if (_posInBuffer >= _buffer.size()) {
// We have to refill the buffer
_buffer.clear();
_posInBuffer = 0;
_index->lookupByKeyContinue(&_context, _lastElement, _buffer, _batchSize);
}
if (_buffer.empty()) {
_iterator.next();
_lastElement = MMFilesSimpleIndexElement();
if (!_iterator.valid()) {
return false;
}
} else {
_lastElement = _buffer.back();
// found something
cb(MMFilesToken{_buffer[_posInBuffer++].revisionId()});
limit--;
}
}
return true;
}
void MMFilesEdgeIndexIterator::reset() {
_posInBuffer = 0;
_buffer.clear();
_iterator.reset();
_lastElement = MMFilesSimpleIndexElement();
}
MMFilesEdgeIndex::MMFilesEdgeIndex(TRI_idx_iid_t iid, arangodb::LogicalCollection* collection)
: Index(iid, collection,
std::vector<std::vector<arangodb::basics::AttributeName>>(
{{arangodb::basics::AttributeName(StaticStrings::FromString,
false)},
{arangodb::basics::AttributeName(StaticStrings::ToString,
false)}}),
false, false),
_edgesFrom(nullptr),
_edgesTo(nullptr),
_numBuckets(1) {
TRI_ASSERT(iid != 0);
if (collection != nullptr) {
// document is a nullptr in the coordinator case
_numBuckets = static_cast<size_t>(collection->indexBuckets());
}
auto context = [this]() -> std::string { return this->context(); };
_edgesFrom = new TRI_MMFilesEdgeIndexHash_t(HashElementKey, HashElementEdge,
IsEqualKeyEdge, IsEqualElementEdge,
IsEqualElementEdgeByKey, _numBuckets,
64, context);
_edgesTo = new TRI_MMFilesEdgeIndexHash_t(
HashElementKey, HashElementEdge, IsEqualKeyEdge, IsEqualElementEdge,
IsEqualElementEdgeByKey, _numBuckets, 64, context);
}
MMFilesEdgeIndex::~MMFilesEdgeIndex() {
delete _edgesFrom;
delete _edgesTo;
}
void MMFilesEdgeIndex::buildSearchValue(TRI_edge_direction_e dir,
std::string const& id, VPackBuilder& builder) {
builder.openArray();
switch (dir) {
case TRI_EDGE_OUT:
builder.openArray();
builder.openObject();
builder.add(StaticStrings::IndexEq, VPackValue(id));
builder.close();
builder.close();
builder.add(VPackValue(VPackValueType::Null));
break;
case TRI_EDGE_IN:
builder.add(VPackValue(VPackValueType::Null));
builder.openArray();
builder.openObject();
builder.add(StaticStrings::IndexEq, VPackValue(id));
builder.close();
builder.close();
break;
case TRI_EDGE_ANY:
builder.openArray();
builder.openObject();
builder.add(StaticStrings::IndexEq, VPackValue(id));
builder.close();
builder.close();
builder.openArray();
builder.openObject();
builder.add(StaticStrings::IndexEq, VPackValue(id));
builder.close();
builder.close();
}
builder.close();
}
void MMFilesEdgeIndex::buildSearchValue(TRI_edge_direction_e dir,
VPackSlice const& id, VPackBuilder& builder) {
TRI_ASSERT(id.isString());
builder.openArray();
switch (dir) {
case TRI_EDGE_OUT:
builder.openArray();
builder.openObject();
builder.add(StaticStrings::IndexEq, id);
builder.close();
builder.close();
builder.add(VPackValue(VPackValueType::Null));
break;
case TRI_EDGE_IN:
builder.add(VPackValue(VPackValueType::Null));
builder.openArray();
builder.openObject();
builder.add(StaticStrings::IndexEq, id);
builder.close();
builder.close();
break;
case TRI_EDGE_ANY:
builder.openArray();
builder.openObject();
builder.add(StaticStrings::IndexEq, id);
builder.close();
builder.close();
builder.openArray();
builder.openObject();
builder.add(StaticStrings::IndexEq, id);
builder.close();
builder.close();
}
builder.close();
}
void MMFilesEdgeIndex::buildSearchValueFromArray(TRI_edge_direction_e dir,
VPackSlice const ids,
VPackBuilder& builder) {
TRI_ASSERT(ids.isArray());
builder.openArray();
switch (dir) {
case TRI_EDGE_OUT:
builder.openArray();
for (auto const& id : VPackArrayIterator(ids)) {
if (id.isString()) {
builder.openObject();
builder.add(StaticStrings::IndexEq, id);
builder.close();
}
}
builder.close();
builder.add(VPackValue(VPackValueType::Null));
break;
case TRI_EDGE_IN:
builder.add(VPackValue(VPackValueType::Null));
builder.openArray();
for (auto const& id : VPackArrayIterator(ids)) {
if (id.isString()) {
builder.openObject();
builder.add(StaticStrings::IndexEq, id);
builder.close();
}
}
builder.close();
break;
case TRI_EDGE_ANY:
builder.openArray();
for (auto const& id : VPackArrayIterator(ids)) {
if (id.isString()) {
builder.openObject();
builder.add(StaticStrings::IndexEq, id);
builder.close();
}
}
builder.close();
builder.openArray();
for (auto const& id : VPackArrayIterator(ids)) {
if (id.isString()) {
builder.openObject();
builder.add(StaticStrings::IndexEq, id);
builder.close();
}
}
builder.close();
}
builder.close();
}
/// @brief return a selectivity estimate for the index
double MMFilesEdgeIndex::selectivityEstimate(arangodb::StringRef const* attribute) const {
if (_edgesFrom == nullptr ||
_edgesTo == nullptr ||
ServerState::instance()->isCoordinator()) {
// use hard-coded selectivity estimate in case of cluster coordinator
return 0.1;
}
if (attribute != nullptr) {
// the index attribute is given here
// now check if we can restrict the selectivity estimation to the correct
// part of the index
if (attribute->compare(StaticStrings::FromString) == 0) {
// _from
return _edgesFrom->selectivity();
} else if (attribute->compare(StaticStrings::ToString) == 0) {
// _to
return _edgesTo->selectivity();
}
// other attribute. now return the average selectivity
}
// return average selectivity of the two index parts
double estimate = (_edgesFrom->selectivity() + _edgesTo->selectivity()) * 0.5;
TRI_ASSERT(estimate >= 0.0 &&
estimate <= 1.00001); // floating-point tolerance
return estimate;
}
/// @brief return the memory usage for the index
size_t MMFilesEdgeIndex::memory() const {
TRI_ASSERT(_edgesFrom != nullptr);
TRI_ASSERT(_edgesTo != nullptr);
return _edgesFrom->memoryUsage() + _edgesTo->memoryUsage();
}
/// @brief return a VelocyPack representation of the index
void MMFilesEdgeIndex::toVelocyPack(VPackBuilder& builder, bool withFigures) const {
Index::toVelocyPack(builder, withFigures);
// hard-coded
builder.add("unique", VPackValue(false));
builder.add("sparse", VPackValue(false));
}
/// @brief return a VelocyPack representation of the index figures
void MMFilesEdgeIndex::toVelocyPackFigures(VPackBuilder& builder) const {
Index::toVelocyPackFigures(builder);
builder.add("from", VPackValue(VPackValueType::Object));
_edgesFrom->appendToVelocyPack(builder);
builder.close();
builder.add("to", VPackValue(VPackValueType::Object));
_edgesTo->appendToVelocyPack(builder);
builder.close();
// builder.add("buckets", VPackValue(_numBuckets));
}
int MMFilesEdgeIndex::insert(TransactionMethods* trx, TRI_voc_rid_t revisionId,
VPackSlice const& doc, bool isRollback) {
MMFilesSimpleIndexElement fromElement(buildFromElement(revisionId, doc));
MMFilesSimpleIndexElement toElement(buildToElement(revisionId, doc));
ManagedDocumentResult result;
IndexLookupContext context(trx, _collection, &result, 1);
_edgesFrom->insert(&context, fromElement, true, isRollback);
try {
_edgesTo->insert(&context, toElement, true, isRollback);
} catch (...) {
// roll back partial insert
_edgesFrom->remove(&context, fromElement);
return TRI_ERROR_OUT_OF_MEMORY;
}
return TRI_ERROR_NO_ERROR;
}
int MMFilesEdgeIndex::remove(TransactionMethods* trx, TRI_voc_rid_t revisionId,
VPackSlice const& doc, bool isRollback) {
MMFilesSimpleIndexElement fromElement(buildFromElement(revisionId, doc));
MMFilesSimpleIndexElement toElement(buildToElement(revisionId, doc));
ManagedDocumentResult result;
IndexLookupContext context(trx, _collection, &result, 1);
try {
_edgesFrom->remove(&context, fromElement);
_edgesTo->remove(&context, toElement);
return TRI_ERROR_NO_ERROR;
} catch (...) {
if (isRollback) {
return TRI_ERROR_NO_ERROR;
}
return TRI_ERROR_ARANGO_DOCUMENT_NOT_FOUND;
}
}
void MMFilesEdgeIndex::batchInsert(TransactionMethods* trx,
std::vector<std::pair<TRI_voc_rid_t, VPackSlice>> const& documents,
arangodb::basics::LocalTaskQueue* queue) {
if (documents.empty()) {
return;
}
std::shared_ptr<std::vector<MMFilesSimpleIndexElement>> fromElements;
fromElements.reset(new std::vector<MMFilesSimpleIndexElement>());
fromElements->reserve(documents.size());
std::shared_ptr<std::vector<MMFilesSimpleIndexElement>> toElements;
toElements.reset(new std::vector<MMFilesSimpleIndexElement>());
toElements->reserve(documents.size());
// functions that will be called for each thread
auto creator = [&trx, this]() -> void* {
ManagedDocumentResult* result = new ManagedDocumentResult;
return new IndexLookupContext(trx, _collection, result, 1);
};
auto destroyer = [](void* userData) {
IndexLookupContext* context = static_cast<IndexLookupContext*>(userData);
delete context->result();
delete context;
};
// TODO: create parallel tasks for this
// _from
for (auto const& it : documents) {
VPackSlice value(TransactionMethods::extractFromFromDocument(it.second));
fromElements->emplace_back(MMFilesSimpleIndexElement(
it.first, value,
static_cast<uint32_t>(value.begin() - it.second.begin())));
}
// _to
for (auto const& it : documents) {
VPackSlice value(TransactionMethods::extractToFromDocument(it.second));
toElements->emplace_back(MMFilesSimpleIndexElement(
it.first, value,
static_cast<uint32_t>(value.begin() - it.second.begin())));
}
_edgesFrom->batchInsert(creator, destroyer, fromElements, queue);
_edgesTo->batchInsert(creator, destroyer, toElements, queue);
}
/// @brief unload the index data from memory
int MMFilesEdgeIndex::unload() {
_edgesFrom->truncate([](MMFilesSimpleIndexElement const&) { return true; });
_edgesTo->truncate([](MMFilesSimpleIndexElement const&) { return true; });
return TRI_ERROR_NO_ERROR;
}
/// @brief provides a size hint for the edge index
int MMFilesEdgeIndex::sizeHint(TransactionMethods* trx, size_t size) {
// we assume this is called when setting up the index and the index
// is still empty
TRI_ASSERT(_edgesFrom->size() == 0);
// set an initial size for the index for some new nodes to be created
// without resizing
ManagedDocumentResult result;
IndexLookupContext context(trx, _collection, &result, 1);
int err = _edgesFrom->resize(&context, size + 2049);
if (err != TRI_ERROR_NO_ERROR) {
return err;
}
// we assume this is called when setting up the index and the index
// is still empty
TRI_ASSERT(_edgesTo->size() == 0);
// set an initial size for the index for some new nodes to be created
// without resizing
return _edgesTo->resize(&context, size + 2049);
}
/// @brief checks whether the index supports the condition
bool MMFilesEdgeIndex::supportsFilterCondition(
arangodb::aql::AstNode const* node,
arangodb::aql::Variable const* reference, size_t itemsInIndex,
size_t& estimatedItems, double& estimatedCost) const {
SimpleAttributeEqualityMatcher matcher(IndexAttributes);
return matcher.matchOne(this, node, reference, itemsInIndex, estimatedItems,
estimatedCost);
}
/// @brief creates an IndexIterator for the given Condition
IndexIterator* MMFilesEdgeIndex::iteratorForCondition(
TransactionMethods* trx,
ManagedDocumentResult* mmdr,
arangodb::aql::AstNode const* node,
arangodb::aql::Variable const* reference, bool reverse) const {
TRI_ASSERT(node->type == aql::NODE_TYPE_OPERATOR_NARY_AND);
TRI_ASSERT(node->numMembers() == 1);
auto comp = node->getMember(0);
// assume a.b == value
auto attrNode = comp->getMember(0);
auto valNode = comp->getMember(1);
if (attrNode->type != aql::NODE_TYPE_ATTRIBUTE_ACCESS) {
// got value == a.b -> flip sides
attrNode = comp->getMember(1);
valNode = comp->getMember(0);
}
TRI_ASSERT(attrNode->type == aql::NODE_TYPE_ATTRIBUTE_ACCESS);
if (comp->type == aql::NODE_TYPE_OPERATOR_BINARY_EQ) {
// a.b == value
return createEqIterator(trx, mmdr, attrNode, valNode);
}
if (comp->type == aql::NODE_TYPE_OPERATOR_BINARY_IN) {
// a.b IN values
if (!valNode->isArray()) {
return nullptr;
}
return createInIterator(trx, mmdr, attrNode, valNode);
}
// operator type unsupported
return nullptr;
}
/// @brief specializes the condition for use with the index
arangodb::aql::AstNode* MMFilesEdgeIndex::specializeCondition(
arangodb::aql::AstNode* node,
arangodb::aql::Variable const* reference) const {
SimpleAttributeEqualityMatcher matcher(IndexAttributes);
return matcher.specializeOne(this, node, reference);
}
/// @brief Transform the list of search slices to search values.
/// This will multiply all IN entries and simply return all other
/// entries.
void MMFilesEdgeIndex::expandInSearchValues(VPackSlice const slice,
VPackBuilder& builder) const {
TRI_ASSERT(slice.isArray());
builder.openArray();
for (auto const& side : VPackArrayIterator(slice)) {
if (side.isNull()) {
builder.add(side);
} else {
TRI_ASSERT(side.isArray());
builder.openArray();
for (auto const& item : VPackArrayIterator(side)) {
TRI_ASSERT(item.isObject());
if (item.hasKey(StaticStrings::IndexEq)) {
TRI_ASSERT(!item.hasKey(StaticStrings::IndexIn));
builder.add(item);
} else {
TRI_ASSERT(item.hasKey(StaticStrings::IndexIn));
VPackSlice list = item.get(StaticStrings::IndexIn);
TRI_ASSERT(list.isArray());
for (auto const& it : VPackArrayIterator(list)) {
builder.openObject();
builder.add(StaticStrings::IndexEq, it);
builder.close();
}
}
}
builder.close();
}
}
builder.close();
}
/// @brief create the iterator
IndexIterator* MMFilesEdgeIndex::createEqIterator(
TransactionMethods* trx,
ManagedDocumentResult* mmdr,
arangodb::aql::AstNode const* attrNode,
arangodb::aql::AstNode const* valNode) const {
// lease builder, but immediately pass it to the unique_ptr so we don't leak
TransactionBuilderLeaser builder(trx);
std::unique_ptr<VPackBuilder> keys(builder.steal());
keys->openArray();
handleValNode(keys.get(), valNode);
TRI_IF_FAILURE("EdgeIndex::noIterator") {
THROW_ARANGO_EXCEPTION(TRI_ERROR_DEBUG);
}
keys->close();
// _from or _to?
bool const isFrom = (attrNode->stringEquals(StaticStrings::FromString));
return new MMFilesEdgeIndexIterator(_collection, trx, mmdr, this, isFrom ? _edgesFrom : _edgesTo, keys);
}
/// @brief create the iterator
IndexIterator* MMFilesEdgeIndex::createInIterator(
TransactionMethods* trx,
ManagedDocumentResult* mmdr,
arangodb::aql::AstNode const* attrNode,
arangodb::aql::AstNode const* valNode) const {
// lease builder, but immediately pass it to the unique_ptr so we don't leak
TransactionBuilderLeaser builder(trx);
std::unique_ptr<VPackBuilder> keys(builder.steal());
keys->openArray();
size_t const n = valNode->numMembers();
for (size_t i = 0; i < n; ++i) {
handleValNode(keys.get(), valNode->getMemberUnchecked(i));
TRI_IF_FAILURE("EdgeIndex::iteratorValNodes") {
THROW_ARANGO_EXCEPTION(TRI_ERROR_DEBUG);
}
}
TRI_IF_FAILURE("EdgeIndex::noIterator") {
THROW_ARANGO_EXCEPTION(TRI_ERROR_DEBUG);
}
keys->close();
// _from or _to?
bool const isFrom = (attrNode->stringEquals(StaticStrings::FromString));
return new MMFilesEdgeIndexIterator(_collection, trx, mmdr, this, isFrom ? _edgesFrom : _edgesTo, keys);
}
/// @brief add a single value node to the iterator's keys
void MMFilesEdgeIndex::handleValNode(VPackBuilder* keys,
arangodb::aql::AstNode const* valNode) const {
if (!valNode->isStringValue() || valNode->getStringLength() == 0) {
return;
}
keys->openObject();
keys->add(StaticStrings::IndexEq,
VPackValuePair(valNode->getStringValue(),
valNode->getStringLength(), VPackValueType::String));
keys->close();
TRI_IF_FAILURE("EdgeIndex::collectKeys") {
THROW_ARANGO_EXCEPTION(TRI_ERROR_DEBUG);
}
}
MMFilesSimpleIndexElement MMFilesEdgeIndex::buildFromElement(TRI_voc_rid_t revisionId, VPackSlice const& doc) const {
TRI_ASSERT(doc.isObject());
VPackSlice value(TransactionMethods::extractFromFromDocument(doc));
TRI_ASSERT(value.isString());
return MMFilesSimpleIndexElement(revisionId, value, static_cast<uint32_t>(value.begin() - doc.begin()));
}
MMFilesSimpleIndexElement MMFilesEdgeIndex::buildToElement(TRI_voc_rid_t revisionId, VPackSlice const& doc) const {
TRI_ASSERT(doc.isObject());
VPackSlice value(TransactionMethods::extractToFromDocument(doc));
TRI_ASSERT(value.isString());
return MMFilesSimpleIndexElement(revisionId, value, static_cast<uint32_t>(value.begin() - doc.begin()));
}
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