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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 "Aql/AstNode.h"
#include "Aql/SortCondition.h"
#include "Basics/Exceptions.h"
#include "Basics/LocalTaskQueue.h"
#include "Basics/StaticStrings.h"
#include "Basics/fasthash.h"
#include "Basics/hashes.h"
#include "Indexes/SimpleAttributeEqualityMatcher.h"
#include "MMFiles/MMFilesCollection.h"
#include "MMFiles/MMFilesIndexLookupContext.h"
#include "MMFilesEdgeIndex.h"
#include "StorageEngine/TransactionState.h"
#include "Transaction/Context.h"
#include "Transaction/Helpers.h"
#include "Transaction/Methods.h"
#include "Utils/CollectionNameResolver.h"
#include "VocBase/LogicalCollection.h"
#include <velocypack/Iterator.h>
#include <velocypack/StringRef.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)}};
MMFilesEdgeIndexIterator::MMFilesEdgeIndexIterator(
LogicalCollection* collection, transaction::Methods* trx,
arangodb::MMFilesEdgeIndex const* index,
TRI_MMFilesEdgeIndexHash_t const* indexImpl, std::unique_ptr<VPackBuilder> keys)
: IndexIterator(collection, trx),
_index(indexImpl),
_context(collection, nullptr, index->fields().size()),
_keys(std::move(keys)),
_iterator(_keys->slice()),
_posInBuffer(0),
_batchSize(1000),
_lastElement() {}
MMFilesEdgeIndexIterator::~MMFilesEdgeIndexIterator() {
if (_keys != nullptr) {
// return the VPackBuilder to the transaction context
_trx->transactionContextPtr()->returnBuilder(_keys.release());
}
}
bool MMFilesEdgeIndexIterator::next(LocalDocumentIdCallback 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
TRI_ASSERT(_posInBuffer < _buffer.size());
cb(LocalDocumentId{_buffer[_posInBuffer++].localDocumentId()});
limit--;
}
}
return true;
}
bool MMFilesEdgeIndexIterator::nextDocument(DocumentCallback const& cb, size_t limit) {
_documentIds.clear();
_documentIds.reserve(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;
}
bool done = 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()) {
done = true;
break;
}
} else {
_lastElement = _buffer.back();
// found something
TRI_ASSERT(_posInBuffer < _buffer.size());
_documentIds.emplace_back(
std::make_pair(_buffer[_posInBuffer++].localDocumentId(), nullptr));
limit--;
}
}
auto physical = static_cast<MMFilesCollection*>(_collection->getPhysical());
physical->readDocumentWithCallback(_trx, _documentIds, cb);
return !done;
}
void MMFilesEdgeIndexIterator::reset() {
_posInBuffer = 0;
_buffer.clear();
_iterator.reset();
_lastElement = MMFilesSimpleIndexElement();
}
MMFilesEdgeIndex::MMFilesEdgeIndex(TRI_idx_iid_t iid, arangodb::LogicalCollection& collection)
: MMFilesIndex(iid, collection, StaticStrings::IndexNameEdge,
std::vector<std::vector<arangodb::basics::AttributeName>>(
{{arangodb::basics::AttributeName(StaticStrings::FromString, false)},
{arangodb::basics::AttributeName(StaticStrings::ToString, false)}}),
false, false) {
TRI_ASSERT(iid != 0);
size_t initialSize = 64;
auto physical = static_cast<MMFilesCollection*>(collection.getPhysical());
TRI_ASSERT(physical != nullptr);
size_t indexBuckets = static_cast<size_t>(physical->indexBuckets());
if (collection.isAStub()) {
// in order to reduce memory usage
indexBuckets = 1;
initialSize = 4;
}
auto context = [this]() -> std::string { return this->context(); };
_edgesFrom.reset(
new TRI_MMFilesEdgeIndexHash_t(MMFilesEdgeIndexHelper(), indexBuckets,
static_cast<uint32_t>(initialSize), context));
_edgesTo.reset(new TRI_MMFilesEdgeIndexHash_t(MMFilesEdgeIndexHelper(), indexBuckets,
static_cast<uint32_t>(initialSize), context));
}
/// @brief return a selectivity estimate for the index
double MMFilesEdgeIndex::selectivityEstimate(arangodb::velocypack::StringRef const& attribute) const {
TRI_ASSERT(!ServerState::instance()->isCoordinator());
if (_unique) {
return 1.0;
}
if (_edgesFrom == nullptr || _edgesTo == nullptr) {
// use hard-coded selectivity estimate in case of cluster coordinator
return 0.1;
}
if (!attribute.empty()) {
// 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,
std::underlying_type<Index::Serialize>::type flags) const {
builder.openObject();
Index::toVelocyPack(builder, flags);
// hard-coded
builder.add(arangodb::StaticStrings::IndexUnique, arangodb::velocypack::Value(false));
builder.add(arangodb::StaticStrings::IndexSparse, arangodb::velocypack::Value(false));
builder.close();
}
/// @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();
}
Result MMFilesEdgeIndex::insert(transaction::Methods& trx, LocalDocumentId const& documentId,
velocypack::Slice const& doc, Index::OperationMode mode) {
Result res;
MMFilesSimpleIndexElement fromElement(buildFromElement(documentId, doc));
MMFilesSimpleIndexElement toElement(buildToElement(documentId, doc));
MMFilesIndexLookupContext context(&_collection, nullptr, 1);
_edgesFrom->insert(&context, fromElement, true, mode == OperationMode::rollback);
try {
_edgesTo->insert(&context, toElement, true, mode == OperationMode::rollback);
} catch (std::bad_alloc const&) {
// roll back partial insert
_edgesFrom->remove(&context, fromElement);
res.reset(TRI_ERROR_OUT_OF_MEMORY);
return addErrorMsg(res);
} catch (...) {
// roll back partial insert
_edgesFrom->remove(&context, fromElement);
res.reset(TRI_ERROR_INTERNAL);
return addErrorMsg(res);
}
return res;
}
Result MMFilesEdgeIndex::remove(transaction::Methods& trx, LocalDocumentId const& documentId,
velocypack::Slice const& doc, Index::OperationMode mode) {
Result res;
MMFilesSimpleIndexElement fromElement(buildFromElement(documentId, doc));
MMFilesSimpleIndexElement toElement(buildToElement(documentId, doc));
MMFilesIndexLookupContext context(&_collection, nullptr, 1);
try {
_edgesFrom->remove(&context, fromElement);
_edgesTo->remove(&context, toElement);
return res;
} catch (...) {
if (mode == OperationMode::rollback) {
return res;
}
res.reset(TRI_ERROR_ARANGO_DOCUMENT_NOT_FOUND);
return addErrorMsg(res);
}
}
void MMFilesEdgeIndex::batchInsert(transaction::Methods& trx,
std::vector<std::pair<LocalDocumentId, VPackSlice>> const& documents,
std::shared_ptr<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 = [this]() -> void* {
return new MMFilesIndexLookupContext(&_collection, nullptr, 1);
};
auto destroyer = [](void* userData) {
MMFilesIndexLookupContext* context = static_cast<MMFilesIndexLookupContext*>(userData);
delete context;
};
// TODO: create parallel tasks for this
// _from
for (auto const& it : documents) {
VPackSlice value(transaction::helpers::extractFromFromDocument(it.second));
fromElements->emplace_back(it.first, value,
static_cast<uint32_t>(value.begin() - it.second.begin()));
}
// _to
for (auto const& it : documents) {
VPackSlice value(transaction::helpers::extractToFromDocument(it.second));
toElements->emplace_back(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
void MMFilesEdgeIndex::unload() {
_edgesFrom->truncate([](MMFilesSimpleIndexElement const&) { return true; });
_edgesTo->truncate([](MMFilesSimpleIndexElement const&) { return true; });
}
/// @brief provides a size hint for the edge index
Result MMFilesEdgeIndex::sizeHint(transaction::Methods& 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
MMFilesIndexLookupContext context(&_collection, nullptr, 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
Index::FilterCosts MMFilesEdgeIndex::supportsFilterCondition(
std::vector<std::shared_ptr<arangodb::Index>> const&,
arangodb::aql::AstNode const* node, arangodb::aql::Variable const* reference,
size_t itemsInIndex) const {
SimpleAttributeEqualityMatcher matcher(IndexAttributes);
return matcher.matchOne(this, node, reference, itemsInIndex);
}
/// @brief creates an IndexIterator for the given Condition
std::unique_ptr<IndexIterator> MMFilesEdgeIndex::iteratorForCondition(
transaction::Methods* trx,
arangodb::aql::AstNode const* node,
arangodb::aql::Variable const* reference, IndexIteratorOptions const& opts) {
TRI_ASSERT(!isSorted() || opts.sorted);
TRI_ASSERT(node != nullptr);
TRI_ASSERT(node->type == aql::NODE_TYPE_OPERATOR_NARY_AND);
TRI_ASSERT(node->numMembers() == 1);
AttributeAccessParts aap(node->getMember(0), reference);
if (aap.opType == aql::NODE_TYPE_OPERATOR_BINARY_EQ) {
// a.b == value
return createEqIterator(trx, aap.attribute, aap.value);
}
if (aap.opType == aql::NODE_TYPE_OPERATOR_BINARY_IN &&
aap.value->isArray()) {
// a.b IN values
return createInIterator(trx, aap.attribute, aap.value);
}
// operator type unsupported
return std::make_unique<EmptyIndexIterator>(&_collection, trx);
}
/// @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 create the iterator
std::unique_ptr<IndexIterator> MMFilesEdgeIndex::createEqIterator(transaction::Methods* trx,
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
transaction::BuilderLeaser 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 std::make_unique<MMFilesEdgeIndexIterator>(&_collection, trx, this,
isFrom ? _edgesFrom.get() : _edgesTo.get(),
std::move(keys));
}
/// @brief create the iterator
std::unique_ptr<IndexIterator> MMFilesEdgeIndex::createInIterator(transaction::Methods* trx,
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
transaction::BuilderLeaser 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 std::make_unique<MMFilesEdgeIndexIterator>(&_collection, trx, this,
isFrom ? _edgesFrom.get() : _edgesTo.get(),
std::move(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(LocalDocumentId const& documentId,
VPackSlice const& doc) const {
TRI_ASSERT(doc.isObject());
VPackSlice value(transaction::helpers::extractFromFromDocument(doc));
TRI_ASSERT(value.isString());
return MMFilesSimpleIndexElement(documentId, value,
static_cast<uint32_t>(value.begin() - doc.begin()));
}
MMFilesSimpleIndexElement MMFilesEdgeIndex::buildToElement(LocalDocumentId const& documentId,
VPackSlice const& doc) const {
TRI_ASSERT(doc.isObject());
VPackSlice value(transaction::helpers::extractToFromDocument(doc));
TRI_ASSERT(value.isString());
return MMFilesSimpleIndexElement(documentId, value,
static_cast<uint32_t>(value.begin() - doc.begin()));
}
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