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arangodb/arangod/RocksDBEngine/RocksDBEdgeIndex.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 Simon Grätzer
/// @author Michael Hackstein
////////////////////////////////////////////////////////////////////////////////
#include "RocksDBEdgeIndex.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/VelocyPackHelper.h"
#include "Cache/CachedValue.h"
#include "Cache/TransactionalCache.h"
#include "Indexes/SimpleAttributeEqualityMatcher.h"
#include "RocksDBEngine/RocksDBCollection.h"
#include "RocksDBEngine/RocksDBCommon.h"
#include "RocksDBEngine/RocksDBKey.h"
#include "RocksDBEngine/RocksDBKeyBounds.h"
#include "RocksDBEngine/RocksDBMethods.h"
#include "RocksDBEngine/RocksDBSettingsManager.h"
#include "RocksDBEngine/RocksDBTransactionState.h"
#include "RocksDBEngine/RocksDBTypes.h"
#include "Scheduler/Scheduler.h"
#include "Scheduler/SchedulerFeature.h"
#include "Transaction/Context.h"
#include "Transaction/Helpers.h"
#include "Transaction/Methods.h"
#include "VocBase/LogicalCollection.h"
#include <rocksdb/db.h>
#include <rocksdb/utilities/transaction_db.h>
#include <rocksdb/utilities/write_batch_with_index.h>
#include <velocypack/Iterator.h>
#include <velocypack/velocypack-aliases.h>
#include <cmath>
using namespace arangodb;
using namespace arangodb::basics;
namespace {
constexpr bool EdgeIndexFillBlockCache = false;
}
RocksDBEdgeIndexWarmupTask::RocksDBEdgeIndexWarmupTask(
std::shared_ptr<basics::LocalTaskQueue> const& queue,
RocksDBEdgeIndex* index,
transaction::Methods* trx,
rocksdb::Slice const& lower,
rocksdb::Slice const& upper)
: LocalTask(queue),
_index(index),
_trx(trx),
_lower(lower.data(), lower.size()),
_upper(upper.data(), upper.size()) {}
void RocksDBEdgeIndexWarmupTask::run() {
try {
_index->warmupInternal(_trx, _lower, _upper);
} catch (...) {
_queue->setStatus(TRI_ERROR_INTERNAL);
}
_queue->join();
}
RocksDBEdgeIndexIterator::RocksDBEdgeIndexIterator(
LogicalCollection* collection, transaction::Methods* trx,
arangodb::RocksDBEdgeIndex const* index,
std::unique_ptr<VPackBuilder> keys, std::shared_ptr<cache::Cache> cache)
: IndexIterator(collection, trx),
_keys(std::move(keys)),
_keysIterator(_keys->slice()),
_index(index),
_bounds(RocksDBKeyBounds::EdgeIndex(0)),
_cache(std::move(cache)),
_builderIterator(arangodb::velocypack::Slice::emptyArraySlice()),
_lastKey(VPackSlice::nullSlice()) {
TRI_ASSERT(_keys != nullptr);
TRI_ASSERT(_keys->slice().isArray());
auto* mthds = RocksDBTransactionState::toMethods(trx);
// intentional copy of the options
rocksdb::ReadOptions options = mthds->iteratorReadOptions();
options.fill_cache = EdgeIndexFillBlockCache;
_iterator = mthds->NewIterator(options, index->columnFamily());
}
RocksDBEdgeIndexIterator::~RocksDBEdgeIndexIterator() {
if (_keys != nullptr) {
// return the VPackBuilder to the transaction context
_trx->transactionContextPtr()->returnBuilder(_keys.release());
}
}
void RocksDBEdgeIndexIterator::resetInplaceMemory() { _builder.clear(); }
void RocksDBEdgeIndexIterator::reset() {
resetInplaceMemory();
_keysIterator.reset();
_lastKey = VPackSlice::nullSlice();
_builderIterator =
VPackArrayIterator(arangodb::velocypack::Slice::emptyArraySlice());
}
// returns true if we have one more key for the index lookup.
// if true, sets the `key` Slice to point to the new key's value
// note that the underlying data for the Slice must remain valid
// as long as the iterator is used and the key is not moved forward.
// returns false if there are no more keys to look for
bool RocksDBEdgeIndexIterator::initKey(VPackSlice& key) {
if (!_keysIterator.valid()) {
// no next key
_lastKey = VPackSlice::nullSlice();
return false;
}
key = _keysIterator.value();
if (key.isObject()) {
key = key.get(StaticStrings::IndexEq);
}
TRI_ASSERT(key.isString());
_lastKey = key;
return true;
}
bool RocksDBEdgeIndexIterator::next(LocalDocumentIdCallback const& cb, size_t limit) {
TRI_ASSERT(_trx->state()->isRunning());
#ifdef ARANGODB_ENABLE_MAINTAINER_MODE
TRI_ASSERT(limit > 0); // Someone called with limit == 0. Api broken
#else
// Gracefully return in production code
// Nothing bad has happened
if (limit == 0) {
return false;
}
#endif
while (limit > 0) {
while (_builderIterator.valid()) {
// We still have unreturned edges in out memory.
// Just plainly return those.
TRI_ASSERT(_builderIterator.value().isNumber());
cb(LocalDocumentId{_builderIterator.value().getNumericValue<uint64_t>()});
limit--;
// Twice advance the iterator
_builderIterator.next();
// We always have <revision,_from> pairs
TRI_ASSERT(_builderIterator.valid());
_builderIterator.next();
if (limit == 0) {
// Limit reached bail out
return true;
}
}
if (!_keysIterator.valid()) {
// We are done iterating
return false;
}
// We have exhausted local memory.
// Now fill it again:
VPackSlice fromToSlice = _keysIterator.value();
if (fromToSlice.isObject()) {
fromToSlice = fromToSlice.get(StaticStrings::IndexEq);
}
TRI_ASSERT(fromToSlice.isString());
StringRef fromTo(fromToSlice);
bool needRocksLookup = true;
if (_cache) {
for (size_t attempts = 0; attempts < 10; ++attempts) {
// Try to read from cache
auto finding = _cache->find(fromTo.data(), (uint32_t)fromTo.size());
if (finding.found()) {
needRocksLookup = false;
// We got sth. in the cache
VPackSlice cachedData(finding.value()->value());
TRI_ASSERT(cachedData.isArray());
if (cachedData.length() / 2 < limit) {
// Directly return it, no need to copy
_builderIterator = VPackArrayIterator(cachedData);
while (_builderIterator.valid()) {
TRI_ASSERT(_builderIterator.value().isNumber());
cb(LocalDocumentId{
_builderIterator.value().getNumericValue<uint64_t>()});
limit--;
// Twice advance the iterator
_builderIterator.next();
// We always have <revision,_from> pairs
TRI_ASSERT(_builderIterator.valid());
_builderIterator.next();
}
_builderIterator = VPackArrayIterator(
arangodb::velocypack::Slice::emptyArraySlice());
} else {
// We need to copy it.
// And then we just get back to beginning of the loop
_builder.clear();
_builder.add(cachedData);
TRI_ASSERT(_builder.slice().isArray());
_builderIterator = VPackArrayIterator(_builder.slice());
// Do not set limit
}
break;
}
if (finding.result().isNot(TRI_ERROR_LOCK_TIMEOUT)) {
// We really have not found an entry.
// Otherwise we do not know yet
break;
}
} // attempts
} // if (_cache)
if (needRocksLookup) {
lookupInRocksDB(fromTo);
}
_keysIterator.next();
}
TRI_ASSERT(limit == 0);
return _builderIterator.valid() || _keysIterator.valid();
}
bool RocksDBEdgeIndexIterator::nextCovering(DocumentCallback const& cb, size_t limit) {
TRI_ASSERT(_trx->state()->isRunning());
#ifdef ARANGODB_ENABLE_MAINTAINER_MODE
TRI_ASSERT(limit > 0); // Someone called with limit == 0. Api broken
#else
// Gracefully return in production code
// Nothing bad has happened
if (limit == 0) {
return false;
}
#endif
while (limit > 0) {
while (_builderIterator.valid()) {
// We still have unreturned edges in memory.
// Just plainly return those.
TRI_ASSERT(_builderIterator.value().isNumber());
cb(LocalDocumentId{_builderIterator.value().getNumericValue<uint64_t>()}, _lastKey);
limit--;
// Twice advance the iterator
_builderIterator.next();
// We always have <revision,_from> pairs
TRI_ASSERT(_builderIterator.valid());
_builderIterator.next();
if (limit == 0) {
// Limit reached. bail out
return true;
}
}
VPackSlice fromToSlice;
if (!initKey(fromToSlice)) {
return false;
}
StringRef fromTo(fromToSlice);
bool needRocksLookup = true;
if (_cache) {
for (size_t attempts = 0; attempts < 10; ++attempts) {
// Try to read from cache
auto finding = _cache->find(fromTo.data(), (uint32_t)fromTo.size());
if (finding.found()) {
needRocksLookup = false;
// We got sth. in the cache
VPackSlice cachedData(finding.value()->value());
TRI_ASSERT(cachedData.isArray());
if (cachedData.length() / 2 < limit) {
// Directly return it, no need to copy
_builderIterator = VPackArrayIterator(cachedData);
while (_builderIterator.valid()) {
TRI_ASSERT(_builderIterator.value().isNumber());
cb(LocalDocumentId{
_builderIterator.value().getNumericValue<uint64_t>()}, _lastKey);
limit--;
// Twice advance the iterator
_builderIterator.next();
// We always have <revision,_from> pairs
TRI_ASSERT(_builderIterator.valid());
_builderIterator.next();
}
_builderIterator = VPackArrayIterator(
arangodb::velocypack::Slice::emptyArraySlice());
} else {
// We need to copy it.
// And then we just get back to beginning of the loop
_builder.clear();
_builder.add(cachedData);
TRI_ASSERT(_builder.slice().isArray());
_builderIterator = VPackArrayIterator(_builder.slice());
// Do not set limit
}
break;
}
if (finding.result().isNot(TRI_ERROR_LOCK_TIMEOUT)) {
// We really have not found an entry.
// Otherwise we do not know yet
break;
}
} // attempts
} // if (_cache)
if (needRocksLookup) {
lookupInRocksDB(fromTo);
}
_keysIterator.next();
}
TRI_ASSERT(limit == 0);
return _builderIterator.valid() || _keysIterator.valid();
}
bool RocksDBEdgeIndexIterator::nextExtra(ExtraCallback const& cb,
size_t limit) {
TRI_ASSERT(_trx->state()->isRunning());
#ifdef ARANGODB_ENABLE_MAINTAINER_MODE
TRI_ASSERT(limit > 0); // Someone called with limit == 0. Api broken
#else
// Gracefully return in production code
// Nothing bad has happened
if (limit == 0) {
return false;
}
#endif
while (limit > 0) {
while (_builderIterator.valid()) {
// We still have unreturned edges in out memory.
// Just plainly return those.
TRI_ASSERT(_builderIterator.value().isNumber());
LocalDocumentId tkn{_builderIterator.value().getNumericValue<uint64_t>()};
_builderIterator.next();
TRI_ASSERT(_builderIterator.valid());
// For now we store the complete opposite _from/_to value
TRI_ASSERT(_builderIterator.value().isString());
cb(tkn, _builderIterator.value());
_builderIterator.next();
limit--;
if (limit == 0) {
// Limit reached bail out
return true;
}
}
if (!_keysIterator.valid()) {
// We are done iterating
return false;
}
// We have exhausted local memory.
// Now fill it again:
VPackSlice fromToSlice = _keysIterator.value();
if (fromToSlice.isObject()) {
fromToSlice = fromToSlice.get(StaticStrings::IndexEq);
}
TRI_ASSERT(fromToSlice.isString());
StringRef fromTo(fromToSlice);
bool needRocksLookup = true;
if (_cache) {
for (size_t attempts = 0; attempts < 10; ++attempts) {
// Try to read from cache
auto finding = _cache->find(fromTo.data(), (uint32_t)fromTo.size());
if (finding.found()) {
needRocksLookup = false;
// We got sth. in the cache
VPackSlice cachedData(finding.value()->value());
TRI_ASSERT(cachedData.isArray());
if (cachedData.length() / 2 < limit) {
// Directly return it, no need to copy
_builderIterator = VPackArrayIterator(cachedData);
while (_builderIterator.valid()) {
TRI_ASSERT(_builderIterator.value().isNumber());
LocalDocumentId tkn{
_builderIterator.value().getNumericValue<uint64_t>()};
_builderIterator.next();
TRI_ASSERT(_builderIterator.valid());
TRI_ASSERT(_builderIterator.value().isString());
cb(tkn, _builderIterator.value());
_builderIterator.next();
limit--;
}
_builderIterator = VPackArrayIterator(
arangodb::velocypack::Slice::emptyArraySlice());
} else {
// We need to copy it.
// And then we just get back to beginning of the loop
_builder.clear();
_builder.add(cachedData);
TRI_ASSERT(_builder.slice().isArray());
_builderIterator = VPackArrayIterator(_builder.slice());
// Do not set limit
}
break;
} // finding found
if (finding.result().isNot(TRI_ERROR_LOCK_TIMEOUT)) {
// We really have not found an entry.
// Otherwise we do not know yet
break;
}
} // attempts
} // if (_cache)
if (needRocksLookup) {
lookupInRocksDB(fromTo);
}
_keysIterator.next();
}
TRI_ASSERT(limit == 0);
return _builderIterator.valid() || _keysIterator.valid();
}
void RocksDBEdgeIndexIterator::lookupInRocksDB(StringRef fromTo) {
// Bad case read from RocksDB
_bounds = RocksDBKeyBounds::EdgeIndexVertex(_index->_objectId, fromTo);
_iterator->Seek(_bounds.start());
resetInplaceMemory();
rocksdb::Comparator const* cmp = _index->comparator();
cache::Cache* cc = _cache.get();
_builder.openArray(true);
auto end = _bounds.end();
while (_iterator->Valid() && (cmp->Compare(_iterator->key(), end) < 0)) {
LocalDocumentId const documentId = RocksDBKey::indexDocumentId(
RocksDBEntryType::EdgeIndexValue, _iterator->key());
// adding revision ID and _from or _to value
_builder.add(VPackValue(documentId.id()));
StringRef vertexId = RocksDBValue::vertexId(_iterator->value());
_builder.add(VPackValuePair(vertexId.data(), vertexId.size(),
VPackValueType::String));
_iterator->Next();
}
_builder.close();
if (cc != nullptr) {
// TODO Add cache retry on next call
// Now we have something in _inplaceMemory.
// It may be an empty array or a filled one, never mind, we cache both
auto entry = cache::CachedValue::construct(
fromTo.data(), static_cast<uint32_t>(fromTo.size()),
_builder.slice().start(),
static_cast<uint64_t>(_builder.slice().byteSize()));
if (entry) {
bool inserted = false;
for (size_t attempts = 0; attempts < 10; attempts++) {
auto status = cc->insert(entry);
if (status.ok()) {
inserted = true;
break;
}
if (status.errorNumber() != TRI_ERROR_LOCK_TIMEOUT) {
break;
}
}
if (!inserted) {
LOG_TOPIC(DEBUG, arangodb::Logger::CACHE) << "Failed to cache: "
<< fromTo.toString();
delete entry;
}
}
}
TRI_ASSERT(_builder.slice().isArray());
_builderIterator = VPackArrayIterator(_builder.slice());
}
// ============================= Index ====================================
uint64_t RocksDBEdgeIndex::HashForKey(const rocksdb::Slice& key) {
std::hash<StringRef> hasher;
// NOTE: This function needs to use the same hashing on the
// indexed VPack as the initial inserter does
StringRef tmp = RocksDBKey::vertexId(key);
return static_cast<uint64_t>(hasher(tmp));
}
RocksDBEdgeIndex::RocksDBEdgeIndex(
TRI_idx_iid_t iid,
arangodb::LogicalCollection& collection,
arangodb::velocypack::Slice const& info,
std::string const& attr
)
: RocksDBIndex(iid, collection, std::vector<std::vector<AttributeName>>(
{{AttributeName(attr, false)}}),
false, false, RocksDBColumnFamily::edge(),
basics::VelocyPackHelper::stringUInt64(info, "objectId"),
!ServerState::instance()->isCoordinator() /*useCache*/),
_directionAttr(attr),
_isFromIndex(attr == StaticStrings::FromString),
_estimator(nullptr) {
TRI_ASSERT(_cf == RocksDBColumnFamily::edge());
if (!ServerState::instance()->isCoordinator()) {
// We activate the estimator only on DBServers
_estimator = std::make_unique<RocksDBCuckooIndexEstimator<uint64_t>>(
RocksDBIndex::ESTIMATOR_SIZE);
TRI_ASSERT(_estimator != nullptr);
}
// edge indexes are always created with ID 1 or 2
TRI_ASSERT(iid == 1 || iid == 2);
TRI_ASSERT(_objectId != 0);
}
RocksDBEdgeIndex::~RocksDBEdgeIndex() {}
/// @brief return a selectivity estimate for the index
double RocksDBEdgeIndex::selectivityEstimate(
arangodb::StringRef const& attribute) const {
TRI_ASSERT(!ServerState::instance()->isCoordinator());
if (_unique) {
return 1.0;
}
if (!attribute.empty() && attribute.compare(_directionAttr)) {
return 0.0;
}
TRI_ASSERT(_estimator != nullptr);
return _estimator->computeEstimate();
}
/// @brief return a VelocyPack representation of the index
void RocksDBEdgeIndex::toVelocyPack(VPackBuilder& builder,
std::underlying_type<Serialize>::type flags) const {
builder.openObject();
RocksDBIndex::toVelocyPack(builder, flags);
builder.add(
arangodb::StaticStrings::IndexUnique,
arangodb::velocypack::Value(false)
);
builder.add(
arangodb::StaticStrings::IndexSparse,
arangodb::velocypack::Value(false)
);
builder.close();
}
Result RocksDBEdgeIndex::insertInternal(transaction::Methods* trx,
RocksDBMethods* mthd,
LocalDocumentId const& documentId,
VPackSlice const& doc,
OperationMode mode) {
Result res;
VPackSlice fromTo = doc.get(_directionAttr);
TRI_ASSERT(fromTo.isString());
auto fromToRef = StringRef(fromTo);
RocksDBKeyLeaser key(trx);
key->constructEdgeIndexValue(_objectId, fromToRef, documentId);
VPackSlice toFrom = _isFromIndex
? transaction::helpers::extractToFromDocument(doc)
: transaction::helpers::extractFromFromDocument(doc);
TRI_ASSERT(toFrom.isString());
RocksDBValue value = RocksDBValue::EdgeIndexValue(StringRef(toFrom));
// blacklist key in cache
blackListKey(fromToRef);
// acquire rocksdb transaction
rocksdb::Status s = mthd->Put(_cf, key.ref(), value.string());
if (s.ok()) {
std::hash<StringRef> hasher;
uint64_t hash = static_cast<uint64_t>(hasher(fromToRef));
RocksDBTransactionState::toState(trx)->trackIndexInsert(
_collection.id(), id(), hash
);
} else {
res.reset(rocksutils::convertStatus(s));
addErrorMsg(res);
}
return res;
}
Result RocksDBEdgeIndex::removeInternal(transaction::Methods* trx,
RocksDBMethods* mthd,
LocalDocumentId const& documentId,
VPackSlice const& doc,
OperationMode mode) {
Result res;
// VPackSlice primaryKey = doc.get(StaticStrings::KeyString);
VPackSlice fromTo = doc.get(_directionAttr);
auto fromToRef = StringRef(fromTo);
TRI_ASSERT(fromTo.isString());
RocksDBKeyLeaser key(trx);
key->constructEdgeIndexValue(_objectId, fromToRef, documentId);
VPackSlice toFrom = _isFromIndex
? transaction::helpers::extractToFromDocument(doc)
: transaction::helpers::extractFromFromDocument(doc);
TRI_ASSERT(toFrom.isString());
RocksDBValue value = RocksDBValue::EdgeIndexValue(StringRef(toFrom));
// blacklist key in cache
blackListKey(fromToRef);
rocksdb::Status s = mthd->Delete(_cf, key.ref());
if (s.ok()) {
std::hash<StringRef> hasher;
uint64_t hash = static_cast<uint64_t>(hasher(fromToRef));
RocksDBTransactionState::toState(trx)->trackIndexRemove(
_collection.id(), id(), hash
);
} else {
res.reset(rocksutils::convertStatus(s));
addErrorMsg(res);
}
return res;
}
void RocksDBEdgeIndex::batchInsert(
transaction::Methods* trx,
std::vector<std::pair<LocalDocumentId, VPackSlice>> const& documents,
std::shared_ptr<arangodb::basics::LocalTaskQueue> queue) {
auto* mthds = RocksDBTransactionState::toMethods(trx);
for (auto const& doc : documents) {
VPackSlice fromTo = doc.second.get(_directionAttr);
TRI_ASSERT(fromTo.isString());
auto fromToRef = StringRef(fromTo);
RocksDBKeyLeaser key(trx);
key->constructEdgeIndexValue(_objectId, fromToRef, doc.first);
blackListKey(fromToRef);
rocksdb::Status s = mthds->Put(_cf, key.ref(), rocksdb::Slice());
if (!s.ok()) {
queue->setStatus(rocksutils::convertStatus(s).errorNumber());
break;
}
}
}
/// @brief checks whether the index supports the condition
bool RocksDBEdgeIndex::supportsFilterCondition(
std::vector<std::shared_ptr<arangodb::Index>> const& allIndexes,
arangodb::aql::AstNode const* node,
arangodb::aql::Variable const* reference, size_t itemsInIndex,
size_t& estimatedItems, double& estimatedCost) const {
SimpleAttributeEqualityMatcher matcher(this->_fields);
return matcher.matchOne(this, node, reference, itemsInIndex, estimatedItems,
estimatedCost);
}
/// @brief creates an IndexIterator for the given Condition
IndexIterator* RocksDBEdgeIndex::iteratorForCondition(
transaction::Methods* trx, ManagedDocumentResult*,
arangodb::aql::AstNode const* node,
arangodb::aql::Variable const* reference,
IndexIteratorOptions const& opts) {
TRI_ASSERT(!isSorted() || opts.sorted);
// get computation node
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);
// got value == a.b -> flip sides
if (attrNode->type != aql::NODE_TYPE_ATTRIBUTE_ACCESS) {
attrNode = comp->getMember(1);
valNode = comp->getMember(0);
}
TRI_ASSERT(attrNode->type == aql::NODE_TYPE_ATTRIBUTE_ACCESS);
TRI_ASSERT(attrNode->stringEquals(_directionAttr));
if (comp->type == aql::NODE_TYPE_OPERATOR_BINARY_EQ) {
// a.b == value
return createEqIterator(trx, attrNode, valNode);
}
if (comp->type == aql::NODE_TYPE_OPERATOR_BINARY_IN) {
// a.b IN values
if (!valNode->isArray()) {
// a.b IN non-array
return new EmptyIndexIterator(&_collection, trx);
}
return createInIterator(trx, attrNode, valNode);
}
// operator type unsupported
return new EmptyIndexIterator(&_collection, trx);
}
/// @brief specializes the condition for use with the index
arangodb::aql::AstNode* RocksDBEdgeIndex::specializeCondition(
arangodb::aql::AstNode* node,
arangodb::aql::Variable const* reference) const {
// SimpleAttributeEqualityMatcher matcher(IndexAttributes);
SimpleAttributeEqualityMatcher matcher(this->_fields);
return matcher.specializeOne(this, node, reference);
}
static std::string FindMedian(rocksdb::Iterator* it,
std::string const& start,
std::string const& end) {
// now that we do know the actual bounds calculate a
// bad approximation for the index median key
size_t min = std::min(start.size(), end.size());
std::string median = std::string(min, '\0');
for (size_t i = 0; i < min; i++) {
median[i] = (start.data()[i] + end.data()[i]) / 2;
}
// now search the beginning of a new vertex ID
it->Seek(median);
if (!it->Valid()) {
return end;
}
do {
median = it->key().ToString();
it->Next();
} while (it->Valid() &&
RocksDBKey::vertexId(it->key()) == RocksDBKey::vertexId(median));
if (!it->Valid()) {
return end;
}
return it->key().ToString(); // median is exclusive upper bound
}
void RocksDBEdgeIndex::warmup(transaction::Methods* trx,
std::shared_ptr<basics::LocalTaskQueue> queue) {
if (!useCache()) {
return;
}
// prepare transaction for parallel read access
RocksDBTransactionState::toState(trx)->prepareForParallelReads();
auto rocksColl = toRocksDBCollection(_collection);
auto* mthds = RocksDBTransactionState::toMethods(trx);
auto bounds = RocksDBKeyBounds::EdgeIndex(_objectId);
uint64_t expectedCount = static_cast<uint64_t>(selectivityEstimate() *
rocksColl->numberDocuments());
// Prepare the cache to be resized for this amount of objects to be inserted.
_cache->sizeHint(expectedCount);
if (expectedCount < 100000) {
LOG_TOPIC(DEBUG, Logger::ENGINES) << "Skipping the multithreaded loading";
auto task = std::make_shared<RocksDBEdgeIndexWarmupTask>(
queue, this, trx, bounds.start(), bounds.end());
queue->enqueue(task);
return;
}
// try to find the right bounds
rocksdb::ReadOptions ro = mthds->iteratorReadOptions();
ro.prefix_same_as_start = false; // key-prefix includes edge (i.e. "collection/vertex")
ro.total_order_seek = true; // otherwise full-index-scan does not work
ro.verify_checksums = false;
ro.fill_cache = EdgeIndexFillBlockCache;
std::unique_ptr<rocksdb::Iterator> it(rocksutils::globalRocksDB()->NewIterator(ro, _cf));
// get the first and last actual key
it->Seek(bounds.start());
if (!it->Valid()) {
LOG_TOPIC(DEBUG, Logger::ENGINES) << "Cannot use multithreaded edge index warmup";
auto task = std::make_shared<RocksDBEdgeIndexWarmupTask>(
queue, this, trx, bounds.start(), bounds.end());
queue->enqueue(task);
return;
}
std::string firstKey = it->key().ToString();
it->SeekForPrev(bounds.end());
if (!it->Valid()) {
LOG_TOPIC(DEBUG, Logger::ENGINES) << "Cannot use multithreaded edge index warmup";
auto task = std::make_shared<RocksDBEdgeIndexWarmupTask>(
queue, this, trx, bounds.start(), bounds.end());
queue->enqueue(task);
return;
}
std::string lastKey = it->key().ToString();
std::string q1 = firstKey, q2, q3, q4, q5 = lastKey;
q3 = FindMedian(it.get(), q1, q5);
if (q3 == lastKey) {
LOG_TOPIC(DEBUG, Logger::ENGINES) << "Cannot use multithreaded edge index warmup";
auto task = std::make_shared<RocksDBEdgeIndexWarmupTask>(
queue, this, trx, bounds.start(), bounds.end());
queue->enqueue(task);
return;
}
q2 = FindMedian(it.get(), q1, q3);
q4 = FindMedian(it.get(), q3, q5);
auto task1 = std::make_shared<RocksDBEdgeIndexWarmupTask>(
queue, this, trx, q1, q2);
queue->enqueue(task1);
auto task2 = std::make_shared<RocksDBEdgeIndexWarmupTask>(
queue, this, trx, q2, q3);
queue->enqueue(task2);
auto task3 = std::make_shared<RocksDBEdgeIndexWarmupTask>(
queue, this, trx, q3, q4);
queue->enqueue(task3);
auto task4 = std::make_shared<RocksDBEdgeIndexWarmupTask>(
queue, this, trx, q4, bounds.end());
queue->enqueue(task4);
}
void RocksDBEdgeIndex::warmupInternal(transaction::Methods* trx,
rocksdb::Slice const& lower,
rocksdb::Slice const& upper) {
auto scheduler = SchedulerFeature::SCHEDULER;
auto rocksColl = toRocksDBCollection(_collection);
bool needsInsert = false;
std::string previous = "";
VPackBuilder builder;
// intentional copy of the read options
auto* mthds = RocksDBTransactionState::toMethods(trx);
rocksdb::Slice const end = upper;
rocksdb::ReadOptions options = mthds->iteratorReadOptions();
options.iterate_upper_bound = &end; // safe to use on rocksb::DB directly
options.prefix_same_as_start = false; // key-prefix includes edge
options.total_order_seek = true; // otherwise full-index-scan does not work
options.verify_checksums = false;
options.fill_cache = EdgeIndexFillBlockCache;
std::unique_ptr<rocksdb::Iterator> it(
rocksutils::globalRocksDB()->NewIterator(options, _cf));
size_t n = 0;
cache::Cache* cc = _cache.get();
for (it->Seek(lower); it->Valid(); it->Next()) {
if (scheduler->isStopping()) {
return;
}
n++;
rocksdb::Slice key = it->key();
StringRef v = RocksDBKey::vertexId(key);
if (previous.empty()) {
// First call.
builder.clear();
previous = v.toString();
bool shouldTry = true;
while (shouldTry) {
auto finding = cc->find(previous.data(), (uint32_t)previous.size());
if (finding.found()) {
shouldTry = false;
needsInsert = false;
} else if ( // shouldTry if failed lookup was just a lock timeout
finding.result().errorNumber() != TRI_ERROR_LOCK_TIMEOUT) {
shouldTry = false;
needsInsert = true;
builder.openArray(true);
}
}
}
if (v != previous) {
if (needsInsert) {
// Switch to next vertex id.
// Store what we have.
builder.close();
while (cc->isBusy()) {
// We should wait here, the cache will reject
// any inserts anyways.
std::this_thread::sleep_for(std::chrono::microseconds(10000));
}
auto entry = cache::CachedValue::construct(
previous.data(), static_cast<uint32_t>(previous.size()),
builder.slice().start(),
static_cast<uint64_t>(builder.slice().byteSize()));
if (entry) {
bool inserted = false;
for (size_t attempts = 0; attempts < 10; attempts++) {
auto status = cc->insert(entry);
if (status.ok()) {
inserted = true;
break;
}
if (status.errorNumber() != TRI_ERROR_LOCK_TIMEOUT) {
break;
}
}
if (!inserted) {
delete entry;
}
}
builder.clear();
}
// Need to store
previous = v.toString();
auto finding = cc->find(previous.data(), (uint32_t)previous.size());
if (finding.found()) {
needsInsert = false;
} else {
needsInsert = true;
builder.openArray(true);
}
}
if (needsInsert) {
LocalDocumentId const docId = RocksDBKey::indexDocumentId(RocksDBEntryType::EdgeIndexValue, key);
if (!rocksColl->readDocumentWithCallback(trx, docId, [&](LocalDocumentId const&, VPackSlice doc) {
builder.add(VPackValue(docId.id()));
VPackSlice toFrom =
_isFromIndex ? transaction::helpers::extractToFromDocument(doc)
: transaction::helpers::extractFromFromDocument(doc);
TRI_ASSERT(toFrom.isString());
builder.add(toFrom);
})) {
#ifdef ARANGODB_ENABLE_MAINTAINER_MODE
// Data Inconsistency.
// We have a revision id without a document...
TRI_ASSERT(false);
#endif
}
}
}
if (!previous.empty() && needsInsert) {
// We still have something to store
builder.close();
auto entry = cache::CachedValue::construct(
previous.data(), static_cast<uint32_t>(previous.size()),
builder.slice().start(),
static_cast<uint64_t>(builder.slice().byteSize()));
if (entry) {
bool inserted = false;
for (size_t attempts = 0; attempts < 10; attempts++) {
auto status = cc->insert(entry);
if (status.ok()) {
inserted = true;
break;
}
if (status.errorNumber() != TRI_ERROR_LOCK_TIMEOUT) {
break;
}
}
if (!inserted) {
delete entry;
}
}
}
LOG_TOPIC(DEBUG, Logger::ENGINES) << "loaded n: " << n ;
}
// ===================== Helpers ==================
/// @brief create the iterator
IndexIterator* RocksDBEdgeIndex::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();
return new RocksDBEdgeIndexIterator(
&_collection, trx, this, std::move(keys), _cache
);
}
/// @brief create the iterator
IndexIterator* RocksDBEdgeIndex::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();
return new RocksDBEdgeIndexIterator(
&_collection, trx, this, std::move(keys), _cache
);
}
/// @brief add a single value node to the iterator's keys
void RocksDBEdgeIndex::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);
}
}
void RocksDBEdgeIndex::afterTruncate(TRI_voc_tick_t tick) {
TRI_ASSERT(_estimator != nullptr);
_estimator->bufferTruncate(tick);
RocksDBIndex::afterTruncate(tick);
}
RocksDBCuckooIndexEstimator<uint64_t>* RocksDBEdgeIndex::estimator() {
return _estimator.get();
}
void RocksDBEdgeIndex::setEstimator(std::unique_ptr<RocksDBCuckooIndexEstimator<uint64_t>> est) {
_estimator = std::move(est);
}
void RocksDBEdgeIndex::recalculateEstimates() {
TRI_ASSERT(_estimator != nullptr);
_estimator->clear();
rocksdb::TransactionDB* db = rocksutils::globalRocksDB();
rocksdb::SequenceNumber seq = db->GetLatestSequenceNumber();
auto bounds = RocksDBKeyBounds::EdgeIndex(_objectId);
rocksdb::Slice const end = bounds.end();
rocksdb::ReadOptions options;
options.iterate_upper_bound = &end; // safe to use on rocksb::DB directly
options.prefix_same_as_start = false; // key-prefix includes edge
options.total_order_seek = true; // otherwise full scan fails
options.verify_checksums = false;
options.fill_cache = false;
std::unique_ptr<rocksdb::Iterator> it(db->NewIterator(options, _cf));
for (it->Seek(bounds.start()); it->Valid(); it->Next()) {
uint64_t hash = RocksDBEdgeIndex::HashForKey(it->key());
_estimator->insert(hash);
}
_estimator->setCommitSeq(seq);
}
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