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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
////////////////////////////////////////////////////////////////////////////////
#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 "Transaction/Context.h"
#include "Transaction/Helpers.h"
#include "Transaction/Methods.h"
#include "VocBase/LogicalCollection.h"
#include "RocksDBEngine/RocksDBCollection.h"
#include "RocksDBEngine/RocksDBCommon.h"
#include "RocksDBEngine/RocksDBCounterManager.h"
#include "RocksDBEngine/RocksDBKey.h"
#include "RocksDBEngine/RocksDBKeyBounds.h"
#include "RocksDBEngine/RocksDBMethods.h"
#include "RocksDBEngine/RocksDBToken.h"
#include "RocksDBEngine/RocksDBTransactionState.h"
#include "RocksDBEngine/RocksDBTypes.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;
RocksDBEdgeIndexIterator::RocksDBEdgeIndexIterator(
LogicalCollection* collection, transaction::Methods* trx,
ManagedDocumentResult* mmdr, arangodb::RocksDBEdgeIndex const* index,
std::unique_ptr<VPackBuilder>& keys, bool useCache, cache::Cache* cache)
: IndexIterator(collection, trx, mmdr, index),
_keys(keys.get()),
_keysIterator(_keys->slice()),
_index(index),
_iterator(rocksutils::toRocksMethods(trx)->NewIterator()),
_arrayIterator(VPackSlice::emptyArraySlice()),
_bounds(RocksDBKeyBounds::EdgeIndex(0)),
_doUpdateBounds(true),
_doUpdateArrayIterator(true),
_useCache(useCache),
_cache(cache),
_cacheValueSize(0) {
keys.release(); // now we have ownership for _keys
TRI_ASSERT(_keys->slice().isArray());
}
RocksDBEdgeIndexIterator::~RocksDBEdgeIndexIterator() {
if (_keys != nullptr) {
// return the VPackBuilder to the transaction context
_trx->transactionContextPtr()->returnBuilder(_keys.release());
}
}
void RocksDBEdgeIndexIterator::updateBounds(StringRef fromTo) {
_bounds = RocksDBKeyBounds::EdgeIndexVertex(_index->_objectId, fromTo);
_iterator->Seek(_bounds.start());
}
StringRef getFromToFromIterator(arangodb::velocypack::ArrayIterator const& it) {
VPackSlice fromTo = it.value();
if (fromTo.isObject()) {
fromTo = fromTo.get(StaticStrings::IndexEq);
}
TRI_ASSERT(fromTo.isString());
return StringRef(fromTo);
}
bool RocksDBEdgeIndexIterator::next(TokenCallback const& cb, size_t limit) {
TRI_ASSERT(_trx->state()->isRunning());
if (limit == 0 || !_keysIterator.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;
}
std::size_t cacheValueSizeLimit = 1000;
// acquire RocksDB collection
RocksDBToken token;
auto iterateCachedValues = [this, &cb, &limit, &token]() {
while (_arrayIterator.valid()) {
VPackSlice edgeKey(_arrayIterator.value());
cb(RocksDBToken(edgeKey.getUInt()));
--limit;
++_arrayIterator;
if (limit == 0) {
_doUpdateArrayIterator = false; // limit hit continue with next batch
return true;
}
}
// reset cache iterator before handling next from/to
_arrayBuffer.clear();
_arrayIterator = VPackArrayIterator(VPackSlice::emptyArraySlice());
return false;
};
while (_keysIterator.valid()) {
TRI_ASSERT(limit > 0);
StringRef fromTo = getFromToFromIterator(_keysIterator);
bool foundInCache = false;
if (_useCache && _doUpdateArrayIterator) {
// try to find cached value
auto f = _cache->find(fromTo.data(), (uint32_t)fromTo.size());
foundInCache = f.found();
if (foundInCache) {
VPackSlice cachedPrimaryKeys(f.value()->value());
TRI_ASSERT(cachedPrimaryKeys.isArray());
// update arraySlice (and copy Buffer if required)
// the finding should be small otherwise we need to release it sooner
if (cachedPrimaryKeys.length() <=
std::min(static_cast<size_t>(40), limit)) {
_arraySlice = cachedPrimaryKeys; // do not copy
} else {
// copy data if there are more documents than the batch size limit
// allows
_arrayBuffer.append(cachedPrimaryKeys.start(),
cachedPrimaryKeys.byteSize());
_arraySlice = VPackSlice(_arrayBuffer.data());
f.release(); // release finding so the cache can be operated on
}
// update cache value iterator
_arrayIterator = VPackArrayIterator(_arraySlice);
// iterate until batch size limit is hit
bool continueWithNextBatch = iterateCachedValues();
if (continueWithNextBatch) {
return true; // exit and continue with next batch
}
}
} else if (_useCache && !_doUpdateArrayIterator) {
// resuming old iterator
foundInCache = true; // do not look up key again!
_doUpdateArrayIterator = true;
bool continueWithNextBatch = iterateCachedValues();
if (continueWithNextBatch) {
return true; // exit and continue with next batch
}
}
if (!foundInCache) {
// cache lookup failed for key value we need to look up
// primary keys in RocksDB
// if there are more documents in the iterator then
// we are not allowed to reset the index.
// if _doUpdateBound is set to false we resume
// returning from an valid iterator after hitting
// the batch size limit
if (_doUpdateBounds) {
updateBounds(fromTo);
if (_useCache) {
_cacheValueBuilder.openArray();
}
} else {
_doUpdateBounds = true;
}
while (_iterator->Valid() &&
(_index->_cmp->Compare(_iterator->key(), _bounds.end()) < 0)) {
StringRef edgeKey = RocksDBKey::primaryKey(_iterator->key());
// lookup real document
bool continueWithNextBatch = lookupDocumentAndUseCb(edgeKey, cb, limit, token);
// build cache value for from/to
if (_useCache) {
if (_cacheValueSize <= cacheValueSizeLimit) {
_cacheValueBuilder.add(VPackValue(token.revisionId()));
++_cacheValueSize;
}
}
_iterator->Next();
// check batch size limit
if (continueWithNextBatch) {
return true; // more documents - function will be re-entered
}
}
// insert cache values that are beyond the cacheValueSizeLimit
if (_useCache && _cacheValueSize <= cacheValueSizeLimit) {
_cacheValueBuilder.close();
auto entry = cache::CachedValue::construct(
fromTo.data(), static_cast<uint32_t>(fromTo.size()),
_cacheValueBuilder.slice().start(),
static_cast<uint64_t>(_cacheValueBuilder.slice().byteSize()));
bool cached = _cache->insert(entry);
if (!cached) {
delete entry;
}
}
// prepare for next key
_cacheValueBuilder.clear();
_cacheValueSize = 0;
} // not found in cache
_keysIterator.next(); // handle next key
}
return false; // no more documents in this iterator
}
// acquire the document token through the primary index
bool RocksDBEdgeIndexIterator::lookupDocumentAndUseCb(
StringRef primaryKey, TokenCallback const& cb,
size_t& limit, RocksDBToken& token){
//we pass the token in as ref to avoid allocations
auto rocksColl = toRocksDBCollection(_collection);
Result res = rocksColl->lookupDocumentToken(_trx, primaryKey, token);
if (res.ok()) {
cb(token);
--limit;
if (limit == 0) {
_doUpdateBounds=false; //limit hit continue with next batch
return true;
}
} // TODO do we need to handle failed lookups here?
return false; // limit not hit continue in while loop
}
void RocksDBEdgeIndexIterator::reset() {
// rest offsets into iterators
_doUpdateBounds = true;
_doUpdateArrayIterator = true;
_cacheValueBuilder.clear();
_arrayBuffer.clear();
_arraySlice = VPackSlice::emptyArraySlice();
_arrayIterator = VPackArrayIterator(_arraySlice);
_keysIterator.reset();
}
// ============================= 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,
VPackSlice const& info,
std::string const& attr)
: RocksDBIndex(iid, collection, std::vector<std::vector<AttributeName>>(
{{AttributeName(attr, false)}}),
false, false,
basics::VelocyPackHelper::stringUInt64(info, "objectId"),
!ServerState::instance()->isCoordinator() /*useCache*/
),
_directionAttr(attr),
_estimator(nullptr) {
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);
}
TRI_ASSERT(iid != 0);
TRI_ASSERT(_objectId != 0);
// if we never hit the assertions we need to remove the
// following code
// FIXME
if (_objectId == 0) {
// disable cache?
_useCache = false;
}
}
RocksDBEdgeIndex::~RocksDBEdgeIndex() {}
/// @brief return a selectivity estimate for the index
double RocksDBEdgeIndex::selectivityEstimate(
arangodb::StringRef const* attribute) const {
if (ServerState::instance()->isCoordinator()) {
// use hard-coded selectivity estimate in case of cluster coordinator
return 0.1;
}
if (attribute != nullptr && attribute->compare(_directionAttr)) {
return 0;
}
TRI_ASSERT(_estimator != nullptr);
return _estimator->computeEstimate();
}
/// @brief return the memory usage for the index
size_t RocksDBEdgeIndex::memory() const {
rocksdb::TransactionDB* db = rocksutils::globalRocksDB();
RocksDBKeyBounds bounds = RocksDBKeyBounds::EdgeIndex(_objectId);
rocksdb::Range r(bounds.start(), bounds.end());
uint64_t out;
db->GetApproximateSizes(&r, 1, &out, true);
return (size_t)out;
}
/// @brief return a VelocyPack representation of the index
void RocksDBEdgeIndex::toVelocyPack(VPackBuilder& builder, bool withFigures,
bool forPersistence) const {
builder.openObject();
RocksDBIndex::toVelocyPack(builder, withFigures, forPersistence);
// add selectivity estimate hard-coded
builder.add("unique", VPackValue(false));
builder.add("sparse", VPackValue(false));
builder.close();
}
int RocksDBEdgeIndex::insert(transaction::Methods* trx,
TRI_voc_rid_t revisionId, VPackSlice const& doc,
bool isRollback) {
VPackSlice primaryKey = doc.get(StaticStrings::KeyString);
VPackSlice fromTo = doc.get(_directionAttr);
TRI_ASSERT(primaryKey.isString() && fromTo.isString());
auto fromToRef = StringRef(fromTo);
RocksDBKey key =
RocksDBKey::EdgeIndexValue(_objectId, fromToRef, StringRef(primaryKey));
// blacklist key in cache
blackListKey(fromToRef);
// acquire rocksdb transaction
RocksDBMethods* mthd = rocksutils::toRocksMethods(trx);
Result r = mthd->Put(rocksdb::Slice(key.string()), rocksdb::Slice(),
rocksutils::index);
if (r.ok()) {
std::hash<StringRef> hasher;
uint64_t hash = static_cast<uint64_t>(hasher(fromToRef));
_estimator->insert(hash);
return TRI_ERROR_NO_ERROR;
} else {
return r.errorNumber();
}
}
int RocksDBEdgeIndex::insertRaw(RocksDBMethods*, TRI_voc_rid_t,
VPackSlice const&) {
THROW_ARANGO_EXCEPTION(TRI_ERROR_NOT_IMPLEMENTED);
}
int RocksDBEdgeIndex::remove(transaction::Methods* trx,
TRI_voc_rid_t revisionId, VPackSlice const& doc,
bool isRollback) {
VPackSlice primaryKey = doc.get(StaticStrings::KeyString);
VPackSlice fromTo = doc.get(_directionAttr);
auto fromToRef = StringRef(fromTo);
TRI_ASSERT(primaryKey.isString() && fromTo.isString());
RocksDBKey key =
RocksDBKey::EdgeIndexValue(_objectId, fromToRef, StringRef(primaryKey));
// blacklist key in cache
blackListKey(fromToRef);
// acquire rocksdb transaction
RocksDBMethods* mthd = rocksutils::toRocksMethods(trx);
Result res = mthd->Delete(rocksdb::Slice(key.string()));
if (res.ok()) {
std::hash<StringRef> hasher;
uint64_t hash = static_cast<uint64_t>(hasher(fromToRef));
_estimator->remove(hash);
return TRI_ERROR_NO_ERROR;
} else {
return res.errorNumber();
}
}
/// optimization for truncateNoTrx, never called in fillIndex
int RocksDBEdgeIndex::removeRaw(RocksDBMethods*, TRI_voc_rid_t,
VPackSlice const&) {
THROW_ARANGO_EXCEPTION(TRI_ERROR_NOT_IMPLEMENTED);
}
void RocksDBEdgeIndex::batchInsert(
transaction::Methods* trx,
std::vector<std::pair<TRI_voc_rid_t, VPackSlice>> const& documents,
std::shared_ptr<arangodb::basics::LocalTaskQueue> queue) {
RocksDBMethods* mthd = rocksutils::toRocksMethods(trx);
for (std::pair<TRI_voc_rid_t, VPackSlice> const& doc : documents) {
VPackSlice primaryKey = doc.second.get(StaticStrings::KeyString);
VPackSlice fromTo = doc.second.get(_directionAttr);
TRI_ASSERT(primaryKey.isString() && fromTo.isString());
auto fromToRef = StringRef(fromTo);
RocksDBKey key =
RocksDBKey::EdgeIndexValue(_objectId, fromToRef, StringRef(primaryKey));
blackListKey(fromToRef);
Result r = mthd->Put(rocksdb::Slice(key.string()), rocksdb::Slice(),
rocksutils::index);
if (!r.ok()) {
queue->setStatus(r.errorNumber());
break;
}
}
}
/// @brief called when the index is dropped
int RocksDBEdgeIndex::drop() {
// First drop the cache all indexes can work without it.
RocksDBIndex::drop();
return rocksutils::removeLargeRange(rocksutils::globalRocksDB(),
RocksDBKeyBounds::EdgeIndex(_objectId))
.errorNumber();
}
/// @brief checks whether the index supports the condition
bool RocksDBEdgeIndex::supportsFilterCondition(
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* mmdr,
arangodb::aql::AstNode const* node,
arangodb::aql::Variable const* reference, bool reverse) {
// 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, mmdr, 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, mmdr, this);
}
return createInIterator(trx, mmdr, attrNode, valNode);
}
// operator type unsupported
return new EmptyIndexIterator(_collection, trx, mmdr, this);
}
/// @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);
}
/// @brief Transform the list of search slices to search values.
/// This will multiply all IN entries and simply return all other
/// entries.
void RocksDBEdgeIndex::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();
}
// ===================== Helpers ==================
/// @brief create the iterator
IndexIterator* RocksDBEdgeIndex::createEqIterator(
transaction::Methods* 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
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, mmdr, this, keys,
useCache(), _cache.get());
}
/// @brief create the iterator
IndexIterator* RocksDBEdgeIndex::createInIterator(
transaction::Methods* 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
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, mmdr, this, keys,
useCache(), _cache.get());
}
/// @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);
}
}
int RocksDBEdgeIndex::cleanup() {
rocksdb::TransactionDB* db = rocksutils::globalRocksDB();
rocksdb::CompactRangeOptions opts;
RocksDBKeyBounds bounds = RocksDBKeyBounds::EdgeIndex(_objectId);
rocksdb::Slice b = bounds.start(), e = bounds.end();
db->CompactRange(opts, &b, &e);
return TRI_ERROR_NO_ERROR;
}
void RocksDBEdgeIndex::serializeEstimate(std::string& output) const {
TRI_ASSERT(_estimator != nullptr);
_estimator->serialize(output);
}
bool RocksDBEdgeIndex::deserializeEstimate(RocksDBCounterManager* mgr) {
TRI_ASSERT(!ServerState::instance()->isCoordinator());
// We simply drop the current estimator and steal the one from recovery
// We are than save for resizing issues in our _estimator format
// and will use the old size.
TRI_ASSERT(mgr != nullptr);
auto tmp = mgr->stealIndexEstimator(_objectId);
if (tmp == nullptr) {
// We expected to receive a stored index estimate, however we got none.
// We use the freshly created estimator but have to recompute it.
return false;
}
_estimator.swap(tmp);
TRI_ASSERT(_estimator != nullptr);
return true;
}
void RocksDBEdgeIndex::recalculateEstimates() {
TRI_ASSERT(_estimator != nullptr);
_estimator->clear();
auto bounds = RocksDBKeyBounds::EdgeIndex(_objectId);
rocksutils::iterateBounds(bounds, [&](rocksdb::Iterator* it) {
uint64_t hash = RocksDBEdgeIndex::HashForKey(it->key());
_estimator->insert(hash);
});
}
Result RocksDBEdgeIndex::postprocessRemove(transaction::Methods* trx,
rocksdb::Slice const& key,
rocksdb::Slice const& value) {
// blacklist keys during truncate
blackListKey(key.data(), key.size());
uint64_t hash = RocksDBEdgeIndex::HashForKey(key);
_estimator->remove(hash);
return {TRI_ERROR_NO_ERROR};
}
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