363 lines
13 KiB
C++
363 lines
13 KiB
C++
/*
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* ReplicationPolicy.cpp
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*
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* This source file is part of the FoundationDB open source project
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*
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* Copyright 2013-2022 Apple Inc. and the FoundationDB project authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "fdbrpc/ReplicationPolicy.h"
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#include "fdbrpc/Replication.h"
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#include "flow/UnitTest.h"
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bool IReplicationPolicy::selectReplicas(Reference<LocalitySet>& fromServers, std::vector<LocalityEntry>& results) {
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return selectReplicas(fromServers, std::vector<LocalityEntry>(), results);
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}
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bool IReplicationPolicy::validate(Reference<LocalitySet> const& solutionSet) const {
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return validate(solutionSet->getEntries(), solutionSet);
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}
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bool IReplicationPolicy::validateFull(bool solved,
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std::vector<LocalityEntry> const& solutionSet,
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std::vector<LocalityEntry> const& alsoServers,
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Reference<LocalitySet> const& fromServers) {
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bool valid = true;
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std::vector<LocalityEntry> totalSolution(solutionSet);
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// Append the also servers, if any
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if (alsoServers.size()) {
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totalSolution.reserve(totalSolution.size() + alsoServers.size());
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totalSolution.insert(totalSolution.end(), alsoServers.begin(), alsoServers.end());
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}
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if (!solved) {
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if (validate(totalSolution, fromServers)) {
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valid = false;
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} else if (validate(fromServers->getGroupEntries(), fromServers)) {
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valid = false;
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}
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} else if (!validate(totalSolution, fromServers)) {
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valid = false;
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} else if (solutionSet.empty()) {
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if (!validate(alsoServers, fromServers)) {
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valid = false;
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}
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} else {
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auto lastSolutionIndex = solutionSet.size() - 1;
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auto missingEntry = totalSolution[lastSolutionIndex];
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totalSolution[lastSolutionIndex] = totalSolution.back();
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totalSolution.pop_back();
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for (int index = 0; index < solutionSet.size() && index < totalSolution.size(); index++) {
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if (validate(totalSolution, fromServers)) {
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valid = false;
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break;
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}
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auto tempMissing = totalSolution[index];
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totalSolution[index] = missingEntry;
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missingEntry = tempMissing;
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}
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}
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return valid;
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}
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bool PolicyOne::selectReplicas(Reference<LocalitySet>& fromServers,
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std::vector<LocalityEntry> const& alsoServers,
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std::vector<LocalityEntry>& results) {
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int totalUsed = 0;
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int itemsUsed = 0;
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if (alsoServers.size()) {
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totalUsed++;
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} else if (fromServers->size()) {
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auto randomEntry = fromServers->random();
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results.push_back(randomEntry);
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itemsUsed++;
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totalUsed++;
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}
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return (totalUsed > 0);
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}
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bool PolicyOne::validate(std::vector<LocalityEntry> const& solutionSet,
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Reference<LocalitySet> const& fromServers) const {
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return ((solutionSet.size() > 0) && (fromServers->size() > 0));
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}
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PolicyAcross::PolicyAcross(int count, std::string const& attribKey, Reference<IReplicationPolicy> const policy)
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: _count(count), _attribKey(attribKey), _policy(policy) {
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return;
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}
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PolicyAcross::PolicyAcross() : _policy(new PolicyOne()) {}
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PolicyAcross::~PolicyAcross() {}
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// Debug purpose only
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// Trace all record entries to help debug
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// fromServers is the servers locality to be printed out.
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void IReplicationPolicy::traceLocalityRecords(Reference<LocalitySet> const& fromServers) {
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std::vector<Reference<LocalityRecord>> const& recordArray = fromServers->getRecordArray();
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TraceEvent("LocalityRecordArray").detail("Size", recordArray.size());
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for (auto& record : recordArray) {
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traceOneLocalityRecord(record, fromServers);
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}
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}
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void IReplicationPolicy::traceOneLocalityRecord(Reference<LocalityRecord> record,
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Reference<LocalitySet> const& fromServers) {
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int localityEntryIndex = record->_entryIndex._id;
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Reference<KeyValueMap> const& dataMap = record->_dataMap;
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std::vector<AttribRecord> const& keyValueArray = dataMap->_keyvaluearray;
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TraceEvent("LocalityRecordInfo")
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.detail("EntryIndex", localityEntryIndex)
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.detail("KeyValueArraySize", keyValueArray.size());
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for (int i = 0; i < keyValueArray.size(); ++i) {
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AttribRecord attribRecord = keyValueArray[i]; // first is key, second is value
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TraceEvent("LocalityRecordInfo")
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.detail("EntryIndex", localityEntryIndex)
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.detail("ArrayIndex", i)
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.detail("Key", attribRecord.first._id)
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.detail("Value", attribRecord.second._id)
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.detail("KeyName", fromServers->keyText(attribRecord.first))
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.detail("ValueName", fromServers->valueText(attribRecord.second));
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}
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}
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// Validate if the team satisfies the replication policy
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// LocalitySet is the base class about the locality information
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// solutionSet is the team to be validated
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// fromServers is the location information of all servers
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// return true if the team satisfies the policy; false otherwise
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bool PolicyAcross::validate(std::vector<LocalityEntry> const& solutionSet,
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Reference<LocalitySet> const& fromServers) const {
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bool valid = true;
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int count = 0;
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// Get the indexKey from the policy name (e.g., zoneid) in _attribKey
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AttribKey indexKey = fromServers->keyIndex(_attribKey);
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auto groupIndexKey = fromServers->getGroupKeyIndex(indexKey);
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std::map<AttribValue, std::vector<LocalityEntry>> validMap;
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for (auto& item : solutionSet) {
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auto value = fromServers->getValueViaGroupKey(item, groupIndexKey);
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if (value.present()) {
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auto itValue = validMap.find(value.get());
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if (itValue != validMap.end()) {
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validMap[value.get()].push_back(item);
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} else {
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validMap[value.get()] = { item };
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}
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}
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}
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if (validMap.size() < _count) {
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valid = false;
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} else {
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for (auto& itValid : validMap) {
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// itValid.second is the vector of LocalityEntries that belong to the same locality
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if (_policy->validate(itValid.second, fromServers)) {
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count++;
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}
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}
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if (count < _count) {
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valid = false;
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}
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}
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return valid;
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}
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// Choose new servers from "least utilized" alsoServers and append the new servers to results
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// fromserverse are the servers that have already been chosen and
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// that should be excluded from being selected as replicas.
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// FIXME: Simplify this function, such as removing unnecessary printf
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// fromServers are the servers that must have;
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// alsoServers are the servers you can choose.
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bool PolicyAcross::selectReplicas(Reference<LocalitySet>& fromServers,
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std::vector<LocalityEntry> const& alsoServers,
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std::vector<LocalityEntry>& results) {
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int count = 0;
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AttribKey indexKey = fromServers->keyIndex(_attribKey);
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auto groupIndexKey = fromServers->getGroupKeyIndex(indexKey);
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int resultsSize, resultsAdded;
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int resultsInit = results.size();
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// Clear the member variables
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_usedValues.clear();
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_newResults.clear();
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_addedResults.resize(_arena, 0);
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for (auto& alsoServer : alsoServers) {
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auto value = fromServers->getValueViaGroupKey(alsoServer, groupIndexKey);
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if (value.present()) {
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auto lowerBound = std::lower_bound(_usedValues.begin(), _usedValues.end(), value.get());
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if ((lowerBound == _usedValues.end()) || (*lowerBound != value.get())) {
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//_selected is a set of processes that have the same indexKey and indexValue (value)
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_selected = fromServers->restrict(indexKey, value.get());
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if (_selected->size()) {
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// Pass only the also array item which are valid for the value
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resultsSize = _newResults.size();
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if (_policy->selectReplicas(_selected, alsoServers, _newResults)) {
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resultsAdded = _newResults.size() - resultsSize;
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if (!resultsAdded) {
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count++;
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} else {
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_addedResults.push_back(_arena, std::pair<int, int>(resultsAdded, resultsSize));
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}
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if (count >= _count)
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break;
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_usedValues.insert(lowerBound, value.get());
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}
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}
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}
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}
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}
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// Process the remaining results, if present
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if ((count < _count) && (_addedResults.size())) {
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// Sort the added results array
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std::sort(_addedResults.begin(), _addedResults.end(), PolicyAcross::compareAddedResults);
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if (g_replicationdebug > 0) {
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LocalitySet::staticDisplayEntries(fromServers, alsoServers, "also");
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LocalitySet::staticDisplayEntries(fromServers, results, "results");
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LocalitySet::staticDisplayEntries(fromServers, _newResults, "add items");
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}
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for (auto& addedResult : _addedResults) {
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count++;
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results.reserve(results.size() + addedResult.first);
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results.insert(results.end(),
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_newResults.begin() + addedResult.second,
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_newResults.begin() + addedResult.second + addedResult.first);
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if (count >= _count)
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break;
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}
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if (g_replicationdebug > 0) {
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LocalitySet::staticDisplayEntries(fromServers, results, "results");
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}
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}
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// Cannot find replica from the least used alsoServers, now try to find replicas from all servers
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// Process the remaining values
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if (count < _count) {
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int recordIndex;
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// Use mutable array so that swaps does not affect actual element array
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auto& mutableArray = fromServers->getMutableEntries();
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for (int checksLeft = fromServers->size(); checksLeft > 0; checksLeft--) {
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if (g_replicationdebug > 0) {
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LocalitySet::staticDisplayEntries(fromServers, mutableArray, "mutable");
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}
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recordIndex = deterministicRandom()->randomInt(0, checksLeft);
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auto& entry = mutableArray[recordIndex];
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auto value = fromServers->getValueViaGroupKey(entry, groupIndexKey);
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if (value.present()) {
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auto lowerBound = std::lower_bound(_usedValues.begin(), _usedValues.end(), value.get());
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if ((lowerBound == _usedValues.end()) || (*lowerBound != value.get())) {
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_selected = fromServers->restrict(indexKey, value.get());
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if (_selected->size()) {
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if (_policy->selectReplicas(_selected, emptyEntryArray, results)) {
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count++;
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if (count >= _count)
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break;
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_usedValues.insert(lowerBound, value.get());
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}
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}
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}
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}
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if (recordIndex != checksLeft - 1) {
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fromServers->swapMutableRecords(recordIndex, checksLeft - 1);
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}
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}
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}
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// Clear the return array, if not satified
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if (count < _count) {
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results.resize(resultsInit);
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count = 0;
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}
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return (count >= _count);
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}
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bool PolicyAnd::validate(std::vector<LocalityEntry> const& solutionSet,
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Reference<LocalitySet> const& fromServers) const {
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bool valid = true;
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for (auto& policy : _policies) {
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if (!policy->validate(solutionSet, fromServers)) {
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valid = false;
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break;
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}
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}
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return valid;
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}
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bool PolicyAnd::selectReplicas(Reference<LocalitySet>& fromServers,
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std::vector<LocalityEntry> const& alsoServers,
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std::vector<LocalityEntry>& results) {
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bool passed = true;
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std::vector<LocalityEntry> newResults(alsoServers);
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// Ensure that the results array is large enough
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if (newResults.capacity() < fromServers->size()) {
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newResults.reserve(fromServers->size());
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}
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for (auto& policy : _sortedPolicies) {
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if (!policy->selectReplicas(fromServers, newResults, newResults)) {
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passed = false;
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break;
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}
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}
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if ((passed) && (newResults.size() > alsoServers.size())) {
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results.reserve(results.size() + newResults.size() - alsoServers.size());
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results.insert(results.end(), newResults.begin() + alsoServers.size(), newResults.end());
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}
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return passed;
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}
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void testPolicySerialization(Reference<IReplicationPolicy>& policy) {
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std::string policyInfo = policy->info();
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BinaryWriter writer(IncludeVersion());
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serializeReplicationPolicy(writer, policy);
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BinaryReader reader(writer.getData(), writer.getLength(), IncludeVersion());
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Reference<IReplicationPolicy> copy;
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serializeReplicationPolicy(reader, copy);
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ASSERT(policy->info() == copy->info());
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}
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void testReplicationPolicy(int nTests) {
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Reference<IReplicationPolicy> policy =
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Reference<IReplicationPolicy>(new PolicyAcross(1, "data_hall", Reference<IReplicationPolicy>(new PolicyOne())));
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testPolicySerialization(policy);
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policy = Reference<IReplicationPolicy>(
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new PolicyAnd({ Reference<IReplicationPolicy>(
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new PolicyAcross(2,
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"data_center",
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Reference<IReplicationPolicy>(new PolicyAcross(
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3, "rack", Reference<IReplicationPolicy>(new PolicyOne()))))),
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Reference<IReplicationPolicy>(
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new PolicyAcross(2,
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"data_center",
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Reference<IReplicationPolicy>(new PolicyAcross(
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2, "data_hall", Reference<IReplicationPolicy>(new PolicyOne()))))) }));
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testPolicySerialization(policy);
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}
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TEST_CASE("/ReplicationPolicy/Serialization") {
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testReplicationPolicy(1);
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return Void();
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}
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