foundationdb/fdbrpc/ReplicationPolicy.h

325 lines
12 KiB
C++

/*
* ReplicationPolicy.h
*
* This source file is part of the FoundationDB open source project
*
* Copyright 2013-2018 Apple Inc. and the FoundationDB project authors
*
* 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.
*/
#ifndef FLOW_REPLICATION_POLICY_H
#define FLOW_REPLICATION_POLICY_H
#pragma once
#include "flow/flow.h"
#include "fdbrpc/ReplicationTypes.h"
template <class Ar>
void serializeReplicationPolicy(Ar& ar, Reference<IReplicationPolicy>& policy);
extern void testReplicationPolicy(int nTests);
struct IReplicationPolicy : public ReferenceCounted<IReplicationPolicy> {
IReplicationPolicy() {}
virtual ~IReplicationPolicy() {}
virtual std::string name() const = 0;
virtual std::string info() const = 0;
virtual void addref() { ReferenceCounted<IReplicationPolicy>::addref(); }
virtual void delref() { ReferenceCounted<IReplicationPolicy>::delref(); }
virtual int maxResults() const = 0;
virtual int depth() const = 0;
virtual bool selectReplicas(Reference<LocalitySet>& fromServers,
std::vector<LocalityEntry> const& alsoServers,
std::vector<LocalityEntry>& results) = 0;
virtual void traceLocalityRecords(Reference<LocalitySet> const& fromServers);
virtual void traceOneLocalityRecord(Reference<LocalityRecord> record, Reference<LocalitySet> const& fromServers);
virtual bool validate(std::vector<LocalityEntry> const& solutionSet,
Reference<LocalitySet> const& fromServers) const = 0;
bool operator==(const IReplicationPolicy& r) const { return info() == r.info(); }
bool operator!=(const IReplicationPolicy& r) const { return info() != r.info(); }
template <class Ar>
void serialize(Ar& ar) {
static_assert(!is_fb_function<Ar>);
Reference<IReplicationPolicy> refThis(this);
serializeReplicationPolicy(ar, refThis);
refThis->delref_no_destroy();
}
virtual void deserializationDone() = 0;
// Utility functions
bool selectReplicas(Reference<LocalitySet>& fromServers, std::vector<LocalityEntry>& results);
bool validate(Reference<LocalitySet> const& solutionSet) const;
bool validateFull(bool solved,
std::vector<LocalityEntry> const& solutionSet,
std::vector<LocalityEntry> const& alsoServers,
Reference<LocalitySet> const& fromServers);
// Returns a set of the attributes that this policy uses in selection and validation.
std::set<std::string> attributeKeys() const {
std::set<std::string> keys;
this->attributeKeys(&keys);
return keys;
}
virtual void attributeKeys(std::set<std::string>*) const = 0;
};
template <class Archive>
inline void load(Archive& ar, Reference<IReplicationPolicy>& value) {
bool present;
ar >> present;
if (present) {
serializeReplicationPolicy(ar, value);
} else {
value.clear();
}
}
template <class Archive>
inline void save(Archive& ar, const Reference<IReplicationPolicy>& value) {
bool present = (value.getPtr() != nullptr);
ar << present;
if (present) {
serializeReplicationPolicy(ar, (Reference<IReplicationPolicy>&)value);
}
}
struct PolicyOne final : IReplicationPolicy, public ReferenceCounted<PolicyOne> {
PolicyOne(){};
explicit PolicyOne(const PolicyOne& o) {}
std::string name() const override { return "One"; }
std::string info() const override { return "1"; }
int maxResults() const override { return 1; }
int depth() const override { return 1; }
bool validate(std::vector<LocalityEntry> const& solutionSet,
Reference<LocalitySet> const& fromServers) const override;
bool selectReplicas(Reference<LocalitySet>& fromServers,
std::vector<LocalityEntry> const& alsoServers,
std::vector<LocalityEntry>& results) override;
template <class Ar>
void serialize(Ar& ar) {
static_assert(!is_fb_function<Ar>);
}
void deserializationDone() override {}
void attributeKeys(std::set<std::string>* set) const override { return; }
};
struct PolicyAcross final : IReplicationPolicy, public ReferenceCounted<PolicyAcross> {
friend struct serializable_traits<PolicyAcross*>;
PolicyAcross(int count, std::string const& attribKey, Reference<IReplicationPolicy> const policy);
explicit PolicyAcross();
explicit PolicyAcross(const PolicyAcross& other) : PolicyAcross(other._count, other._attribKey, other._policy) {}
~PolicyAcross() override;
std::string name() const override { return "Across"; }
std::string embeddedPolicyName() const { return _policy->name(); }
int getCount() const { return _count; }
std::string info() const override { return format("%s^%d x ", _attribKey.c_str(), _count) + _policy->info(); }
int maxResults() const override { return _count * _policy->maxResults(); }
int depth() const override { return 1 + _policy->depth(); }
bool validate(std::vector<LocalityEntry> const& solutionSet,
Reference<LocalitySet> const& fromServers) const override;
bool selectReplicas(Reference<LocalitySet>& fromServers,
std::vector<LocalityEntry> const& alsoServers,
std::vector<LocalityEntry>& results) override;
template <class Ar>
void serialize(Ar& ar) {
static_assert(!is_fb_function<Ar>);
serializer(ar, _attribKey, _count);
serializeReplicationPolicy(ar, _policy);
}
void deserializationDone() override {}
static bool compareAddedResults(const std::pair<int, int>& rhs, const std::pair<int, int>& lhs) {
return (rhs.first < lhs.first) || (!(lhs.first < rhs.first) && (rhs.second < lhs.second));
}
void attributeKeys(std::set<std::string>* set) const override {
set->insert(_attribKey);
_policy->attributeKeys(set);
}
Reference<IReplicationPolicy> embeddedPolicy() const { return _policy; }
const std::string& attributeKey() const { return _attribKey; }
protected:
int _count;
std::string _attribKey;
Reference<IReplicationPolicy> _policy;
// Cache temporary members
std::vector<AttribValue> _usedValues;
std::vector<LocalityEntry> _newResults;
Reference<LocalitySet> _selected;
VectorRef<std::pair<int, int>> _addedResults;
Arena _arena;
};
struct PolicyAnd final : IReplicationPolicy, public ReferenceCounted<PolicyAnd> {
friend struct serializable_traits<PolicyAnd*>;
PolicyAnd(std::vector<Reference<IReplicationPolicy>> policies) : _policies(policies), _sortedPolicies(policies) {
// Sort the policy array
std::sort(_sortedPolicies.begin(), _sortedPolicies.end(), PolicyAnd::comparePolicy);
}
explicit PolicyAnd(const PolicyAnd& other) : _policies(other._policies), _sortedPolicies(other._sortedPolicies) {}
explicit PolicyAnd() {}
std::string name() const override { return "And"; }
std::string info() const override {
std::string infoText;
for (auto& policy : _policies) {
infoText += ((infoText.length()) ? " & (" : "(") + policy->info() + ")";
}
if (_policies.size())
infoText = "(" + infoText + ")";
return infoText;
}
int maxResults() const override {
int resultsMax = 0;
for (auto& policy : _policies) {
resultsMax += policy->maxResults();
}
return resultsMax;
}
int depth() const override {
int policyDepth, depthMax = 0;
for (auto& policy : _policies) {
policyDepth = policy->depth();
if (policyDepth > depthMax) {
depthMax = policyDepth;
}
}
return depthMax;
}
bool validate(std::vector<LocalityEntry> const& solutionSet,
Reference<LocalitySet> const& fromServers) const override;
bool selectReplicas(Reference<LocalitySet>& fromServers,
std::vector<LocalityEntry> const& alsoServers,
std::vector<LocalityEntry>& results) override;
static bool comparePolicy(const Reference<IReplicationPolicy>& rhs, const Reference<IReplicationPolicy>& lhs) {
return (lhs->maxResults() < rhs->maxResults()) ||
(!(rhs->maxResults() < lhs->maxResults()) && (lhs->depth() < rhs->depth()));
}
template <class Ar>
void serialize(Ar& ar) {
static_assert(!is_fb_function<Ar>);
int count = _policies.size();
serializer(ar, count);
_policies.resize(count);
for (int i = 0; i < count; i++) {
serializeReplicationPolicy(ar, _policies[i]);
}
if (Ar::isDeserializing) {
_sortedPolicies = _policies;
std::sort(_sortedPolicies.begin(), _sortedPolicies.end(), PolicyAnd::comparePolicy);
}
}
void deserializationDone() override {
_sortedPolicies = _policies;
std::sort(_sortedPolicies.begin(), _sortedPolicies.end(), PolicyAnd::comparePolicy);
}
void attributeKeys(std::set<std::string>* set) const override {
for (const Reference<IReplicationPolicy>& r : _policies) {
r->attributeKeys(set);
}
}
protected:
std::vector<Reference<IReplicationPolicy>> _policies;
std::vector<Reference<IReplicationPolicy>> _sortedPolicies;
};
template <class Ar>
void serializeReplicationPolicy(Ar& ar, Reference<IReplicationPolicy>& policy) {
// To change this serialization, ProtocolVersion::ReplicationPolicy must be updated, and downgrades need to be
// considered
if (Ar::isDeserializing) {
StringRef name;
serializer(ar, name);
if (name == LiteralStringRef("One")) {
PolicyOne* pointer = new PolicyOne();
pointer->serialize(ar);
policy = Reference<IReplicationPolicy>(pointer);
} else if (name == LiteralStringRef("Across")) {
PolicyAcross* pointer = new PolicyAcross(0, "", Reference<IReplicationPolicy>());
pointer->serialize(ar);
policy = Reference<IReplicationPolicy>(pointer);
} else if (name == LiteralStringRef("And")) {
PolicyAnd* pointer = new PolicyAnd{};
pointer->serialize(ar);
policy = Reference<IReplicationPolicy>(pointer);
} else if (name == LiteralStringRef("None")) {
policy = Reference<IReplicationPolicy>();
} else {
TraceEvent(SevError, "SerializingInvalidPolicyType").detail("PolicyName", name);
}
} else {
std::string name = policy ? policy->name() : "None";
Standalone<StringRef> nameRef = StringRef(name);
serializer(ar, nameRef);
if (name == "One") {
((PolicyOne*)policy.getPtr())->serialize(ar);
} else if (name == "Across") {
((PolicyAcross*)policy.getPtr())->serialize(ar);
} else if (name == "And") {
((PolicyAnd*)policy.getPtr())->serialize(ar);
} else if (name == "None") {
} else {
TraceEvent(SevError, "SerializingInvalidPolicyType").detail("PolicyName", name);
}
}
}
template <>
struct dynamic_size_traits<Reference<IReplicationPolicy>> : std::true_type {
private:
using T = Reference<IReplicationPolicy>;
public:
template <class Context>
static size_t size(const T& value, Context& context) {
// size gets called multiple times. If this becomes a performance problem, we can perform the
// serialization once and cache the result as a mutable member of IReplicationPolicy
BinaryWriter writer{ AssumeVersion(context.protocolVersion()) };
::save(writer, value);
return writer.getLength();
}
// Guaranteed to be called only once during serialization
template <class Context>
static void save(uint8_t* out, const T& value, Context& context) {
BinaryWriter writer{ AssumeVersion(context.protocolVersion()) };
::save(writer, value);
memcpy(out, writer.getData(), writer.getLength());
}
// Context is an arbitrary type that is plumbed by reference throughout the
// load call tree.
template <class Context>
static void load(const uint8_t* buf, size_t sz, Reference<IReplicationPolicy>& value, Context& context) {
StringRef str(buf, sz);
BinaryReader reader(str, AssumeVersion(context.protocolVersion()));
::load(reader, value);
}
};
#endif