foundationdb/fdbclient/PaxosConfigTransaction.acto...

431 lines
14 KiB
C++

/*
* PaxosConfigTransaction.actor.cpp
*
* 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.
*/
#include "fdbclient/DatabaseContext.h"
#include "fdbclient/PaxosConfigTransaction.h"
#include "flow/actorcompiler.h" // must be last include
class CommitQuorum {
ActorCollection actors{ false };
std::vector<ConfigTransactionInterface> ctis;
size_t failed{ 0 };
size_t successful{ 0 };
size_t maybeCommitted{ 0 };
Promise<Void> result;
Standalone<VectorRef<ConfigMutationRef>> mutations;
ConfigCommitAnnotation annotation;
ConfigTransactionCommitRequest getCommitRequest(ConfigGeneration generation) const {
return ConfigTransactionCommitRequest(generation, mutations, annotation);
}
void updateResult() {
if (successful >= ctis.size() / 2 + 1 && result.canBeSet()) {
result.send(Void());
} else if (failed >= ctis.size() / 2 + 1 && result.canBeSet()) {
// Rollforwards could cause a version that didn't have quorum to
// commit, so send commit_unknown_result instead of commit_failed.
result.sendError(commit_unknown_result());
} else {
// Check if it is possible to ever receive quorum agreement
auto totalRequestsOutstanding = ctis.size() - (failed + successful + maybeCommitted);
if ((failed + totalRequestsOutstanding < ctis.size() / 2 + 1) &&
(successful + totalRequestsOutstanding < ctis.size() / 2 + 1) && result.canBeSet()) {
result.sendError(commit_unknown_result());
}
}
}
ACTOR static Future<Void> addRequestActor(CommitQuorum* self,
ConfigGeneration generation,
ConfigTransactionInterface cti) {
try {
wait(retryBrokenPromise(cti.commit, self->getCommitRequest(generation)));
++self->successful;
} catch (Error& e) {
// self might be destroyed if this actor is canceled
if (e.code() == error_code_actor_cancelled) {
throw;
}
if (e.code() == error_code_not_committed) {
++self->failed;
} else {
++self->maybeCommitted;
}
}
self->updateResult();
return Void();
}
public:
CommitQuorum() = default;
explicit CommitQuorum(std::vector<ConfigTransactionInterface> const& ctis) : ctis(ctis) {}
void set(KeyRef key, ValueRef value) {
if (key == configTransactionDescriptionKey) {
annotation.description = ValueRef(annotation.arena(), value);
} else {
mutations.push_back_deep(mutations.arena(),
IKnobCollection::createSetMutation(mutations.arena(), key, value));
}
}
void clear(KeyRef key) {
if (key == configTransactionDescriptionKey) {
annotation.description = ""_sr;
} else {
mutations.push_back_deep(mutations.arena(), IKnobCollection::createClearMutation(mutations.arena(), key));
}
}
void setTimestamp() { annotation.timestamp = now(); }
size_t expectedSize() const { return annotation.expectedSize() + mutations.expectedSize(); }
Future<Void> commit(ConfigGeneration generation) {
// Send commit message to all replicas, even those that did not return the used replica.
// This way, slow replicas are kept up date.
for (const auto& cti : ctis) {
actors.add(addRequestActor(this, generation, cti));
}
return result.getFuture();
}
bool committed() const { return result.isSet(); }
};
class GetGenerationQuorum {
ActorCollection actors{ false };
std::vector<ConfigTransactionInterface> ctis;
std::map<ConfigGeneration, std::vector<ConfigTransactionInterface>> seenGenerations;
Promise<ConfigGeneration> result;
size_t totalRepliesReceived{ 0 };
size_t maxAgreement{ 0 };
Optional<Version> lastSeenLiveVersion;
Future<ConfigGeneration> getGenerationFuture;
ACTOR static Future<Void> addRequestActor(GetGenerationQuorum* self, ConfigTransactionInterface cti) {
ConfigTransactionGetGenerationReply reply = wait(
retryBrokenPromise(cti.getGeneration, ConfigTransactionGetGenerationRequest{ self->lastSeenLiveVersion }));
++self->totalRepliesReceived;
auto gen = reply.generation;
self->lastSeenLiveVersion = std::max(gen.liveVersion, self->lastSeenLiveVersion.orDefault(::invalidVersion));
auto& replicas = self->seenGenerations[gen];
replicas.push_back(cti);
self->maxAgreement = std::max(replicas.size(), self->maxAgreement);
if (replicas.size() >= self->ctis.size() / 2 + 1 && !self->result.isSet()) {
self->result.send(gen);
} else if (self->maxAgreement + (self->ctis.size() - self->totalRepliesReceived) <
(self->ctis.size() / 2 + 1)) {
if (!self->result.isError()) {
self->result.sendError(failed_to_reach_quorum());
}
}
return Void();
}
ACTOR static Future<ConfigGeneration> getGenerationActor(GetGenerationQuorum* self) {
state int retries = 0;
loop {
for (const auto& cti : self->ctis) {
self->actors.add(addRequestActor(self, cti));
}
try {
choose {
when(ConfigGeneration generation = wait(self->result.getFuture())) { return generation; }
when(wait(self->actors.getResult())) { ASSERT(false); }
}
} catch (Error& e) {
if (e.code() == error_code_failed_to_reach_quorum) {
TEST(true); // Failed to reach quorum getting generation
wait(delayJittered(0.01 * (1 << retries)));
++retries;
self->actors.clear(false);
self->result.reset();
self->totalRepliesReceived = 0;
self->maxAgreement = 0;
} else {
throw e;
}
}
}
}
public:
GetGenerationQuorum() = default;
explicit GetGenerationQuorum(std::vector<ConfigTransactionInterface> const& ctis,
Optional<Version> const& lastSeenLiveVersion = {})
: ctis(ctis), lastSeenLiveVersion(lastSeenLiveVersion) {}
Future<ConfigGeneration> getGeneration() {
if (!getGenerationFuture.isValid()) {
getGenerationFuture = getGenerationActor(this);
}
return getGenerationFuture;
}
bool isReady() const {
return getGenerationFuture.isValid() && getGenerationFuture.isReady() && !getGenerationFuture.isError();
}
Optional<ConfigGeneration> getCachedGeneration() const {
return isReady() ? getGenerationFuture.get() : Optional<ConfigGeneration>{};
}
std::vector<ConfigTransactionInterface> getReadReplicas() const {
ASSERT(isReady());
return seenGenerations.at(getGenerationFuture.get());
}
Optional<Version> getLastSeenLiveVersion() const { return lastSeenLiveVersion; }
};
class PaxosConfigTransactionImpl {
std::vector<ConfigTransactionInterface> ctis;
GetGenerationQuorum getGenerationQuorum;
CommitQuorum commitQuorum;
int numRetries{ 0 };
Optional<UID> dID;
Database cx;
ACTOR static Future<Optional<Value>> get(PaxosConfigTransactionImpl* self, Key key) {
state ConfigKey configKey = ConfigKey::decodeKey(key);
ConfigGeneration generation = wait(self->getGenerationQuorum.getGeneration());
// TODO: Load balance
ConfigTransactionGetReply reply = wait(retryBrokenPromise(
self->getGenerationQuorum.getReadReplicas()[0].get, ConfigTransactionGetRequest{ generation, configKey }));
if (reply.value.present()) {
return reply.value.get().toValue();
} else {
return Optional<Value>{};
}
}
ACTOR static Future<RangeResult> getConfigClasses(PaxosConfigTransactionImpl* self) {
ConfigGeneration generation = wait(self->getGenerationQuorum.getGeneration());
// TODO: Load balance
ConfigTransactionGetConfigClassesReply reply =
wait(retryBrokenPromise(self->getGenerationQuorum.getReadReplicas()[0].getClasses,
ConfigTransactionGetConfigClassesRequest{ generation }));
RangeResult result;
result.reserve(result.arena(), reply.configClasses.size());
for (const auto& configClass : reply.configClasses) {
result.push_back_deep(result.arena(), KeyValueRef(configClass, ""_sr));
}
return result;
}
ACTOR static Future<RangeResult> getKnobs(PaxosConfigTransactionImpl* self, Optional<Key> configClass) {
ConfigGeneration generation = wait(self->getGenerationQuorum.getGeneration());
// TODO: Load balance
ConfigTransactionGetKnobsReply reply =
wait(retryBrokenPromise(self->getGenerationQuorum.getReadReplicas()[0].getKnobs,
ConfigTransactionGetKnobsRequest{ generation, configClass }));
RangeResult result;
result.reserve(result.arena(), reply.knobNames.size());
for (const auto& knobName : reply.knobNames) {
result.push_back_deep(result.arena(), KeyValueRef(knobName, ""_sr));
}
return result;
}
ACTOR static Future<Void> commit(PaxosConfigTransactionImpl* self) {
ConfigGeneration generation = wait(self->getGenerationQuorum.getGeneration());
self->commitQuorum.setTimestamp();
wait(self->commitQuorum.commit(generation));
return Void();
}
ACTOR static Future<Void> onError(PaxosConfigTransactionImpl* self, Error e) {
// TODO: Improve this:
TraceEvent("ConfigIncrementOnError").error(e).detail("NumRetries", self->numRetries);
if (e.code() == error_code_transaction_too_old || e.code() == error_code_not_committed) {
wait(delay((1 << self->numRetries++) * 0.01 * deterministicRandom()->random01()));
self->reset();
return Void();
}
throw e;
}
public:
Future<Version> getReadVersion() {
return map(getGenerationQuorum.getGeneration(), [](auto const& gen) { return gen.committedVersion; });
}
Optional<Version> getCachedReadVersion() const {
auto gen = getGenerationQuorum.getCachedGeneration();
if (gen.present()) {
return gen.get().committedVersion;
} else {
return {};
}
}
Version getCommittedVersion() const {
return commitQuorum.committed() ? getGenerationQuorum.getCachedGeneration().get().liveVersion
: ::invalidVersion;
}
int64_t getApproximateSize() const { return commitQuorum.expectedSize(); }
void set(KeyRef key, ValueRef value) { commitQuorum.set(key, value); }
void clear(KeyRef key) { commitQuorum.clear(key); }
Future<Optional<Value>> get(Key const& key) { return get(this, key); }
Future<RangeResult> getRange(KeyRangeRef keys) {
if (keys == configClassKeys) {
return getConfigClasses(this);
} else if (keys == globalConfigKnobKeys) {
return getKnobs(this, {});
} else if (configKnobKeys.contains(keys) && keys.singleKeyRange()) {
const auto configClass = keys.begin.removePrefix(configKnobKeys.begin);
return getKnobs(this, configClass);
} else {
throw invalid_config_db_range_read();
}
}
Future<Void> onError(Error const& e) { return onError(this, e); }
void debugTransaction(UID dID) { this->dID = dID; }
void reset() {
getGenerationQuorum = GetGenerationQuorum{ ctis };
commitQuorum = CommitQuorum{ ctis };
}
void fullReset() {
numRetries = 0;
dID = {};
reset();
}
void checkDeferredError(Error const& deferredError) const {
if (deferredError.code() != invalid_error_code) {
throw deferredError;
}
if (cx.getPtr()) {
cx->checkDeferredError();
}
}
Future<Void> commit() { return commit(this); }
PaxosConfigTransactionImpl(Database const& cx) : cx(cx) {
auto coordinators = cx->getConnectionRecord()->getConnectionString().coordinators();
ctis.reserve(coordinators.size());
for (const auto& coordinator : coordinators) {
ctis.emplace_back(coordinator);
}
getGenerationQuorum = GetGenerationQuorum{ ctis };
commitQuorum = CommitQuorum{ ctis };
}
PaxosConfigTransactionImpl(std::vector<ConfigTransactionInterface> const& ctis)
: ctis(ctis), getGenerationQuorum(ctis), commitQuorum(ctis) {}
};
Future<Version> PaxosConfigTransaction::getReadVersion() {
return impl->getReadVersion();
}
Optional<Version> PaxosConfigTransaction::getCachedReadVersion() const {
return impl->getCachedReadVersion();
}
Future<Optional<Value>> PaxosConfigTransaction::get(Key const& key, Snapshot) {
return impl->get(key);
}
Future<RangeResult> PaxosConfigTransaction::getRange(KeySelector const& begin,
KeySelector const& end,
int limit,
Snapshot snapshot,
Reverse reverse) {
if (reverse) {
throw client_invalid_operation();
}
return impl->getRange(KeyRangeRef(begin.getKey(), end.getKey()));
}
Future<RangeResult> PaxosConfigTransaction::getRange(KeySelector begin,
KeySelector end,
GetRangeLimits limits,
Snapshot snapshot,
Reverse reverse) {
if (reverse) {
throw client_invalid_operation();
}
return impl->getRange(KeyRangeRef(begin.getKey(), end.getKey()));
}
void PaxosConfigTransaction::set(KeyRef const& key, ValueRef const& value) {
return impl->set(key, value);
}
void PaxosConfigTransaction::clear(KeyRef const& key) {
return impl->clear(key);
}
Future<Void> PaxosConfigTransaction::commit() {
return impl->commit();
}
Version PaxosConfigTransaction::getCommittedVersion() const {
return impl->getCommittedVersion();
}
int64_t PaxosConfigTransaction::getApproximateSize() const {
return impl->getApproximateSize();
}
void PaxosConfigTransaction::setOption(FDBTransactionOptions::Option option, Optional<StringRef> value) {
// TODO: Support using this option to determine atomicity
}
Future<Void> PaxosConfigTransaction::onError(Error const& e) {
return impl->onError(e);
}
void PaxosConfigTransaction::cancel() {
// TODO: Implement someday
throw client_invalid_operation();
}
void PaxosConfigTransaction::reset() {
impl->reset();
}
void PaxosConfigTransaction::fullReset() {
impl->fullReset();
}
void PaxosConfigTransaction::debugTransaction(UID dID) {
impl->debugTransaction(dID);
}
void PaxosConfigTransaction::checkDeferredError() const {
impl->checkDeferredError(deferredError);
}
PaxosConfigTransaction::PaxosConfigTransaction(std::vector<ConfigTransactionInterface> const& ctis)
: impl(PImpl<PaxosConfigTransactionImpl>::create(ctis)) {}
PaxosConfigTransaction::PaxosConfigTransaction() = default;
PaxosConfigTransaction::~PaxosConfigTransaction() = default;
void PaxosConfigTransaction::setDatabase(Database const& cx) {
impl = PImpl<PaxosConfigTransactionImpl>::create(cx);
}