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foundationdb/fdbserver/LogSystem.h

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/*
* LogSystem.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 FDBSERVER_LOGSYSTEM_H
#define FDBSERVER_LOGSYSTEM_H
#include <set>
#include <vector>
#include "fdbserver/TLogInterface.h"
#include "fdbserver/WorkerInterface.actor.h"
#include "fdbclient/DatabaseConfiguration.h"
#include "flow/IndexedSet.h"
#include "fdbrpc/ReplicationPolicy.h"
#include "fdbrpc/Locality.h"
#include "fdbrpc/Replication.h"
struct DBCoreState;
struct TLogSet;
struct CoreTLogSet;
class LogSet : NonCopyable, public ReferenceCounted<LogSet> {
public:
std::vector<Reference<AsyncVar<OptionalInterface<TLogInterface>>>> logServers;
std::vector<Reference<AsyncVar<OptionalInterface<TLogInterface>>>> logRouters;
int32_t tLogWriteAntiQuorum;
int32_t tLogReplicationFactor;
std::vector< LocalityData > tLogLocalities; // Stores the localities of the log servers
TLogVersion tLogVersion;
Reference<IReplicationPolicy> tLogPolicy;
Reference<LocalitySet> logServerSet;
std::vector<int> logIndexArray;
std::vector<LocalityEntry> logEntryArray;
bool isLocal;
int8_t locality;
Version startVersion;
std::vector<Future<TLogLockResult>> replies;
std::vector<std::vector<int>> satelliteTagLocations;
LogSet() : tLogWriteAntiQuorum(0), tLogReplicationFactor(0), isLocal(true), locality(tagLocalityInvalid), startVersion(invalidVersion) {}
LogSet(const TLogSet& tlogSet);
LogSet(const CoreTLogSet& coreSet);
std::string logRouterString() {
std::string result;
for(int i = 0; i < logRouters.size(); i++) {
if(i>0) {
result += ", ";
}
result += logRouters[i]->get().id().toString();
}
return result;
}
bool hasLogRouter(UID id) {
for (const auto& router : logRouters) {
if (router->get().id() == id) {
return true;
}
}
return false;
}
std::string logServerString() {
std::string result;
for(int i = 0; i < logServers.size(); i++) {
if(i>0) {
result += ", ";
}
result += logServers[i]->get().id().toString();
}
return result;
}
void populateSatelliteTagLocations(int logRouterTags, int oldLogRouterTags) {
satelliteTagLocations.clear();
satelliteTagLocations.resize(std::max(logRouterTags,oldLogRouterTags) + 1);
std::map<int,int> server_usedBest;
std::set<std::pair<int,int>> used_servers;
for(int i = 0; i < tLogLocalities.size(); i++) {
used_servers.insert(std::make_pair(0,i));
}
Reference<LocalitySet> serverSet = Reference<LocalitySet>(new LocalityMap<std::pair<int,int>>());
LocalityMap<std::pair<int,int>>* serverMap = (LocalityMap<std::pair<int,int>>*) serverSet.getPtr();
std::vector<std::pair<int,int>> resultPairs;
for(int loc = 0; loc < satelliteTagLocations.size(); loc++) {
int team = loc;
if(loc < logRouterTags) {
team = loc + 1;
} else if(loc == logRouterTags) {
team = 0;
}
bool teamComplete = false;
alsoServers.resize(1);
serverMap->clear();
resultPairs.clear();
for(auto& used_idx : used_servers) {
auto entry = serverMap->add(tLogLocalities[used_idx.second], &used_idx);
if(!resultPairs.size()) {
resultPairs.push_back(used_idx);
alsoServers[0] = entry;
}
resultEntries.clear();
if( serverSet->selectReplicas(tLogPolicy, alsoServers, resultEntries) ) {
for(auto& entry : resultEntries) {
resultPairs.push_back(*serverMap->getObject(entry));
}
int firstBestUsed = server_usedBest[resultPairs[0].second];
for(int i = 1; i < resultPairs.size(); i++) {
int thisBestUsed = server_usedBest[resultPairs[i].second];
if(thisBestUsed < firstBestUsed) {
std::swap(resultPairs[0], resultPairs[i]);
firstBestUsed = thisBestUsed;
}
}
server_usedBest[resultPairs[0].second]++;
for(auto& res : resultPairs) {
satelliteTagLocations[team].push_back(res.second);
used_servers.erase(res);
res.first++;
used_servers.insert(res);
}
teamComplete = true;
break;
}
}
ASSERT(teamComplete);
}
checkSatelliteTagLocations();
}
void checkSatelliteTagLocations() {
std::vector<int> usedBest;
std::vector<int> used;
usedBest.resize(tLogLocalities.size());
used.resize(tLogLocalities.size());
for(auto team : satelliteTagLocations) {
usedBest[team[0]]++;
for(auto loc : team) {
used[loc]++;
}
}
int minUsedBest = satelliteTagLocations.size();
int maxUsedBest = 0;
for(auto i : usedBest) {
minUsedBest = std::min(minUsedBest, i);
maxUsedBest = std::max(maxUsedBest, i);
}
int minUsed = satelliteTagLocations.size();
int maxUsed = 0;
for(auto i : used) {
minUsed = std::min(minUsed, i);
maxUsed = std::max(maxUsed, i);
}
bool foundDuplicate = false;
std::set<Optional<Key>> zones;
std::set<Optional<Key>> dcs;
for(auto& loc : tLogLocalities) {
if(zones.count(loc.zoneId())) {
foundDuplicate = true;
break;
}
zones.insert(loc.zoneId());
dcs.insert(loc.dcId());
}
bool moreThanOneDC = dcs.size() > 1 ? true : false;
TraceEvent(((maxUsed - minUsed > 1) || (maxUsedBest - minUsedBest > 1)) ? (g_network->isSimulated() && !foundDuplicate && !moreThanOneDC ? SevError : SevWarnAlways) : SevInfo, "CheckSatelliteTagLocations").detail("MinUsed", minUsed).detail("MaxUsed", maxUsed).detail("MinUsedBest", minUsedBest).detail("MaxUsedBest", maxUsedBest).detail("DuplicateZones", foundDuplicate).detail("NumOfDCs", dcs.size());
}
int bestLocationFor( Tag tag ) {
if(locality == tagLocalitySatellite) {
return satelliteTagLocations[tag == txsTag ? 0 : tag.id + 1][0];
}
//the following logic supports upgrades from 5.X
if(tag == txsTag) return txsTagOld % logServers.size();
return tag.id % logServers.size();
}
void updateLocalitySet( std::vector<LocalityData> const& localities ) {
LocalityMap<int>* logServerMap;
logServerSet = Reference<LocalitySet>(new LocalityMap<int>());
logServerMap = (LocalityMap<int>*) logServerSet.getPtr();
logEntryArray.clear();
logEntryArray.reserve(localities.size());
logIndexArray.clear();
logIndexArray.reserve(localities.size());
for( int i = 0; i < localities.size(); i++ ) {
logIndexArray.push_back(i);
logEntryArray.push_back(logServerMap->add(localities[i], &logIndexArray.back()));
}
}
bool satisfiesPolicy( const std::vector<LocalityEntry>& locations ) {
resultEntries.clear();
// Run the policy, assert if unable to satify
bool result = logServerSet->selectReplicas(tLogPolicy, locations, resultEntries);
ASSERT(result);
return resultEntries.size() == 0;
}
void getPushLocations(std::vector<Tag> const& tags, std::vector<int>& locations, int locationOffset,
bool allLocations = false) {
if(locality == tagLocalitySatellite) {
for(auto& t : tags) {
if(t == txsTag || t.locality == tagLocalityLogRouter) {
for(int loc : satelliteTagLocations[t == txsTag ? 0 : t.id + 1]) {
locations.push_back(locationOffset + loc);
}
}
}
uniquify(locations);
return;
}
newLocations.clear();
alsoServers.clear();
resultEntries.clear();
if (allLocations) {
// special handling for allLocations
TraceEvent("AllLocationsSet");
for (int i = 0; i < logServers.size(); i++) {
newLocations.push_back(i);
}
} else {
for (auto& t : tags) {
if (locality == tagLocalitySpecial || t.locality == locality || t.locality < 0) {
newLocations.push_back(bestLocationFor(t));
}
}
}
uniquify( newLocations );
if (newLocations.size())
alsoServers.reserve(newLocations.size());
// Convert locations to the also servers
for (auto location : newLocations) {
locations.push_back(locationOffset + location);
alsoServers.push_back(logEntryArray[location]);
}
// Run the policy, assert if unable to satify
bool result = logServerSet->selectReplicas(tLogPolicy, alsoServers, resultEntries);
ASSERT(result);
// Add the new servers to the location array
LocalityMap<int>* logServerMap = (LocalityMap<int>*) logServerSet.getPtr();
for (auto entry : resultEntries) {
locations.push_back(locationOffset + *logServerMap->getObject(entry));
}
//TraceEvent("GetPushLocations").detail("Policy", tLogPolicy->info())
// .detail("Results", locations.size()).detail("Selection", logServerSet->size())
// .detail("Included", alsoServers.size()).detail("Duration", timer() - t);
}
private:
std::vector<LocalityEntry> alsoServers, resultEntries;
std::vector<int> newLocations;
};
struct ILogSystem {
// Represents a particular (possibly provisional) epoch of the log subsystem
struct IPeekCursor {
//clones the peek cursor, however you cannot call getMore() on the cloned cursor.
virtual Reference<IPeekCursor> cloneNoMore() = 0;
virtual void setProtocolVersion( ProtocolVersion version ) = 0;
//if hasMessage() returns true, getMessage(), getMessageWithTags(), or reader() can be called.
//does not modify the cursor
virtual bool hasMessage() = 0;
//pre: only callable if hasMessage() returns true
//return the tags associated with the message for the current sequence
virtual const std::vector<Tag>& getTags() = 0;
//pre: only callable if hasMessage() returns true
//returns the arena containing the contents of getMessage(), getMessageWithTags(), and reader()
virtual Arena& arena() = 0;
//pre: only callable if hasMessage() returns true
//returns an arena reader for the next message
//caller cannot call getMessage(), getMessageWithTags(), and reader()
//the caller must advance the reader before calling nextMessage()
virtual ArenaReader* reader() = 0;
//pre: only callable if hasMessage() returns true
//caller cannot call getMessage(), getMessageWithTags(), and reader()
//return the contents of the message for the current sequence
virtual StringRef getMessage() = 0;
//pre: only callable if hasMessage() returns true
//caller cannot call getMessage(), getMessageWithTags(), and reader()
//return the contents of the message for the current sequence
virtual StringRef getMessageWithTags() = 0;
//pre: only callable after getMessage(), getMessageWithTags(), or reader()
//post: hasMessage() and version() have been updated
//hasMessage() will never return false "in the middle" of a version (that is, if it does return false, version().subsequence will be zero) < FIXME: Can we lose this property?
virtual void nextMessage() = 0;
//advances the cursor to the supplied LogMessageVersion, and updates hasMessage
virtual void advanceTo(LogMessageVersion n) = 0;
//returns immediately if hasMessage() returns true.
//returns when either the result of hasMessage() or version() has changed, or a cursor has internally been exhausted.
virtual Future<Void> getMore(TaskPriority taskID = TaskPriority::TLogPeekReply) = 0;
//returns when the failure monitor detects that the servers associated with the cursor are failed
virtual Future<Void> onFailed() = 0;
//returns false if:
// (1) the failure monitor detects that the servers associated with the cursor is failed
// (2) the interface is not present
// (3) the cursor cannot return any more results
virtual bool isActive() = 0;
//returns true if the cursor cannot return any more results
virtual bool isExhausted() = 0;
// Returns the smallest possible message version which the current message (if any) or a subsequent message might have
// (If hasMessage(), this is therefore the message version of the current message)
virtual const LogMessageVersion& version() = 0;
//So far, the cursor has returned all messages which both satisfy the criteria passed to peek() to create the cursor AND have (popped(),0) <= message version number <= version()
//Other messages might have been skipped
virtual Version popped() = 0;
// Returns the maximum version known to have been pushed (not necessarily durably) into the log system (0 is always a possible result!)
virtual Version getMaxKnownVersion() { return 0; }
virtual Version getMinKnownCommittedVersion() = 0;
virtual void addref() = 0;
virtual void delref() = 0;
};
struct ServerPeekCursor : IPeekCursor, ReferenceCounted<ServerPeekCursor> {
Reference<AsyncVar<OptionalInterface<TLogInterface>>> interf;
Tag tag;
TLogPeekReply results;
ArenaReader rd;
LogMessageVersion messageVersion, end;
Version poppedVersion;
int32_t messageLength, rawLength;
std::vector<Tag> tags;
bool hasMsg;
Future<Void> more;
UID randomID;
bool returnIfBlocked;
bool onlySpilled;
bool parallelGetMore;
int sequence;
Deque<Future<TLogPeekReply>> futureResults;
Future<Void> interfaceChanged;
ServerPeekCursor( Reference<AsyncVar<OptionalInterface<TLogInterface>>> const& interf, Tag tag, Version begin, Version end, bool returnIfBlocked, bool parallelGetMore );
ServerPeekCursor( TLogPeekReply const& results, LogMessageVersion const& messageVersion, LogMessageVersion const& end, int32_t messageLength, int32_t rawLength, bool hasMsg, Version poppedVersion, Tag tag );
virtual Reference<IPeekCursor> cloneNoMore();
virtual void setProtocolVersion( ProtocolVersion version );
virtual Arena& arena();
virtual ArenaReader* reader();
virtual bool hasMessage();
virtual void nextMessage();
virtual StringRef getMessage();
virtual StringRef getMessageWithTags();
virtual const std::vector<Tag>& getTags();
virtual void advanceTo(LogMessageVersion n);
virtual Future<Void> getMore(TaskPriority taskID = TaskPriority::TLogPeekReply);
virtual Future<Void> onFailed();
virtual bool isActive();
virtual bool isExhausted();
virtual const LogMessageVersion& version();
virtual Version popped();
virtual Version getMinKnownCommittedVersion();
virtual void addref() {
ReferenceCounted<ServerPeekCursor>::addref();
}
virtual void delref() {
ReferenceCounted<ServerPeekCursor>::delref();
}
virtual Version getMaxKnownVersion() { return results.maxKnownVersion; }
};
struct MergedPeekCursor : IPeekCursor, ReferenceCounted<MergedPeekCursor> {
Reference<LogSet> logSet;
std::vector< Reference<IPeekCursor> > serverCursors;
std::vector<LocalityEntry> locations;
std::vector< std::pair<LogMessageVersion, int> > sortedVersions;
Tag tag;
int bestServer, currentCursor, readQuorum;
Optional<LogMessageVersion> nextVersion;
LogMessageVersion messageVersion;
bool hasNextMessage;
UID randomID;
int tLogReplicationFactor;
MergedPeekCursor( std::vector< Reference<ILogSystem::IPeekCursor> > const& serverCursors, Version begin );
MergedPeekCursor( std::vector<Reference<AsyncVar<OptionalInterface<TLogInterface>>>> const& logServers, int bestServer, int readQuorum, Tag tag, Version begin, Version end, bool parallelGetMore, std::vector<LocalityData> const& tLogLocalities, Reference<IReplicationPolicy> const tLogPolicy, int tLogReplicationFactor );
MergedPeekCursor( std::vector< Reference<IPeekCursor> > const& serverCursors, LogMessageVersion const& messageVersion, int bestServer, int readQuorum, Optional<LogMessageVersion> nextVersion, Reference<LogSet> logSet, int tLogReplicationFactor );
virtual Reference<IPeekCursor> cloneNoMore();
virtual void setProtocolVersion( ProtocolVersion version );
virtual Arena& arena();
virtual ArenaReader* reader();
void calcHasMessage();
void updateMessage(bool usePolicy);
virtual bool hasMessage();
virtual void nextMessage();
virtual StringRef getMessage();
virtual StringRef getMessageWithTags();
virtual const std::vector<Tag>& getTags();
virtual void advanceTo(LogMessageVersion n);
virtual Future<Void> getMore(TaskPriority taskID = TaskPriority::TLogPeekReply);
virtual Future<Void> onFailed();
virtual bool isActive();
virtual bool isExhausted();
virtual const LogMessageVersion& version();
virtual Version popped();
virtual Version getMinKnownCommittedVersion();
virtual void addref() {
ReferenceCounted<MergedPeekCursor>::addref();
}
virtual void delref() {
ReferenceCounted<MergedPeekCursor>::delref();
}
};
struct SetPeekCursor : IPeekCursor, ReferenceCounted<SetPeekCursor> {
std::vector<Reference<LogSet>> logSets;
std::vector< std::vector< Reference<IPeekCursor> > > serverCursors;
Tag tag;
int bestSet, bestServer, currentSet, currentCursor;
std::vector<LocalityEntry> locations;
std::vector< std::pair<LogMessageVersion, int> > sortedVersions;
Optional<LogMessageVersion> nextVersion;
LogMessageVersion messageVersion;
bool hasNextMessage;
bool useBestSet;
UID randomID;
SetPeekCursor( std::vector<Reference<LogSet>> const& logSets, int bestSet, int bestServer, Tag tag, Version begin, Version end, bool parallelGetMore );
SetPeekCursor( std::vector<Reference<LogSet>> const& logSets, std::vector< std::vector< Reference<IPeekCursor> > > const& serverCursors, LogMessageVersion const& messageVersion, int bestSet, int bestServer, Optional<LogMessageVersion> nextVersion, bool useBestSet );
virtual Reference<IPeekCursor> cloneNoMore();
virtual void setProtocolVersion( ProtocolVersion version );
virtual Arena& arena();
virtual ArenaReader* reader();
void calcHasMessage();
void updateMessage(int logIdx, bool usePolicy);
virtual bool hasMessage();
virtual void nextMessage();
virtual StringRef getMessage();
virtual StringRef getMessageWithTags();
virtual const std::vector<Tag>& getTags();
virtual void advanceTo(LogMessageVersion n);
virtual Future<Void> getMore(TaskPriority taskID = TaskPriority::TLogPeekReply);
virtual Future<Void> onFailed();
virtual bool isActive();
virtual bool isExhausted();
virtual const LogMessageVersion& version();
virtual Version popped();
virtual Version getMinKnownCommittedVersion();
virtual void addref() {
ReferenceCounted<SetPeekCursor>::addref();
}
virtual void delref() {
ReferenceCounted<SetPeekCursor>::delref();
}
};
struct MultiCursor : IPeekCursor, ReferenceCounted<MultiCursor> {
std::vector<Reference<IPeekCursor>> cursors;
std::vector<LogMessageVersion> epochEnds;
Version poppedVersion;
MultiCursor( std::vector<Reference<IPeekCursor>> cursors, std::vector<LogMessageVersion> epochEnds );
virtual Reference<IPeekCursor> cloneNoMore();
virtual void setProtocolVersion( ProtocolVersion version );
virtual Arena& arena();
virtual ArenaReader* reader();
virtual bool hasMessage();
virtual void nextMessage();
virtual StringRef getMessage();
virtual StringRef getMessageWithTags();
virtual const std::vector<Tag>& getTags();
virtual void advanceTo(LogMessageVersion n);
virtual Future<Void> getMore(TaskPriority taskID = TaskPriority::TLogPeekReply);
virtual Future<Void> onFailed();
virtual bool isActive();
virtual bool isExhausted();
virtual const LogMessageVersion& version();
virtual Version popped();
virtual Version getMinKnownCommittedVersion();
virtual void addref() {
ReferenceCounted<MultiCursor>::addref();
}
virtual void delref() {
ReferenceCounted<MultiCursor>::delref();
}
};
struct BufferedCursor : IPeekCursor, ReferenceCounted<BufferedCursor> {
struct BufferedMessage {
Arena arena;
StringRef message;
std::vector<Tag> tags;
LogMessageVersion version;
BufferedMessage() {}
BufferedMessage( Arena arena, StringRef message, const std::vector<Tag>& tags, const LogMessageVersion& version ) : arena(arena), message(message), tags(tags), version(version) {}
bool operator < (BufferedMessage const& r) const {
return version < r.version;
}
bool operator == (BufferedMessage const& r) const {
return version == r.version;
}
};
std::vector<Reference<IPeekCursor>> cursors;
std::vector<BufferedMessage> messages;
int messageIndex;
LogMessageVersion messageVersion;
Version end;
bool hasNextMessage;
//FIXME: collectTags is needed to support upgrades from 5.X to 6.0. Remove this code when we no longer support that upgrade.
bool collectTags;
std::vector<Tag> tags;
void combineMessages();
BufferedCursor( std::vector<Reference<IPeekCursor>> cursors, Version begin, Version end, bool collectTags );
virtual Reference<IPeekCursor> cloneNoMore();
virtual void setProtocolVersion( ProtocolVersion version );
virtual Arena& arena();
virtual ArenaReader* reader();
virtual bool hasMessage();
virtual void nextMessage();
virtual StringRef getMessage();
virtual StringRef getMessageWithTags();
virtual const std::vector<Tag>& getTags();
virtual void advanceTo(LogMessageVersion n);
virtual Future<Void> getMore(TaskPriority taskID = TaskPriority::TLogPeekReply);
virtual Future<Void> onFailed();
virtual bool isActive();
virtual bool isExhausted();
virtual const LogMessageVersion& version();
virtual Version popped();
virtual Version getMinKnownCommittedVersion();
virtual void addref() {
ReferenceCounted<BufferedCursor>::addref();
}
virtual void delref() {
ReferenceCounted<BufferedCursor>::delref();
}
};
virtual void addref() = 0;
virtual void delref() = 0;
virtual std::string describe() = 0;
virtual UID getDebugID() = 0;
virtual void toCoreState( DBCoreState& ) = 0;
virtual bool remoteStorageRecovered() = 0;
virtual Future<Void> onCoreStateChanged() = 0;
// Returns if and when the output of toCoreState() would change (for example, when older logs can be discarded from the state)
virtual void coreStateWritten( DBCoreState const& newState ) = 0;
// Called when a core state has been written to the coordinators
virtual Future<Void> onError() = 0;
// Never returns normally, but throws an error if the subsystem stops working
//Future<Void> push( UID bundle, int64_t seq, VectorRef<TaggedMessageRef> messages );
virtual Future<Version> push( Version prevVersion, Version version, Version knownCommittedVersion, Version minKnownCommittedVersion, struct LogPushData& data, Optional<UID> debugID = Optional<UID>() ) = 0;
// Waits for the version number of the bundle (in this epoch) to be prevVersion (i.e. for all pushes ordered earlier)
// Puts the given messages into the bundle, each with the given tags, and with message versions (version, 0) - (version, N)
// Changes the version number of the bundle to be version (unblocking the next push)
// Returns when the preceding changes are durable. (Later we will need multiple return signals for diffferent durability levels)
// If the current epoch has ended, push will not return, and the pushed messages will not be visible in any subsequent epoch (but may become visible in this epoch)
virtual Reference<IPeekCursor> peek( UID dbgid, Version begin, Tag tag, bool parallelGetMore = false ) = 0;
// Returns (via cursor interface) a stream of messages with the given tag and message versions >= (begin, 0), ordered by message version
// If pop was previously or concurrently called with upTo > begin, the cursor may not return all such messages. In that case cursor->popped() will
// be greater than begin to reflect that.
virtual Reference<IPeekCursor> peek( UID dbgid, Version begin, Optional<Version> end, std::vector<Tag> tags, bool parallelGetMore = false ) = 0;
// Same contract as peek(), but for a set of tags
virtual Reference<IPeekCursor> peekSingle( UID dbgid, Version begin, Tag tag, std::vector<std::pair<Version,Tag>> history = std::vector<std::pair<Version,Tag>>() ) = 0;
// Same contract as peek(), but blocks until the preferred log server(s) for the given tag are available (and is correspondingly less expensive)
virtual Reference<IPeekCursor> peekLogRouter( UID dbgid, Version begin, Tag tag ) = 0;
// Same contract as peek(), but can only peek from the logs elected in the same generation.
// If the preferred log server is down, a different log from the same generation will merge results locally before sending them to the log router.
virtual Reference<IPeekCursor> peekSpecial( UID dbgid, Version begin, Tag tag, int8_t peekLocality, Version localEnd ) = 0;
// Same contract as peek(), but it allows specifying a preferred peek locality for tags that do not have locality
virtual Version getKnownCommittedVersion() = 0;
virtual Future<Void> onKnownCommittedVersionChange() = 0;
virtual void pop( Version upTo, Tag tag, Version knownCommittedVersion = 0, int8_t popLocality = tagLocalityInvalid ) = 0;
// Permits, but does not require, the log subsystem to strip `tag` from any or all messages with message versions < (upTo,0)
// The popping of any given message may be arbitrarily delayed.
virtual Future<Void> confirmEpochLive( Optional<UID> debugID = Optional<UID>() ) = 0;
// Returns success after confirming that pushes in the current epoch are still possible
virtual Future<Void> endEpoch() = 0;
// Ends the current epoch without starting a new one
static Reference<ILogSystem> fromServerDBInfo( UID const& dbgid, struct ServerDBInfo const& db, bool useRecoveredAt = false, Optional<PromiseStream<Future<Void>>> addActor = Optional<PromiseStream<Future<Void>>>() );
static Reference<ILogSystem> fromLogSystemConfig( UID const& dbgid, struct LocalityData const&, struct LogSystemConfig const&, bool excludeRemote = false, bool useRecoveredAt = false, Optional<PromiseStream<Future<Void>>> addActor = Optional<PromiseStream<Future<Void>>>() );
// Constructs a new ILogSystem implementation from the given ServerDBInfo/LogSystemConfig. Might return a null reference if there isn't a fully recovered log system available.
// The caller can peek() the returned log system and can push() if it has version numbers reserved for it and prevVersions
static Reference<ILogSystem> fromOldLogSystemConfig( UID const& dbgid, struct LocalityData const&, struct LogSystemConfig const& );
// Constructs a new ILogSystem implementation from the old log data within a ServerDBInfo/LogSystemConfig. Might return a null reference if there isn't a fully recovered log system available.
static Future<Void> recoverAndEndEpoch(Reference<AsyncVar<Reference<ILogSystem>>> const& outLogSystem, UID const& dbgid, DBCoreState const& oldState, FutureStream<TLogRejoinRequest> const& rejoins, LocalityData const& locality, bool* forceRecovery);
// Constructs a new ILogSystem implementation based on the given oldState and rejoining log servers
// Ensures that any calls to push or confirmEpochLive in the current epoch but strictly later than change_epoch will not return
// Whenever changes in the set of available log servers require restarting recovery with a different end sequence, outLogSystem will be changed to a new ILogSystem
virtual Version getEnd() = 0;
// Call only on an ILogSystem obtained from recoverAndEndEpoch()
// Returns the first unreadable version number of the recovered epoch (i.e. message version numbers < (get_end(), 0) will be readable)
virtual Future<Reference<ILogSystem>> newEpoch( struct RecruitFromConfigurationReply const& recr, Future<struct RecruitRemoteFromConfigurationReply> const& fRemoteWorkers, DatabaseConfiguration const& config,
LogEpoch recoveryCount, int8_t primaryLocality, int8_t remoteLocality, std::vector<Tag> const& allTags, Reference<AsyncVar<bool>> const& recruitmentStalled ) = 0;
// Call only on an ILogSystem obtained from recoverAndEndEpoch()
// Returns an ILogSystem representing a new epoch immediately following this one. The new epoch is only provisional until the caller updates the coordinated DBCoreState
virtual LogSystemConfig getLogSystemConfig() = 0;
// Returns the physical configuration of this LogSystem, that could be used to construct an equivalent LogSystem using fromLogSystemConfig()
virtual Standalone<StringRef> getLogsValue() = 0;
virtual Future<Void> onLogSystemConfigChange() = 0;
// Returns when the log system configuration has changed due to a tlog rejoin.
virtual void getPushLocations(std::vector<Tag> const& tags, std::vector<int>& locations, bool allLocations = false) = 0;
virtual bool hasRemoteLogs() = 0;
virtual Tag getRandomRouterTag() = 0;
virtual void stopRejoins() = 0;
// Returns the pseudo tag to be popped for the given process class. If the
// process class doesn't use pseudo tag, return the same tag.
virtual Tag getPseudoPopTag(Tag tag, ProcessClass::ClassType type) = 0;
virtual bool isPseudoLocality(int8_t locality) = 0;
virtual Version popPseudoLocalityTag(int8_t locality, Version upTo) = 0;
};
struct LengthPrefixedStringRef {
// Represents a pointer to a string which is prefixed by a 4-byte length
// A LengthPrefixedStringRef is only pointer-sized (8 bytes vs 12 bytes for StringRef), but the corresponding string is 4 bytes bigger, and
// substring operations aren't efficient as they are with StringRef. It's a good choice when there might be lots of references to the same
// exact string.
uint32_t* length;
StringRef toStringRef() const { ASSERT(length); return StringRef( (uint8_t*)(length+1), *length ); }
int expectedSize() const { ASSERT(length); return *length; }
uint32_t* getLengthPtr() const { return length; }
LengthPrefixedStringRef() : length(NULL) {}
LengthPrefixedStringRef(uint32_t* length) : length(length) {}
};
template<class T>
struct CompareFirst {
bool operator() (T const& lhs, T const& rhs) const {
return lhs.first < rhs.first;
}
};
struct LogPushData : NonCopyable {
// Log subsequences have to start at 1 (the MergedPeekCursor relies on this to make sure we never have !hasMessage() in the middle of data for a version
explicit LogPushData(Reference<ILogSystem> logSystem) : logSystem(logSystem), subsequence(1), hasExecOp(false) {
for(auto& log : logSystem->getLogSystemConfig().tLogs) {
if(log.isLocal) {
for(int i = 0; i < log.tLogs.size(); i++) {
messagesWriter.push_back( BinaryWriter( AssumeVersion(currentProtocolVersion) ) );
}
}
}
}
// addTag() adds a tag for the *next* message to be added
void addTag( Tag tag ) {
next_message_tags.push_back( tag );
}
template<class T>
void addTags(T tags) {
next_message_tags.insert(next_message_tags.end(), tags.begin(), tags.end());
}
void addMessage( StringRef rawMessageWithoutLength, bool usePreviousLocations = false ) {
if( !usePreviousLocations ) {
prev_tags.clear();
if(logSystem->hasRemoteLogs()) {
prev_tags.push_back( logSystem->getRandomRouterTag() );
}
for(auto& tag : next_message_tags) {
prev_tags.push_back(tag);
}
msg_locations.clear();
logSystem->getPushLocations( prev_tags, msg_locations );
next_message_tags.clear();
}
uint32_t subseq = this->subsequence++;
for(int loc : msg_locations) {
messagesWriter[loc] << uint32_t(rawMessageWithoutLength.size() + sizeof(subseq) + sizeof(uint16_t) + sizeof(Tag)*prev_tags.size()) << subseq << uint16_t(prev_tags.size());
for(auto& tag : prev_tags)
messagesWriter[loc] << tag;
messagesWriter[loc].serializeBytes(rawMessageWithoutLength);
}
}
template <class T>
void addTypedMessage(T const& item, bool allLocations = false) {
prev_tags.clear();
if(logSystem->hasRemoteLogs()) {
prev_tags.push_back( logSystem->getRandomRouterTag() );
}
for(auto& tag : next_message_tags) {
prev_tags.push_back(tag);
}
msg_locations.clear();
logSystem->getPushLocations(prev_tags, msg_locations, allLocations);
uint32_t subseq = this->subsequence++;
for(int loc : msg_locations) {
// FIXME: memcpy after the first time
BinaryWriter& wr = messagesWriter[loc];
int offset = wr.getLength();
wr << uint32_t(0) << subseq << uint16_t(prev_tags.size());
for(auto& tag : prev_tags)
wr << tag;
wr << item;
*(uint32_t*)((uint8_t*)wr.getData() + offset) = wr.getLength() - offset - sizeof(uint32_t);
}
next_message_tags.clear();
}
Standalone<StringRef> getMessages(int loc) {
return messagesWriter[loc].toValue();
}
void setHasExecOp() { hasExecOp = true; }
bool getHasExecOp() { return hasExecOp; }
private:
Reference<ILogSystem> logSystem;
std::vector<Tag> next_message_tags;
std::vector<Tag> prev_tags;
std::vector<BinaryWriter> messagesWriter;
std::vector<int> msg_locations;
uint32_t subsequence;
bool hasExecOp;
};
#endif
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