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Address review comments. Refactor getLeader function to mask the first 7 bits of changeID and return the masked LeaderInfo.

This commit is contained in:
Balachandar Namasivayam 2018-06-01 18:23:24 -07:00
parent 9f55ccd4a5
commit 59bfa74197
3 changed files with 37 additions and 33 deletions
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2
fdbclient/CoordinationInterface.h
View File

@ -93,7 +93,7 @@ private:
struct LeaderInfo {
UID changeID;
uint64_t mask = ~(127ll << 57);
static const uint64_t mask = ~(127ll << 57);
Value serializedInfo;
bool forward; // If true, serializedInfo is a connection string instead!

62
fdbclient/MonitorLeader.actor.cpp
View File

@ -326,49 +326,53 @@ ACTOR Future<Void> monitorNominee( Key key, ClientLeaderRegInterface coord, Asyn
// Also used in fdbserver/LeaderElection.actor.cpp!
// bool represents if the LeaderInfo is a majority answer or not.
Optional<std::pair<LeaderInfo, bool>> getLeader( vector<Optional<LeaderInfo>> nominees ) {
// If any coordinator says that the quorum is forwarded, then it is
for(int i=0; i<nominees.size(); i++)
if (nominees[i].present() && nominees[i].get().forward)
return std::pair<LeaderInfo, bool>(nominees[i].get(), true);
// This function also masks the first 7 bits of changeId of the nominees and returns the Leader with masked changeId
Optional<std::pair<LeaderInfo, bool>> getLeader( const vector<Optional<LeaderInfo>>& nominees ) {
vector<LeaderInfo> maskedNominees;
maskedNominees.reserve(nominees.size());
for (auto &nominee : nominees) {
if (nominee.present()) {
maskedNominees.push_back(nominee.get());
maskedNominees.back().changeID = UID(maskedNominees.back().changeID.first() & LeaderInfo::mask, maskedNominees.back().changeID.second());
}
}
if(!nominees.size())
// If any coordinator says that the quorum is forwarded, then it is
for(int i=0; i<maskedNominees.size(); i++)
if (maskedNominees[i].forward)
return std::pair<LeaderInfo, bool>(maskedNominees[i], true);
if(!maskedNominees.size())
return Optional<std::pair<LeaderInfo, bool>>();
std::sort(nominees.begin(), nominees.end(),
[](const Optional<LeaderInfo>& l, const Optional<LeaderInfo>& r) {
if (!l.present())
return true;
if (!r.present())
return false;
return UID(l.get().changeID.first() & l.get().mask, l.get().changeID.second()) < UID(r.get().changeID.first() & r.get().mask, r.get().changeID.second());
});
std::sort(maskedNominees.begin(), maskedNominees.end(),
[](const LeaderInfo& l, const LeaderInfo& r) { return l.changeID < r.changeID; });
int bestCount = 0;
Optional<LeaderInfo> bestNominee;
Optional<LeaderInfo> currentNominee;
LeaderInfo bestNominee;
LeaderInfo currentNominee;
int curCount = 0;
for (int i = 0; i < nominees.size(); i++) {
if (nominees[i].present()) {
if (currentNominee.present() && currentNominee.get().equalInternalId(nominees[i].get())) {
curCount++;
}
else {
currentNominee = nominees[i];
curCount = 1;
}
for (int i = 0; i < maskedNominees.size(); i++) {
if (currentNominee.equalInternalId(maskedNominees[i])) {
curCount++;
}
else {
if (curCount > bestCount) {
bestNominee = currentNominee;
bestCount = curCount;
}
currentNominee = maskedNominees[i];
curCount = 1;
}
}
if (curCount > bestCount) {
bestNominee = currentNominee;
bestCount = curCount;
}
if (bestCount >= nominees.size() / 2 + 1)
return std::pair<LeaderInfo, bool>(bestNominee.get(), true);
if (bestNominee.present())
return std::pair<LeaderInfo, bool>(bestNominee.get(), false);
return Optional<std::pair<LeaderInfo, bool>>();
return std::pair<LeaderInfo, bool>(bestNominee, true);
return std::pair<LeaderInfo, bool>(bestNominee, false);
}
struct MonitorLeaderInfo {

6
fdbserver/LeaderElection.actor.cpp
View File

@ -25,7 +25,7 @@
#include "fdbserver/CoordinationInterface.h"
#include "fdbclient/MonitorLeader.h"
Optional<std::pair<LeaderInfo, bool>> getLeader( vector<Optional<LeaderInfo>> nominees );
Optional<std::pair<LeaderInfo, bool>> getLeader( const vector<Optional<LeaderInfo>>& nominees );
ACTOR Future<Void> submitCandidacy( Key key, LeaderElectionRegInterface coord, LeaderInfo myInfo, UID prevChangeID, Reference<AsyncVar<vector<Optional<LeaderInfo>>>> nominees, int index ) {
loop {
@ -128,14 +128,14 @@ ACTOR Future<Void> tryBecomeLeaderInternal( ServerCoordinators coordinators, Val
coordinators.ccf->notifyConnected();
}
if (leader.present() && leader.get().second && leader.get().first.changeID == myInfo.changeID) {
if (leader.present() && leader.get().second && leader.get().first.equalInternalId(myInfo)) {
TraceEvent("BecomingLeader", myInfo.changeID);
ASSERT( leader.get().first.serializedInfo == proposedSerializedInterface );
outSerializedLeader->set( leader.get().first.serializedInfo );
iAmLeader = true;
break;
}
if (leader.present() && leader.get().second) {
if (leader.present()) {
TraceEvent("LeaderChanged", myInfo.changeID).detail("ToID", leader.get().first.changeID);
if (leader.get().first.serializedInfo != proposedSerializedInterface) // We never set outSerializedLeader to our own interface unless we are ready to become leader!
outSerializedLeader->set( leader.get().first.serializedInfo );