SERVER-36052 Remove _rsConfig.getProtocolVersion() check as part of pv0 code cleanup.

6 files changed, 41 insertions, 117 deletions

diff --git a/src/mongo/db/repl/oplog_fetcher.cpp b/src/mongo/db/repl/oplog_fetcher.cpp
index 6545bace758..7a0ebb75d2e 100644
--- a/src/mongo/db/repl/oplog_fetcher.cpp
+++ b/src/mongo/db/repl/oplog_fetcher.cpp
@@ -72,11 +72,7 @@ Milliseconds calculateAwaitDataTimeout(const ReplSetConfig& config) {
     // Under protocol version 1, make the awaitData timeout (maxTimeMS) dependent on the election
     // timeout. This enables the sync source to communicate liveness of the primary to secondaries.
     // We never wait longer than 30 seconds.
-    // Under protocol version 0, use a default timeout of 2 seconds for awaitData.
-    if (config.getProtocolVersion() == 1LL) {
-        return std::min((config.getElectionTimeoutPeriod() / 2), maximumAwaitDataTimeoutMS);
-    }
-    return OplogFetcher::kDefaultProtocolZeroAwaitDataTimeout;
+    return std::min((config.getElectionTimeoutPeriod() / 2), maximumAwaitDataTimeoutMS);
 }
 
 /**
diff --git a/src/mongo/db/repl/repl_set_config.cpp b/src/mongo/db/repl/repl_set_config.cpp
index d6d4470203e..fcbe828bf2b 100644
--- a/src/mongo/db/repl/repl_set_config.cpp
+++ b/src/mongo/db/repl/repl_set_config.cpp
@@ -166,19 +166,9 @@ Status ReplSetConfig::_initialize(const BSONObj& cfg, bool forInitiate, OID defa
     // Parse protocol version
     //
     status = bsonExtractIntegerField(cfg, kProtocolVersionFieldName, &_protocolVersion);
-    if (!status.isOK()) {
-        if (status != ErrorCodes::NoSuchKey) {
-            return status;
-        }
-        if (forInitiate) {
-            // Default protocolVersion to 1 when initiating a new set.
-            _protocolVersion = 1;
-        }
-        // If protocolVersion field is missing but this *isn't* for an initiate, leave
-        // _protocolVersion at it's default of 0 for now.  It will error later on, during
-        // validate().
-        // TODO(spencer): Remove this after 4.0, when we no longer need mixed-version support
-        // with versions that don't always include the protocolVersion field.
+    // If 'protocolVersion' field is missing for initiate, then _protocolVersion defaults to 1.
+    if (!(status.isOK() || (status == ErrorCodes::NoSuchKey && forInitiate))) {
+        return status;
     }
 
     //
diff --git a/src/mongo/db/repl/repl_set_config.h b/src/mongo/db/repl/repl_set_config.h
index 04bbae18722..7887b95f8be 100644
--- a/src/mongo/db/repl/repl_set_config.h
+++ b/src/mongo/db/repl/repl_set_config.h
@@ -311,7 +311,7 @@ public:
      * Gets the protocol version for this configuration.
      *
      * The protocol version number currently determines what election protocol is used by the
-     * cluster; 0 is the default and indicates the old 3.0 election protocol.
+     * cluster; 1 is the default.
      */
     long long getProtocolVersion() const {
         return _protocolVersion;
@@ -396,7 +396,7 @@ private:
     int _totalVotingMembers = 0;
     ReplSetTagConfig _tagConfig;
     StringMap<ReplSetTagPattern> _customWriteConcernModes;
-    long long _protocolVersion = 0;
+    long long _protocolVersion = 1;
     bool _configServer = false;
     OID _replicaSetId;
     ConnectionString _connectionString;
diff --git a/src/mongo/db/repl/replication_coordinator_impl.cpp b/src/mongo/db/repl/replication_coordinator_impl.cpp
index 51b7313efa9..37ca8a67292 100644
--- a/src/mongo/db/repl/replication_coordinator_impl.cpp
+++ b/src/mongo/db/repl/replication_coordinator_impl.cpp
@@ -577,16 +577,13 @@ void ReplicationCoordinatorImpl::_finishLoadLocalConfig(
         }
     }
 
-    long long term = OpTime::kUninitializedTerm;
-    if (localConfig.getProtocolVersion() == 1) {
-        // Restore the current term according to the terms of last oplog entry and last vote.
-        // The initial term of OpTime() is 0.
-        term = lastOpTime.getTerm();
-        if (lastVoteStatus.isOK()) {
-            long long lastVoteTerm = lastVoteStatus.getValue().getTerm();
-            if (term < lastVoteTerm) {
-                term = lastVoteTerm;
-            }
+    // Restore the current term according to the terms of last oplog entry and last vote.
+    // The initial term of OpTime() is 0.
+    long long term = lastOpTime.getTerm();
+    if (lastVoteStatus.isOK()) {
+        long long lastVoteTerm = lastVoteStatus.getValue().getTerm();
+        if (term < lastVoteTerm) {
+            term = lastVoteTerm;
         }
     }
 
@@ -2380,10 +2377,7 @@ Status ReplicationCoordinatorImpl::processReplSetInitiate(OperationContext* opCt
     // In pv1, the TopologyCoordinator has not set the term yet. It will be set to kInitialTerm if
     // the initiate succeeds so we pass that here.
     status = checkQuorumForInitiate(
-        _replExecutor.get(),
-        newConfig,
-        myIndex.getValue(),
-        newConfig.getProtocolVersion() == 1 ? OpTime::kInitialTerm : OpTime::kUninitializedTerm);
+        _replExecutor.get(), newConfig, myIndex.getValue(), OpTime::kInitialTerm);
 
     if (!status.isOK()) {
         error() << "replSetInitiate failed; " << status;
@@ -2749,6 +2743,7 @@ ReplicationCoordinatorImpl::PostMemberStateUpdateAction
 ReplicationCoordinatorImpl::_setCurrentRSConfig_inlock(OperationContext* opCtx,
                                                        const ReplSetConfig& newConfig,
                                                        int myIndex) {
+    invariant(newConfig.getProtocolVersion() == 1);
     invariant(_settings.usingReplSets());
     _cancelHeartbeats_inlock();
     _setConfigState_inlock(kConfigSteady);
@@ -2762,17 +2757,6 @@ ReplicationCoordinatorImpl::_setCurrentRSConfig_inlock(OperationContext* opCtx,
     _rsConfig = newConfig;
     _protVersion.store(_rsConfig.getProtocolVersion());
 
-    // Warn if this config has protocol version 0
-    if (newConfig.getProtocolVersion() == 0 &&
-        (!oldConfig.isInitialized() || oldConfig.getProtocolVersion() == 1)) {
-        log() << startupWarningsLog;
-        log() << "** WARNING: This replica set was configured with protocol version 0."
-              << startupWarningsLog;
-        log() << "**          This protocol version is deprecated and subject to be removed "
-              << startupWarningsLog;
-        log() << "**          in a future version." << startupWarningsLog;
-    }
-
     // Warn if running --nojournal and writeConcernMajorityJournalDefault = false
     StorageEngine* storageEngine = opCtx->getServiceContext()->getStorageEngine();
     if (storageEngine && !storageEngine->isDurable() &&
@@ -2814,24 +2798,6 @@ ReplicationCoordinatorImpl::_setCurrentRSConfig_inlock(OperationContext* opCtx,
     }
     _updateLastCommittedOpTime_inlock();
 
-    // Set election id if we're primary.
-    if (oldConfig.isInitialized() && _memberState.primary()) {
-        if (oldConfig.getProtocolVersion() > newConfig.getProtocolVersion()) {
-            // Downgrade
-            invariant(newConfig.getProtocolVersion() == 0);
-            _electionId = OID::gen();
-            auto ts = LogicalClock::get(getServiceContext())->reserveTicks(1).asTimestamp();
-            _topCoord->setElectionInfo(_electionId, ts);
-        } else if (oldConfig.getProtocolVersion() < newConfig.getProtocolVersion()) {
-            // Upgrade
-            invariant(newConfig.getProtocolVersion() == 1);
-            invariant(_topCoord->getTerm() != OpTime::kUninitializedTerm);
-            _electionId = OID::fromTerm(_topCoord->getTerm());
-            auto ts = LogicalClock::get(getServiceContext())->reserveTicks(1).asTimestamp();
-            _topCoord->setElectionInfo(_electionId, ts);
-        }
-    }
-
     return action;
 }
 
diff --git a/src/mongo/db/repl/replication_coordinator_impl_heartbeat_v1_test.cpp b/src/mongo/db/repl/replication_coordinator_impl_heartbeat_v1_test.cpp
index 6ecb25d00c8..61a63ca9225 100644
--- a/src/mongo/db/repl/replication_coordinator_impl_heartbeat_v1_test.cpp
+++ b/src/mongo/db/repl/replication_coordinator_impl_heartbeat_v1_test.cpp
@@ -279,8 +279,8 @@ TEST_F(ReplCoordHBV1Test,
     responseBuilder << "ok" << 1;
     hbResp.addToBSON(&responseBuilder);
     net->scheduleResponse(
-        noi, startDate + Milliseconds(200), makeResponseStatus(responseBuilder.obj()));
-    assertRunUntil(startDate + Milliseconds(2200));
+        noi, startDate + Milliseconds(50), makeResponseStatus(responseBuilder.obj()));
+    assertRunUntil(startDate + Milliseconds(550));
 
     // Because the new config is stored using an out-of-band thread, we need to perform some
     // extra synchronization to let the executor finish the heartbeat reconfig.  We know that
diff --git a/src/mongo/db/repl/topology_coordinator.cpp b/src/mongo/db/repl/topology_coordinator.cpp
index f4746332d86..5016ddc8e81 100644
--- a/src/mongo/db/repl/topology_coordinator.cpp
+++ b/src/mongo/db/repl/topology_coordinator.cpp
@@ -134,15 +134,8 @@ bool _hasOnlyAuthErrorUpHeartbeats(const std::vector<MemberData>& hbdata, const
     return foundAuthError;
 }
 
-void appendOpTime(BSONObjBuilder* bob,
-                  const char* elemName,
-                  const OpTime& opTime,
-                  const long long pv) {
-    if (pv == 1) {
-        opTime.append(bob, elemName);
-    } else {
-        bob->append(elemName, opTime.getTimestamp());
-    }
+void appendOpTime(BSONObjBuilder* bob, const char* elemName, const OpTime& opTime) {
+    opTime.append(bob, elemName);
 }
 }  // namespace
 
@@ -709,14 +702,12 @@ HeartbeatResponseAction TopologyCoordinator::processHeartbeatResponse(
     //
     // Arbiters also decrease their heartbeat interval to at most half the election timeout period.
     Milliseconds heartbeatInterval = _rsConfig.getHeartbeatInterval();
-    if (_rsConfig.getProtocolVersion() == 1) {
-        if (getMemberState().arbiter()) {
-            heartbeatInterval = std::min(_rsConfig.getElectionTimeoutPeriod() / 2,
-                                         _rsConfig.getHeartbeatInterval());
-        } else if (getSyncSourceAddress().empty() && !_iAmPrimary()) {
-            heartbeatInterval = std::min(_rsConfig.getElectionTimeoutPeriod() / 2,
-                                         _rsConfig.getHeartbeatInterval() / 4);
-        }
+    if (getMemberState().arbiter()) {
+        heartbeatInterval =
+            std::min(_rsConfig.getElectionTimeoutPeriod() / 2, _rsConfig.getHeartbeatInterval());
+    } else if (getSyncSourceAddress().empty() && !_iAmPrimary()) {
+        heartbeatInterval = std::min(_rsConfig.getElectionTimeoutPeriod() / 2,
+                                     _rsConfig.getHeartbeatInterval() / 4);
     }
 
     const Milliseconds alreadyElapsed = now - hbStats.getLastHeartbeatStartDate();
@@ -807,7 +798,6 @@ HeartbeatResponseAction TopologyCoordinator::processHeartbeatResponse(
     }
 
     HeartbeatResponseAction nextAction;
-    invariant(_rsConfig.getProtocolVersion() == 1);
     nextAction = _updatePrimaryFromHBDataV1(memberIndex, originalState, now);
 
     nextAction.setNextHeartbeatStartDate(nextHeartbeatStartDate);
@@ -1406,7 +1396,7 @@ void TopologyCoordinator::prepareStatusResponse(const ReplSetStatusArgs& rsStatu
         response->append("stateStr", myState.toString());
         response->append("uptime", rsStatusArgs.selfUptime);
 
-        appendOpTime(response, "optime", lastOpApplied, _rsConfig.getProtocolVersion());
+        appendOpTime(response, "optime", lastOpApplied);
 
         response->appendDate("optimeDate",
                              Date_t::fromDurationSinceEpoch(Seconds(lastOpApplied.getSecs())));
@@ -1437,7 +1427,7 @@ void TopologyCoordinator::prepareStatusResponse(const ReplSetStatusArgs& rsStatu
             bb.append("stateStr", myState.toString());
             bb.append("uptime", rsStatusArgs.selfUptime);
             if (!_selfConfig().isArbiter()) {
-                appendOpTime(&bb, "optime", lastOpApplied, _rsConfig.getProtocolVersion());
+                appendOpTime(&bb, "optime", lastOpApplied);
                 bb.appendDate("optimeDate",
                               Date_t::fromDurationSinceEpoch(Seconds(lastOpApplied.getSecs())));
             }
@@ -1490,12 +1480,8 @@ void TopologyCoordinator::prepareStatusResponse(const ReplSetStatusArgs& rsStatu
                 it->getUpSince() != Date_t() ? durationCount<Seconds>(now - it->getUpSince()) : 0));
             bb.append("uptime", uptime);
             if (!itConfig.isArbiter()) {
-                appendOpTime(
-                    &bb, "optime", it->getHeartbeatAppliedOpTime(), _rsConfig.getProtocolVersion());
-                appendOpTime(&bb,
-                             "optimeDurable",
-                             it->getHeartbeatDurableOpTime(),
-                             _rsConfig.getProtocolVersion());
+                appendOpTime(&bb, "optime", it->getHeartbeatAppliedOpTime());
+                appendOpTime(&bb, "optimeDurable", it->getHeartbeatDurableOpTime());
 
                 bb.appendDate("optimeDate",
                               Date_t::fromDurationSinceEpoch(
@@ -1571,8 +1557,8 @@ void TopologyCoordinator::prepareStatusResponse(const ReplSetStatusArgs& rsStatu
         rsStatusArgs.readConcernMajorityOpTime.append(&optimes, "readConcernMajorityOpTime");
     }
 
-    appendOpTime(&optimes, "appliedOpTime", lastOpApplied, _rsConfig.getProtocolVersion());
-    appendOpTime(&optimes, "durableOpTime", lastOpDurable, _rsConfig.getProtocolVersion());
+    appendOpTime(&optimes, "appliedOpTime", lastOpApplied);
+    appendOpTime(&optimes, "durableOpTime", lastOpDurable);
     response->append("optimes", optimes.obj());
     if (lastStableRecoveryTimestamp) {
         // Only include this field if the storage engine supports RTT.
@@ -1636,14 +1622,10 @@ void TopologyCoordinator::fillMemberData(BSONObjBuilder* result) {
         for (const auto& memberData : _memberData) {
             BSONObjBuilder entry(replicationProgress.subobjStart());
             const auto lastDurableOpTime = memberData.getLastDurableOpTime();
-            if (_rsConfig.getProtocolVersion() == 1) {
-                BSONObjBuilder opTime(entry.subobjStart("optime"));
-                opTime.append("ts", lastDurableOpTime.getTimestamp());
-                opTime.append("term", lastDurableOpTime.getTerm());
-                opTime.done();
-            } else {
-                entry.append("optime", lastDurableOpTime.getTimestamp());
-            }
+            BSONObjBuilder opTime(entry.subobjStart("optime"));
+            opTime.append("ts", lastDurableOpTime.getTimestamp());
+            opTime.append("term", lastDurableOpTime.getTerm());
+            opTime.done();
             entry.append("host", memberData.getHostAndPort().toString());
             if (_selfIndex >= 0) {
                 const int memberId = memberData.getMemberId();
@@ -1818,15 +1800,9 @@ void TopologyCoordinator::updateConfig(const ReplSetConfig& newConfig, int selfI
     invariant(_role != Role::kCandidate);
     invariant(selfIndex < newConfig.getNumMembers());
 
-    // Reset term on startup and upgrade/downgrade of protocol version.
-    if (!_rsConfig.isInitialized() ||
-        _rsConfig.getProtocolVersion() != newConfig.getProtocolVersion()) {
-        if (newConfig.getProtocolVersion() == 1) {
-            _term = OpTime::kInitialTerm;
-        } else {
-            invariant(newConfig.getProtocolVersion() == 0);
-            _term = OpTime::kUninitializedTerm;
-        }
+    // Reset term on startup.
+    if (!_rsConfig.isInitialized()) {
+        _term = OpTime::kInitialTerm;
         LOG(1) << "Updated term in topology coordinator to " << _term << " due to new config";
     }
 
@@ -1941,8 +1917,6 @@ TopologyCoordinator::UnelectableReasonMask TopologyCoordinator::_getMyUnelectabl
         result |= NotSecondary;
     }
 
-    // Election rules only for protocol version 1.
-    invariant(_rsConfig.getProtocolVersion() == 1);
     if (reason == StartElectionReason::kPriorityTakeover && !_amIFreshEnoughForPriorityTakeover()) {
         result |= NotCloseEnoughToLatestForPriorityTakeover;
     }
@@ -2488,8 +2462,7 @@ bool TopologyCoordinator::shouldChangeSyncSource(
         return true;
     }
 
-    if (_rsConfig.getProtocolVersion() == 1 &&
-        replMetadata.getConfigVersion() != _rsConfig.getConfigVersion()) {
+    if (replMetadata.getConfigVersion() != _rsConfig.getConfigVersion()) {
         log() << "Choosing new sync source because the config version supplied by " << currentSource
               << ", " << replMetadata.getConfigVersion() << ", does not match ours, "
               << _rsConfig.getConfigVersion();
@@ -2497,7 +2470,6 @@ bool TopologyCoordinator::shouldChangeSyncSource(
     }
 
     const int currentSourceIndex = _rsConfig.findMemberIndexByHostAndPort(currentSource);
-    // PV0 doesn't use metadata, we have to consult _rsConfig.
     if (currentSourceIndex == -1) {
         log() << "Choosing new sync source because " << currentSource.toString()
               << " is not in our config";
@@ -2534,8 +2506,8 @@ bool TopologyCoordinator::shouldChangeSyncSource(
     // Change sync source if they are not ahead of us, and don't have a sync source,
     // unless they are primary.
     const OpTime myLastOpTime = getMyLastAppliedOpTime();
-    if (_rsConfig.getProtocolVersion() == 1 && syncSourceIndex == -1 &&
-        currentSourceOpTime <= myLastOpTime && primaryIndex != currentSourceIndex) {
+    if (syncSourceIndex == -1 && currentSourceOpTime <= myLastOpTime &&
+        primaryIndex != currentSourceIndex) {
         std::stringstream logMessage;
         logMessage << "Choosing new sync source because our current sync source, "
                    << currentSource.toString() << ", has an OpTime (" << currentSourceOpTime