SERVER-56361: revert FTDC diagnostics

11 files changed, 69 insertions, 429 deletions

diff --git a/jstests/noPassthrough/ftdc_connection_pool.js b/jstests/noPassthrough/ftdc_connection_pool.js
index 351713c5a8c..f1fb7336aa0 100644
--- a/jstests/noPassthrough/ftdc_connection_pool.js
+++ b/jstests/noPassthrough/ftdc_connection_pool.js
@@ -24,12 +24,6 @@ load('jstests/libs/ftdc.js');
     assert(stats.hasOwnProperty('totalAvailable'));
     assert(stats.hasOwnProperty('totalCreated'));
     assert(stats.hasOwnProperty('totalRefreshing'));
-    assert("getHostAndRefresh" in stats["replicaSetMonitor"]);
-    const getHostStats = stats["replicaSetMonitor"]["getHostAndRefresh"];
-    assert(getHostStats.hasOwnProperty('currentlyActive'));
-    assert("hello" in stats["replicaSetMonitor"]);
-    const helloStats = stats["replicaSetMonitor"]["hello"];
-    assert(helloStats.hasOwnProperty('currentlyActive'));
 
     // The connPoolStats command reply has "hosts", but FTDC's stats do not.
     assert(!stats.hasOwnProperty('hosts'));
diff --git a/src/mongo/client/SConscript b/src/mongo/client/SConscript
index 5a930faa1f5..0f8b225c8ab 100644
--- a/src/mongo/client/SConscript
+++ b/src/mongo/client/SConscript
@@ -186,8 +186,7 @@ clientDriverEnv.Library(
         'global_conn_pool.cpp',
         'replica_set_monitor.cpp',
         'replica_set_monitor_manager.cpp',
-        'replica_set_monitor_stats.cpp',
-        'replica_set_monitor_transport.cpp',
+	'replica_set_monitor_transport.cpp',
     ],
     LIBDEPS=[
         '$BUILD_DIR/mongo/db/write_concern_options',
diff --git a/src/mongo/client/replica_set_monitor.cpp b/src/mongo/client/replica_set_monitor.cpp
index a274aaa3e4f..7d01c32b2c5 100644
--- a/src/mongo/client/replica_set_monitor.cpp
+++ b/src/mongo/client/replica_set_monitor.cpp
@@ -99,7 +99,7 @@ const int64_t unknownLatency = numeric_limits<int64_t>::max();
 // After this period of time, RSM logging becomes more verbose.
 static constexpr int kRsmVerbosityThresholdTimeoutSec = 20;
 // When 'is master' reply latency is over 2 sec, it will be logged.
-static constexpr Milliseconds kSlowIsMasterThreshold{500};
+static constexpr int kSlowIsMasterThresholdMicros = 2L * 1000 * 1000;
 
 static Seconds kHelloTimeout = Seconds{10};
 
@@ -132,11 +132,6 @@ bool hostsEqual(const Node& lhs, const HostAndPort& rhs) {
     return lhs.host == rhs;
 }
 
-ReplicaSetMonitorManagerStats* testOnlyManagerStats() {
-    static ReplicaSetMonitorManagerStats* stats = new ReplicaSetMonitorManagerStats();
-    return stats;
-}
-
 // Allows comparing two Nodes, or a HostAndPort and a Node.
 // NOTE: the two HostAndPort overload is only needed to support extra checks in some STL
 // implementations. For simplicity, no comparator should be used with collections of just
@@ -230,30 +225,21 @@ Milliseconds ReplicaSetMonitor::getHelloTimeout() {
 
 ReplicaSetMonitor::ReplicaSetMonitor(StringData name,
                                      const std::set<HostAndPort>& seeds,
-                                     ReplicaSetMonitorTransportPtr transport,
-                                     ReplicaSetMonitorManagerStats* managerStats)
+                                     ReplicaSetMonitorTransportPtr transport)
     : _state(std::make_shared<SetState>(name, seeds)),
       _executor(globalRSMonitorManager.getExecutor()),
-      _rsmTransport(std::move(transport)),
-      _stats(managerStats) {}
+      _rsmTransport(std::move(transport)) {}
 
 ReplicaSetMonitor::ReplicaSetMonitor(const MongoURI& uri,
-                                     std::unique_ptr<ReplicaSetMonitorTransport> transport,
-                                     ReplicaSetMonitorManagerStats* managerStats)
+                                     std::unique_ptr<ReplicaSetMonitorTransport> transport)
     : _state(std::make_shared<SetState>(uri)),
       _executor(globalRSMonitorManager.getExecutor()),
-      _rsmTransport(std::move(transport)),
-      _stats(managerStats) {}
+      _rsmTransport(std::move(transport)) {}
 
 void ReplicaSetMonitor::init() {
     _scheduleRefresh(_executor->now());
 }
 
-// Test only constructor.
-ReplicaSetMonitor::ReplicaSetMonitor(const SetStatePtr& initialState,
-                                     ReplicaSetMonitorManagerStats* managerStats)
-    : _state(initialState), _stats(managerStats ? managerStats : testOnlyManagerStats()) {}
-
 ReplicaSetMonitor::~ReplicaSetMonitor() {
     // need this lock because otherwise can get race with _scheduleRefresh()
     stdx::lock_guard<stdx::mutex> lk(_mutex);
@@ -326,8 +312,7 @@ StatusWith<HostAndPort> ReplicaSetMonitor::getHostOrRefresh(const ReadPreference
             return {std::move(out)};
     }
 
-    const Timer startTimer;
-    const auto statsCollector = _stats.collectGetHostAndRefreshStats();
+    const auto startTimeMs = Date_t::now();
 
     while (true) {
         // We might not have found any matching hosts due to the scan, which just completed may have
@@ -344,7 +329,7 @@ StatusWith<HostAndPort> ReplicaSetMonitor::getHostOrRefresh(const ReadPreference
             return {ErrorCodes::ShutdownInProgress, str::stream() << "Server is shutting down"};
         }
 
-        const Milliseconds remaining = maxWait - Milliseconds(startTimer.millis());
+        const Milliseconds remaining = maxWait - (Date_t::now() - startTimeMs);
 
         if (remaining < kFindHostMaxBackOffTime || areRefreshRetriesDisabledForTest.load()) {
             break;
@@ -367,7 +352,7 @@ HostAndPort ReplicaSetMonitor::getMasterOrUassert() {
 Refresher ReplicaSetMonitor::startOrContinueRefresh() {
     stdx::lock_guard<stdx::mutex> lk(_state->mutex);
 
-    Refresher out(_state, _executor, _rsmTransport.get(), &_stats);
+    Refresher out(_state, _executor, _rsmTransport.get());
     DEV _state->checkInvariants();
     return out;
 }
@@ -536,13 +521,8 @@ void ReplicaSetMonitor::markAsRemoved() {
 
 Refresher::Refresher(const SetStatePtr& setState,
                      executor::TaskExecutor* executor,
-                     ReplicaSetMonitorTransport* transport,
-                     ReplicaSetMonitorStats* stats)
-    : _set(setState),
-      _scan(setState->currentScan),
-      _executor(executor),
-      _rsmTransport(transport),
-      _stats(stats) {
+                     ReplicaSetMonitorTransport* transport)
+    : _set(setState), _scan(setState->currentScan), _executor(executor), _rsmTransport(transport) {
     if (_scan)
         return;  // participate in in-progress scan
 
@@ -926,7 +906,7 @@ HostAndPort Refresher::_refreshUntilMatches(const ReadPreferenceSetting* criteri
                 {
                     Timer timer;
                     auto helloFuture = _rsmTransport->sayHello(
-                        ns.host, _set->name, _set->setUri, getHelloTimeout(), _stats);
+                        ns.host, _set->name, _set->setUri, getHelloTimeout());
                     helloReplyStatus = helloFuture.getNoThrow();
                     pingMicros = timer.micros();
                 }
@@ -1085,9 +1065,9 @@ void Node::update(const IsMasterReply& reply, bool verbose) {
             // update latency with smoothed moving average (1/4th the delta)
             latencyMicros += (reply.latencyMicros - latencyMicros) / 4;
         }
-        if (Milliseconds(reply.latencyMicros / 1000) > kSlowIsMasterThreshold) {
-            log() << "Slow ReplicaSet Monitor reply for " << reply.setName << " from " << host
-                  << ": " << reply.raw << " (" << (reply.latencyMicros / 1000) << " ms)";
+        if (reply.latencyMicros > kSlowIsMasterThresholdMicros) {  // > 2 seconds.
+            log() << "ReplicaSet Monitor received reply with latency above 2 seconds: "
+                  << reply.raw;
         }
     }
 
diff --git a/src/mongo/client/replica_set_monitor.h b/src/mongo/client/replica_set_monitor.h
index 2ca2fd89df1..115696c04ca 100644
--- a/src/mongo/client/replica_set_monitor.h
+++ b/src/mongo/client/replica_set_monitor.h
@@ -32,13 +32,13 @@
 
 #include <atomic>
 #include <memory>
+#include <memory>
 #include <set>
 #include <string>
 
 #include "mongo/base/disallow_copying.h"
 #include "mongo/base/string_data.h"
 #include "mongo/client/mongo_uri.h"
-#include "mongo/client/replica_set_monitor_stats.h"
 #include "mongo/client/replica_set_monitor_transport.h"
 #include "mongo/executor/task_executor.h"
 #include "mongo/platform/atomic_word.h"
@@ -74,12 +74,9 @@ public:
      */
     ReplicaSetMonitor(StringData name,
                       const std::set<HostAndPort>& seeds,
-                      ReplicaSetMonitorTransportPtr transport,
-                      ReplicaSetMonitorManagerStats* managerStats);
+                      ReplicaSetMonitorTransportPtr transport);
 
-    ReplicaSetMonitor(const MongoURI& uri,
-                      ReplicaSetMonitorTransportPtr transport,
-                      ReplicaSetMonitorManagerStats* managerStats);
+    ReplicaSetMonitor(const MongoURI& uri, ReplicaSetMonitorTransportPtr transport);
 
     /**
      * Schedules the initial refresh task into task executor.
@@ -278,10 +275,8 @@ public:
 
     /**
      * Allows tests to set initial conditions and introspect the current state.
-     * This constructor is used only in tests.
      */
-    explicit ReplicaSetMonitor(const SetStatePtr& initialState,
-                               ReplicaSetMonitorManagerStats* managerStats = nullptr);
+    explicit ReplicaSetMonitor(const SetStatePtr& initialState) : _state(initialState) {}
     ~ReplicaSetMonitor();
 
     /**
@@ -318,8 +313,6 @@ private:
     executor::TaskExecutor* _executor;
     AtomicBool _isRemovedFromManager{false};
     ReplicaSetMonitorTransportPtr _rsmTransport;
-
-    ReplicaSetMonitorStats _stats;
 };
 
 
@@ -364,8 +357,7 @@ public:
      */
     explicit Refresher(const SetStatePtr& setState,
                        executor::TaskExecutor* executor,
-                       ReplicaSetMonitorTransport* transport,
-                       ReplicaSetMonitorStats* stats);
+                       ReplicaSetMonitorTransport* transport);
 
     struct NextStep {
         enum StepKind {
@@ -444,7 +436,6 @@ private:
 
     executor::TaskExecutor* _executor;
     ReplicaSetMonitorTransport* _rsmTransport;
-    ReplicaSetMonitorStats* const _stats;
 };
 
 }  // namespace mongo
diff --git a/src/mongo/client/replica_set_monitor_manager.cpp b/src/mongo/client/replica_set_monitor_manager.cpp
index d305f790d55..7345fd95fc8 100644
--- a/src/mongo/client/replica_set_monitor_manager.cpp
+++ b/src/mongo/client/replica_set_monitor_manager.cpp
@@ -159,8 +159,7 @@ shared_ptr<ReplicaSetMonitor> ReplicaSetMonitorManager::getOrCreateMonitor(
     if (!transport) {
         transport = makeRsmTransport();
     }
-    auto newMonitor =
-        std::make_shared<ReplicaSetMonitor>(setName, servers, std::move(transport), &_stats);
+    auto newMonitor = std::make_shared<ReplicaSetMonitor>(setName, servers, std::move(transport));
     _monitors[setName] = newMonitor;
     newMonitor->init();
     return newMonitor;
@@ -181,7 +180,7 @@ shared_ptr<ReplicaSetMonitor> ReplicaSetMonitorManager::getOrCreateMonitor(
 
     log() << "Starting new replica set monitor for " << uri.toString();
 
-    auto newMonitor = std::make_shared<ReplicaSetMonitor>(uri, std::move(transport), &_stats);
+    auto newMonitor = std::make_shared<ReplicaSetMonitor>(uri, std::move(transport));
     _monitors[setName] = newMonitor;
     newMonitor->init();
     return newMonitor;
@@ -254,20 +253,16 @@ void ReplicaSetMonitorManager::report(BSONObjBuilder* builder, bool forFTDC) {
     // calling ShardRegistry::updateConfigServerConnectionString.
     auto setNames = getAllSetNames();
 
-    {
-        BSONObjBuilder setStats(
-            builder->subobjStart(forFTDC ? "replicaSetPingTimesMillis" : "replicaSets"));
-
-        for (const auto& setName : setNames) {
-            auto monitor = getMonitor(setName);
-            if (!monitor) {
-                continue;
-            }
-            monitor->appendInfo(setStats, forFTDC);
+    BSONObjBuilder setStats(
+        builder->subobjStart(forFTDC ? "replicaSetPingTimesMillis" : "replicaSets"));
+
+    for (const auto& setName : setNames) {
+        auto monitor = getMonitor(setName);
+        if (!monitor) {
+            continue;
         }
+        monitor->appendInfo(setStats, forFTDC);
     }
-
-    _stats.report(builder, forFTDC);
 }
 
 TaskExecutor* ReplicaSetMonitorManager::getExecutor() {
diff --git a/src/mongo/client/replica_set_monitor_manager.h b/src/mongo/client/replica_set_monitor_manager.h
index 181ae80481c..89bee98cfc8 100644
--- a/src/mongo/client/replica_set_monitor_manager.h
+++ b/src/mongo/client/replica_set_monitor_manager.h
@@ -34,7 +34,6 @@
 #include <vector>
 
 #include "mongo/base/disallow_copying.h"
-#include "mongo/client/replica_set_monitor_stats.h"
 #include "mongo/client/replica_set_monitor_transport.h"
 #include "mongo/executor/task_executor.h"
 #include "mongo/stdx/mutex.h"
@@ -121,9 +120,6 @@ private:
 
     // set to true when shutdown has been called.
     bool _isShutdown{false};
-
-    // Internally synchronized.
-    ReplicaSetMonitorManagerStats _stats;
 };
 
 }  // namespace mongo
diff --git a/src/mongo/client/replica_set_monitor_stats.cpp b/src/mongo/client/replica_set_monitor_stats.cpp
deleted file mode 100644
index 1eb1e183de5..00000000000
--- a/src/mongo/client/replica_set_monitor_stats.cpp
+++ /dev/null
@@ -1,146 +0,0 @@
-/**
- *    Copyright (C) 2021-present MongoDB, Inc.
- *
- *    This program is free software: you can redistribute it and/or modify
- *    it under the terms of the Server Side Public License, version 1,
- *    as published by MongoDB, Inc.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    Server Side Public License for more details.
- *
- *    You should have received a copy of the Server Side Public License
- *    along with this program. If not, see
- *    <http://www.mongodb.com/licensing/server-side-public-license>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the Server Side Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#include "mongo/client/replica_set_monitor_stats.h"
-#include "mongo/bson/bsonobjbuilder.h"
-
-namespace mongo {
-
-constexpr Microseconds ReplicaSetMonitorManagerStats::kMaxLatencyDefaultResetTimeout;
-
-static constexpr char kRSMPrefix[] = "replicaSetMonitor";
-static constexpr char kGetHostPrefix[] = "getHostAndRefresh";
-static constexpr char kHelloPrefix[] = "hello";
-
-ReplicaSetMonitorManagerStats::ReplicaSetMonitorManagerStats(Microseconds resetTimeout)
-    : _resetTimeout(resetTimeout) {}
-
-void ReplicaSetMonitorManagerStats::report(BSONObjBuilder* builder, bool forFTDC) {
-    if (!forFTDC) {
-        return;
-    }
-    BSONObjBuilder rsmStats(builder->subobjStart(kRSMPrefix));
-    {
-        BSONObjBuilder getHostStats(rsmStats.subobjStart(kGetHostPrefix));
-        getHostStats.appendNumber("totalCalls", _getHostAndRefreshTotal);
-        getHostStats.appendNumber("currentlyActive", _getHostAndRefreshCurrent);
-        getHostStats.appendNumber("totalLatencyMicros", _getHostAndRefreshAggregateLatency);
-
-        stdx::lock_guard<stdx::mutex> lk(_mutex);
-        getHostStats.appendNumber("maxLatencyMicros",
-                                  durationCount<Microseconds>(_getHostAndRefreshMaxLatency));
-    }
-    {
-        BSONObjBuilder helloStats(rsmStats.subobjStart(kHelloPrefix));
-        helloStats.appendNumber("totalCalls", _helloTotal);
-        helloStats.appendNumber("currentlyActive", _helloCurrent);
-        helloStats.appendNumber("totalLatencyMicros", _helloAggregateLatency);
-
-        stdx::lock_guard<stdx::mutex> lk(_mutex);
-        helloStats.appendNumber("maxLatencyMicros", durationCount<Microseconds>(_helloMaxLatency));
-    }
-}
-
-void ReplicaSetMonitorManagerStats::enterGetHostAndRefresh() {
-    _getHostAndRefreshTotal.increment(1);
-    _getHostAndRefreshCurrent.increment(1);
-}
-
-static auto kProcessLatency = [](Microseconds& currentMaxLatency,
-                                 Microseconds& newLatency,
-                                 Timer& resetTimer,
-                                 Microseconds resetTimeout) {
-    bool replace = false;
-    if (newLatency > currentMaxLatency) {
-        replace = true;
-    }
-    if (Microseconds(resetTimer.micros()) > resetTimeout) {
-        replace = true;
-        resetTimer.reset();
-    }
-    if (replace) {
-        currentMaxLatency = newLatency;
-    }
-};
-
-void ReplicaSetMonitorManagerStats::leaveGetHostAndRefresh(Microseconds latency) {
-    _getHostAndRefreshCurrent.decrement(1);
-    _getHostAndRefreshAggregateLatency.increment(latency.count());
-
-    stdx::lock_guard<stdx::mutex> lk(_mutex);
-    kProcessLatency(_getHostAndRefreshMaxLatency,
-                    latency,
-                    _lastTimeGetHostAndRefreshMaxLatencyUpdated,
-                    _resetTimeout);
-}
-
-void ReplicaSetMonitorManagerStats::enterHello() {
-    _helloTotal.increment(1);
-    _helloCurrent.increment(1);
-}
-
-void ReplicaSetMonitorManagerStats::leaveHello(Microseconds latency) {
-    _helloCurrent.decrement(1);
-    _helloAggregateLatency.increment(latency.count());
-
-    stdx::lock_guard<stdx::mutex> lk(_mutex);
-    kProcessLatency(_helloMaxLatency, latency, _lastTimeHelloMaxLatencyUpdated, _resetTimeout);
-}
-
-
-ReplicaSetMonitorStats::ReplicaSetMonitorStats(ReplicaSetMonitorManagerStats* managerStats)
-    : _managerStats(managerStats) {}
-
-void ReplicaSetMonitorStats::_enterGetHostAndRefresh() {
-    _getHostAndRefreshTotal.increment(1);
-    _getHostAndRefreshCurrent.increment(1);
-    _managerStats->enterGetHostAndRefresh();
-}
-
-void ReplicaSetMonitorStats::_leaveGetHostAndRefresh(const Timer& suppliedTimer) {
-    const Microseconds latency = Microseconds(suppliedTimer.micros());
-    _getHostAndRefreshCurrent.decrement(1);
-    _getHostAndRefreshAggregateLatency.increment(latency.count());
-    _managerStats->leaveGetHostAndRefresh(latency);
-}
-
-void ReplicaSetMonitorStats::_enterHello() {
-    _helloTotal.increment(1);
-    _helloCurrent.increment(1);
-    _managerStats->enterHello();
-}
-
-void ReplicaSetMonitorStats::_leaveHello(const Timer& suppliedTimer) {
-    const Microseconds latency = Microseconds(suppliedTimer.micros());
-    _helloCurrent.decrement(1);
-    _helloLatency.increment(latency.count());
-    _managerStats->leaveHello(latency);
-}
-
-}  // namespace mongo
diff --git a/src/mongo/client/replica_set_monitor_stats.h b/src/mongo/client/replica_set_monitor_stats.h
deleted file mode 100644
index caaf49e6e28..00000000000
--- a/src/mongo/client/replica_set_monitor_stats.h
+++ /dev/null
@@ -1,127 +0,0 @@
-/**
- *    Copyright (C) 2021-present MongoDB, Inc.
- *
- *    This program is free software: you can redistribute it and/or modify
- *    it under the terms of the Server Side Public License, version 1,
- *    as published by MongoDB, Inc.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    Server Side Public License for more details.
- *
- *    You should have received a copy of the Server Side Public License
- *    along with this program. If not, see
- *    <http://www.mongodb.com/licensing/server-side-public-license>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the Server Side Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#pragma once
-
-#include <functional>
-#include <memory>
-
-#include "mongo/base/counter.h"
-#include "mongo/util/duration.h"
-#include "mongo/util/scopeguard.h"
-#include "mongo/util/timer.h"
-
-namespace mongo {
-
-// Common and aggregate stats for all RSMs.
-class ReplicaSetMonitorManagerStats {
-public:
-    static constexpr Microseconds kMaxLatencyDefaultResetTimeout{1 * 1000 * 1000};
-
-    explicit ReplicaSetMonitorManagerStats(
-        Microseconds resetTimeout = kMaxLatencyDefaultResetTimeout);
-
-    /**
-     * Reports information about the replica sets tracked by us, for diagnostic purposes.
-     */
-    void report(BSONObjBuilder* builder, bool forFTDC);
-
-    void enterGetHostAndRefresh();
-    void leaveGetHostAndRefresh(Microseconds latency);
-
-    void enterHello();
-    void leaveHello(Microseconds latency);
-
-private:
-    const Microseconds _resetTimeout;
-
-    mutable stdx::mutex _mutex;  // NOLINT.
-
-    // Stats for the outer loop of getHostAndRefresh().
-
-    Counter64 _getHostAndRefreshTotal;
-    Counter64 _getHostAndRefreshCurrent;
-    Counter64 _getHostAndRefreshAggregateLatency;
-
-    Timer _lastTimeGetHostAndRefreshMaxLatencyUpdated;
-    // Keeps track of largest individual RSM latency registered during last time period.
-    Microseconds _getHostAndRefreshMaxLatency;
-
-    Counter64 _helloTotal;
-    Counter64 _helloCurrent;
-    Counter64 _helloAggregateLatency;
-
-    Timer _lastTimeHelloMaxLatencyUpdated;
-    Microseconds _helloMaxLatency;
-};
-
-// Stats for an RSM.
-class ReplicaSetMonitorStats {
-public:
-    explicit ReplicaSetMonitorStats(ReplicaSetMonitorManagerStats* managerStats);
-
-    /**
-     * Returns a scope guard class instance to collect statistics.
-     * Invokes 'completionCallback' on leaving the scope.
-     * Callbacks arg: calculated latency.
-     */
-    auto collectGetHostAndRefreshStats() {
-        _enterGetHostAndRefresh();
-        return MakeGuard(
-            [ this, timer = std::make_shared<Timer>() ] { _leaveGetHostAndRefresh(*timer); });
-    }
-
-    auto collectHelloStats() {
-        _enterHello();
-        return MakeGuard([ this, timer = std::make_shared<Timer>() ] { _leaveHello(*timer); });
-    }
-
-private:
-    void _enterGetHostAndRefresh();
-    void _leaveGetHostAndRefresh(const Timer& suppliedTimer);
-
-    void _enterHello();
-    void _leaveHello(const Timer& suppliedTimer);
-
-    // Not owned. Instance of ReplicaSetMonitorManagerStats is owned by
-    // global ReplicaSetMonitorManager, which is never destroyed.
-    ReplicaSetMonitorManagerStats* _managerStats;
-
-    // Stats for the outer loop of getHostAndRefresh().
-
-    Counter64 _getHostAndRefreshTotal;
-    Counter64 _getHostAndRefreshCurrent;
-    Counter64 _getHostAndRefreshAggregateLatency;
-
-    Counter64 _helloTotal;
-    Counter64 _helloCurrent;
-    Counter64 _helloLatency;
-};
-
-}  // namespace mongo
diff --git a/src/mongo/client/replica_set_monitor_test.cpp b/src/mongo/client/replica_set_monitor_test.cpp
index 471d1ae27a7..7540854d9ce 100644
--- a/src/mongo/client/replica_set_monitor_test.cpp
+++ b/src/mongo/client/replica_set_monitor_test.cpp
@@ -59,11 +59,6 @@ std::vector<HostAndPort> basicSeedsBuilder() {
 const std::vector<HostAndPort> basicSeeds = basicSeedsBuilder();
 const std::set<HostAndPort> basicSeedsSet(basicSeeds.begin(), basicSeeds.end());
 
-struct StatsForTest {
-    ReplicaSetMonitorManagerStats managerStats;
-    ReplicaSetMonitorStats stats{&managerStats};
-};
-
 // NOTE: Unless stated otherwise, all tests assume exclusive access to state belongs to the
 // current (only) thread, so they do not lock SetState::mutex before examining state. This is
 // NOT something that non-test code should do.
@@ -352,8 +347,7 @@ TEST(ReplicaSetMonitor, IsMasterSecondaryWithTags) {
 
 TEST(ReplicaSetMonitor, CheckAllSeedsSerial) {
     SetStatePtr state = std::make_shared<SetState>("name", basicSeedsSet);
-    StatsForTest stats;
-    Refresher refresher(state, nullptr, nullptr, &stats.stats);
+    Refresher refresher(state, nullptr, nullptr);
 
     set<HostAndPort> seen;
 
@@ -401,8 +395,7 @@ TEST(ReplicaSetMonitor, CheckAllSeedsSerial) {
 
 TEST(ReplicaSetMonitor, CheckAllSeedsParallel) {
     SetStatePtr state = std::make_shared<SetState>("name", basicSeedsSet);
-    StatsForTest stats;
-    Refresher refresher(state, nullptr, nullptr, &stats.stats);
+    Refresher refresher(state, nullptr, nullptr);
 
     set<HostAndPort> seen;
 
@@ -460,8 +453,7 @@ TEST(ReplicaSetMonitor, CheckAllSeedsParallel) {
 
 TEST(ReplicaSetMonitor, NoMasterInitAllUp) {
     SetStatePtr state = std::make_shared<SetState>("name", basicSeedsSet);
-    StatsForTest stats;
-    Refresher refresher(state, nullptr, nullptr, &stats.stats);
+    Refresher refresher(state, nullptr, nullptr);
 
     set<HostAndPort> seen;
 
@@ -508,8 +500,7 @@ TEST(ReplicaSetMonitor, NoMasterInitAllUp) {
 
 TEST(ReplicaSetMonitor, MasterNotInSeeds_NoPrimaryInIsMaster) {
     SetStatePtr state = std::make_shared<SetState>("name", basicSeedsSet);
-    StatsForTest stats;
-    Refresher refresher(state, nullptr, nullptr, &stats.stats);
+    Refresher refresher(state, nullptr, nullptr);
 
     set<HostAndPort> seen;
 
@@ -586,8 +577,7 @@ TEST(ReplicaSetMonitor, MasterNotInSeeds_NoPrimaryInIsMaster) {
 
 TEST(ReplicaSetMonitor, MasterNotInSeeds_PrimaryInIsMaster) {
     SetStatePtr state = std::make_shared<SetState>("name", basicSeedsSet);
-    StatsForTest stats;
-    Refresher refresher(state, nullptr, nullptr, &stats.stats);
+    Refresher refresher(state, nullptr, nullptr);
 
     set<HostAndPort> seen;
 
@@ -653,8 +643,7 @@ TEST(ReplicaSetMonitor, SlavesUsableEvenIfNoMaster) {
     std::set<HostAndPort> seeds;
     seeds.insert(HostAndPort("a"));
     SetStatePtr state = std::make_shared<SetState>("name", seeds);
-    StatsForTest stats;
-    Refresher refresher(state, nullptr, nullptr, &stats.stats);
+    Refresher refresher(state, nullptr, nullptr);
 
     const ReadPreferenceSetting secondary(ReadPreference::SecondaryOnly, TagSet());
 
@@ -696,8 +685,7 @@ TEST(ReplicaSetMonitor, SlavesUsableEvenIfNoMaster) {
 // Test multiple nodes that claim to be master (we use a last-wins policy)
 TEST(ReplicaSetMonitor, MultipleMasterLastNodeWins) {
     SetStatePtr state = std::make_shared<SetState>("name", basicSeedsSet);
-    StatsForTest stats;
-    Refresher refresher(state, nullptr, nullptr, &stats.stats);
+    Refresher refresher(state, nullptr, nullptr);
 
     set<HostAndPort> seen;
 
@@ -760,8 +748,7 @@ TEST(ReplicaSetMonitor, MultipleMasterLastNodeWins) {
 // Test nodes disagree about who is in the set, master is source of truth
 TEST(ReplicaSetMonitor, MasterIsSourceOfTruth) {
     SetStatePtr state = std::make_shared<SetState>("name", basicSeedsSet);
-    StatsForTest stats;
-    Refresher refresher(state, nullptr, nullptr, &stats.stats);
+    Refresher refresher(state, nullptr, nullptr);
 
     BSONArray primaryHosts = BSON_ARRAY("a"
                                         << "b"
@@ -802,8 +789,7 @@ TEST(ReplicaSetMonitor, MasterIsSourceOfTruth) {
 // Test multiple master nodes that disagree about set membership
 TEST(ReplicaSetMonitor, MultipleMastersDisagree) {
     SetStatePtr state = std::make_shared<SetState>("name", basicSeedsSet);
-    StatsForTest stats;
-    Refresher refresher(state, nullptr, nullptr, &stats.stats);
+    Refresher refresher(state, nullptr, nullptr);
 
     BSONArray hostsForSeed[3];
     hostsForSeed[0] = BSON_ARRAY("a"
@@ -901,8 +887,7 @@ TEST(ReplicaSetMonitor, MultipleMastersDisagree) {
 // Ensure getMatchingHost returns hosts even if scan is ongoing
 TEST(ReplicaSetMonitor, GetMatchingDuringScan) {
     SetStatePtr state = std::make_shared<SetState>("name", basicSeedsSet);
-    StatsForTest stats;
-    Refresher refresher(state, nullptr, nullptr, &stats.stats);
+    Refresher refresher(state, nullptr, nullptr);
 
     const ReadPreferenceSetting primaryOnly(ReadPreference::PrimaryOnly, TagSet());
     const ReadPreferenceSetting secondaryOnly(ReadPreference::SecondaryOnly, TagSet());
@@ -1005,8 +990,7 @@ TEST(ReplicaSetMonitor, OutOfBandFailedHost) {
 // Newly elected primary with electionId >= maximum electionId seen by the Refresher
 TEST(ReplicaSetMonitorTests, NewPrimaryWithMaxElectionId) {
     SetStatePtr state = std::make_shared<SetState>("name", basicSeedsSet);
-    StatsForTest stats;
-    Refresher refresher(state, nullptr, nullptr, &stats.stats);
+    Refresher refresher(state, nullptr, nullptr);
 
     set<HostAndPort> seen;
 
@@ -1072,8 +1056,7 @@ TEST(ReplicaSetMonitorTests, NewPrimaryWithMaxElectionId) {
 // Ignore electionId of secondaries
 TEST(ReplicaSetMonitorTests, IgnoreElectionIdFromSecondaries) {
     SetStatePtr state = std::make_shared<SetState>("name", basicSeedsSet);
-    StatsForTest stats;
-    Refresher refresher(state, nullptr, nullptr, &stats.stats);
+    Refresher refresher(state, nullptr, nullptr);
 
     set<HostAndPort> seen;
 
@@ -1120,8 +1103,7 @@ TEST(ReplicaSetMonitorTests, IgnoreElectionIdFromSecondaries) {
 // Stale Primary with obsolete electionId
 TEST(ReplicaSetMonitorTests, StalePrimaryWithObsoleteElectionId) {
     SetStatePtr state = std::make_shared<SetState>("name", basicSeedsSet);
-    StatsForTest stats;
-    Refresher refresher(state, nullptr, nullptr, &stats.stats);
+    Refresher refresher(state, nullptr, nullptr);
 
     const OID firstElectionId = OID::gen();
     const OID secondElectionId = OID::gen();
@@ -1251,8 +1233,7 @@ TEST(ReplicaSetMonitor, PrimaryIsUpCheck) {
  */
 TEST(ReplicaSetMonitorTests, TwoPrimaries2ndHasNewerConfigVersion) {
     SetStatePtr state = std::make_shared<SetState>("name", basicSeedsSet);
-    StatsForTest stats;
-    Refresher refresher(state, nullptr, nullptr, &stats.stats);
+    Refresher refresher(state, nullptr, nullptr);
 
     auto ns = refresher.getNextStep();
     ASSERT_EQUALS(ns.step, NextStep::CONTACT_HOST);
@@ -1314,8 +1295,7 @@ TEST(ReplicaSetMonitorTests, TwoPrimaries2ndHasNewerConfigVersion) {
  */
 TEST(ReplicaSetMonitorTests, TwoPrimaries2ndHasOlderConfigVersion) {
     SetStatePtr state = std::make_shared<SetState>("name", basicSeedsSet);
-    StatsForTest stats;
-    Refresher refresher(state, nullptr, nullptr, &stats.stats);
+    Refresher refresher(state, nullptr, nullptr);
 
     auto ns = refresher.getNextStep();
     ASSERT_EQUALS(ns.step, NextStep::CONTACT_HOST);
@@ -1375,8 +1355,7 @@ TEST(ReplicaSetMonitorTests, TwoPrimaries2ndHasOlderConfigVersion) {
  */
 TEST(ReplicaSetMonitor, MaxStalenessMSMatch) {
     SetStatePtr state = std::make_shared<SetState>("name", basicSeedsSet);
-    StatsForTest stats;
-    Refresher refresher(state, nullptr, nullptr, &stats.stats);
+    Refresher refresher(state, nullptr, nullptr);
     repl::OpTime opTime{Timestamp{10, 10}, 10};
 
     const ReadPreferenceSetting secondary(ReadPreference::SecondaryOnly, TagSet(), Seconds(100));
@@ -1429,8 +1408,7 @@ TEST(ReplicaSetMonitor, MaxStalenessMSMatch) {
  */
 TEST(ReplicaSetMonitor, MaxStalenessMSNoMatch) {
     SetStatePtr state = std::make_shared<SetState>("name", basicSeedsSet);
-    StatsForTest stats;
-    Refresher refresher(state, nullptr, nullptr, &stats.stats);
+    Refresher refresher(state, nullptr, nullptr);
     repl::OpTime opTime{Timestamp{10, 10}, 10};
 
     const ReadPreferenceSetting secondary(ReadPreference::SecondaryOnly, TagSet(), Seconds(200));
@@ -1482,8 +1460,7 @@ TEST(ReplicaSetMonitor, MaxStalenessMSNoMatch) {
  */
 TEST(ReplicaSetMonitor, MaxStalenessMSNoPrimaryMatch) {
     SetStatePtr state = std::make_shared<SetState>("name", basicSeedsSet);
-    StatsForTest stats;
-    Refresher refresher(state, nullptr, nullptr, &stats.stats);
+    Refresher refresher(state, nullptr, nullptr);
     repl::OpTime opTime{Timestamp{10, 10}, 10};
 
     const ReadPreferenceSetting secondary(ReadPreference::SecondaryOnly, TagSet(), Seconds(200));
@@ -1538,8 +1515,7 @@ TEST(ReplicaSetMonitor, MaxStalenessMSNoPrimaryMatch) {
  */
 TEST(ReplicaSetMonitor, MaxStalenessMSAllFailed) {
     SetStatePtr state = std::make_shared<SetState>("name", basicSeedsSet);
-    StatsForTest stats;
-    Refresher refresher(state, nullptr, nullptr, &stats.stats);
+    Refresher refresher(state, nullptr, nullptr);
     repl::OpTime opTime{Timestamp{10, 10}, 10};
 
     const ReadPreferenceSetting secondary(ReadPreference::SecondaryOnly, TagSet(), Seconds(200));
@@ -1593,8 +1569,7 @@ TEST(ReplicaSetMonitor, MaxStalenessMSAllFailed) {
  */
 TEST(ReplicaSetMonitor, MaxStalenessMSAllButPrimaryFailed) {
     SetStatePtr state = std::make_shared<SetState>("name", basicSeedsSet);
-    StatsForTest stats;
-    Refresher refresher(state, nullptr, nullptr, &stats.stats);
+    Refresher refresher(state, nullptr, nullptr);
     repl::OpTime opTime{Timestamp{10, 10}, 10};
 
     const ReadPreferenceSetting secondary(ReadPreference::SecondaryOnly, TagSet(), Seconds(200));
@@ -1647,8 +1622,7 @@ TEST(ReplicaSetMonitor, MaxStalenessMSAllButPrimaryFailed) {
  */
 TEST(ReplicaSetMonitor, MaxStalenessMSOneSecondaryFailed) {
     SetStatePtr state = std::make_shared<SetState>("name", basicSeedsSet);
-    StatsForTest stats;
-    Refresher refresher(state, nullptr, nullptr, &stats.stats);
+    Refresher refresher(state, nullptr, nullptr);
     repl::OpTime opTime{Timestamp{10, 10}, 10};
 
     const ReadPreferenceSetting secondary(ReadPreference::SecondaryOnly, TagSet(), Seconds(200));
@@ -1700,8 +1674,7 @@ TEST(ReplicaSetMonitor, MaxStalenessMSOneSecondaryFailed) {
  */
 TEST(ReplicaSetMonitor, MaxStalenessMSNonStaleSecondaryMatched) {
     SetStatePtr state = std::make_shared<SetState>("name", basicSeedsSet);
-    StatsForTest stats;
-    Refresher refresher(state, nullptr, nullptr, &stats.stats);
+    Refresher refresher(state, nullptr, nullptr);
     repl::OpTime opTime{Timestamp{10, 10}, 10};
 
     const ReadPreferenceSetting secondary(ReadPreference::SecondaryOnly, TagSet(), Seconds(200));
@@ -1754,8 +1727,7 @@ TEST(ReplicaSetMonitor, MaxStalenessMSNonStaleSecondaryMatched) {
  */
 TEST(ReplicaSetMonitor, MaxStalenessMSNoLastWrite) {
     SetStatePtr state = std::make_shared<SetState>("name", basicSeedsSet);
-    StatsForTest stats;
-    Refresher refresher(state, nullptr, nullptr, &stats.stats);
+    Refresher refresher(state, nullptr, nullptr);
 
     const ReadPreferenceSetting secondary(ReadPreference::SecondaryOnly, TagSet(), Seconds(200));
     BSONArray hosts = BSON_ARRAY("a"
@@ -1797,8 +1769,7 @@ TEST(ReplicaSetMonitor, MaxStalenessMSNoLastWrite) {
  */
 TEST(ReplicaSetMonitor, MaxStalenessMSZeroNoLastWrite) {
     SetStatePtr state = std::make_shared<SetState>("name", basicSeedsSet);
-    StatsForTest stats;
-    Refresher refresher(state, nullptr, nullptr, &stats.stats);
+    Refresher refresher(state, nullptr, nullptr);
 
     const ReadPreferenceSetting secondary(ReadPreference::SecondaryOnly, TagSet(), Seconds(0));
     BSONArray hosts = BSON_ARRAY("a"
@@ -1840,8 +1811,7 @@ TEST(ReplicaSetMonitor, MaxStalenessMSZeroNoLastWrite) {
  */
 TEST(ReplicaSetMonitor, MinOpTimeMatched) {
     SetStatePtr state = std::make_shared<SetState>("name", basicSeedsSet);
-    StatsForTest stats;
-    Refresher refresher(state, nullptr, nullptr, &stats.stats);
+    Refresher refresher(state, nullptr, nullptr);
 
     repl::OpTime minOpTimeSetting{Timestamp{10, 10}, 10};
     repl::OpTime opTimeNonStale{Timestamp{10, 10}, 11};
@@ -1886,8 +1856,7 @@ TEST(ReplicaSetMonitor, MinOpTimeMatched) {
  */
 TEST(ReplicaSetMonitor, MinOpTimeNotMatched) {
     SetStatePtr state = std::make_shared<SetState>("name", basicSeedsSet);
-    StatsForTest stats;
-    Refresher refresher(state, nullptr, nullptr, &stats.stats);
+    Refresher refresher(state, nullptr, nullptr);
 
     repl::OpTime minOpTimeSetting{Timestamp{10, 10}, 10};
     repl::OpTime opTimeNonStale{Timestamp{10, 10}, 11};
@@ -1932,8 +1901,7 @@ TEST(ReplicaSetMonitor, MinOpTimeNotMatched) {
  */
 TEST(ReplicaSetMonitor, MinOpTimeIgnored) {
     SetStatePtr state = std::make_shared<SetState>("name", basicSeedsSet);
-    StatsForTest stats;
-    Refresher refresher(state, nullptr, nullptr, &stats.stats);
+    Refresher refresher(state, nullptr, nullptr);
 
     repl::OpTime minOpTimeSetting{Timestamp{10, 10}, 10};
     repl::OpTime opTimeStale{Timestamp{10, 10}, 9};
diff --git a/src/mongo/client/replica_set_monitor_transport.cpp b/src/mongo/client/replica_set_monitor_transport.cpp
index 7b3a6e74ef1..58cc7fa5671 100644
--- a/src/mongo/client/replica_set_monitor_transport.cpp
+++ b/src/mongo/client/replica_set_monitor_transport.cpp
@@ -44,12 +44,10 @@ const int kLogLevel = 2;
 ReplicaSetMonitorTransport::~ReplicaSetMonitorTransport() {}
 
 
-Future<BSONObj> ReplicaSetMonitorDbClientTransport::sayHello(
-    HostAndPort host,
-    const std::string& setName,
-    const MongoURI& setUri,
-    Milliseconds timeout,
-    ReplicaSetMonitorStats* stats) noexcept {
+Future<BSONObj> ReplicaSetMonitorDbClientTransport::sayHello(HostAndPort host,
+                                                             const std::string& setName,
+                                                             const MongoURI& setUri,
+                                                             Milliseconds timeout) noexcept {
     MongoURI targetURI;
     const auto& hostStr = host.toString();
     Timer timer;
@@ -64,7 +62,6 @@ Future<BSONObj> ReplicaSetMonitorDbClientTransport::sayHello(
 
         LOG(kLogLevel) << "ReplicaSetMonitor " << setName << " sending hello request to "
                        << hostStr;
-        const auto statsCollector = stats->collectHelloStats();
         ScopedDbConnection conn(targetURI, durationCount<Seconds>(timeout));
         bool ignoredOutParam = false;
         BSONObj reply;
@@ -87,12 +84,10 @@ ReplicaSetMonitorExecutorTransport::ReplicaSetMonitorExecutorTransport(
     executor::TaskExecutor* executor)
     : _executor(executor) {}
 
-Future<BSONObj> ReplicaSetMonitorExecutorTransport::sayHello(
-    HostAndPort host,
-    const std::string& setName,
-    const MongoURI& setUri,
-    Milliseconds timeout,
-    ReplicaSetMonitorStats* stats) noexcept {
+Future<BSONObj> ReplicaSetMonitorExecutorTransport::sayHello(HostAndPort host,
+                                                             const std::string& setName,
+                                                             const MongoURI& setUri,
+                                                             Milliseconds timeout) noexcept {
     try {
         auto pf = makePromiseFuture<BSONObj>();
         BSONObjBuilder bob;
@@ -110,8 +105,7 @@ Future<BSONObj> ReplicaSetMonitorExecutorTransport::sayHello(
         auto swCbHandle = _executor->scheduleRemoteCommand(std::move(request), [
             this,
             setName,
-            requestState = std::make_shared<HelloRequest>(host, std::move(pf.promise)),
-            statsCollector = stats->collectHelloStats()
+            requestState = std::make_shared<HelloRequest>(host, std::move(pf.promise))
         ](const executor::TaskExecutor::RemoteCommandCallbackArgs& result) mutable {
             LOG(kLogLevel) << "Replica set monitor " << setName << " received reply from "
                            << requestState->host.toString() << ": "
diff --git a/src/mongo/client/replica_set_monitor_transport.h b/src/mongo/client/replica_set_monitor_transport.h
index 660d5d4041a..cf6d3607dc2 100644
--- a/src/mongo/client/replica_set_monitor_transport.h
+++ b/src/mongo/client/replica_set_monitor_transport.h
@@ -31,7 +31,6 @@
 #include "mongo/platform/basic.h"
 
 #include "mongo/client/mongo_uri.h"
-#include "mongo/client/replica_set_monitor_stats.h"
 #include "mongo/executor/task_executor.h"
 #include "mongo/s/is_mongos.h"
 #include "mongo/transport/transport_layer.h"
@@ -55,8 +54,7 @@ public:
     virtual Future<BSONObj> sayHello(HostAndPort host,
                                      const std::string& setName,
                                      const MongoURI& setUri,
-                                     Milliseconds timeout,
-                                     ReplicaSetMonitorStats* stats) noexcept = 0;
+                                     Milliseconds timeout) noexcept = 0;
     virtual ~ReplicaSetMonitorTransport();
 };
 using ReplicaSetMonitorTransportPtr = std::unique_ptr<ReplicaSetMonitorTransport>;
@@ -70,8 +68,7 @@ public:
     Future<BSONObj> sayHello(HostAndPort host,
                              const std::string& setName,
                              const MongoURI& setUri,
-                             Milliseconds timeout,
-                             ReplicaSetMonitorStats* stats) noexcept override;
+                             Milliseconds timeout) noexcept override;
 };
 
 /**
@@ -86,8 +83,7 @@ public:
     Future<BSONObj> sayHello(HostAndPort host,
                              const std::string& setName,
                              const MongoURI& setUri,
-                             Milliseconds timeout,
-                             ReplicaSetMonitorStats* stats) noexcept override;
+                             Milliseconds timeout) noexcept override;
 
 private:
     void _haltIfIncompatibleServer(Status status);