SERVER-44635 MR in Agg: Remove in-line mapReduce execution statistics

10 files changed, 14 insertions, 524 deletions

diff --git a/src/mongo/db/commands/SConscript b/src/mongo/db/commands/SConscript
index bbc0780edb6..f7e219f6a65 100644
--- a/src/mongo/db/commands/SConscript
+++ b/src/mongo/db/commands/SConscript
@@ -507,22 +507,11 @@ env.Library(
 )
 
 env.Library(
-    target='map_reduce_stats',
-    source=[
-        'map_reduce_stats.cpp',
-    ],
-    LIBDEPS=[
-        '$BUILD_DIR/mongo/db/pipeline/pipeline',
-    ]
-)
-
-env.Library(
     target='map_reduce_agg',
     source=[
         'map_reduce_agg.cpp',
     ],
     LIBDEPS=[
-        '$BUILD_DIR/mongo/db/commands/map_reduce_stats',
         '$BUILD_DIR/mongo/db/commands/servers',
         '$BUILD_DIR/mongo/db/db_raii',
         '$BUILD_DIR/mongo/db/index/index_access_methods',
@@ -556,7 +545,6 @@ env.CppUnitTest(
     source=[
         "map_reduce_agg_test.cpp",
         "map_reduce_parse_test.cpp",
-        "map_reduce_stats_test.cpp",
     ],
     LIBDEPS=[
         '$BUILD_DIR/mongo/db/auth/authmocks',
diff --git a/src/mongo/db/commands/map_reduce_agg.cpp b/src/mongo/db/commands/map_reduce_agg.cpp
index fe066c6da0c..f4c61322c03 100644
--- a/src/mongo/db/commands/map_reduce_agg.cpp
+++ b/src/mongo/db/commands/map_reduce_agg.cpp
@@ -41,7 +41,6 @@
 #include "mongo/db/commands.h"
 #include "mongo/db/commands/map_reduce_agg.h"
 #include "mongo/db/commands/map_reduce_javascript_code.h"
-#include "mongo/db/commands/map_reduce_stats.h"
 #include "mongo/db/commands/mr_common.h"
 #include "mongo/db/curop.h"
 #include "mongo/db/db_raii.h"
@@ -97,16 +96,6 @@ auto makeExpressionContext(OperationContext* opCtx, const MapReduce& parsedMr) {
     return expCtx;
 }
 
-std::vector<CommonStats> extractStats(const Pipeline& pipeline) {
-    std::vector<CommonStats> pipelineStats;
-
-    for (const auto& stage : pipeline.getSources()) {
-        pipelineStats.push_back(stage->getCommonStats());
-    }
-
-    return pipelineStats;
-}
-
 }  // namespace
 
 bool runAggregationMapReduce(OperationContext* opCtx,
@@ -146,14 +135,8 @@ bool runAggregationMapReduce(OperationContext* opCtx,
         CurOp::get(opCtx)->debug().setPlanSummaryMetrics(planSummaryStats);
 
 
-        MapReduceStats mapReduceStats(extractStats(*runnablePipeline),
-                                      MapReduceStats::ResponseType::kUnsharded,
-                                      boost::get_optional_value_or(parsedMr.getVerbose(), false),
-                                      cmdTimer.millis());
-
         if (parsedMr.getOutOptions().getOutputType() == OutputType::InMemory) {
-            map_reduce_output_format::appendInlineResponse(
-                std::move(resultArray), mapReduceStats, &result);
+            map_reduce_output_format::appendInlineResponse(std::move(resultArray), &result);
         } else {
             // For output to collection, pipeline execution should not return any results.
             invariant(resultArray.isEmpty());
@@ -161,7 +144,6 @@ bool runAggregationMapReduce(OperationContext* opCtx,
             map_reduce_output_format::appendOutResponse(
                 parsedMr.getOutOptions().getDatabaseName(),
                 parsedMr.getOutOptions().getCollectionName(),
-                mapReduceStats,
                 &result);
         }
 
diff --git a/src/mongo/db/commands/map_reduce_stats.cpp b/src/mongo/db/commands/map_reduce_stats.cpp
deleted file mode 100644
index bff4dfd8732..00000000000
--- a/src/mongo/db/commands/map_reduce_stats.cpp
+++ /dev/null
@@ -1,138 +0,0 @@
-/**
- *    Copyright (C) 2019-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/platform/basic.h"
-
-#include "mongo/db/commands/map_reduce_stats.h"
-
-#include "mongo/db/pipeline/document_source.h"
-
-namespace mongo {
-
-MapReduceStats::MapReduceStats(const std::vector<CommonStats>& pipelineStats,
-                               ResponseType responseType,
-                               bool verbose,
-                               int executionTime)
-    : _responseType(responseType), _verbose(verbose), _executionTime(executionTime) {
-
-    long long prevTime = 0;
-    bool projectSeen = false;
-    for (const auto& stageStats : pipelineStats) {
-        const auto stageName = stageStats.stageTypeStr;
-
-        // While a mapReduce pipeline may include a $match, $sort and/or $limit stage they will be
-        // absorbed by the $cursor stage push down to the query sub-system. The exception to this is
-        // a $match with empty query predicate, which will not be pushed down.
-        if (stageName == "$cursor"_sd || stageName == "$match"_sd) {
-            _counts.input = stageStats.advanced;
-        } else if (stageName == "$project"_sd) {
-            if (!projectSeen) {
-                _timing.map = stageStats.executionTimeMillis - prevTime;
-                projectSeen = true;
-            }
-        } else if (stageName == "$unwind"_sd) {
-            _counts.emit = stageStats.advanced;
-        } else if (stageName == "$group"_sd) {
-            _timing.reduce = stageStats.executionTimeMillis - prevTime;
-            _counts.output = stageStats.advanced;
-        } else {
-            invariant(stageName == "$out"_sd || stageName == "$internalOutToDifferentDB"_sd ||
-                          stageName == "$merge"_sd,
-                      stageName);
-        }
-
-        prevTime = stageStats.executionTimeMillis;
-    }
-}
-
-void MapReduceStats::appendStats(BSONObjBuilder* resultBuilder) const {
-    *resultBuilder << "timeMillis" << _executionTime;
-
-    if (_verbose) {
-        appendTiming(resultBuilder);
-    }
-
-    appendCounts(resultBuilder);
-
-    if (_responseType == ResponseType::kSharded) {
-        appendShardCounts(resultBuilder);
-        appendPostProcessCounts(resultBuilder);
-    }
-}
-
-void MapReduceStats::appendCounts(BSONObjBuilder* resultBuilder) const {
-    BSONObjBuilder countBuilder = resultBuilder->subobjStart("counts");
-    countBuilder.appendNumber("input", _counts.input);
-    countBuilder.appendNumber("emit", _counts.emit);
-    countBuilder.appendNumber("output", _counts.output);
-    countBuilder.doneFast();
-}
-
-void MapReduceStats::appendTiming(BSONObjBuilder* resultBuilder) const {
-    BSONObjBuilder timingBuilder = resultBuilder->subobjStart("timing");
-    if (_responseType == ResponseType::kUnsharded) {
-        timingBuilder.appendIntOrLL("mapTime", _timing.map);
-        timingBuilder.appendIntOrLL("reduceTime", _timing.reduce);
-        timingBuilder.appendIntOrLL("total", _executionTime);
-    } else {
-        invariant(_responseType == ResponseType::kSharded);
-        // TODO SERVER-43290: Add support for sharded collection statistics.
-        timingBuilder << "shardProcessing" << 0;
-        timingBuilder << "postProcessing" << 0;
-    }
-    timingBuilder.doneFast();
-}
-
-void MapReduceStats::appendShardCounts(BSONObjBuilder* resultBuilder) const {
-    BSONObjBuilder shardCountsBuilder = resultBuilder->subobjStart("shardCounts");
-
-    // TODO SERVER-43290: Add support for sharded collection statistics.
-    BSONObjBuilder dummyShardBuilder = shardCountsBuilder.subobjStart("shardName-rs0/host:port");
-    dummyShardBuilder << "input" << 0;
-    dummyShardBuilder << "emit" << 0;
-    dummyShardBuilder << "output" << 0;
-    dummyShardBuilder.doneFast();
-
-    shardCountsBuilder.doneFast();
-}
-
-void MapReduceStats::appendPostProcessCounts(BSONObjBuilder* resultBuilder) const {
-    BSONObjBuilder countsBuilder = resultBuilder->subobjStart("postProcessCounts");
-
-    // TODO SERVER-43290: Add support for sharded collection statistics.
-    BSONObjBuilder dummyMergeBuilder = countsBuilder.subobjStart("shardName-rs0/host:port");
-    dummyMergeBuilder << "input" << 0;
-    dummyMergeBuilder << "emit" << 0;
-    dummyMergeBuilder << "output" << 0;
-    dummyMergeBuilder.doneFast();
-
-    countsBuilder.doneFast();
-}
-
-}  // namespace mongo
diff --git a/src/mongo/db/commands/map_reduce_stats.h b/src/mongo/db/commands/map_reduce_stats.h
deleted file mode 100644
index 0e9cf22468d..00000000000
--- a/src/mongo/db/commands/map_reduce_stats.h
+++ /dev/null
@@ -1,95 +0,0 @@
-/**
- *    Copyright (C) 2019-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 <vector>
-
-#include "mongo/bson/bsonobjbuilder.h"
-#include "mongo/db/exec/plan_stats.h"
-
-namespace mongo {
-
-/**
- * Responsible for building the set of statistics required for a MapReduce command response and
- * appending to a response message.
- */
-class MapReduceStats {
-public:
-    /**
-     * The mapReduce command response format differs when run against a sharded vs unsharded
-     * collection.
-     */
-    enum class ResponseType {
-        kUnsharded,
-        kSharded,
-    };
-
-    MapReduceStats(const std::vector<CommonStats>& stageStatistics,
-                   ResponseType responseType,
-                   bool verbose,
-                   int executionTime);
-
-    void appendStats(BSONObjBuilder* resultBuilder) const;
-
-    /**
-     * Creates a dummy MapReduceStats instance for use in unit testing.
-     */
-    static MapReduceStats createForTest() {
-        return MapReduceStats();
-    }
-
-private:
-    struct StageCounts {
-        size_t input = 0;
-        size_t emit = 0;
-        size_t output = 0;
-    } _counts;
-
-    struct StageTiming {
-        long long map = 0;
-        long long reduce = 0;
-    } _timing;
-
-    MapReduceStats() = default;
-
-    void appendCounts(BSONObjBuilder* resultBuilder) const;
-
-    void appendTiming(BSONObjBuilder* resultBuilder) const;
-
-    void appendShardCounts(BSONObjBuilder* resultBuilder) const;
-
-    void appendPostProcessCounts(BSONObjBuilder* resultBuilder) const;
-
-    const ResponseType _responseType = ResponseType::kUnsharded;
-    const bool _verbose = false;
-    const int _executionTime = 0;
-};
-
-}  // namespace mongo
diff --git a/src/mongo/db/commands/map_reduce_stats_test.cpp b/src/mongo/db/commands/map_reduce_stats_test.cpp
deleted file mode 100644
index a769e47b564..00000000000
--- a/src/mongo/db/commands/map_reduce_stats_test.cpp
+++ /dev/null
@@ -1,203 +0,0 @@
-/**
- *    Copyright (C) 2019-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/platform/basic.h"
-
-#include <vector>
-
-#include "mongo/bson/bsonobjbuilder.h"
-#include "mongo/db/commands/map_reduce_stats.h"
-#include "mongo/db/exec/plan_stats.h"
-#include "mongo/db/json.h"
-#include "mongo/unittest/death_test.h"
-#include "mongo/unittest/unittest.h"
-
-using namespace std::literals::string_literals;
-
-namespace mongo {
-namespace {
-
-class MapReduceStatsTest : public mongo::unittest::Test {
-public:
-    MapReduceStatsTest() = default;
-
-    std::vector<CommonStats> buildMapReducePipelineStats() const {
-        std::vector<CommonStats> pipelineStats;
-
-        size_t docCount = 100;
-        long long execTimeMs = 0;
-
-        pipelineStats.push_back(_buildStatsForStage("$cursor", docCount, execTimeMs));
-
-        execTimeMs += 5;
-        pipelineStats.push_back(_buildStatsForStage("$project", docCount, execTimeMs));
-
-        docCount *= 2;
-        execTimeMs += 5;
-        pipelineStats.push_back(_buildStatsForStage("$unwind", docCount, execTimeMs));
-
-        docCount -= 20;
-        execTimeMs += 5;
-        pipelineStats.push_back(_buildStatsForStage("$group", docCount, execTimeMs));
-
-        if (_addFinalize) {
-            execTimeMs += 5;
-            pipelineStats.push_back(_buildStatsForStage("$project", docCount, execTimeMs));
-        }
-
-        if (_addOut) {
-            execTimeMs += 5;
-            pipelineStats.push_back(_buildStatsForStage("$out", docCount, execTimeMs));
-        }
-
-        if (_addMerge) {
-            execTimeMs += 5;
-            pipelineStats.push_back(_buildStatsForStage("$merge", docCount, execTimeMs));
-        }
-
-        if (_addInvalidStageName) {
-            execTimeMs += 5;
-            pipelineStats.push_back(_buildStatsForStage("$changeStreams", docCount, execTimeMs));
-        }
-
-        return pipelineStats;
-    }
-
-    void addFinalizeProject() {
-        _addFinalize = true;
-    }
-    void addOut() {
-        _addOut = true;
-    }
-    void addMerge() {
-        _addMerge = true;
-    }
-    void addInvalidStageForMapReduce() {
-        _addInvalidStageName = true;
-    }
-
-private:
-    CommonStats _buildStatsForStage(const char* name, size_t count, long long timeMillis) const {
-        CommonStats stageStats(name);
-        stageStats.advanced = count;
-        stageStats.executionTimeMillis = timeMillis;
-        return stageStats;
-    }
-
-    bool _addFinalize = false;
-    bool _addOut = false;
-    bool _addMerge = false;
-    bool _addInvalidStageName = false;
-};
-
-
-TEST_F(MapReduceStatsTest, ConfirmStatsUnsharded) {
-    MapReduceStats mapReduceStats(buildMapReducePipelineStats(),
-                                  MapReduceStats::ResponseType::kUnsharded,
-                                  false,  // Not verbose
-                                  99);    // Total time
-
-    BSONObjBuilder objBuilder;
-    mapReduceStats.appendStats(&objBuilder);
-    ASSERT_BSONOBJ_EQ(fromjson("{timeMillis: 99,"
-                               "counts: {input: 100, emit: 200, output: 180}}"),
-                      objBuilder.obj());
-}
-
-
-TEST_F(MapReduceStatsTest, ConfirmStatsUnshardedVerbose) {
-    MapReduceStats mapReduceStats(buildMapReducePipelineStats(),
-                                  MapReduceStats::ResponseType::kUnsharded,
-                                  true,  // Verbose
-                                  99);   // Total time
-
-    BSONObjBuilder objBuilder;
-    mapReduceStats.appendStats(&objBuilder);
-    ASSERT_BSONOBJ_EQ(fromjson("{timeMillis: 99,"
-                               "timing: { mapTime: 5, reduceTime: 5, total: 99 },"
-                               "counts: {input: 100, emit: 200, output: 180}}"),
-                      objBuilder.obj());
-}
-
-TEST_F(MapReduceStatsTest, ConfirmStatsUnshardedWithOutStage) {
-    addOut();
-
-    MapReduceStats mapReduceStats(buildMapReducePipelineStats(),
-                                  MapReduceStats::ResponseType::kUnsharded,
-                                  false,  // Not verbose
-                                  99);    // Total time
-
-    BSONObjBuilder objBuilder;
-    mapReduceStats.appendStats(&objBuilder);
-    ASSERT_BSONOBJ_EQ(fromjson("{timeMillis: 99,"
-                               "counts: {input: 100, emit: 200, output: 180}}"),
-                      objBuilder.obj());
-}
-
-TEST_F(MapReduceStatsTest, ConfirmStatsUnshardedWithMergeStage) {
-    addMerge();
-    MapReduceStats mapReduceStats(buildMapReducePipelineStats(),
-                                  MapReduceStats::ResponseType::kUnsharded,
-                                  false,  // Not verbose
-                                  99);    // Total time
-
-    BSONObjBuilder objBuilder;
-    mapReduceStats.appendStats(&objBuilder);
-    ASSERT_BSONOBJ_EQ(fromjson("{timeMillis: 99,"
-                               "counts: {input: 100, emit: 200, output: 180}}"),
-                      objBuilder.obj());
-}
-
-TEST_F(MapReduceStatsTest, ConfirmStatsUnshardedWithFinalizeProjectStage) {
-    addFinalizeProject();
-    MapReduceStats mapReduceStats(buildMapReducePipelineStats(),
-                                  MapReduceStats::ResponseType::kUnsharded,
-                                  false,  // Not verbose
-                                  99);    // Total time
-
-    BSONObjBuilder objBuilder;
-    mapReduceStats.appendStats(&objBuilder);
-    ASSERT_BSONOBJ_EQ(fromjson("{timeMillis: 99,"
-                               "counts: {input: 100, emit: 200, output: 180}}"),
-                      objBuilder.obj());
-}
-
-DEATH_TEST_F(MapReduceStatsTest,
-             DeathByUnknownStage,
-             "Invariant failure stageName == \"$out\"_sd || stageName == "
-             "\"$internalOutToDifferentDB\"_sd || stageName == \"$merge\"_sd") {
-    addInvalidStageForMapReduce();
-    MapReduceStats mapReduceStats(buildMapReducePipelineStats(),
-                                  MapReduceStats::ResponseType::kUnsharded,
-                                  false,  // Not verbose
-                                  99);    // Total time
-}
-
-}  // namespace
-}  // namespace mongo
diff --git a/src/mongo/db/query/SConscript b/src/mongo/db/query/SConscript
index 950e4722834..ce94ea3a0c5 100644
--- a/src/mongo/db/query/SConscript
+++ b/src/mongo/db/query/SConscript
@@ -123,7 +123,6 @@ env.Library(
     ],
     LIBDEPS=[
         '$BUILD_DIR/mongo/base',
-        '$BUILD_DIR/mongo/db/commands/map_reduce_stats',
         '$BUILD_DIR/mongo/db/namespace_string',
     ],
 )
diff --git a/src/mongo/db/query/map_reduce_output_format.cpp b/src/mongo/db/query/map_reduce_output_format.cpp
index 23d8e9eee5a..cafbe483319 100644
--- a/src/mongo/db/query/map_reduce_output_format.cpp
+++ b/src/mongo/db/query/map_reduce_output_format.cpp
@@ -29,28 +29,21 @@
 
 #include "mongo/platform/basic.h"
 
-#include "mongo/db/commands/map_reduce_stats.h"
 #include "mongo/db/query/map_reduce_output_format.h"
 
 namespace mongo::map_reduce_output_format {
 
-void appendInlineResponse(BSONArray&& documents,
-                          const MapReduceStats& mapReduceStats,
-                          BSONObjBuilder* resultBuilder) {
+void appendInlineResponse(BSONArray&& documents, BSONObjBuilder* resultBuilder) {
     resultBuilder->appendArray("results", documents);
-    mapReduceStats.appendStats(resultBuilder);
 }
 
 void appendOutResponse(boost::optional<std::string> outDb,
                        std::string outColl,
-                       const MapReduceStats& mapReduceStats,
                        BSONObjBuilder* resultBuilder) {
     if (outDb) {
         resultBuilder->append("result", BSON("db" << *outDb << "collection" << outColl));
     } else {
         resultBuilder->append("result", outColl);
     }
-
-    mapReduceStats.appendStats(resultBuilder);
 }
 }  // namespace mongo::map_reduce_output_format
diff --git a/src/mongo/db/query/map_reduce_output_format.h b/src/mongo/db/query/map_reduce_output_format.h
index b993d2c49ad..5189323d80e 100644
--- a/src/mongo/db/query/map_reduce_output_format.h
+++ b/src/mongo/db/query/map_reduce_output_format.h
@@ -30,27 +30,23 @@
 #pragma once
 
 #include "mongo/bson/bsonobjbuilder.h"
-#include "mongo/db/commands/map_reduce_stats.h"
 
 /**
- * A collection of functions responsible for building a mapReduce command response from a result set
- * and pipeline execution statistics.
+ * A collection of functions responsible for building a mapReduce command response from a result
+ * set.
  */
 namespace mongo::map_reduce_output_format {
 
 /**
  * Appends an inline mapReduce command response to 'resultBuilder'.
  */
-void appendInlineResponse(BSONArray&& documents,
-                          const MapReduceStats& mapReduceStats,
-                          BSONObjBuilder* resultBuilder);
+void appendInlineResponse(BSONArray&& documents, BSONObjBuilder* resultBuilder);
 
 /**
  * Appends an output-to-collection mapReduce command response to 'resultBuilder'.
  */
 void appendOutResponse(boost::optional<std::string> outDb,
                        std::string outColl,
-                       const MapReduceStats& mapReduceStats,
                        BSONObjBuilder* resultBuilder);
 
 }  // namespace mongo::map_reduce_output_format
diff --git a/src/mongo/db/query/map_reduce_output_format_test.cpp b/src/mongo/db/query/map_reduce_output_format_test.cpp
index f0d89dd3275..aabd28181b4 100644
--- a/src/mongo/db/query/map_reduce_output_format_test.cpp
+++ b/src/mongo/db/query/map_reduce_output_format_test.cpp
@@ -47,57 +47,27 @@ TEST(MapReduceOutputFormat, FormatInlineMapReduceResponse) {
     documents.append(BSON("b" << 1));
 
     BSONObjBuilder builder;
-    map_reduce_output_format::appendInlineResponse(
-        documents.arr(), MapReduceStats::createForTest(), &builder);
-    ASSERT_BSONOBJ_EQ(fromjson("{results: [{a: 1}, {b: 1}],"
-                               "timeMillis: 0,"
-                               "counts: {input: 0, emit: 0, output: 0}}"),
-                      builder.obj());
-}
-
-TEST(MapReduceOutputFormat, FormatVerboseInlineMapReduceResponse) {
-    BSONArrayBuilder documents;
-    documents.append(BSON("a" << 1));
-    documents.append(BSON("b" << 1));
-
-    BSONObjBuilder builder;
-    map_reduce_output_format::appendInlineResponse(
-        documents.arr(), MapReduceStats::createForTest(), &builder);
-    ASSERT_BSONOBJ_EQ(fromjson("{results: [{a: 1}, {b: 1}],"
-                               "timeMillis: 0,"
-                               "counts: {input: 0, emit: 0, output: 0}}"),
-                      builder.obj());
+    map_reduce_output_format::appendInlineResponse(documents.arr(), &builder);
+    ASSERT_BSONOBJ_EQ(fromjson("{results: [{a: 1}, {b: 1}]}"), builder.obj());
 }
 
 TEST(MapReduceOutputFormat, FormatEmptyInlineMapReduceResponse) {
     BSONArrayBuilder documents;
     BSONObjBuilder builder;
-    map_reduce_output_format::appendInlineResponse(
-        documents.arr(), MapReduceStats::createForTest(), &builder);
-    ASSERT_BSONOBJ_EQ(fromjson("{results: [],"
-                               "timeMillis: 0,"
-                               "counts: {input: 0, emit: 0, output: 0}}"),
-                      builder.obj());
+    map_reduce_output_format::appendInlineResponse(documents.arr(), &builder);
+    ASSERT_BSONOBJ_EQ(fromjson("{results: []}"), builder.obj());
 }
 
 TEST(MapReduceOutputFormat, FormatNonInlineMapReduceResponseWithoutDb) {
     BSONObjBuilder builder;
-    map_reduce_output_format::appendOutResponse(
-        boost::none, "c", MapReduceStats::createForTest(), &builder);
-    ASSERT_BSONOBJ_EQ(fromjson("{result: \"c\","
-                               "timeMillis: 0,"
-                               "counts: {input: 0, emit: 0, output: 0}}"),
-                      builder.obj());
+    map_reduce_output_format::appendOutResponse(boost::none, "c", &builder);
+    ASSERT_BSONOBJ_EQ(fromjson("{result: \"c\"}"), builder.obj());
 }
 
 TEST(MapReduceOutputFormat, FormatNonInlineMapReduceResponseWithDb) {
     BSONObjBuilder builder;
-    map_reduce_output_format::appendOutResponse(
-        "db"s, "c", MapReduceStats::createForTest(), &builder);
-    ASSERT_BSONOBJ_EQ(fromjson("{result: {db: \"db\", collection: \"c\"},"
-                               "timeMillis: 0,"
-                               "counts: {input: 0, emit: 0, output: 0}}"),
-                      builder.obj());
+    map_reduce_output_format::appendOutResponse("db"s, "c", &builder);
+    ASSERT_BSONOBJ_EQ(fromjson("{result: {db: \"db\", collection: \"c\"}}"), builder.obj());
 }
 
 }  // namespace
diff --git a/src/mongo/s/commands/cluster_map_reduce_agg.cpp b/src/mongo/s/commands/cluster_map_reduce_agg.cpp
index 71f3deb8aa1..a7f12be3980 100644
--- a/src/mongo/s/commands/cluster_map_reduce_agg.cpp
+++ b/src/mongo/s/commands/cluster_map_reduce_agg.cpp
@@ -217,12 +217,10 @@ bool runAggregationMapReduce(OperationContext* opCtx,
                 bab.append(elem.embeddedObject());
             return bab.arr();
         }();
-        map_reduce_output_format::appendInlineResponse(
-            std::move(exhaustedResults), MapReduceStats::createForTest(), &result);
+        map_reduce_output_format::appendInlineResponse(std::move(exhaustedResults), &result);
     } else {
         map_reduce_output_format::appendOutResponse(parsedMr.getOutOptions().getDatabaseName(),
                                                     parsedMr.getOutOptions().getCollectionName(),
-                                                    MapReduceStats::createForTest(),
                                                     &result);
     }