SERVER-35069 Explain should include command being explained

24 files changed, 173 insertions, 28 deletions

diff --git a/jstests/core/explain_includes_command.js b/jstests/core/explain_includes_command.js
new file mode 100644
index 00000000000..633770118db
--- /dev/null
+++ b/jstests/core/explain_includes_command.js
@@ -0,0 +1,53 @@
+/*
+ * Confirms that the explain command includes the command object that was run.
+ *
+ * @tags: [requires_fcv_49, sbe_incompatible]
+ */
+(function() {
+"use strict";
+const collName = "explain_includes_command";
+
+db[collName].drop();
+assert.commandWorked(db[collName].insert({_id: 0}));
+assert.commandWorked(db[collName].insert({_id: 1}));
+assert.commandWorked(db[collName].insert({_id: 2}));
+
+/*
+ * Runs explain on 'cmdToExplain' and ensures that the explain output contains the expected
+ * 'command' field.
+ */
+function testExplainContainsCommand(cmdToExplain) {
+    const verbosity = ["queryPlanner", "executionStats", "allPlansExecution"];
+    for (const option of verbosity) {
+        const explainOutput = db.runCommand({explain: cmdToExplain, verbosity: option});
+        assert("command" in explainOutput);
+        const explainCmd = explainOutput["command"];
+        for (let key of Object.keys(cmdToExplain)) {
+            assert.eq(explainCmd[key], cmdToExplain[key]);
+        }
+    }
+}
+
+// Test 'find'.
+testExplainContainsCommand({find: collName, filter: {}});
+testExplainContainsCommand({find: collName, filter: {_id: 1}});
+
+// Test 'aggregate'.
+testExplainContainsCommand({aggregate: collName, pipeline: [{$match: {_id: 1}}], cursor: {}});
+
+// Test 'update'.
+testExplainContainsCommand({update: collName, updates: [{q: {_id: 1}, u: {_id: 10}}]});
+
+// Test 'delete'.
+testExplainContainsCommand({delete: collName, deletes: [{q: {_id: 1}, limit: 0}]});
+
+// Test 'findAndModify'.
+testExplainContainsCommand({findAndModify: collName, query: {_id: 10}, update: {_id: 1}});
+testExplainContainsCommand({findAndModify: collName, query: {_id: 1}, remove: true});
+
+// Test 'count'.
+testExplainContainsCommand({count: collName, query: {_id: 1}});
+
+// Test 'distinct'.
+testExplainContainsCommand({distinct: collName, key: "a"});
+})();
diff --git a/src/mongo/db/commands/count_cmd.cpp b/src/mongo/db/commands/count_cmd.cpp
index ed880886f40..2f9a844950b 100644
--- a/src/mongo/db/commands/count_cmd.cpp
+++ b/src/mongo/db/commands/count_cmd.cpp
@@ -198,7 +198,7 @@ public:
         auto exec = std::move(statusWithPlanExecutor.getValue());
 
         auto bodyBuilder = result->getBodyBuilder();
-        Explain::explainStages(exec.get(), collection, verbosity, BSONObj(), &bodyBuilder);
+        Explain::explainStages(exec.get(), collection, verbosity, BSONObj(), cmdObj, &bodyBuilder);
         return Status::OK();
     }
 
diff --git a/src/mongo/db/commands/distinct.cpp b/src/mongo/db/commands/distinct.cpp
index ab5f0145184..24ff3604b35 100644
--- a/src/mongo/db/commands/distinct.cpp
+++ b/src/mongo/db/commands/distinct.cpp
@@ -180,7 +180,8 @@ public:
             getExecutorDistinct(&collection, QueryPlannerParams::DEFAULT, &parsedDistinct));
 
         auto bodyBuilder = result->getBodyBuilder();
-        Explain::explainStages(executor.get(), collection, verbosity, BSONObj(), &bodyBuilder);
+        Explain::explainStages(
+            executor.get(), collection, verbosity, BSONObj(), cmdObj, &bodyBuilder);
         return Status::OK();
     }
 
diff --git a/src/mongo/db/commands/find_and_modify.cpp b/src/mongo/db/commands/find_and_modify.cpp
index cade28cbfa1..4586958eeb7 100644
--- a/src/mongo/db/commands/find_and_modify.cpp
+++ b/src/mongo/db/commands/find_and_modify.cpp
@@ -299,7 +299,7 @@ public:
 
             auto bodyBuilder = result->getBodyBuilder();
             Explain::explainStages(
-                exec.get(), collection.getCollection(), verbosity, BSONObj(), &bodyBuilder);
+                exec.get(), collection.getCollection(), verbosity, BSONObj(), cmdObj, &bodyBuilder);
         } else {
             auto request = UpdateRequest();
             request.setNamespaceString(nsString);
@@ -323,7 +323,7 @@ public:
 
             auto bodyBuilder = result->getBodyBuilder();
             Explain::explainStages(
-                exec.get(), collection.getCollection(), verbosity, BSONObj(), &bodyBuilder);
+                exec.get(), collection.getCollection(), verbosity, BSONObj(), cmdObj, &bodyBuilder);
         }
 
         return Status::OK();
diff --git a/src/mongo/db/commands/find_cmd.cpp b/src/mongo/db/commands/find_cmd.cpp
index afcb39f35c9..142d6bb9464 100644
--- a/src/mongo/db/commands/find_cmd.cpp
+++ b/src/mongo/db/commands/find_cmd.cpp
@@ -298,7 +298,8 @@ public:
 
             auto bodyBuilder = result->getBodyBuilder();
             // Got the execution tree. Explain it.
-            Explain::explainStages(exec.get(), collection, verbosity, BSONObj(), &bodyBuilder);
+            Explain::explainStages(
+                exec.get(), collection, verbosity, BSONObj(), _request.body, &bodyBuilder);
         }
 
         /**
diff --git a/src/mongo/db/commands/map_reduce_agg.cpp b/src/mongo/db/commands/map_reduce_agg.cpp
index 84ec6647e60..4e404097d93 100644
--- a/src/mongo/db/commands/map_reduce_agg.cpp
+++ b/src/mongo/db/commands/map_reduce_agg.cpp
@@ -144,7 +144,7 @@ bool runAggregationMapReduce(OperationContext* opCtx,
 
         if (expCtx->explain) {
             Explain::explainPipeline(
-                exec.get(), false /* executePipeline  */, *expCtx->explain, &result);
+                exec.get(), false /* executePipeline  */, *expCtx->explain, cmd, &result);
         }
 
         PlanSummaryStats planSummaryStats;
diff --git a/src/mongo/db/commands/run_aggregate.cpp b/src/mongo/db/commands/run_aggregate.cpp
index 753c6ca1f79..7c8f6565026 100644
--- a/src/mongo/db/commands/run_aggregate.cpp
+++ b/src/mongo/db/commands/run_aggregate.cpp
@@ -761,7 +761,7 @@ Status runAggregate(OperationContext* opCtx,
         auto bodyBuilder = result->getBodyBuilder();
         if (auto pipelineExec = dynamic_cast<PlanExecutorPipeline*>(explainExecutor)) {
             Explain::explainPipeline(
-                pipelineExec, true /* executePipeline */, *(expCtx->explain), &bodyBuilder);
+                pipelineExec, true /* executePipeline */, *(expCtx->explain), cmdObj, &bodyBuilder);
         } else {
             invariant(explainExecutor->getOpCtx() == opCtx);
             // The explainStages() function for a non-pipeline executor may need to execute the plan
@@ -773,6 +773,7 @@ Status runAggregate(OperationContext* opCtx,
                                    ctx->getCollection(),
                                    *(expCtx->explain),
                                    BSON("optimizedPipeline" << true),
+                                   cmdObj,
                                    &bodyBuilder);
         }
     } else {
diff --git a/src/mongo/db/commands/write_commands/write_commands.cpp b/src/mongo/db/commands/write_commands/write_commands.cpp
index af7b96c9741..de4e0632cb8 100644
--- a/src/mongo/db/commands/write_commands/write_commands.cpp
+++ b/src/mongo/db/commands/write_commands/write_commands.cpp
@@ -557,8 +557,12 @@ private:
                                                           &parsedUpdate,
                                                           verbosity));
             auto bodyBuilder = result->getBodyBuilder();
-            Explain::explainStages(
-                exec.get(), collection.getCollection(), verbosity, BSONObj(), &bodyBuilder);
+            Explain::explainStages(exec.get(),
+                                   collection.getCollection(),
+                                   verbosity,
+                                   BSONObj(),
+                                   _commandObj,
+                                   &bodyBuilder);
         }
 
         write_ops::Update _batch;
@@ -600,8 +604,9 @@ private:
     class Invocation final : public InvocationBase {
     public:
         Invocation(const WriteCommand* cmd, const OpMsgRequest& request)
-            : InvocationBase(cmd, request), _batch(DeleteOp::parse(request)) {}
-
+            : InvocationBase(cmd, request),
+              _batch(DeleteOp::parse(request)),
+              _commandObj(request.body) {}
 
     private:
         NamespaceString ns() const override {
@@ -654,11 +659,17 @@ private:
                                                           &parsedDelete,
                                                           verbosity));
             auto bodyBuilder = result->getBodyBuilder();
-            Explain::explainStages(
-                exec.get(), collection.getCollection(), verbosity, BSONObj(), &bodyBuilder);
+            Explain::explainStages(exec.get(),
+                                   collection.getCollection(),
+                                   verbosity,
+                                   BSONObj(),
+                                   _commandObj,
+                                   &bodyBuilder);
         }
 
         write_ops::Delete _batch;
+
+        const BSONObj& _commandObj;
     };
 
     std::unique_ptr<CommandInvocation> parse(OperationContext*,
diff --git a/src/mongo/db/pipeline/document_source_cursor.cpp b/src/mongo/db/pipeline/document_source_cursor.cpp
index a9310e2ca7c..2bfc196c45c 100644
--- a/src/mongo/db/pipeline/document_source_cursor.cpp
+++ b/src/mongo/db/pipeline/document_source_cursor.cpp
@@ -228,6 +228,7 @@ Value DocumentSourceCursor::serialize(boost::optional<ExplainOptions::Verbosity>
                                _execStatus,
                                _winningPlanTrialStats,
                                BSONObj(),
+                               BSONObj(),
                                &explainStatsBuilder);
     }
 
diff --git a/src/mongo/db/query/explain.cpp b/src/mongo/db/query/explain.cpp
index a921e706501..17257934cc8 100644
--- a/src/mongo/db/query/explain.cpp
+++ b/src/mongo/db/query/explain.cpp
@@ -66,6 +66,7 @@
 
 namespace mongo {
 namespace {
+
 /**
  * Adds the 'queryPlanner' explain section to the BSON object being built by 'out'.
  *
@@ -269,6 +270,7 @@ void Explain::explainStages(PlanExecutor* exec,
                             Status executePlanStatus,
                             boost::optional<PlanExplainer::PlanStatsDetails> winningPlanTrialStats,
                             BSONObj extraInfo,
+                            const BSONObj& command,
                             BSONObjBuilder* out) {
     //
     // Use the stats trees to produce explain BSON.
@@ -281,11 +283,14 @@ void Explain::explainStages(PlanExecutor* exec,
     if (verbosity >= ExplainOptions::Verbosity::kExecStats) {
         generateExecutionInfo(exec, verbosity, executePlanStatus, winningPlanTrialStats, out);
     }
+
+    explain_common::appendIfRoom(command, "command", out);
 }
 
 void Explain::explainPipeline(PlanExecutor* exec,
                               bool executePipeline,
                               ExplainOptions::Verbosity verbosity,
+                              const BSONObj& command,
                               BSONObjBuilder* out) {
     invariant(exec);
     invariant(out);
@@ -303,12 +308,15 @@ void Explain::explainPipeline(PlanExecutor* exec,
     *out << "stages" << Value(pipelineExec->writeExplainOps(verbosity));
 
     explain_common::generateServerInfo(out);
+
+    explain_common::appendIfRoom(command, "command", out);
 }
 
 void Explain::explainStages(PlanExecutor* exec,
                             const CollectionPtr& collection,
                             ExplainOptions::Verbosity verbosity,
                             BSONObj extraInfo,
+                            const BSONObj& command,
                             BSONObjBuilder* out) {
     auto&& explainer = exec->getPlanExplainer();
     auto winningPlanTrialStats = explainer.getWinningPlanStats(verbosity);
@@ -331,8 +339,14 @@ void Explain::explainStages(PlanExecutor* exec,
         }
     }
 
-    explainStages(
-        exec, *collectionPtr, verbosity, executePlanStatus, winningPlanTrialStats, extraInfo, out);
+    explainStages(exec,
+                  *collectionPtr,
+                  verbosity,
+                  executePlanStatus,
+                  winningPlanTrialStats,
+                  extraInfo,
+                  command,
+                  out);
 
     explain_common::generateServerInfo(out);
 }
diff --git a/src/mongo/db/query/explain.h b/src/mongo/db/query/explain.h
index b59cccb1c96..453e518d85a 100644
--- a/src/mongo/db/query/explain.h
+++ b/src/mongo/db/query/explain.h
@@ -59,6 +59,8 @@ public:
      *
      * The 'extraInfo' parameter specifies additional information to include into the output.
      *
+     * The 'command' parameter represents the command object that is being explained.
+     *
      * Does not take ownership of its arguments.
      *
      * During this call it may be required to execute the plan to collect statistics. If the
@@ -72,6 +74,7 @@ public:
                               const CollectionPtr& collection,
                               ExplainOptions::Verbosity verbosity,
                               BSONObj extraInfo,
+                              const BSONObj& command,
                               BSONObjBuilder* out);
     /**
      * Adds "queryPlanner" and "executionStats" (if requested in verbosity) fields to 'out'. Unlike
@@ -88,6 +91,7 @@ public:
      * query wasn't executed).
      * - 'winningPlanTrialStats' is the stats of the winning plan during the trial period. May be
      * nullptr.
+     * - 'command' represents the command object that is being explained.
      * - 'out' is the builder for the explain output.
      */
     static void explainStages(
@@ -97,6 +101,7 @@ public:
         Status executePlanStatus,
         boost::optional<PlanExplainer::PlanStatsDetails> winningPlanTrialStats,
         BSONObj extraInfo,
+        const BSONObj& command,
         BSONObjBuilder* out);
 
     /**
@@ -108,10 +113,13 @@ public:
      * If 'verbosity' >= 'kExecStats' the 'executePipeline' flag is used to indicate whether the
      * pipeline needs to be executed first, before the stats is collected. Otherwise, it is assumed
      * that the plan was already executed until EOF and the stats are ready for collection.
+     *
+     * The 'command' parameter represents the command object that is being explained.
      */
     static void explainPipeline(PlanExecutor* exec,
                                 bool executePipeline,
                                 ExplainOptions::Verbosity verbosity,
+                                const BSONObj& command,
                                 BSONObjBuilder* out);
 
     /**
diff --git a/src/mongo/db/query/explain_common.cpp b/src/mongo/db/query/explain_common.cpp
index 01242acf6fd..fd0b918bb69 100644
--- a/src/mongo/db/query/explain_common.cpp
+++ b/src/mongo/db/query/explain_common.cpp
@@ -47,4 +47,24 @@ void generateServerInfo(BSONObjBuilder* out) {
     serverBob.doneFast();
 }
 
+bool appendIfRoom(const BSONObj& toAppend, StringData fieldName, BSONObjBuilder* out) {
+    if ((out->len() + toAppend.objsize()) < BSONObjMaxUserSize) {
+        out->append(fieldName, toAppend);
+        return true;
+    }
+
+    // The reserved buffer size for the warning message if 'out' exceeds the max BSON user size.
+    const int warningMsgSize = fieldName.size() + 60;
+
+    // Unless 'out' has already exceeded the max BSON user size, add a warning indicating
+    // that data has been truncated.
+    if (out->len() < BSONObjMaxUserSize - warningMsgSize) {
+        out->append("warning",
+                    str::stream() << "'" << fieldName << "'"
+                                  << " has been omitted due to BSON size limit");
+    }
+
+    return false;
+}
+
 }  // namespace mongo::explain_common
diff --git a/src/mongo/db/query/explain_common.h b/src/mongo/db/query/explain_common.h
index d9b035beb8f..bc5637cebd1 100644
--- a/src/mongo/db/query/explain_common.h
+++ b/src/mongo/db/query/explain_common.h
@@ -43,4 +43,10 @@ namespace mongo::explain_common {
  */
 void generateServerInfo(BSONObjBuilder* out);
 
+/**
+ * Conditionally appends a BSONObj to 'bob' depending on whether or not the maximum user size for a
+ * BSON object will be exceeded.
+ */
+bool appendIfRoom(const BSONObj& toAppend, StringData fieldName, BSONObjBuilder* out);
+
 }  // namespace mongo::explain_common
diff --git a/src/mongo/db/query/find.cpp b/src/mongo/db/query/find.cpp
index f344eb7cfca..36bf3c974ed 100644
--- a/src/mongo/db/query/find.cpp
+++ b/src/mongo/db/query/find.cpp
@@ -634,8 +634,12 @@ bool runQuery(OperationContext* opCtx,
         bb.skip(sizeof(QueryResult::Value));
 
         BSONObjBuilder explainBob;
-        Explain::explainStages(
-            exec.get(), collection.getCollection(), verbosity, BSONObj(), &explainBob);
+        Explain::explainStages(exec.get(),
+                               collection.getCollection(),
+                               verbosity,
+                               BSONObj(),
+                               upconvertedQuery,
+                               &explainBob);
 
         // Add the resulting object to the return buffer.
         BSONObj explainObj = explainBob.obj();
diff --git a/src/mongo/dbtests/query_stage_multiplan.cpp b/src/mongo/dbtests/query_stage_multiplan.cpp
index 2ac93c0e04d..3275bcaed17 100644
--- a/src/mongo/dbtests/query_stage_multiplan.cpp
+++ b/src/mongo/dbtests/query_stage_multiplan.cpp
@@ -511,8 +511,12 @@ TEST_F(QueryStageMultiPlanTest, MPSExplainAllPlans) {
     ASSERT_EQ(root->bestPlanIdx(), 0);
 
     BSONObjBuilder bob;
-    Explain::explainStages(
-        exec.get(), ctx.getCollection(), ExplainOptions::Verbosity::kExecAllPlans, BSONObj(), &bob);
+    Explain::explainStages(exec.get(),
+                           ctx.getCollection(),
+                           ExplainOptions::Verbosity::kExecAllPlans,
+                           BSONObj(),
+                           BSONObj(),
+                           &bob);
     BSONObj explained = bob.done();
 
     ASSERT_EQ(explained["executionStats"]["nReturned"].Int(), nDocs);
diff --git a/src/mongo/s/commands/cluster_count_cmd.cpp b/src/mongo/s/commands/cluster_count_cmd.cpp
index 00e186d4d05..fc8c7495194 100644
--- a/src/mongo/s/commands/cluster_count_cmd.cpp
+++ b/src/mongo/s/commands/cluster_count_cmd.cpp
@@ -264,7 +264,7 @@ public:
 
         auto bodyBuilder = result->getBodyBuilder();
         return ClusterExplain::buildExplainResult(
-            opCtx, shardResponses, mongosStageName, millisElapsed, &bodyBuilder);
+            opCtx, shardResponses, mongosStageName, millisElapsed, cmdObj, &bodyBuilder);
     }
 
 private:
diff --git a/src/mongo/s/commands/cluster_distinct_cmd.cpp b/src/mongo/s/commands/cluster_distinct_cmd.cpp
index 9f836644ff5..41475a8cec2 100644
--- a/src/mongo/s/commands/cluster_distinct_cmd.cpp
+++ b/src/mongo/s/commands/cluster_distinct_cmd.cpp
@@ -156,7 +156,7 @@ public:
 
         auto bodyBuilder = result->getBodyBuilder();
         return ClusterExplain::buildExplainResult(
-            opCtx, shardResponses, mongosStageName, millisElapsed, &bodyBuilder);
+            opCtx, shardResponses, mongosStageName, millisElapsed, cmdObj, &bodyBuilder);
     }
 
     bool run(OperationContext* opCtx,
diff --git a/src/mongo/s/commands/cluster_explain.cpp b/src/mongo/s/commands/cluster_explain.cpp
index 356f6c7c7a1..8c4cdb5e699 100644
--- a/src/mongo/s/commands/cluster_explain.cpp
+++ b/src/mongo/s/commands/cluster_explain.cpp
@@ -327,6 +327,7 @@ Status ClusterExplain::buildExplainResult(
     const vector<AsyncRequestsSender::Response>& shardResponses,
     const char* mongosStageName,
     long long millisElapsed,
+    const BSONObj& command,
     BSONObjBuilder* out) {
     // Explain only succeeds if all shards support the explain command.
     try {
@@ -338,6 +339,7 @@ Status ClusterExplain::buildExplainResult(
     buildPlannerInfo(opCtx, shardResponses, mongosStageName, out);
     buildExecStats(shardResponses, mongosStageName, millisElapsed, out);
     explain_common::generateServerInfo(out);
+    appendIfRoom(out, command, "command");
 
     return Status::OK();
 }
diff --git a/src/mongo/s/commands/cluster_explain.h b/src/mongo/s/commands/cluster_explain.h
index 23e7f799194..60570c855d3 100644
--- a/src/mongo/s/commands/cluster_explain.h
+++ b/src/mongo/s/commands/cluster_explain.h
@@ -69,6 +69,7 @@ public:
         const std::vector<AsyncRequestsSender::Response>& shardResponses,
         const char* mongosStageName,
         long long millisElapsed,
+        const BSONObj& command,
         BSONObjBuilder* out);
 
 
diff --git a/src/mongo/s/commands/cluster_find_and_modify_cmd.cpp b/src/mongo/s/commands/cluster_find_and_modify_cmd.cpp
index 0dba2c8ba40..2bfbb451bfd 100644
--- a/src/mongo/s/commands/cluster_find_and_modify_cmd.cpp
+++ b/src/mongo/s/commands/cluster_find_and_modify_cmd.cpp
@@ -264,8 +264,12 @@ public:
             shard->getId(), response, shard->getConnString().getServers().front()};
 
         auto bodyBuilder = result->getBodyBuilder();
-        return ClusterExplain::buildExplainResult(
-            opCtx, {arsResponse}, ClusterExplain::kSingleShard, millisElapsed, &bodyBuilder);
+        return ClusterExplain::buildExplainResult(opCtx,
+                                                  {arsResponse},
+                                                  ClusterExplain::kSingleShard,
+                                                  millisElapsed,
+                                                  cmdObj,
+                                                  &bodyBuilder);
     }
 
     bool run(OperationContext* opCtx,
diff --git a/src/mongo/s/commands/cluster_find_cmd.cpp b/src/mongo/s/commands/cluster_find_cmd.cpp
index 3bd8ff6c7c3..c1fc600c88e 100644
--- a/src/mongo/s/commands/cluster_find_cmd.cpp
+++ b/src/mongo/s/commands/cluster_find_cmd.cpp
@@ -179,8 +179,12 @@ public:
                     ClusterExplain::getStageNameForReadOp(shardResponses.size(), _request.body);
 
                 auto bodyBuilder = result->getBodyBuilder();
-                uassertStatusOK(ClusterExplain::buildExplainResult(
-                    opCtx, shardResponses, mongosStageName, millisElapsed, &bodyBuilder));
+                uassertStatusOK(ClusterExplain::buildExplainResult(opCtx,
+                                                                   shardResponses,
+                                                                   mongosStageName,
+                                                                   millisElapsed,
+                                                                   _request.body,
+                                                                   &bodyBuilder));
 
             } catch (const ExceptionFor<ErrorCodes::CommandOnShardedViewNotSupportedOnMongod>& ex) {
                 auto bodyBuilder = result->getBodyBuilder();
diff --git a/src/mongo/s/commands/cluster_write_cmd.cpp b/src/mongo/s/commands/cluster_write_cmd.cpp
index 1340e023275..48d1d36d206 100644
--- a/src/mongo/s/commands/cluster_write_cmd.cpp
+++ b/src/mongo/s/commands/cluster_write_cmd.cpp
@@ -596,8 +596,12 @@ private:
         _commandOpWrite(
             opCtx, _batchedRequest.getNS(), explainCmd, targetingBatchItem, &shardResponses);
         auto bodyBuilder = result->getBodyBuilder();
-        uassertStatusOK(ClusterExplain::buildExplainResult(
-            opCtx, shardResponses, ClusterExplain::kWriteOnShards, timer.millis(), &bodyBuilder));
+        uassertStatusOK(ClusterExplain::buildExplainResult(opCtx,
+                                                           shardResponses,
+                                                           ClusterExplain::kWriteOnShards,
+                                                           timer.millis(),
+                                                           _request->body,
+                                                           &bodyBuilder));
     }
 
     NamespaceString ns() const override {
diff --git a/src/mongo/s/commands/strategy.cpp b/src/mongo/s/commands/strategy.cpp
index 12559d00c9f..44a5f0ad044 100644
--- a/src/mongo/s/commands/strategy.cpp
+++ b/src/mongo/s/commands/strategy.cpp
@@ -1339,6 +1339,6 @@ void Strategy::explainFind(OperationContext* opCtx,
         ClusterExplain::getStageNameForReadOp(shardResponses.size(), findCommand);
 
     uassertStatusOK(ClusterExplain::buildExplainResult(
-        opCtx, shardResponses, mongosStageName, millisElapsed, out));
+        opCtx, shardResponses, mongosStageName, millisElapsed, findCommand, out));
 }
 }  // namespace mongo
diff --git a/src/mongo/s/query/cluster_aggregate.cpp b/src/mongo/s/query/cluster_aggregate.cpp
index 4b2da5f2b34..e99c6b70ad5 100644
--- a/src/mongo/s/query/cluster_aggregate.cpp
+++ b/src/mongo/s/query/cluster_aggregate.cpp
@@ -352,6 +352,12 @@ Status ClusterAggregate::runAggregate(OperationContext* opCtx,
         updateHostsTargetedMetrics(opCtx, namespaces.executionNss, cm, involvedNamespaces);
         // Report usage statistics for each stage in the pipeline.
         liteParsedPipeline.tickGlobalStageCounters();
+
+        // Add 'command' object to explain output.
+        if (expCtx->explain) {
+            explain_common::appendIfRoom(
+                request.serializeToCommandObj().toBson(), "command", result);
+        }
     }
     return status;
 }