SERVER-64978 Add metrics to track if a plan was recovered from the plan cache

16 files changed, 82 insertions, 28 deletions

diff --git a/src/mongo/db/curop.cpp b/src/mongo/db/curop.cpp
index 9c362854d97..a01bb33437f 100644
--- a/src/mongo/db/curop.cpp
+++ b/src/mongo/db/curop.cpp
@@ -831,6 +831,7 @@ void OpDebug::report(OperationContext* opCtx,
     OPDEBUG_TOATTR_HELP_BOOL(hasSortStage);
     OPDEBUG_TOATTR_HELP_BOOL(usedDisk);
     OPDEBUG_TOATTR_HELP_BOOL(fromMultiPlanner);
+    OPDEBUG_TOATTR_HELP_BOOL(fromPlanCache);
     if (replanReason) {
         bool replanned = true;
         OPDEBUG_TOATTR_HELP_BOOL(replanned);
@@ -999,6 +1000,7 @@ void OpDebug::append(OperationContext* opCtx,
     OPDEBUG_APPEND_BOOL(b, hasSortStage);
     OPDEBUG_APPEND_BOOL(b, usedDisk);
     OPDEBUG_APPEND_BOOL(b, fromMultiPlanner);
+    OPDEBUG_APPEND_BOOL(b, fromPlanCache);
     if (replanReason) {
         bool replanned = true;
         OPDEBUG_APPEND_BOOL(b, replanned);
@@ -1228,6 +1230,9 @@ std::function<BSONObj(ProfileFilter::Args)> OpDebug::appendStaged(StringSet requ
     addIfNeeded("fromMultiPlanner", [](auto field, auto args, auto& b) {
         OPDEBUG_APPEND_BOOL2(b, field, args.op.fromMultiPlanner);
     });
+    addIfNeeded("fromPlanCache", [](auto field, auto args, auto& b) {
+        OPDEBUG_APPEND_BOOL2(b, field, args.op.fromPlanCache);
+    });
     addIfNeeded("replanned", [](auto field, auto args, auto& b) {
         if (args.op.replanReason) {
             OPDEBUG_APPEND_BOOL2(b, field, true);
@@ -1443,6 +1448,7 @@ void OpDebug::setPlanSummaryMetrics(const PlanSummaryStats& planSummaryStats) {
     sortTotalDataSizeBytes = planSummaryStats.sortTotalDataSizeBytes;
     keysSorted = planSummaryStats.keysSorted;
     fromMultiPlanner = planSummaryStats.fromMultiPlanner;
+    fromPlanCache = planSummaryStats.fromPlanCache;
     replanReason = planSummaryStats.replanReason;
 }
 
diff --git a/src/mongo/db/curop.h b/src/mongo/db/curop.h
index d0e5d13313d..29a63981b68 100644
--- a/src/mongo/db/curop.h
+++ b/src/mongo/db/curop.h
@@ -251,6 +251,7 @@ public:
     // single solution).
     bool fromMultiPlanner{false};
 
+    bool fromPlanCache{false};
     // True if a replan was triggered during the execution of this operation.
     boost::optional<std::string> replanReason;
 
diff --git a/src/mongo/db/query/cqf_get_executor.cpp b/src/mongo/db/query/cqf_get_executor.cpp
index 3143822a986..355146d85ce 100644
--- a/src/mongo/db/query/cqf_get_executor.cpp
+++ b/src/mongo/db/query/cqf_get_executor.cpp
@@ -342,7 +342,8 @@ static std::unique_ptr<PlanExecutor, PlanExecutor::Deleter> optimizeAndCreateExe
         MultipleCollectionAccessor(collection),
         QueryPlannerParams::Options::DEFAULT,
         nss,
-        std::move(yieldPolicy)));
+        std::move(yieldPolicy),
+        false /*isFromPlanCache*/));
     return planExec;
 }
 
diff --git a/src/mongo/db/query/get_executor.cpp b/src/mongo/db/query/get_executor.cpp
index 3e8653eb229..cb1113404a2 100644
--- a/src/mongo/db/query/get_executor.cpp
+++ b/src/mongo/db/query/get_executor.cpp
@@ -521,10 +521,17 @@ public:
     std::tuple<std::unique_ptr<PlanStage>, std::unique_ptr<QuerySolution>> extractResultData() {
         return std::make_tuple(std::move(_root), std::move(_solution));
     }
+    void setRecoveredFromPlanCache(bool val) {
+        _fromPlanCache = val;
+    }
+    bool isRecoveredFromPlanCache() {
+        return _fromPlanCache;
+    }
 
 private:
     std::unique_ptr<PlanStage> _root;
     std::unique_ptr<QuerySolution> _solution;
+    bool _fromPlanCache{false};
 };
 
 /**
@@ -601,12 +608,21 @@ public:
         _recoveredPinnedCacheEntry = pinnedEntry;
     }
 
+    void setRecoveredFromPlanCache(bool val) {
+        _fromPlanCache = val;
+    }
+
+    bool isRecoveredFromPlanCache() {
+        return _fromPlanCache;
+    }
+
 private:
     QuerySolutionVector _solutions;
     PlanStageVector _roots;
     boost::optional<size_t> _decisionWorks;
     bool _needSubplanning{false};
     bool _recoveredPinnedCacheEntry{false};
+    bool _fromPlanCache{false};
 };
 
 /**
@@ -1156,6 +1172,7 @@ protected:
                 result->setDecisionWorks(cacheEntry->decisionWorks);
                 result->setRecoveredPinnedCacheEntry(cacheEntry->isPinned());
                 result->emplace(std::make_pair(std::move(root), std::move(stageData)));
+                result->setRecoveredFromPlanCache(true);
                 return result;
             }
         }
@@ -1197,7 +1214,7 @@ protected:
 
                 result->emplace(std::move(execTree), std::move(querySolution));
                 result->setDecisionWorks(cs->decisionWorks);
-
+                result->setRecoveredFromPlanCache(true);
                 return result;
             }
         }
@@ -1308,7 +1325,7 @@ std::unique_ptr<sbe::RuntimePlanner> makeRuntimePlannerIfNeeded(
     invariant(numSolutions == 1);
 
     // If we have a single solution and the plan is not pinned or plan contains a hash_lookup stage,
-    // we will need we will need to do the runtime planning to check if the cached plan still
+    // we will need to do the runtime planning to check if the cached plan still
     // performs efficiently, or requires re-planning.
     tassert(6693503, "PlanStageData must be present", planStageData);
     const bool hasHashLookup = !planStageData->foreignHashJoinCollections.empty();
@@ -1411,7 +1428,6 @@ StatusWith<std::unique_ptr<PlanExecutor, PlanExecutor::Deleter>> getSlotBasedExe
     // Prepare the SBE tree for execution.
     stage_builder::prepareSlotBasedExecutableTree(
         opCtx, root.get(), &data, *cq, collections, yieldPolicy.get(), true);
-
     return plan_executor_factory::make(opCtx,
                                        std::move(cq),
                                        std::move(solutions[0]),
@@ -1420,7 +1436,8 @@ StatusWith<std::unique_ptr<PlanExecutor, PlanExecutor::Deleter>> getSlotBasedExe
                                        collections,
                                        plannerParams.options,
                                        std::move(nss),
-                                       std::move(yieldPolicy));
+                                       std::move(yieldPolicy),
+                                       planningResult->isRecoveredFromPlanCache());
 }
 }  // namespace
 
diff --git a/src/mongo/db/query/plan_cache.h b/src/mongo/db/query/plan_cache.h
index 752d5cfa4dd..2fc422c0ca2 100644
--- a/src/mongo/db/query/plan_cache.h
+++ b/src/mongo/db/query/plan_cache.h
@@ -706,8 +706,8 @@ private:
             // We do nothing.
             res.shouldBeCreated = false;
         } else if (newWorks > oldWorks) {
-            // This plan performed worse than expected. Rather than immediately overwriting the
-            // cache, lower the bar to what is considered good performance and keep the entry
+            // The cached plan performed worse than expected. Rather than immediately overwriting
+            // the cache, lower the bar to what is considered good performance and keep the entry
             // inactive.
 
             // Be sure that 'works' always grows by at least 1, in case its current
@@ -725,7 +725,7 @@ private:
             res.shouldBeCreated = true;
             res.increasedWorks.emplace(increasedWorks);
         } else {
-            // This plan performed just as well or better than we expected, based on the
+            // This cached plan performed just as well or better than we expected, based on the
             // inactive entry's works. We use this as an indicator that it's safe to
             // cache (as an active entry) the plan this query used for the future.
             if (callbacks) {
diff --git a/src/mongo/db/query/plan_executor_factory.cpp b/src/mongo/db/query/plan_executor_factory.cpp
index 2403ff7c353..1ff8d5660b8 100644
--- a/src/mongo/db/query/plan_executor_factory.cpp
+++ b/src/mongo/db/query/plan_executor_factory.cpp
@@ -27,6 +27,7 @@
  *    it in the license file.
  */
 
+#include <iostream>
 
 #include "mongo/platform/basic.h"
 
@@ -128,7 +129,8 @@ StatusWith<std::unique_ptr<PlanExecutor, PlanExecutor::Deleter>> make(
     const MultipleCollectionAccessor& collections,
     size_t plannerOptions,
     NamespaceString nss,
-    std::unique_ptr<PlanYieldPolicySBE> yieldPolicy) {
+    std::unique_ptr<PlanYieldPolicySBE> yieldPolicy,
+    bool planIsFromCache) {
     auto&& [rootStage, data] = root;
 
     LOGV2_DEBUG(4822860,
@@ -137,17 +139,21 @@ StatusWith<std::unique_ptr<PlanExecutor, PlanExecutor::Deleter>> make(
                 "slots"_attr = data.debugString(),
                 "stages"_attr = sbe::DebugPrinter{}.print(*rootStage));
 
-    return {{new PlanExecutorSBE(
-                 opCtx,
-                 std::move(cq),
-                 std::move(optimizerData),
-                 {makeVector<sbe::plan_ranker::CandidatePlan>(sbe::plan_ranker::CandidatePlan{
-                      std::move(solution), std::move(rootStage), std::move(data)}),
-                  0},
-                 plannerOptions & QueryPlannerParams::RETURN_OWNED_DATA,
-                 std::move(nss),
-                 false,
-                 std::move(yieldPolicy)),
+    return {{new PlanExecutorSBE(opCtx,
+                                 std::move(cq),
+                                 std::move(optimizerData),
+                                 {makeVector<sbe::plan_ranker::CandidatePlan>(
+                                      sbe::plan_ranker::CandidatePlan{std::move(solution),
+                                                                      std::move(rootStage),
+                                                                      std::move(data),
+                                                                      false,
+                                                                      Status::OK(),
+                                                                      planIsFromCache}),
+                                  0},
+                                 plannerOptions & QueryPlannerParams::RETURN_OWNED_DATA,
+                                 std::move(nss),
+                                 false,
+                                 std::move(yieldPolicy)),
              PlanExecutor::Deleter{opCtx}}};
 }
 
diff --git a/src/mongo/db/query/plan_executor_factory.h b/src/mongo/db/query/plan_executor_factory.h
index bf41f169af9..be7ab263a88 100644
--- a/src/mongo/db/query/plan_executor_factory.h
+++ b/src/mongo/db/query/plan_executor_factory.h
@@ -118,7 +118,8 @@ StatusWith<std::unique_ptr<PlanExecutor, PlanExecutor::Deleter>> make(
     const MultipleCollectionAccessor& collections,
     size_t plannerOptions,
     NamespaceString nss,
-    std::unique_ptr<PlanYieldPolicySBE> yieldPolicy);
+    std::unique_ptr<PlanYieldPolicySBE> yieldPolicy,
+    bool isFromPlanCache);
 
 /**
  * Similar to the factory function above in that it also constructs an executor for the winning SBE
diff --git a/src/mongo/db/query/plan_executor_sbe.cpp b/src/mongo/db/query/plan_executor_sbe.cpp
index 920cd17715b..bd62138da46 100644
--- a/src/mongo/db/query/plan_executor_sbe.cpp
+++ b/src/mongo/db/query/plan_executor_sbe.cpp
@@ -27,7 +27,6 @@
  *    it in the license file.
  */
 
-
 #include "mongo/platform/basic.h"
 
 #include "mongo/db/query/plan_executor_sbe.h"
@@ -102,9 +101,8 @@ PlanExecutorSBE::PlanExecutorSBE(OperationContext* opCtx,
         _yieldPolicy->clearRegisteredPlans();
         _yieldPolicy->registerPlan(_root.get());
     }
-
     const auto isMultiPlan = candidates.plans.size() > 1;
-
+    const auto isCachedCandidate = candidates.winner().isCachedCandidate;
     if (!_cq || !_cq->getExpCtx()->explain) {
         // If we're not in explain mode, there is no need to keep rejected candidate plans around.
         candidates.plans.clear();
@@ -123,6 +121,7 @@ PlanExecutorSBE::PlanExecutorSBE(OperationContext* opCtx,
                                                   std::move(optimizerData),
                                                   std::move(candidates.plans),
                                                   isMultiPlan,
+                                                  isCachedCandidate,
                                                   _rootData.debugInfo);
 }
 
diff --git a/src/mongo/db/query/plan_explainer_factory.cpp b/src/mongo/db/query/plan_explainer_factory.cpp
index 544ab33fdd2..4f762aec167 100644
--- a/src/mongo/db/query/plan_explainer_factory.cpp
+++ b/src/mongo/db/query/plan_explainer_factory.cpp
@@ -57,6 +57,7 @@ std::unique_ptr<PlanExplainer> make(sbe::PlanStage* root,
                                     std::vector<sbe::plan_ranker::CandidatePlan> rejectedCandidates,
                                     bool isMultiPlan) {
     // Pre-compute Debugging info for explain use.
+
     auto debugInfoSBE = std::make_shared<const plan_cache_debug_info::DebugInfoSBE>(
         plan_cache_util::buildDebugInfo(solution));
     return std::make_unique<PlanExplainerSBE>(root,
@@ -65,6 +66,7 @@ std::unique_ptr<PlanExplainer> make(sbe::PlanStage* root,
                                               std::move(optimizerData),
                                               std::move(rejectedCandidates),
                                               isMultiPlan,
+                                              false, /* isFromPlanCache */
                                               debugInfoSBE);
 }
 
@@ -75,6 +77,7 @@ std::unique_ptr<PlanExplainer> make(
     std::unique_ptr<optimizer::AbstractABTPrinter> optimizerData,
     std::vector<sbe::plan_ranker::CandidatePlan> rejectedCandidates,
     bool isMultiPlan,
+    bool isFromPlanCache,
     std::shared_ptr<const plan_cache_debug_info::DebugInfoSBE> debugInfoSBE) {
     // TODO SERVER-64882: Consider invariant(debugInfoSBE) as we may not need to create a
     // DebugInfoSBE from QuerySolution after the feature flag is removed. We currently need it
@@ -90,6 +93,7 @@ std::unique_ptr<PlanExplainer> make(
                                               std::move(optimizerData),
                                               std::move(rejectedCandidates),
                                               isMultiPlan,
+                                              isFromPlanCache,
                                               debugInfoSBE);
 }
 }  // namespace mongo::plan_explainer_factory
diff --git a/src/mongo/db/query/plan_explainer_factory.h b/src/mongo/db/query/plan_explainer_factory.h
index 5e24a755747..0b3c008304b 100644
--- a/src/mongo/db/query/plan_explainer_factory.h
+++ b/src/mongo/db/query/plan_explainer_factory.h
@@ -61,5 +61,6 @@ std::unique_ptr<PlanExplainer> make(
     std::unique_ptr<optimizer::AbstractABTPrinter> optimizerData,
     std::vector<sbe::plan_ranker::CandidatePlan> rejectedCandidates,
     bool isMultiPlan,
+    bool isFromPlanCache,
     std::shared_ptr<const plan_cache_debug_info::DebugInfoSBE> debugInfo);
 }  // namespace mongo::plan_explainer_factory
diff --git a/src/mongo/db/query/plan_explainer_impl.cpp b/src/mongo/db/query/plan_explainer_impl.cpp
index 0b70636945a..dc118081b33 100644
--- a/src/mongo/db/query/plan_explainer_impl.cpp
+++ b/src/mongo/db/query/plan_explainer_impl.cpp
@@ -722,6 +722,10 @@ void PlanExplainerImpl::getSummaryStats(PlanSummaryStats* statsOut) const {
             const CachedPlanStats* cachedStats =
                 static_cast<const CachedPlanStats*>(cachedPlan->getSpecificStats());
             statsOut->replanReason = cachedStats->replanReason;
+            // Nonnull replanReason indicates cached plan was less effecient than expected and an
+            // alternative plan was chosen.
+            statsOut->replanReason ? statsOut->fromPlanCache = false
+                                   : statsOut->fromPlanCache = true;
         } else if (STAGE_MULTI_PLAN == stages[i]->stageType()) {
             statsOut->fromMultiPlanner = true;
         } else if (STAGE_COLLSCAN == stages[i]->stageType()) {
diff --git a/src/mongo/db/query/plan_explainer_sbe.cpp b/src/mongo/db/query/plan_explainer_sbe.cpp
index e14eebb59b4..fd4232ce1a9 100644
--- a/src/mongo/db/query/plan_explainer_sbe.cpp
+++ b/src/mongo/db/query/plan_explainer_sbe.cpp
@@ -370,6 +370,7 @@ void PlanExplainerSBE::getSummaryStats(PlanSummaryStats* statsOut) const {
     auto common = _root->getCommonStats();
     statsOut->nReturned = common->advances;
     statsOut->fromMultiPlanner = isMultiPlan();
+    statsOut->fromPlanCache = isFromCache();
     statsOut->totalKeysExamined = 0;
     statsOut->totalDocsExamined = 0;
     statsOut->replanReason = _rootData->replanReason;
diff --git a/src/mongo/db/query/plan_explainer_sbe.h b/src/mongo/db/query/plan_explainer_sbe.h
index 5dc97f90641..f97e972de88 100644
--- a/src/mongo/db/query/plan_explainer_sbe.h
+++ b/src/mongo/db/query/plan_explainer_sbe.h
@@ -48,6 +48,7 @@ public:
                      std::unique_ptr<optimizer::AbstractABTPrinter> optimizerData,
                      std::vector<sbe::plan_ranker::CandidatePlan> rejectedCandidates,
                      bool isMultiPlan,
+                     bool isCachedPlan,
                      std::shared_ptr<const plan_cache_debug_info::DebugInfoSBE> debugInfo)
         : PlanExplainer{solution},
           _root{root},
@@ -56,6 +57,7 @@ public:
           _optimizerData(std::move(optimizerData)),
           _rejectedCandidates{std::move(rejectedCandidates)},
           _isMultiPlan{isMultiPlan},
+          _isFromPlanCache{isCachedPlan},
           _debugInfo{debugInfo} {
         tassert(5968203, "_debugInfo should not be null", _debugInfo);
     }
@@ -63,7 +65,9 @@ public:
     bool isMultiPlan() const final {
         return _isMultiPlan;
     }
-
+    bool isFromCache() const {
+        return _isFromPlanCache;
+    }
     const ExplainVersion& getVersion() const final;
     std::string getPlanSummary() const final;
     void getSummaryStats(PlanSummaryStats* statsOut) const final;
@@ -97,6 +101,7 @@ private:
 
     const std::vector<sbe::plan_ranker::CandidatePlan> _rejectedCandidates;
     const bool _isMultiPlan{false};
+    const bool _isFromPlanCache{false};
     // Pre-computed debugging info so we don't necessarily have to collect them from QuerySolution.
     // All plans recovered from the same cached entry share the same debug info.
     const std::shared_ptr<const plan_cache_debug_info::DebugInfoSBE> _debugInfo;
diff --git a/src/mongo/db/query/plan_ranker.h b/src/mongo/db/query/plan_ranker.h
index 8a6a2c18ad9..d456aa69d31 100644
--- a/src/mongo/db/query/plan_ranker.h
+++ b/src/mongo/db/query/plan_ranker.h
@@ -189,6 +189,8 @@ struct BaseCandidatePlan {
     // If the candidate plan has failed in a recoverable fashion during the trial run, contains a
     // non-OK status.
     Status status{Status::OK()};
+    // Indicates whether this candidate plan was retrieved from the cache.
+    bool isCachedCandidate{false};
     // Any results produced during the plan's execution prior to scoring are retained here.
     std::deque<ResultType> results;
     // This is used to track the original plan with clean PlanStage tree and the auxiliary data.
diff --git a/src/mongo/db/query/plan_summary_stats.h b/src/mongo/db/query/plan_summary_stats.h
index 59e3985662f..ae8e3e7abc8 100644
--- a/src/mongo/db/query/plan_summary_stats.h
+++ b/src/mongo/db/query/plan_summary_stats.h
@@ -110,6 +110,8 @@ struct PlanSummaryStats {
     // candidates?
     bool fromMultiPlanner = false;
 
+    // Was this plan recovered from the cache?
+    bool fromPlanCache = false;
     // Was a replan triggered during the execution of this query?
     boost::optional<std::string> replanReason;
 
diff --git a/src/mongo/db/query/sbe_cached_solution_planner.cpp b/src/mongo/db/query/sbe_cached_solution_planner.cpp
index 0cbf5623a5f..e7584b1f3d1 100644
--- a/src/mongo/db/query/sbe_cached_solution_planner.cpp
+++ b/src/mongo/db/query/sbe_cached_solution_planner.cpp
@@ -93,7 +93,6 @@ CandidatePlans CachedSolutionPlanner::plan(
                 _opCtx, _collections, _cq, *solutions[0], _yieldPolicy);
         }
     }
-
     // If the '_decisionReads' is not present then we do not run a trial period, keeping the current
     // plan.
     if (!_decisionReads) {
@@ -110,7 +109,9 @@ CandidatePlans CachedSolutionPlanner::plan(
                                                       std::move(roots[0].first),
                                                       std::move(roots[0].second),
                                                       false /* exitedEarly*/,
-                                                      Status::OK()}),
+                                                      Status::OK(),
+                                                      true,
+                                                      /*isFromPlanCache */}),
                 0};
     }
 
@@ -131,6 +132,7 @@ CandidatePlans CachedSolutionPlanner::plan(
         {},    /* optimizedData */
         {},    /* rejectedCandidates */
         false, /* isMultiPlan */
+        true,  /* isFromPlanCache */
         candidate.data.debugInfo
             ? std::make_unique<plan_cache_debug_info::DebugInfoSBE>(*candidate.data.debugInfo)
             : nullptr);
@@ -185,7 +187,9 @@ plan_ranker::CandidatePlan CachedSolutionPlanner::collectExecutionStatsForCached
                                          std::move(root),
                                          std::move(data),
                                          false /* exitedEarly*/,
-                                         Status::OK()};
+                                         Status::OK(),
+                                         true,
+                                         /*is Cached plan*/};
 
     ON_BLOCK_EXIT([rootPtr = candidate.root.get()] { rootPtr->detachFromTrialRunTracker(); });