SERVER-63102 Introduce internalQueryPlanEvaluationWorksSber5.3.0-alpha3

The 'internalQueryPlanEvaluationWorks' parameter now only
affects the classic engine. The newly added parameter has
similar behavior, but applies only to queries using SBE.

3 files changed, 14 insertions, 9 deletions

diff --git a/src/mongo/db/exec/multi_plan.cpp b/src/mongo/db/exec/multi_plan.cpp
index 892d05cb5ca..96aaf4ca52d 100644
--- a/src/mongo/db/exec/multi_plan.cpp
+++ b/src/mongo/db/exec/multi_plan.cpp
@@ -163,8 +163,11 @@ Status MultiPlanStage::pickBestPlan(PlanYieldPolicy* yieldPolicy) {
     // make sense.
     auto optTimer = getOptTimer();
 
-    size_t numWorks = trial_period::getTrialPeriodMaxWorks(
-        opCtx(), collection(), internalQueryPlanEvaluationCollFraction.load());
+    const size_t numWorks =
+        trial_period::getTrialPeriodMaxWorks(opCtx(),
+                                             collection(),
+                                             internalQueryPlanEvaluationWorks.load(),
+                                             internalQueryPlanEvaluationCollFraction.load());
     size_t numResults = trial_period::getTrialPeriodNumToReturn(*_query);
 
     try {
diff --git a/src/mongo/db/exec/trial_period_utils.cpp b/src/mongo/db/exec/trial_period_utils.cpp
index 2472885c7ed..b158f297b47 100644
--- a/src/mongo/db/exec/trial_period_utils.cpp
+++ b/src/mongo/db/exec/trial_period_utils.cpp
@@ -36,13 +36,12 @@
 namespace mongo::trial_period {
 size_t getTrialPeriodMaxWorks(OperationContext* opCtx,
                               const CollectionPtr& collection,
+                              int maxWorksParam,
                               double collFraction) {
-    // Run each plan some number of times. This number is at least as great as
-    // 'internalQueryPlanEvaluationWorks', but may be larger for big collections.
-    size_t numWorks = internalQueryPlanEvaluationWorks.load();
+    size_t numWorks = static_cast<size_t>(maxWorksParam);
     if (collection) {
-        numWorks = std::max(static_cast<size_t>(internalQueryPlanEvaluationWorks.load()),
-                            static_cast<size_t>(collFraction * collection->numRecords(opCtx)));
+        numWorks =
+            std::max(numWorks, static_cast<size_t>(collFraction * collection->numRecords(opCtx)));
     }
 
     return numWorks;
diff --git a/src/mongo/db/exec/trial_period_utils.h b/src/mongo/db/exec/trial_period_utils.h
index 53a9c91a889..f8e4d4a725f 100644
--- a/src/mongo/db/exec/trial_period_utils.h
+++ b/src/mongo/db/exec/trial_period_utils.h
@@ -39,11 +39,14 @@ namespace trial_period {
 /**
  * Returns the number of times that we are willing to work a plan during a trial period.
  *
- * Calculated based on a fixed query knob and the size of the collection multiplied by
- * 'collFraction'.
+ * Calculated with the following formula, where "|collection|" denotes the approximate number of
+ * documents in the collection:
+ *
+ *   max(maxWorksParam, collFraction * |collection|)
  */
 size_t getTrialPeriodMaxWorks(OperationContext* opCtx,
                               const CollectionPtr& collection,
+                              int maxWorksParam,
                               double collFraction);
 
 /**