SERVER-66551 Rename internalQueryEnableSlotBasedExecutionEngine back to internalQueryForceClassicEngine

14 files changed, 42 insertions, 85 deletions

diff --git a/src/mongo/db/commands/plan_cache_clear_command.cpp b/src/mongo/db/commands/plan_cache_clear_command.cpp
index a3e8fcfc1fb..daf4bb18937 100644
--- a/src/mongo/db/commands/plan_cache_clear_command.cpp
+++ b/src/mongo/db/commands/plan_cache_clear_command.cpp
@@ -92,7 +92,7 @@ Status clear(OperationContext* opCtx,
         // sbe::isQuerySbeCompatible here.
         const size_t plannerOptions = 0;
         if (feature_flags::gFeatureFlagSbePlanCache.isEnabledAndIgnoreFCV() &&
-            cq->getEnableSlotBasedExecutionEngine() &&
+            !cq->getForceClassicEngine() &&
             sbe::isQuerySbeCompatible(&collection, cq.get(), plannerOptions)) {
             cq->setSbeCompatible(true);
             sbe::getPlanCache(opCtx).remove(
diff --git a/src/mongo/db/pipeline/pipeline_d.cpp b/src/mongo/db/pipeline/pipeline_d.cpp
index ff034ff6cc0..fbba650d37d 100644
--- a/src/mongo/db/pipeline/pipeline_d.cpp
+++ b/src/mongo/db/pipeline/pipeline_d.cpp
@@ -110,14 +110,14 @@ namespace {
  * pipeline to prepare for pushdown of $group and $lookup into the inner query layer so that it
  * can be executed using SBE.
  * Group stages are extracted from the pipeline when all of the following conditions are met:
- *    0. When the 'internalQueryEnableSlotBasedExecutionEngine' feature flag is 'true'.
+ *    0. When the 'internalQueryForceClassicEngine' feature flag is 'false'.
  *    1. When 'allowDiskUse' is false. We currently don't support spilling in the SBE HashAgg
  *       stage. This will change once that is supported when SERVER-58436 is complete.
  *    2. When the DocumentSourceGroup has 'doingMerge=false', this will change when we implement
  *       hash table spilling in SERVER-58436.
  *
  * Lookup stages are extracted from the pipeline when all of the following conditions are met:
- *    0. When the 'internalQueryEnableSlotBasedExecutionEngine' feature flag is 'true'.
+ *    0. When the 'internalQueryForceClassicEngine' feature flag is 'false'.
  *    1. When the 'featureFlagSBELookupPushdown' feature flag is 'true'.
  *    2. The $lookup uses only the 'localField'/'foreignField' syntax (no pipelines).
  *    3. The foreign collection is neither sharded nor a view.
@@ -138,7 +138,7 @@ std::vector<std::unique_ptr<InnerPipelineStageInterface>> extractSbeCompatibleSt
     }
 
     // No pushdown if we're using the classic engine.
-    if (!cq->getEnableSlotBasedExecutionEngine()) {
+    if (cq->getForceClassicEngine()) {
         return {};
     }
 
diff --git a/src/mongo/db/query/canonical_query.cpp b/src/mongo/db/query/canonical_query.cpp
index 7df5350daac..2271f4ce494 100644
--- a/src/mongo/db/query/canonical_query.cpp
+++ b/src/mongo/db/query/canonical_query.cpp
@@ -195,7 +195,7 @@ Status CanonicalQuery::init(OperationContext* opCtx,
     _findCommand = std::move(findCommand);
 
     _canHaveNoopMatchNodes = canHaveNoopMatchNodes;
-    _enableSlotBasedExecutionEngine = internalQueryEnableSlotBasedExecutionEngine.load();
+    _forceClassicEngine = internalQueryForceClassicEngine.load();
 
     auto validStatus = isValid(root.get(), *_findCommand);
     if (!validStatus.isOK()) {
@@ -545,7 +545,7 @@ CanonicalQuery::QueryShapeString CanonicalQuery::encodeKey() const {
     // TODO SERVER-61507: remove '_pipeline.empty()' check. Canonical queries with pushed down
     // $group/$lookup stages are not SBE-compatible until SERVER-61507 is complete.
     return (feature_flags::gFeatureFlagSbePlanCache.isEnabledAndIgnoreFCV() &&
-            _enableSlotBasedExecutionEngine && _sbeCompatible && _pipeline.empty())
+            !_forceClassicEngine && _sbeCompatible && _pipeline.empty())
         ? canonical_query_encoder::encodeSBE(*this)
         : canonical_query_encoder::encode(*this);
 }
diff --git a/src/mongo/db/query/canonical_query.h b/src/mongo/db/query/canonical_query.h
index 9f25a92740b..661b66f0458 100644
--- a/src/mongo/db/query/canonical_query.h
+++ b/src/mongo/db/query/canonical_query.h
@@ -221,8 +221,8 @@ public:
         return _explain;
     }
 
-    bool getEnableSlotBasedExecutionEngine() const {
-        return _enableSlotBasedExecutionEngine;
+    bool getForceClassicEngine() const {
+        return _forceClassicEngine;
     }
 
     void setSbeCompatible(bool sbeCompatible) {
@@ -304,8 +304,8 @@ private:
 
     bool _explain = false;
 
-    // Determines whether the SBE engine is enabled.
-    bool _enableSlotBasedExecutionEngine = false;
+    // Determines whether the classic engine must be used.
+    bool _forceClassicEngine = true;
 
     // True if this query can be executed by the SBE.
     bool _sbeCompatible = false;
diff --git a/src/mongo/db/query/canonical_query_encoder.cpp b/src/mongo/db/query/canonical_query_encoder.cpp
index bfbaa2544c5..a6a94915e91 100644
--- a/src/mongo/db/query/canonical_query_encoder.cpp
+++ b/src/mongo/db/query/canonical_query_encoder.cpp
@@ -667,7 +667,7 @@ CanonicalQuery::QueryShapeString encode(const CanonicalQuery& cq) {
 
     // This encoding can be removed once the classic query engine reaches EOL and SBE is used
     // exclusively for all query execution.
-    keyBuilder << kEncodeEngineSection << (cq.getEnableSlotBasedExecutionEngine() ? "t" : "f");
+    keyBuilder << kEncodeEngineSection << (cq.getForceClassicEngine() ? "f" : "t");
 
     return keyBuilder.str();
 }
diff --git a/src/mongo/db/query/canonical_query_encoder_test.cpp b/src/mongo/db/query/canonical_query_encoder_test.cpp
index 27e8ae74707..486b4f2d14f 100644
--- a/src/mongo/db/query/canonical_query_encoder_test.cpp
+++ b/src/mongo/db/query/canonical_query_encoder_test.cpp
@@ -148,9 +148,8 @@ TEST(CanonicalQueryEncoderTest, ComputeKey) {
 
     // The computed key depends on which execution engine is enabled. As such, we disable SBE for
     // this test so that the test doesn't break should the default value of
-    // 'internalQueryEnableSlotBasedExecutionEngine' change in the future.
-    RAIIServerParameterControllerForTest controllerSBE(
-        "internalQueryEnableSlotBasedExecutionEngine", false);
+    // 'internalQueryForceClassicEngine' change in the future.
+    RAIIServerParameterControllerForTest controllerSBE("internalQueryForceClassicEngine", true);
 
     // No sorts
     testComputeKey("{}", "{}", "{}", "an@f");
@@ -224,9 +223,8 @@ TEST(CanonicalQueryEncoderTest, ComputeKey) {
 TEST(CanonicalQueryEncoderTest, EncodeNotEqualNullPredicates) {
     // The computed key depends on which execution engine is enabled. As such, we disable SBE for
     // this test so that the test doesn't break should the default value of
-    // 'internalQueryEnableSlotBasedExecutionEngine' change in the future.
-    RAIIServerParameterControllerForTest controllerSBE(
-        "internalQueryEnableSlotBasedExecutionEngine", false);
+    // 'internalQueryForceClassicEngine' change in the future.
+    RAIIServerParameterControllerForTest controllerSBE("internalQueryForceClassicEngine", true);
 
     // With '$eq', '$gte', and '$lte' negation comparison to 'null'.
     testComputeKey("{a: {$not: {$eq: null}}}", "{}", "{_id: 0, a: 1}", "ntnot_eq_null[eqa]|a@f");
@@ -246,9 +244,8 @@ TEST(CanonicalQueryEncoderTest, EncodeNotEqualNullPredicates) {
 TEST(CanonicalQueryEncoderTest, ComputeKeyEscaped) {
     // The computed key depends on which execution engine is enabled. As such, we disable SBE for
     // this test so that the test doesn't break should the default value of
-    // 'internalQueryEnableSlotBasedExecutionEngine' change in the future.
-    RAIIServerParameterControllerForTest controllerSBE(
-        "internalQueryEnableSlotBasedExecutionEngine", false);
+    // 'internalQueryForceClassicEngine' change in the future.
+    RAIIServerParameterControllerForTest controllerSBE("internalQueryForceClassicEngine", true);
     // Field name in query.
     testComputeKey("{'a,[]~|-<>': 1}", "{}", "{}", "eqa\\,\\[\\]\\~\\|\\-<>@f");
 
@@ -284,9 +281,8 @@ TEST(CanonicalQueryEncoderTest, ComputeKeyGeoWithin) {
 TEST(CanonicalQueryEncoderTest, ComputeKeyGeoNear) {
     // The computed key depends on which execution engine is enabled. As such, we disable SBE for
     // this test so that the test doesn't break should the default value of
-    // 'internalQueryEnableSlotBasedExecutionEngine' change in the future.
-    RAIIServerParameterControllerForTest controllerSBE(
-        "internalQueryEnableSlotBasedExecutionEngine", false);
+    // 'internalQueryForceClassicEngine' change in the future.
+    RAIIServerParameterControllerForTest controllerSBE("internalQueryForceClassicEngine", true);
 
     testComputeKey("{a: {$near: [0,0], $maxDistance:0.3 }}", "{}", "{}", "gnanrfl@f");
     testComputeKey("{a: {$nearSphere: [0,0], $maxDistance: 0.31 }}", "{}", "{}", "gnanssp@f");
@@ -301,8 +297,7 @@ TEST(CanonicalQueryEncoderTest, ComputeKeyGeoNear) {
 TEST(CanonicalQueryEncoderTest, ComputeKeyRegexDependsOnFlags) {
     // The computed key depends on which execution engine is enabled. As such, we enable SBE for
     // this test in order to ensure that we have coverage for both SBE and the classic engine.
-    RAIIServerParameterControllerForTest controllerSBE(
-        "internalQueryEnableSlotBasedExecutionEngine", true);
+    RAIIServerParameterControllerForTest controllerSBE("internalQueryForceClassicEngine", false);
     testComputeKey("{a: {$regex: \"sometext\"}}", "{}", "{}", "rea@t");
     testComputeKey("{a: {$regex: \"sometext\", $options: \"\"}}", "{}", "{}", "rea@t");
 
@@ -335,9 +330,8 @@ TEST(CanonicalQueryEncoderTest, ComputeKeyRegexDependsOnFlags) {
 TEST(CanonicalQueryEncoderTest, ComputeKeyMatchInDependsOnPresenceOfRegexAndFlags) {
     // The computed key depends on which execution engine is enabled. As such, we disable SBE for
     // this test so that the test doesn't break should the default value of
-    // 'internalQueryEnableSlotBasedExecutionEngine' change in the future.
-    RAIIServerParameterControllerForTest controllerSBE(
-        "internalQueryEnableSlotBasedExecutionEngine", false);
+    // 'internalQueryForceClassicEngine' change in the future.
+    RAIIServerParameterControllerForTest controllerSBE("internalQueryForceClassicEngine", true);
 
     // Test that an $in containing a single regex is unwrapped to $regex.
     testComputeKey("{a: {$in: [/foo/]}}", "{}", "{}", "rea@f");
@@ -386,9 +380,8 @@ TEST(CanonicalQueryEncoderTest, ComputeKeyMatchInDependsOnPresenceOfRegexAndFlag
 TEST(CanonicalQueryEncoderTest, CheckCollationIsEncoded) {
     // The computed key depends on which execution engine is enabled. As such, we disable SBE for
     // this test so that the test doesn't break should the default value of
-    // 'internalQueryEnableSlotBasedExecutionEngine' change in the future.
-    RAIIServerParameterControllerForTest controllerSBE(
-        "internalQueryEnableSlotBasedExecutionEngine", false);
+    // 'internalQueryForceClassicEngine' change in the future.
+    RAIIServerParameterControllerForTest controllerSBE("internalQueryForceClassicEngine", true);
 
     unique_ptr<CanonicalQuery> cq(canonicalize(
         fromjson("{a: 1, b: 1}"), {}, {}, fromjson("{locale: 'mock_reverse_string'}")));
@@ -400,8 +393,7 @@ TEST(CanonicalQueryEncoderTest, ComputeKeySBE) {
     // Generated cache keys should be treated as opaque to the user.
 
     // SBE must be enabled in order to generate SBE plan cache keys.
-    RAIIServerParameterControllerForTest controllerSBE(
-        "internalQueryEnableSlotBasedExecutionEngine", true);
+    RAIIServerParameterControllerForTest controllerSBE("internalQueryForceClassicEngine", false);
 
     // TODO SERVER-61314: Remove when featureFlagSbePlanCache is removed.
     RAIIServerParameterControllerForTest controllerSBEPlanCache("featureFlagSbePlanCache", true);
diff --git a/src/mongo/db/query/explain.cpp b/src/mongo/db/query/explain.cpp
index 4ec9e8d9e7d..414badb8332 100644
--- a/src/mongo/db/query/explain.cpp
+++ b/src/mongo/db/query/explain.cpp
@@ -96,7 +96,7 @@ void generatePlannerInfo(PlanExecutor* exec,
             QuerySettingsDecoration::get(collection->getSharedDecorations());
         if (exec->getCanonicalQuery()->isSbeCompatible() &&
             feature_flags::gFeatureFlagSbePlanCache.isEnabledAndIgnoreFCV() &&
-            exec->getCanonicalQuery()->getEnableSlotBasedExecutionEngine() &&
+            !exec->getCanonicalQuery()->getForceClassicEngine() &&
             // TODO(SERVER-61507): Remove pipeline check once lowered pipelines are integrated with
             // SBE plan cache.
             exec->getCanonicalQuery()->pipeline().empty()) {
diff --git a/src/mongo/db/query/get_executor.cpp b/src/mongo/db/query/get_executor.cpp
index 537ec7d5c69..f1a6be4d958 100644
--- a/src/mongo/db/query/get_executor.cpp
+++ b/src/mongo/db/query/get_executor.cpp
@@ -1386,7 +1386,7 @@ StatusWith<std::unique_ptr<PlanExecutor, PlanExecutor::Deleter>> getExecutor(
     const auto& mainColl = collections.getMainCollection();
     canonicalQuery->setSbeCompatible(
         sbe::isQuerySbeCompatible(&mainColl, canonicalQuery.get(), plannerOptions));
-    return canonicalQuery->getEnableSlotBasedExecutionEngine() && canonicalQuery->isSbeCompatible()
+    return !canonicalQuery->getForceClassicEngine() && canonicalQuery->isSbeCompatible()
         ? getSlotBasedExecutor(opCtx,
                                collections,
                                std::move(canonicalQuery),
diff --git a/src/mongo/db/query/plan_cache_key_info_test.cpp b/src/mongo/db/query/plan_cache_key_info_test.cpp
index 472b1f0ab9c..7235386e7f4 100644
--- a/src/mongo/db/query/plan_cache_key_info_test.cpp
+++ b/src/mongo/db/query/plan_cache_key_info_test.cpp
@@ -420,17 +420,17 @@ TEST(PlanCacheKeyInfoTest, DifferentQueryEngines) {
                       false,                         // sparse
                       IndexEntry::Identifier{""})};  // name
 
-    // Helper to construct a plan cache key given the 'enableSlotBasedExecutionEngine' flag.
-    auto constructPlanCacheKey = [&](bool enableSlotBasedExecutionEngine) {
-        RAIIServerParameterControllerForTest controller{
-            "internalQueryEnableSlotBasedExecutionEngine", enableSlotBasedExecutionEngine};
+    // Helper to construct a plan cache key given the 'forceClassicEngine' flag.
+    auto constructPlanCacheKey = [&](bool forceClassicEngine) {
+        RAIIServerParameterControllerForTest controller{"internalQueryForceClassicEngine",
+                                                        forceClassicEngine};
         const auto queryStr = "{a: 0}";
         unique_ptr<CanonicalQuery> cq(canonicalize(queryStr));
         return makeKey(*cq, indexCores);
     };
 
-    const auto classicEngineKey = constructPlanCacheKey(false);
-    const auto noClassicEngineKey = constructPlanCacheKey(true);
+    const auto classicEngineKey = constructPlanCacheKey(true);
+    const auto noClassicEngineKey = constructPlanCacheKey(false);
 
     // Check that the two plan cache keys are not equal because the plans were created under
     // different engines.
diff --git a/src/mongo/db/query/query_knobs.idl b/src/mongo/db/query/query_knobs.idl
index 5120ec5f1d3..7e2fee1563f 100644
--- a/src/mongo/db/query/query_knobs.idl
+++ b/src/mongo/db/query/query_knobs.idl
@@ -653,13 +653,13 @@ server_parameters:
     default: false
     on_update: plan_cache_util::clearSbeCacheOnParameterChange
 
-  internalQueryEnableSlotBasedExecutionEngine:
-    description: "If true, the system will use the SBE execution engine for eligible queries,
-      otherwise all queries will execute using the classic execution engine."
+  internalQueryForceClassicEngine:
+    description: "If true, the system will use the classic execution engine for all queries,
+      otherwise eligible queries will execute using the SBE execution engine."
     set_at: [ startup, runtime ]
-    cpp_varname: "internalQueryEnableSlotBasedExecutionEngine"
+    cpp_varname: "internalQueryForceClassicEngine"
     cpp_vartype: AtomicWord<bool>
-    default: false
+    default: true
 
   internalQueryAppendIdToSetWindowFieldsSort:
     description: "If true, appends _id to the sort stage generated by desugaring $setWindowFields to
diff --git a/src/mongo/db/query/query_planner.cpp b/src/mongo/db/query/query_planner.cpp
index 69c679888f8..fa810499cb4 100644
--- a/src/mongo/db/query/query_planner.cpp
+++ b/src/mongo/db/query/query_planner.cpp
@@ -212,7 +212,7 @@ void tryToAddColumnScan(const QueryPlannerParams& params,
         // We only want to use the columnar index if we can avoid fetching the whole document.
         return;
     }
-    if (!query.isSbeCompatible() || !query.getEnableSlotBasedExecutionEngine()) {
+    if (!query.isSbeCompatible() || query.getForceClassicEngine()) {
         // We only support column scans in SBE.
         return;
     }
diff --git a/src/mongo/db/query/query_planner_columnar_test.cpp b/src/mongo/db/query/query_planner_columnar_test.cpp
index 10c92f6cebd..2d255ebbeeb 100644
--- a/src/mongo/db/query/query_planner_columnar_test.cpp
+++ b/src/mongo/db/query/query_planner_columnar_test.cpp
@@ -85,8 +85,7 @@ protected:
 
 private:
     // SBE must be enabled in order to test columnar indexes.
-    RAIIServerParameterControllerForTest _controllerSBE{
-        "internalQueryEnableSlotBasedExecutionEngine", true};
+    RAIIServerParameterControllerForTest _controllerSBE{"internalQueryForceClassicEngine", false};
 };
 
 TEST_F(QueryPlannerColumnarTest, InclusionProjectionUsesColumnarIndex) {
diff --git a/src/mongo/dbtests/query_stage_multiplan.cpp b/src/mongo/dbtests/query_stage_multiplan.cpp
index ce40f343858..3552cf095fd 100644
--- a/src/mongo/dbtests/query_stage_multiplan.cpp
+++ b/src/mongo/dbtests/query_stage_multiplan.cpp
@@ -551,8 +551,7 @@ TEST_F(QueryStageMultiPlanTest, MPSExplainAllPlans) {
 //
 // This is a regression test for SERVER-20111.
 TEST_F(QueryStageMultiPlanTest, MPSSummaryStats) {
-    RAIIServerParameterControllerForTest controller("internalQueryEnableSlotBasedExecutionEngine",
-                                                    false);
+    RAIIServerParameterControllerForTest controller("internalQueryForceClassicEngine", true);
 
     const int N = 5000;
     for (int i = 0; i < N; ++i) {
diff --git a/src/mongo/shell/servers.js b/src/mongo/shell/servers.js
index 9d39eced9a9..c48527ba68f 100644
--- a/src/mongo/shell/servers.js
+++ b/src/mongo/shell/servers.js
@@ -643,20 +643,6 @@ var _isMongodVersionEqualOrAfter = function(version1, version2) {
     return false;
 };
 
-// Returns if version2 came before version 1.
-var _isMongodVersionBefore = function(version1, version2) {
-    var versionParts1 = _convertVersionToIntegerArray(version1);
-    var versionParts2 = _convertVersionToIntegerArray(version2);
-    if (versionParts2[0] < versionParts1[0] ||
-        (versionParts2[0] === versionParts1[0] && versionParts2[1] < versionParts1[1]) ||
-        (versionParts2[0] === versionParts1[0] && versionParts2[1] === versionParts1[1] &&
-         versionParts2[2] < versionParts1[2])) {
-        return true;
-    }
-
-    return false;
-};
-
 // Removes a setParameter parameter from mongods or mongoses running a version that won't recognize
 // them.
 var _removeSetParameterIfBeforeVersion = function(
@@ -672,24 +658,6 @@ var _removeSetParameterIfBeforeVersion = function(
     }
 };
 
-// Similar to the function above, but accepts two versions such that if the configured binVersion is
-// between the specified versions, it removes the setParameter parameter.
-var _removeSetParameterIfBetweenSpecifiedVersions = function(
-    opts, parameterName, afterVersion, beforeVersion, isMongos = false) {
-    var processString = isMongos ? "mongos" : "mongod";
-    var versionCompatible = (opts.binVersion === "" || opts.binVersion === undefined ||
-                             // For 'opts.binVersion' to be compatible with 'parameterName', it must
-                             // be GTE 'afterVersion' or LT 'beforeVersion'.
-                             _isMongodVersionEqualOrAfter(afterVersion, opts.binVersion) ||
-                             _isMongodVersionBefore(beforeVersion, opts.binVersion));
-    if (!versionCompatible && opts.setParameter && opts.setParameter[parameterName] != undefined) {
-        print("Removing '" + parameterName + "' setParameter with value " +
-              opts.setParameter[parameterName] + " because it isn't compatible with " +
-              processString + " running version " + opts.binVersion);
-        delete opts.setParameter[parameterName];
-    }
-};
-
 /**
  * @option {object} opts
  *
@@ -735,8 +703,7 @@ MongoRunner.mongodOptions = function(opts = {}) {
         opts, "enableDefaultWriteConcernUpdatesForInitiate", "5.0.0");
     _removeSetParameterIfBeforeVersion(opts, "enableReconfigRollbackCommittedWritesCheck", "5.0.0");
     _removeSetParameterIfBeforeVersion(opts, "featureFlagRetryableFindAndModify", "5.0.0");
-    _removeSetParameterIfBetweenSpecifiedVersions(
-        opts, "internalQueryEnableSlotBasedExecutionEngine", "6.0.0", "5.1.0");
+    _removeSetParameterIfBeforeVersion(opts, "internalQueryForceClassicEngine", "5.1.0");
     _removeSetParameterIfBeforeVersion(opts, "allowMultipleArbiters", "5.3.0");
 
     if (!opts.logFile && opts.useLogFiles) {