SERVER-16857 Delete MMAPv1 diskloc invalidations.

 - Removes of PlanStage::invalidate().
 - Removes RecordCursor::invalidate() from the storage API.
 - Removes CursorManager::invalidateDocument().

46 files changed, 106 insertions, 641 deletions

diff --git a/src/mongo/db/exec/and_hash.cpp b/src/mongo/db/exec/and_hash.cpp
index 0ae93e9ad3a..d2d0661ffb2 100644
--- a/src/mongo/db/exec/and_hash.cpp
+++ b/src/mongo/db/exec/and_hash.cpp
@@ -383,57 +383,6 @@ PlanStage::StageState AndHashStage::hashOtherChildren(WorkingSetID* out) {
     }
 }
 
-// TODO SERVER-16857: Delete this method, as the invalidation mechanism was only needed for the
-// MMAPv1 storage engine.
-void AndHashStage::doInvalidate(OperationContext* opCtx,
-                                const RecordId& dl,
-                                InvalidationType type) {
-    // TODO remove this since calling isEOF is illegal inside of doInvalidate().
-    if (isEOF()) {
-        return;
-    }
-
-    // Invalidation can happen to our warmup results.  If that occurs just
-    // flag it and forget about it.
-    for (size_t i = 0; i < _lookAheadResults.size(); ++i) {
-        if (WorkingSet::INVALID_ID != _lookAheadResults[i]) {
-            WorkingSetMember* member = _ws->get(_lookAheadResults[i]);
-            if (member->hasRecordId() && member->recordId == dl) {
-                WorkingSetCommon::fetchAndInvalidateRecordId(opCtx, member, _collection);
-                _lookAheadResults[i] = WorkingSet::INVALID_ID;
-            }
-        }
-    }
-
-    // If it's a deletion, we have to forget about the RecordId, and since the AND-ing is by
-    // RecordId we can't continue processing it even with the object.
-    //
-    // If it's a mutation the predicates implied by the AND-ing may no longer be true.
-    //
-    // So, we flag and try to pick it up later.
-    DataMap::iterator it = _dataMap.find(dl);
-    if (_dataMap.end() != it) {
-        WorkingSetID id = it->second;
-        WorkingSetMember* member = _ws->get(id);
-        verify(member->recordId == dl);
-
-        if (_hashingChildren) {
-            ++_specificStats.flaggedInProgress;
-        } else {
-            ++_specificStats.flaggedButPassed;
-        }
-
-        // Update memory stats.
-        _memUsage -= member->getMemUsage();
-
-        // The RecordId is about to be invalidated.  Fetch it and clear the RecordId.
-        WorkingSetCommon::fetchAndInvalidateRecordId(opCtx, member, _collection);
-
-        // And don't return it from this stage.
-        _dataMap.erase(it);
-    }
-}
-
 unique_ptr<PlanStageStats> AndHashStage::getStats() {
     _commonStats.isEOF = isEOF();
 
diff --git a/src/mongo/db/exec/and_hash.h b/src/mongo/db/exec/and_hash.h
index 92996adba31..fa558922223 100644
--- a/src/mongo/db/exec/and_hash.h
+++ b/src/mongo/db/exec/and_hash.h
@@ -40,15 +40,10 @@
 namespace mongo {
 
 /**
- * Reads from N children, each of which must have a valid RecordId.  Uses a hash table to
- * intersect the outputs of the N children, and outputs the intersection.
+ * Reads from N children, each of which must have a valid RecordId. Uses a hash table to intersect
+ * the outputs of the N children based on their record ids, and outputs the intersection.
  *
- * Preconditions: Valid RecordId.  More than one child.
- *
- * Any RecordId that we keep a reference to that is invalidated before we are able to return it
- * is fetched and added to the WorkingSet as "flagged for further review."  Because this stage
- * operates with RecordIds, we are unable to evaluate the AND for the invalidated RecordId, and it
- * must be fully matched later.
+ * Preconditions: Valid RecordId. More than one child.
  */
 class AndHashStage final : public PlanStage {
 public:
@@ -73,8 +68,6 @@ public:
     StageState doWork(WorkingSetID* out) final;
     bool isEOF() final;
 
-    void doInvalidate(OperationContext* opCtx, const RecordId& dl, InvalidationType type) final;
-
     StageType stageType() const final {
         return STAGE_AND_HASH;
     }
diff --git a/src/mongo/db/exec/and_sorted.cpp b/src/mongo/db/exec/and_sorted.cpp
index b5e3cfa24fd..d81e897cd68 100644
--- a/src/mongo/db/exec/and_sorted.cpp
+++ b/src/mongo/db/exec/and_sorted.cpp
@@ -227,35 +227,6 @@ PlanStage::StageState AndSortedStage::moveTowardTargetRecordId(WorkingSetID* out
     }
 }
 
-
-// TODO SERVER-16857: Delete this method, as the invalidation mechanism was only needed for the
-// MMAPv1 storage engine.
-void AndSortedStage::doInvalidate(OperationContext* opCtx,
-                                  const RecordId& dl,
-                                  InvalidationType type) {
-    // TODO remove this since calling isEOF is illegal inside of doInvalidate().
-    if (isEOF()) {
-        return;
-    }
-
-    if (dl == _targetRecordId) {
-        // We're in the middle of moving children forward until they hit _targetRecordId, which is
-        // no
-        // longer a valid target.  If it's a deletion we can't AND it with anything, if it's a
-        // mutation the predicates implied by the AND may no longer be true.  So no matter what,
-        // fetch it, flag for review, and find another _targetRecordId.
-        ++_specificStats.flagged;
-
-        // The RecordId could still be a valid result so flag it and save it for later.
-        WorkingSetCommon::fetchAndInvalidateRecordId(opCtx, _ws->get(_targetId), _collection);
-
-        _targetId = WorkingSet::INVALID_ID;
-        _targetNode = numeric_limits<size_t>::max();
-        _targetRecordId = RecordId();
-        _workingTowardRep = std::queue<size_t>();
-    }
-}
-
 unique_ptr<PlanStageStats> AndSortedStage::getStats() {
     _commonStats.isEOF = isEOF();
 
diff --git a/src/mongo/db/exec/and_sorted.h b/src/mongo/db/exec/and_sorted.h
index 28ba43b954a..889b38c69c5 100644
--- a/src/mongo/db/exec/and_sorted.h
+++ b/src/mongo/db/exec/and_sorted.h
@@ -39,16 +39,10 @@
 namespace mongo {
 
 /**
- * Reads from N children, each of which must have a valid RecordId.  Assumes each child produces
- * RecordIds in sorted order.  Outputs the intersection of the RecordIds outputted by the
- * children.
+ * Reads from N children, each of which must have a valid RecordId. Assumes each child produces
+ * RecordIds in sorted order. Outputs the intersection of the RecordIds outputted by the children.
  *
- * Preconditions: Valid RecordId.  More than one child.
- *
- * Any RecordId that we keep a reference to that is invalidated before we are able to return it
- * is fetched and added to the WorkingSet as "flagged for further review."  Because this stage
- * operates with RecordIds, we are unable to evaluate the AND for the invalidated RecordId, and it
- * must be fully matched later.
+ * Preconditions: Valid RecordId. More than one child.
  */
 class AndSortedStage final : public PlanStage {
 public:
@@ -59,8 +53,6 @@ public:
     StageState doWork(WorkingSetID* out) final;
     bool isEOF() final;
 
-    void doInvalidate(OperationContext* opCtx, const RecordId& dl, InvalidationType type) final;
-
     StageType stageType() const final {
         return STAGE_AND_SORTED;
     }
diff --git a/src/mongo/db/exec/cached_plan.cpp b/src/mongo/db/exec/cached_plan.cpp
index 7e59ea230c6..01ca4bd2e37 100644
--- a/src/mongo/db/exec/cached_plan.cpp
+++ b/src/mongo/db/exec/cached_plan.cpp
@@ -100,7 +100,7 @@ Status CachedPlanStage::pickBestPlan(PlanYieldPolicy* yieldPolicy) {
             WorkingSetMember* member = _ws->get(id);
             // Ensure that the BSONObj underlying the WorkingSetMember is owned in case we yield.
             member->makeObjOwnedIfNeeded();
-            _results.push_back(id);
+            _results.push(id);
 
             if (_results.size() >= numResults) {
                 // Once a plan returns enough results, stop working. Update cache with stats
@@ -194,7 +194,10 @@ Status CachedPlanStage::tryYield(PlanYieldPolicy* yieldPolicy) {
 
 Status CachedPlanStage::replan(PlanYieldPolicy* yieldPolicy, bool shouldCache) {
     // We're going to start over with a new plan. Clear out info from our old plan.
-    _results.clear();
+    {
+        std::queue<WorkingSetID> emptyQueue;
+        _results.swap(emptyQueue);
+    }
     _ws->clear();
     _children.clear();
 
@@ -287,7 +290,7 @@ PlanStage::StageState CachedPlanStage::doWork(WorkingSetID* out) {
     // First exhaust any results buffered during the trial period.
     if (!_results.empty()) {
         *out = _results.front();
-        _results.pop_front();
+        _results.pop();
         return PlanStage::ADVANCED;
     }
 
@@ -295,17 +298,6 @@ PlanStage::StageState CachedPlanStage::doWork(WorkingSetID* out) {
     return child()->work(out);
 }
 
-void CachedPlanStage::doInvalidate(OperationContext* opCtx,
-                                   const RecordId& dl,
-                                   InvalidationType type) {
-    for (auto it = _results.begin(); it != _results.end(); ++it) {
-        WorkingSetMember* member = _ws->get(*it);
-        if (member->hasRecordId() && member->recordId == dl) {
-            WorkingSetCommon::fetchAndInvalidateRecordId(opCtx, member, _collection);
-        }
-    }
-}
-
 std::unique_ptr<PlanStageStats> CachedPlanStage::getStats() {
     _commonStats.isEOF = isEOF();
 
diff --git a/src/mongo/db/exec/cached_plan.h b/src/mongo/db/exec/cached_plan.h
index 9d149860811..e8de18d7bca 100644
--- a/src/mongo/db/exec/cached_plan.h
+++ b/src/mongo/db/exec/cached_plan.h
@@ -28,8 +28,8 @@
 
 #pragma once
 
-#include <list>
 #include <memory>
+#include <queue>
 
 #include "mongo/db/exec/plan_stage.h"
 #include "mongo/db/exec/working_set.h"
@@ -65,8 +65,6 @@ public:
 
     StageState doWork(WorkingSetID* out) final;
 
-    void doInvalidate(OperationContext* opCtx, const RecordId& dl, InvalidationType type) final;
-
     StageType stageType() const final {
         return STAGE_CACHED_PLAN;
     }
@@ -136,7 +134,7 @@ private:
     std::unique_ptr<QuerySolution> _replannedQs;
 
     // Any results produced during trial period execution are kept here.
-    std::list<WorkingSetID> _results;
+    std::queue<WorkingSetID> _results;
 
     // When a stage requests a yield for document fetch, it gives us back a RecordFetcher*
     // to use to pull the record into memory. We take ownership of the RecordFetcher here,
diff --git a/src/mongo/db/exec/collection_scan.cpp b/src/mongo/db/exec/collection_scan.cpp
index 162caf4cf3e..e2c51ea7304 100644
--- a/src/mongo/db/exec/collection_scan.cpp
+++ b/src/mongo/db/exec/collection_scan.cpp
@@ -121,12 +121,12 @@ PlanStage::StageState CollectionScan::doWork(WorkingSetID* out) {
 
             if (!_lastSeenId.isNull()) {
                 invariant(_params.tailable);
-                // Seek to where we were last time. If it no longer exists, mark us as dead
-                // since we want to signal an error rather than silently dropping data from the
-                // stream. This is related to the _lastSeenId handling in invalidate. Note that
-                // we want to return the record *after* this one since we have already returned
-                // this one. This is only possible in the tailing case because that is the only
-                // time we'd need to create a cursor after already getting a record out of it.
+                // Seek to where we were last time. If it no longer exists, mark us as dead since we
+                // want to signal an error rather than silently dropping data from the stream.
+                //
+                // Note that we want to return the record *after* this one since we have already
+                // returned this one. This is only possible in the tailing case because that is the
+                // only time we'd need to create a cursor after already getting a record out of it.
                 if (!_cursor->seekExact(_lastSeenId)) {
                     _isDead = true;
                     Status status(ErrorCodes::CappedPositionLost,
@@ -234,29 +234,6 @@ bool CollectionScan::isEOF() {
     return _commonStats.isEOF || _isDead;
 }
 
-void CollectionScan::doInvalidate(OperationContext* opCtx,
-                                  const RecordId& id,
-                                  InvalidationType type) {
-    // We don't care about mutations since we apply any filters to the result when we (possibly)
-    // return it.
-    if (INVALIDATION_DELETION != type) {
-        return;
-    }
-
-    // If we're here, 'id' is being deleted.
-
-    // Deletions can harm the underlying RecordCursor so we must pass them down.
-    if (_cursor) {
-        _cursor->invalidate(opCtx, id);
-    }
-
-    if (_params.tailable && id == _lastSeenId) {
-        // This means that deletes have caught up to the reader. We want to error in this case
-        // so readers don't miss potentially important data.
-        _isDead = true;
-    }
-}
-
 void CollectionScan::doSaveState() {
     if (_cursor) {
         _cursor->save();
diff --git a/src/mongo/db/exec/collection_scan.h b/src/mongo/db/exec/collection_scan.h
index 65ee541b6e5..1a997a01ac1 100644
--- a/src/mongo/db/exec/collection_scan.h
+++ b/src/mongo/db/exec/collection_scan.h
@@ -58,7 +58,6 @@ public:
     StageState doWork(WorkingSetID* out) final;
     bool isEOF() final;
 
-    void doInvalidate(OperationContext* opCtx, const RecordId& dl, InvalidationType type) final;
     void doSaveState() final;
     void doRestoreState() final;
     void doDetachFromOperationContext() final;
diff --git a/src/mongo/db/exec/collection_scan_common.h b/src/mongo/db/exec/collection_scan_common.h
index 50f3c25975e..302b38f131a 100644
--- a/src/mongo/db/exec/collection_scan_common.h
+++ b/src/mongo/db/exec/collection_scan_common.h
@@ -45,8 +45,7 @@ struct CollectionScanParams {
     // not owned
     const Collection* collection = nullptr;
 
-    // isNull by default.  If you specify any value for this, you're responsible for the RecordId
-    // not being invalidated before the first call to work(...).
+    // The RecordId to which we should seek to as the first document of the scan.
     RecordId start;
 
     // If present, the collection scan will stop and return EOF the first time it sees a document
diff --git a/src/mongo/db/exec/count_scan.cpp b/src/mongo/db/exec/count_scan.cpp
index f6746dfa50d..a5132ffe9a8 100644
--- a/src/mongo/db/exec/count_scan.cpp
+++ b/src/mongo/db/exec/count_scan.cpp
@@ -94,7 +94,6 @@ CountScan::CountScan(OperationContext* opCtx, CountScanParams params, WorkingSet
                                        /*compareFieldNames*/ false) <= 0);
 }
 
-
 PlanStage::StageState CountScan::doWork(WorkingSetID* out) {
     if (_commonStats.isEOF)
         return PlanStage::IS_EOF;
@@ -166,21 +165,6 @@ void CountScan::doReattachToOperationContext() {
         _cursor->reattachToOperationContext(getOpCtx());
 }
 
-void CountScan::doInvalidate(OperationContext* opCtx, const RecordId& dl, InvalidationType type) {
-    // The only state we're responsible for holding is what RecordIds to drop.  If a document
-    // mutates the underlying index cursor will deal with it.
-    if (INVALIDATION_MUTATION == type) {
-        return;
-    }
-
-    // If we see this RecordId again, it may not be the same document it was before, so we want
-    // to return it if we see it again.
-    stdx::unordered_set<RecordId, RecordId::Hasher>::iterator it = _returned.find(dl);
-    if (it != _returned.end()) {
-        _returned.erase(it);
-    }
-}
-
 unique_ptr<PlanStageStats> CountScan::getStats() {
     unique_ptr<PlanStageStats> ret = make_unique<PlanStageStats>(_commonStats, STAGE_COUNT_SCAN);
 
diff --git a/src/mongo/db/exec/count_scan.h b/src/mongo/db/exec/count_scan.h
index f3f84ff8d57..f9c69cdede1 100644
--- a/src/mongo/db/exec/count_scan.h
+++ b/src/mongo/db/exec/count_scan.h
@@ -114,7 +114,6 @@ public:
     void doRestoreState() final;
     void doDetachFromOperationContext() final;
     void doReattachToOperationContext() final;
-    void doInvalidate(OperationContext* opCtx, const RecordId& dl, InvalidationType type) final;
 
     StageType stageType() const final {
         return STAGE_COUNT_SCAN;
@@ -136,7 +135,7 @@ private:
     std::unique_ptr<SortedDataInterface::Cursor> _cursor;
 
     // Could our index have duplicates?  If so, we use _returned to dedup.
-    bool _shouldDedup;
+    const bool _shouldDedup;
     stdx::unordered_set<RecordId, RecordId::Hasher> _returned;
 
     CountScanParams _params;
diff --git a/src/mongo/db/exec/delete.cpp b/src/mongo/db/exec/delete.cpp
index 623535ef946..7c6fd19b5ed 100644
--- a/src/mongo/db/exec/delete.cpp
+++ b/src/mongo/db/exec/delete.cpp
@@ -157,11 +157,7 @@ PlanStage::StageState DeleteStage::doWork(WorkingSetID* out) {
     // We want to free this member when we return, unless we need to retry deleting or returning it.
     ScopeGuard memberFreer = MakeGuard(&WorkingSet::free, _ws, id);
 
-    if (!member->hasRecordId()) {
-        // We expect to be here because of an invalidation causing a force-fetch.
-        ++_specificStats.nInvalidateSkips;
-        return PlanStage::NEED_TIME;
-    }
+    invariant(member->hasRecordId());
     RecordId recordId = member->recordId;
     // Deletes can't have projections. This means that covering analysis will always add
     // a fetch. We should always get fetched data, and never just key data.
diff --git a/src/mongo/db/exec/fetch.cpp b/src/mongo/db/exec/fetch.cpp
index 6895a58ca3b..001e7010c54 100644
--- a/src/mongo/db/exec/fetch.cpp
+++ b/src/mongo/db/exec/fetch.cpp
@@ -164,18 +164,6 @@ void FetchStage::doReattachToOperationContext() {
         _cursor->reattachToOperationContext(getOpCtx());
 }
 
-void FetchStage::doInvalidate(OperationContext* opCtx, const RecordId& dl, InvalidationType type) {
-    // It's possible that the recordId getting invalidated is the one we're about to
-    // fetch. In this case we do a "forced fetch" and put the WSM in owned object state.
-    if (WorkingSet::INVALID_ID != _idRetrying) {
-        WorkingSetMember* member = _ws->get(_idRetrying);
-        if (member->hasRecordId() && (member->recordId == dl)) {
-            // Fetch it now and kill the recordId.
-            WorkingSetCommon::fetchAndInvalidateRecordId(opCtx, member, _collection);
-        }
-    }
-}
-
 PlanStage::StageState FetchStage::returnIfMatches(WorkingSetMember* member,
                                                   WorkingSetID memberID,
                                                   WorkingSetID* out) {
diff --git a/src/mongo/db/exec/fetch.h b/src/mongo/db/exec/fetch.h
index a1c78c970c6..02c143a2c33 100644
--- a/src/mongo/db/exec/fetch.h
+++ b/src/mongo/db/exec/fetch.h
@@ -64,7 +64,6 @@ public:
     void doRestoreState() final;
     void doDetachFromOperationContext() final;
     void doReattachToOperationContext() final;
-    void doInvalidate(OperationContext* opCtx, const RecordId& dl, InvalidationType type) final;
 
     StageType stageType() const final {
         return STAGE_FETCH;
diff --git a/src/mongo/db/exec/geo_near.cpp b/src/mongo/db/exec/geo_near.cpp
index 4e19b43a662..80923c4f55e 100644
--- a/src/mongo/db/exec/geo_near.cpp
+++ b/src/mongo/db/exec/geo_near.cpp
@@ -739,11 +739,8 @@ StatusWith<NearStage::CoveredInterval*>  //
     _children.emplace_back(
         new FetchStageWithMatch(opCtx, workingSet, scan, docMatcher, collection));
 
-    return StatusWith<CoveredInterval*>(new CoveredInterval(_children.back().get(),
-                                                            true,
-                                                            nextBounds.getInner(),
-                                                            nextBounds.getOuter(),
-                                                            isLastInterval));
+    return StatusWith<CoveredInterval*>(new CoveredInterval(
+        _children.back().get(), nextBounds.getInner(), nextBounds.getOuter(), isLastInterval));
 }
 
 StatusWith<double> GeoNear2DStage::computeDistance(WorkingSetMember* member) {
@@ -1094,11 +1091,8 @@ StatusWith<NearStage::CoveredInterval*>  //
     // FetchStage owns index scan
     _children.emplace_back(new FetchStage(opCtx, workingSet, scan, _nearParams.filter, collection));
 
-    return StatusWith<CoveredInterval*>(new CoveredInterval(_children.back().get(),
-                                                            true,
-                                                            nextBounds.getInner(),
-                                                            nextBounds.getOuter(),
-                                                            isLastInterval));
+    return StatusWith<CoveredInterval*>(new CoveredInterval(
+        _children.back().get(), nextBounds.getInner(), nextBounds.getOuter(), isLastInterval));
 }
 
 StatusWith<double> GeoNear2DSphereStage::computeDistance(WorkingSetMember* member) {
diff --git a/src/mongo/db/exec/idhack.cpp b/src/mongo/db/exec/idhack.cpp
index d8f4f12ba82..366d9f7ca56 100644
--- a/src/mongo/db/exec/idhack.cpp
+++ b/src/mongo/db/exec/idhack.cpp
@@ -208,23 +208,6 @@ void IDHackStage::doReattachToOperationContext() {
         _recordCursor->reattachToOperationContext(getOpCtx());
 }
 
-void IDHackStage::doInvalidate(OperationContext* opCtx, const RecordId& dl, InvalidationType type) {
-    // Since updates can't mutate the '_id' field, we can ignore mutation invalidations.
-    if (INVALIDATION_MUTATION == type) {
-        return;
-    }
-
-    // It's possible that the RecordId getting invalidated is the one we're about to
-    // fetch. In this case we do a "forced fetch" and put the WSM in owned object state.
-    if (WorkingSet::INVALID_ID != _idBeingPagedIn) {
-        WorkingSetMember* member = _workingSet->get(_idBeingPagedIn);
-        if (member->hasRecordId() && (member->recordId == dl)) {
-            // Fetch it now and kill the RecordId.
-            WorkingSetCommon::fetchAndInvalidateRecordId(opCtx, member, _collection);
-        }
-    }
-}
-
 // static
 bool IDHackStage::supportsQuery(Collection* collection, const CanonicalQuery& query) {
     return !query.getQueryRequest().showRecordId() && query.getQueryRequest().getHint().isEmpty() &&
diff --git a/src/mongo/db/exec/idhack.h b/src/mongo/db/exec/idhack.h
index efb3b4aace3..16a7982860f 100644
--- a/src/mongo/db/exec/idhack.h
+++ b/src/mongo/db/exec/idhack.h
@@ -69,7 +69,6 @@ public:
     void doRestoreState() final;
     void doDetachFromOperationContext() final;
     void doReattachToOperationContext() final;
-    void doInvalidate(OperationContext* opCtx, const RecordId& dl, InvalidationType type) final;
 
     /**
      * ID Hack has a very strict criteria for the queries it supports.
diff --git a/src/mongo/db/exec/index_scan.cpp b/src/mongo/db/exec/index_scan.cpp
index 1110ed78799..45f45da73f4 100644
--- a/src/mongo/db/exec/index_scan.cpp
+++ b/src/mongo/db/exec/index_scan.cpp
@@ -258,22 +258,6 @@ void IndexScan::doReattachToOperationContext() {
         _indexCursor->reattachToOperationContext(getOpCtx());
 }
 
-void IndexScan::doInvalidate(OperationContext* opCtx, const RecordId& dl, InvalidationType type) {
-    // The only state we're responsible for holding is what RecordIds to drop.  If a document
-    // mutates the underlying index cursor will deal with it.
-    if (INVALIDATION_MUTATION == type) {
-        return;
-    }
-
-    // If we see this RecordId again, it may not be the same document it was before, so we want
-    // to return it if we see it again.
-    stdx::unordered_set<RecordId, RecordId::Hasher>::iterator it = _returned.find(dl);
-    if (it != _returned.end()) {
-        ++_specificStats.seenInvalidated;
-        _returned.erase(it);
-    }
-}
-
 std::unique_ptr<PlanStageStats> IndexScan::getStats() {
     // WARNING: this could be called even if the collection was dropped.  Do not access any
     // catalog information here.
diff --git a/src/mongo/db/exec/index_scan.h b/src/mongo/db/exec/index_scan.h
index e9f86959f99..d1e1bffbe24 100644
--- a/src/mongo/db/exec/index_scan.h
+++ b/src/mongo/db/exec/index_scan.h
@@ -135,7 +135,6 @@ public:
     void doRestoreState() final;
     void doDetachFromOperationContext() final;
     void doReattachToOperationContext() final;
-    void doInvalidate(OperationContext* opCtx, const RecordId& dl, InvalidationType type) final;
 
     StageType stageType() const final {
         return STAGE_IXSCAN;
diff --git a/src/mongo/db/exec/merge_sort.cpp b/src/mongo/db/exec/merge_sort.cpp
index b8343869a60..0e2249fdb74 100644
--- a/src/mongo/db/exec/merge_sort.cpp
+++ b/src/mongo/db/exec/merge_sort.cpp
@@ -166,29 +166,6 @@ PlanStage::StageState MergeSortStage::doWork(WorkingSetID* out) {
     return PlanStage::ADVANCED;
 }
 
-
-void MergeSortStage::doInvalidate(OperationContext* opCtx,
-                                  const RecordId& dl,
-                                  InvalidationType type) {
-    // Go through our data and see if we're holding on to the invalidated RecordId.
-    for (list<StageWithValue>::iterator valueIt = _mergingData.begin();
-         valueIt != _mergingData.end();
-         valueIt++) {
-        WorkingSetMember* member = _ws->get(valueIt->id);
-        if (member->hasRecordId() && (dl == member->recordId)) {
-            // Fetch the about-to-be mutated result.
-            WorkingSetCommon::fetchAndInvalidateRecordId(opCtx, member, _collection);
-            ++_specificStats.forcedFetches;
-        }
-    }
-
-    // If we see the deleted RecordId again it is not the same record as it once was so we still
-    // want to return it.
-    if (_dedup && INVALIDATION_DELETION == type) {
-        _seen.erase(dl);
-    }
-}
-
 // Is lhs less than rhs?  Note that priority_queue is a max heap by default so we invert
 // the return from the expected value.
 bool MergeSortStage::StageWithValueComparison::operator()(const MergingRef& lhs,
diff --git a/src/mongo/db/exec/merge_sort.h b/src/mongo/db/exec/merge_sort.h
index a1dac80c770..25b4127f786 100644
--- a/src/mongo/db/exec/merge_sort.h
+++ b/src/mongo/db/exec/merge_sort.h
@@ -66,8 +66,6 @@ public:
     bool isEOF() final;
     StageState doWork(WorkingSetID* out) final;
 
-    void doInvalidate(OperationContext* opCtx, const RecordId& dl, InvalidationType type) final;
-
     StageType stageType() const final {
         return STAGE_SORT_MERGE;
     }
@@ -79,49 +77,15 @@ public:
     static const char* kStageType;
 
 private:
-    // Not owned by us.
-    const Collection* _collection;
-
-    // Not owned by us.
-    WorkingSet* _ws;
-
-    // The pattern that we're sorting by.
-    BSONObj _pattern;
-
-    // Null if this merge sort stage orders strings according to simple binary compare. If non-null,
-    // represents the collator used to compare strings.
-    const CollatorInterface* _collator;
-
-    // Are we deduplicating on RecordId?
-    bool _dedup;
-
-    // Which RecordIds have we seen?
-    stdx::unordered_set<RecordId, RecordId::Hasher> _seen;
-
-    // In order to pick the next smallest value, we need each child work(...) until it produces
-    // a result.  This is the queue of children that haven't given us a result yet.
-    std::queue<PlanStage*> _noResultToMerge;
-
-    // There is some confusing STL wrangling going on below.  Here's a guide:
-    //
-    // We want to keep a priority_queue of results so we can quickly return the min result.
-    //
-    // If we receive an invalidate, we need to iterate over any cached state to see if the
-    // invalidate is relevant.
-    //
-    // We can't iterate over a priority_queue, so we keep the actual cached state in a list and
-    // have a priority_queue of iterators into that list.
-    //
-    // Why an iterator instead of a pointer?  We need to be able to use the information in the
-    // priority_queue to remove the item from the list and quickly.
-
     struct StageWithValue {
         StageWithValue() : id(WorkingSet::INVALID_ID), stage(NULL) {}
         WorkingSetID id;
         PlanStage* stage;
     };
 
-    // We have a priority queue of these.
+    // This stage maintains a priority queue of results from each child stage so that it can quickly
+    // return the next result according to the sort order. A value in the priority queue is a
+    // MergingRef, an iterator which refers to a buffered (WorkingSetMember, child stage) pair.
     typedef std::list<StageWithValue>::iterator MergingRef;
 
     // The comparison function used in our priority queue.
@@ -140,6 +104,29 @@ private:
         const CollatorInterface* _collator;
     };
 
+    // Not owned by us.
+    const Collection* _collection;
+
+    // Not owned by us.
+    WorkingSet* _ws;
+
+    // The pattern that we're sorting by.
+    BSONObj _pattern;
+
+    // Null if this merge sort stage orders strings according to simple binary compare. If non-null,
+    // represents the collator used to compare strings.
+    const CollatorInterface* _collator;
+
+    // Are we deduplicating on RecordId?
+    const bool _dedup;
+
+    // Which RecordIds have we seen?
+    stdx::unordered_set<RecordId, RecordId::Hasher> _seen;
+
+    // In order to pick the next smallest value, we need each child work(...) until it produces
+    // a result.  This is the queue of children that haven't given us a result yet.
+    std::queue<PlanStage*> _noResultToMerge;
+
     // The min heap of the results we're returning.
     std::priority_queue<MergingRef, std::vector<MergingRef>, StageWithValueComparison> _merging;
 
diff --git a/src/mongo/db/exec/multi_iterator.cpp b/src/mongo/db/exec/multi_iterator.cpp
index 6652ab1c798..64056ff9c67 100644
--- a/src/mongo/db/exec/multi_iterator.cpp
+++ b/src/mongo/db/exec/multi_iterator.cpp
@@ -131,21 +131,6 @@ void MultiIteratorStage::doReattachToOperationContext() {
     }
 }
 
-void MultiIteratorStage::doInvalidate(OperationContext* opCtx,
-                                      const RecordId& dl,
-                                      InvalidationType type) {
-    switch (type) {
-        case INVALIDATION_DELETION:
-            for (size_t i = 0; i < _iterators.size(); i++) {
-                _iterators[i]->invalidate(opCtx, dl);
-            }
-            break;
-        case INVALIDATION_MUTATION:
-            // no-op
-            break;
-    }
-}
-
 unique_ptr<PlanStageStats> MultiIteratorStage::getStats() {
     unique_ptr<PlanStageStats> ret =
         make_unique<PlanStageStats>(_commonStats, STAGE_MULTI_ITERATOR);
diff --git a/src/mongo/db/exec/multi_iterator.h b/src/mongo/db/exec/multi_iterator.h
index 6e7e6946472..78909adc72d 100644
--- a/src/mongo/db/exec/multi_iterator.h
+++ b/src/mongo/db/exec/multi_iterator.h
@@ -60,7 +60,6 @@ public:
     void doRestoreState() final;
     void doDetachFromOperationContext() final;
     void doReattachToOperationContext() final;
-    void doInvalidate(OperationContext* opCtx, const RecordId& dl, InvalidationType type) final;
 
     // Returns empty PlanStageStats object
     std::unique_ptr<PlanStageStats> getStats() final;
diff --git a/src/mongo/db/exec/multi_plan.cpp b/src/mongo/db/exec/multi_plan.cpp
index 04e79b2ecbf..4b2d60269f7 100644
--- a/src/mongo/db/exec/multi_plan.cpp
+++ b/src/mongo/db/exec/multi_plan.cpp
@@ -111,7 +111,7 @@ PlanStage::StageState MultiPlanStage::doWork(WorkingSetID* out) {
     // Look for an already produced result that provides the data the caller wants.
     if (!bestPlan.results.empty()) {
         *out = bestPlan.results.front();
-        bestPlan.results.pop_front();
+        bestPlan.results.pop();
         return PlanStage::ADVANCED;
     }
 
@@ -236,7 +236,7 @@ Status MultiPlanStage::pickBestPlan(PlanYieldPolicy* yieldPolicy) {
     std::vector<size_t> candidateOrder = ranking->candidateOrder;
 
     CandidatePlan& bestCandidate = _candidates[_bestPlanIdx];
-    std::list<WorkingSetID>& alreadyProduced = bestCandidate.results;
+    const auto& alreadyProduced = bestCandidate.results;
     const auto& bestSolution = bestCandidate.solution;
 
     LOG(5) << "Winning solution:\n" << redact(bestSolution->toString());
@@ -360,7 +360,7 @@ bool MultiPlanStage::workAllPlans(size_t numResults, PlanYieldPolicy* yieldPolic
             // Ensure that the BSONObj underlying the WorkingSetMember is owned in case we choose to
             // return the results from the 'candidate' plan.
             member->makeObjOwnedIfNeeded();
-            candidate.results.push_back(id);
+            candidate.results.push(id);
 
             // Once a plan returns enough results, stop working.
             if (candidate.results.size() >= numResults) {
@@ -410,45 +410,6 @@ bool MultiPlanStage::workAllPlans(size_t numResults, PlanYieldPolicy* yieldPolic
     return !doneWorking;
 }
 
-namespace {
-
-void invalidateHelper(OperationContext* opCtx,
-                      WorkingSet* ws,  // may flag for review
-                      const RecordId& recordId,
-                      list<WorkingSetID>* idsToInvalidate,
-                      const Collection* collection) {
-    for (auto it = idsToInvalidate->begin(); it != idsToInvalidate->end(); ++it) {
-        WorkingSetMember* member = ws->get(*it);
-        if (member->hasRecordId() && member->recordId == recordId) {
-            WorkingSetCommon::fetchAndInvalidateRecordId(opCtx, member, collection);
-        }
-    }
-}
-
-}  // namespace
-
-void MultiPlanStage::doInvalidate(OperationContext* opCtx,
-                                  const RecordId& recordId,
-                                  InvalidationType type) {
-    if (_failure) {
-        return;
-    }
-
-    if (bestPlanChosen()) {
-        CandidatePlan& bestPlan = _candidates[_bestPlanIdx];
-        invalidateHelper(opCtx, bestPlan.ws, recordId, &bestPlan.results, _collection);
-        if (hasBackupPlan()) {
-            CandidatePlan& backupPlan = _candidates[_backupPlanIdx];
-            invalidateHelper(opCtx, backupPlan.ws, recordId, &backupPlan.results, _collection);
-        }
-    } else {
-        for (size_t ix = 0; ix < _candidates.size(); ++ix) {
-            invalidateHelper(
-                opCtx, _candidates[ix].ws, recordId, &_candidates[ix].results, _collection);
-        }
-    }
-}
-
 bool MultiPlanStage::hasBackupPlan() const {
     return kNoSuchPlan != _backupPlanIdx;
 }
diff --git a/src/mongo/db/exec/multi_plan.h b/src/mongo/db/exec/multi_plan.h
index 5d6369e3c0d..5b118653d9a 100644
--- a/src/mongo/db/exec/multi_plan.h
+++ b/src/mongo/db/exec/multi_plan.h
@@ -84,8 +84,6 @@ public:
 
     StageState doWork(WorkingSetID* out) final;
 
-    void doInvalidate(OperationContext* opCtx, const RecordId& dl, InvalidationType type) final;
-
     StageType stageType() const final {
         return STAGE_MULTI_PLAN;
     }
diff --git a/src/mongo/db/exec/near.cpp b/src/mongo/db/exec/near.cpp
index 7424adca28d..8621c8fa2b7 100644
--- a/src/mongo/db/exec/near.cpp
+++ b/src/mongo/db/exec/near.cpp
@@ -57,12 +57,10 @@ NearStage::NearStage(OperationContext* opCtx,
 NearStage::~NearStage() {}
 
 NearStage::CoveredInterval::CoveredInterval(PlanStage* covering,
-                                            bool dedupCovering,
                                             double minDistance,
                                             double maxDistance,
                                             bool inclusiveMax)
     : covering(covering),
-      dedupCovering(dedupCovering),
       minDistance(minDistance),
       maxDistance(maxDistance),
       inclusiveMax(inclusiveMax) {}
@@ -187,7 +185,7 @@ PlanStage::StageState NearStage::bufferNext(WorkingSetID* toReturn, Status* erro
     WorkingSetMember* nextMember = _workingSet->get(nextMemberID);
 
     // The child stage may not dedup so we must dedup them ourselves.
-    if (_nextInterval->dedupCovering && nextMember->hasRecordId()) {
+    if (nextMember->hasRecordId()) {
         if (_seenDocuments.end() != _seenDocuments.find(nextMember->recordId)) {
             _workingSet->free(nextMemberID);
             return PlanStage::NEED_TIME;
@@ -212,7 +210,7 @@ PlanStage::StageState NearStage::bufferNext(WorkingSetID* toReturn, Status* erro
     nextMember->makeObjOwnedIfNeeded();
     _resultBuffer.push(SearchResult(nextMemberID, memberDistance));
 
-    // Store the member's RecordId, if available, for quick invalidation
+    // Store the member's RecordId, if available, for deduping.
     if (nextMember->hasRecordId()) {
         _seenDocuments.insert(std::make_pair(nextMember->recordId, nextMemberID));
     }
@@ -266,9 +264,10 @@ PlanStage::StageState NearStage::advanceNext(WorkingSetID* toReturn) {
     // The next document in _resultBuffer is in the search interval, so we can return it.
     _resultBuffer.pop();
 
-    // If we're returning something, take it out of our RecordId -> WSID map so that future
-    // calls to invalidate don't cause us to take action for a RecordId we're done with.
     *toReturn = resultID;
+
+    // If we're returning something, take it out of our RecordId -> WSID map. This keeps
+    // '_seenDocuments' in sync with '_resultBuffer'.
     WorkingSetMember* member = _workingSet->get(*toReturn);
     if (member->hasRecordId()) {
         _seenDocuments.erase(member->recordId);
@@ -284,23 +283,6 @@ bool NearStage::isEOF() {
     return SearchState_Finished == _searchState;
 }
 
-void NearStage::doInvalidate(OperationContext* opCtx, const RecordId& dl, InvalidationType type) {
-    // If a result is in _resultBuffer and has a RecordId it will be in _seenDocuments as
-    // well. It's safe to return the result w/o the RecordId, so just fetch the result.
-    stdx::unordered_map<RecordId, WorkingSetID, RecordId::Hasher>::iterator seenIt =
-        _seenDocuments.find(dl);
-
-    if (seenIt != _seenDocuments.end()) {
-        WorkingSetMember* member = _workingSet->get(seenIt->second);
-        verify(member->hasRecordId());
-        WorkingSetCommon::fetchAndInvalidateRecordId(opCtx, member, _collection);
-        verify(!member->hasRecordId());
-
-        // Don't keep it around in the seen map since there's no valid RecordId anymore
-        _seenDocuments.erase(seenIt);
-    }
-}
-
 unique_ptr<PlanStageStats> NearStage::getStats() {
     unique_ptr<PlanStageStats> ret = make_unique<PlanStageStats>(_commonStats, _stageType);
     ret->specific.reset(_specificStats.clone());
diff --git a/src/mongo/db/exec/near.h b/src/mongo/db/exec/near.h
index d5971aa3949..ab13d2e16b4 100644
--- a/src/mongo/db/exec/near.h
+++ b/src/mongo/db/exec/near.h
@@ -80,15 +80,8 @@ namespace mongo {
  * correctness does not depend on interval size.
  *
  * The child stage may return duplicate documents, so it is the responsibility of NearStage to
- * deduplicate. Every document in _resultBuffer is kept track of in _seenDocuments. When a
- * document is returned or invalidated, it is removed from _seenDocuments.
- *
- * TODO: If a document is indexed in multiple cells (Polygons, PolyLines, etc.), there is a
- * possibility that it will be returned more than once. Since doInvalidate() force fetches a
- * document and removes it from _seenDocuments, NearStage will not deduplicate if it encounters
- * another instance of this document. This will only occur if two cells for a document are in the
- * same interval and the invalidation occurs between the scan of the first cell and the second, so
- * NearStage no longer knows that it's seen this document before.
+ * deduplicate. Every document in _resultBuffer is kept track of in _seenDocuments. When a document
+ * is returned, it is removed from _seenDocuments.
  *
  * TODO: Right now the interface allows the nextCovering() to be adaptive, but doesn't allow
  * aborting and shrinking a covered range being buffered if we guess wrong.
@@ -102,8 +95,6 @@ public:
     bool isEOF() final;
     StageState doWork(WorkingSetID* out) final;
 
-    void doInvalidate(OperationContext* opCtx, const RecordId& dl, InvalidationType type) final;
-
     StageType stageType() const final;
     std::unique_ptr<PlanStageStats> getStats() final;
     const SpecificStats* getSpecificStats() const final;
@@ -169,9 +160,7 @@ private:
     // Generic state for progressive near search
     //
 
-    // Not owned here
     WorkingSet* const _workingSet;
-    // Not owned here, used for fetching buffered results before invalidation
     Collection* const _collection;
 
     // A progressive search works in stages of buffering and then advancing
@@ -182,8 +171,7 @@ private:
         SearchState_Finished
     } _searchState;
 
-    // May need to track disklocs from the child stage to do our own deduping, also to do
-    // invalidation of buffered results.
+    // Tracks RecordIds from the child stage to do our own deduping.
     stdx::unordered_map<RecordId, WorkingSetID, RecordId::Hasher> _seenDocuments;
 
     // Stats for the stage covering this interval
@@ -212,14 +200,9 @@ private:
  * A covered interval over which a portion of a near search can be run.
  */
 struct NearStage::CoveredInterval {
-    CoveredInterval(PlanStage* covering,
-                    bool dedupCovering,
-                    double minDistance,
-                    double maxDistance,
-                    bool inclusiveMax);
+    CoveredInterval(PlanStage* covering, double minDistance, double maxDistance, bool inclusiveMax);
 
     PlanStage* const covering;  // Owned in PlanStage::_children.
-    const bool dedupCovering;
 
     const double minDistance;
     const double maxDistance;
diff --git a/src/mongo/db/exec/or.cpp b/src/mongo/db/exec/or.cpp
index 89b811a2487..2d79d242ea2 100644
--- a/src/mongo/db/exec/or.cpp
+++ b/src/mongo/db/exec/or.cpp
@@ -120,23 +120,6 @@ PlanStage::StageState OrStage::doWork(WorkingSetID* out) {
     return childStatus;
 }
 
-void OrStage::doInvalidate(OperationContext* opCtx, const RecordId& dl, InvalidationType type) {
-    // TODO remove this since calling isEOF is illegal inside of doInvalidate().
-    if (isEOF()) {
-        return;
-    }
-
-    // If we see DL again it is not the same record as it once was so we still want to
-    // return it.
-    if (_dedup && INVALIDATION_DELETION == type) {
-        stdx::unordered_set<RecordId, RecordId::Hasher>::iterator it = _seen.find(dl);
-        if (_seen.end() != it) {
-            ++_specificStats.recordIdsForgotten;
-            _seen.erase(dl);
-        }
-    }
-}
-
 unique_ptr<PlanStageStats> OrStage::getStats() {
     _commonStats.isEOF = isEOF();
 
diff --git a/src/mongo/db/exec/or.h b/src/mongo/db/exec/or.h
index 0fd68249a5d..aa1a4b15015 100644
--- a/src/mongo/db/exec/or.h
+++ b/src/mongo/db/exec/or.h
@@ -37,11 +37,9 @@
 namespace mongo {
 
 /**
- * This stage outputs the union of its children.  It optionally deduplicates on RecordId.
+ * This stage outputs the union of its children. It optionally deduplicates on RecordId.
  *
  * Preconditions: Valid RecordId.
- *
- * If we're deduping, we may fail to dedup any invalidated RecordId properly.
  */
 class OrStage final : public PlanStage {
 public:
@@ -55,8 +53,6 @@ public:
 
     StageState doWork(WorkingSetID* out) final;
 
-    void doInvalidate(OperationContext* opCtx, const RecordId& dl, InvalidationType type) final;
-
     StageType stageType() const final {
         return STAGE_OR;
     }
@@ -78,7 +74,7 @@ private:
     size_t _currentChild;
 
     // True if we dedup on RecordId, false otherwise.
-    bool _dedup;
+    const bool _dedup;
 
     // Which RecordIds have we returned?
     stdx::unordered_set<RecordId, RecordId::Hasher> _seen;
diff --git a/src/mongo/db/exec/pipeline_proxy.h b/src/mongo/db/exec/pipeline_proxy.h
index 04ac712de71..3793fc7c3ba 100644
--- a/src/mongo/db/exec/pipeline_proxy.h
+++ b/src/mongo/db/exec/pipeline_proxy.h
@@ -68,12 +68,6 @@ public:
         MONGO_UNREACHABLE;
     }
 
-    void doInvalidate(OperationContext* opCtx, const RecordId& rid, InvalidationType type) final {
-        // A PlanExecutor with a PipelineProxyStage should be registered with the global cursor
-        // manager, so should not receive invalidations.
-        MONGO_UNREACHABLE;
-    }
-
     /**
      * Pass through the last oplog timestamp from the proxied pipeline.
      */
diff --git a/src/mongo/db/exec/plan_stage.cpp b/src/mongo/db/exec/plan_stage.cpp
index c532242264e..5cc653c5b8c 100644
--- a/src/mongo/db/exec/plan_stage.cpp
+++ b/src/mongo/db/exec/plan_stage.cpp
@@ -74,15 +74,6 @@ void PlanStage::restoreState() {
     doRestoreState();
 }
 
-void PlanStage::invalidate(OperationContext* opCtx, const RecordId& dl, InvalidationType type) {
-    ++_commonStats.invalidates;
-    for (auto&& child : _children) {
-        child->invalidate(opCtx, dl, type);
-    }
-
-    doInvalidate(opCtx, dl, type);
-}
-
 void PlanStage::detachFromOperationContext() {
     invariant(_opCtx);
     _opCtx = nullptr;
diff --git a/src/mongo/db/exec/plan_stage.h b/src/mongo/db/exec/plan_stage.h
index 33204c84839..896b8878e41 100644
--- a/src/mongo/db/exec/plan_stage.h
+++ b/src/mongo/db/exec/plan_stage.h
@@ -33,7 +33,6 @@
 
 #include "mongo/db/exec/plan_stats.h"
 #include "mongo/db/exec/working_set.h"
-#include "mongo/db/invalidation_type.h"
 
 namespace mongo {
 
@@ -246,21 +245,6 @@ public:
      */
     void reattachToOperationContext(OperationContext* opCtx);
 
-    /**
-     * Notifies a stage that a RecordId is going to be deleted (or in-place updated) so that the
-     * stage can invalidate or modify any state required to continue processing without this
-     * RecordId.
-     *
-     * Can only be called after a saveState but before a restoreState.
-     *
-     * The provided OperationContext should be used if any work needs to be performed during the
-     * invalidate (as the state of the stage must be saved before any calls to invalidate, the
-     * stage's own OperationContext is inactive during the invalidate and should not be used).
-     *
-     * Propagates to all children, then calls doInvalidate().
-     */
-    void invalidate(OperationContext* opCtx, const RecordId& dl, InvalidationType type);
-
     /*
      * Releases any resources held by this stage. It is an error to use a PlanStage in any way after
      * calling dispose(). Does not throw exceptions.
@@ -381,11 +365,6 @@ protected:
      */
     virtual void doDispose() {}
 
-    /**
-     * Does the stage-specific invalidation work.
-     */
-    virtual void doInvalidate(OperationContext* opCtx, const RecordId& dl, InvalidationType type) {}
-
     ClockSource* getClock() const;
 
     OperationContext* getOpCtx() const {
diff --git a/src/mongo/db/exec/plan_stats.h b/src/mongo/db/exec/plan_stats.h
index 434a4dda1a3..b7f0c7d9469 100644
--- a/src/mongo/db/exec/plan_stats.h
+++ b/src/mongo/db/exec/plan_stats.h
@@ -60,7 +60,6 @@ struct CommonStats {
           works(0),
           yields(0),
           unyields(0),
-          invalidates(0),
           advanced(0),
           needTime(0),
           needYield(0),
@@ -73,7 +72,6 @@ struct CommonStats {
     size_t works;
     size_t yields;
     size_t unyields;
-    size_t invalidates;
 
     // How many times was this state the return value of work(...)?
     size_t advanced;
@@ -138,20 +136,13 @@ private:
 };
 
 struct AndHashStats : public SpecificStats {
-    AndHashStats() : flaggedButPassed(0), flaggedInProgress(0), memUsage(0), memLimit(0) {}
+    AndHashStats() = default;
 
     SpecificStats* clone() const final {
         AndHashStats* specific = new AndHashStats(*this);
         return specific;
     }
 
-    // Invalidation counters.
-    // How many results had the AND fully evaluated but were invalidated?
-    size_t flaggedButPassed;
-
-    // How many results were mid-AND but got flagged?
-    size_t flaggedInProgress;
-
     // How many entries are in the map after each child?
     // child 'i' produced children[i].common.advanced RecordIds, of which mapAfterChild[i] were
     // intersections.
@@ -161,14 +152,14 @@ struct AndHashStats : public SpecificStats {
     // commonstats.advanced is how many passed.
 
     // What's our current memory usage?
-    size_t memUsage;
+    size_t memUsage = 0u;
 
     // What's our memory limit?
-    size_t memLimit;
+    size_t memLimit = 0u;
 };
 
 struct AndSortedStats : public SpecificStats {
-    AndSortedStats() : flagged(0) {}
+    AndSortedStats() = default;
 
     SpecificStats* clone() const final {
         AndSortedStats* specific = new AndSortedStats(*this);
@@ -177,9 +168,6 @@ struct AndSortedStats : public SpecificStats {
 
     // How many results from each child did not pass the AND?
     std::vector<size_t> failedAnd;
-
-    // How many results were flagged via invalidation?
-    size_t flagged;
 };
 
 struct CachedPlanStats : public SpecificStats {
@@ -281,17 +269,13 @@ struct CountScanStats : public SpecificStats {
 };
 
 struct DeleteStats : public SpecificStats {
-    DeleteStats() : docsDeleted(0), nInvalidateSkips(0) {}
+    DeleteStats() = default;
 
     SpecificStats* clone() const final {
         return new DeleteStats(*this);
     }
 
-    size_t docsDeleted;
-
-    // Invalidated documents can be force-fetched, causing the now invalid RecordId to
-    // be thrown out. The delete stage skips over any results which do not have a RecordId.
-    size_t nInvalidateSkips;
+    size_t docsDeleted = 0u;
 };
 
 struct DistinctScanStats : public SpecificStats {
@@ -345,7 +329,7 @@ struct EnsureSortedStats : public SpecificStats {
 };
 
 struct FetchStats : public SpecificStats {
-    FetchStats() : alreadyHasObj(0), forcedFetches(0), docsExamined(0) {}
+    FetchStats() = default;
 
     SpecificStats* clone() const final {
         FetchStats* specific = new FetchStats(*this);
@@ -353,13 +337,10 @@ struct FetchStats : public SpecificStats {
     }
 
     // Have we seen anything that already had an object?
-    size_t alreadyHasObj;
-
-    // How many records were we forced to fetch as the result of an invalidation?
-    size_t forcedFetches;
+    size_t alreadyHasObj = 0u;
 
     // The total number of full documents touched by the fetch stage.
-    size_t docsExamined;
+    size_t docsExamined = 0u;
 };
 
 struct GroupStats : public SpecificStats {
@@ -401,7 +382,6 @@ struct IndexScanStats : public SpecificStats {
           isUnique(false),
           dupsTested(0),
           dupsDropped(0),
-          seenInvalidated(0),
           keysExamined(0),
           seeks(0) {}
 
@@ -448,9 +428,6 @@ struct IndexScanStats : public SpecificStats {
     size_t dupsTested;
     size_t dupsDropped;
 
-    size_t seenInvalidated;
-    // TODO: we could track key sizes here.
-
     // Number of entries retrieved from the index during the scan.
     size_t keysExamined;
 
@@ -486,18 +463,15 @@ struct MultiPlanStats : public SpecificStats {
 };
 
 struct OrStats : public SpecificStats {
-    OrStats() : dupsTested(0), dupsDropped(0), recordIdsForgotten(0) {}
+    OrStats() = default;
 
     SpecificStats* clone() const final {
         OrStats* specific = new OrStats(*this);
         return specific;
     }
 
-    size_t dupsTested;
-    size_t dupsDropped;
-
-    // How many calls to invalidate(...) actually removed a RecordId from our deduping map?
-    size_t recordIdsForgotten;
+    size_t dupsTested = 0u;
+    size_t dupsDropped = 0u;
 };
 
 struct ProjectionStats : public SpecificStats {
@@ -513,42 +487,36 @@ struct ProjectionStats : public SpecificStats {
 };
 
 struct SortStats : public SpecificStats {
-    SortStats() : forcedFetches(0), memUsage(0), memLimit(0) {}
+    SortStats() = default;
 
     SpecificStats* clone() const final {
         SortStats* specific = new SortStats(*this);
         return specific;
     }
 
-    // How many records were we forced to fetch as the result of an invalidation?
-    size_t forcedFetches;
-
     // What's our current memory usage?
-    size_t memUsage;
+    size_t memUsage = 0u;
 
     // What's our memory limit?
-    size_t memLimit;
+    size_t memLimit = 0u;
 
     // The number of results to return from the sort.
-    size_t limit;
+    size_t limit = 0u;
 
     // The pattern according to which we are sorting.
     BSONObj sortPattern;
 };
 
 struct MergeSortStats : public SpecificStats {
-    MergeSortStats() : dupsTested(0), dupsDropped(0), forcedFetches(0) {}
+    MergeSortStats() = default;
 
     SpecificStats* clone() const final {
         MergeSortStats* specific = new MergeSortStats(*this);
         return specific;
     }
 
-    size_t dupsTested;
-    size_t dupsDropped;
-
-    // How many records were we forced to fetch as the result of an invalidation?
-    size_t forcedFetches;
+    size_t dupsTested = 0u;
+    size_t dupsDropped = 0u;
 
     // The pattern according to which we are sorting.
     BSONObj sortPattern;
@@ -610,8 +578,7 @@ struct UpdateStats : public SpecificStats {
           nModified(0),
           isDocReplacement(false),
           fastmodinsert(false),
-          inserted(false),
-          nInvalidateSkips(0) {}
+          inserted(false) {}
 
     SpecificStats* clone() const final {
         return new UpdateStats(*this);
@@ -636,11 +603,6 @@ struct UpdateStats : public SpecificStats {
 
     // The object that was inserted. This is an empty document if no insert was performed.
     BSONObj objInserted;
-
-    // Invalidated documents can be force-fetched, causing the now invalid RecordId to
-    // be thrown out. The update stage skips over any results which do not have the
-    // RecordId to update.
-    size_t nInvalidateSkips;
 };
 
 struct TextStats : public SpecificStats {
diff --git a/src/mongo/db/exec/projection.cpp b/src/mongo/db/exec/projection.cpp
index 7bcadd0675b..aabd85106a5 100644
--- a/src/mongo/db/exec/projection.cpp
+++ b/src/mongo/db/exec/projection.cpp
@@ -150,11 +150,6 @@ Status ProjectionStage::transform(WorkingSetMember* member) {
 
     BSONObjBuilder bob;
 
-    // Note that even if our fast path analysis is bug-free something that is
-    // covered might be invalidated and just be an obj.  In this case we just go
-    // through the SIMPLE_DOC path which is still correct if the covered data
-    // is not available.
-    //
     // SIMPLE_DOC implies that we expect an object so it's kind of redundant.
     if ((ProjectionStageParams::SIMPLE_DOC == _projImpl) || member->hasObj()) {
         // If we got here because of SIMPLE_DOC the planner shouldn't have messed up.
diff --git a/src/mongo/db/exec/queued_data_stage_test.cpp b/src/mongo/db/exec/queued_data_stage_test.cpp
index de09994b2a0..cac5a0c1625 100644
--- a/src/mongo/db/exec/queued_data_stage_test.cpp
+++ b/src/mongo/db/exec/queued_data_stage_test.cpp
@@ -90,7 +90,6 @@ TEST_F(QueuedDataStageTest, validateStats) {
     const CommonStats* stats = mock->getCommonStats();
     ASSERT_EQUALS(stats->yields, 0U);
     ASSERT_EQUALS(stats->unyields, 0U);
-    ASSERT_EQUALS(stats->invalidates, 0U);
     ASSERT_EQUALS(stats->works, 0U);
     ASSERT_EQUALS(stats->needTime, 0U);
     ASSERT_EQUALS(stats->advanced, 0U);
@@ -118,10 +117,6 @@ TEST_F(QueuedDataStageTest, validateStats) {
     mock->restoreState();
     ASSERT_EQUALS(stats->unyields, 1U);
 
-    // invalidates
-    const RecordId dl(0, 0);
-    mock->invalidate(NULL, dl, INVALIDATION_MUTATION);
-    ASSERT_EQUALS(stats->invalidates, 1U);
 
     // and now we are d1U, but must trigger EOF with getStats()
     ASSERT_FALSE(stats->isEOF);
diff --git a/src/mongo/db/exec/sort.cpp b/src/mongo/db/exec/sort.cpp
index 243e8bf7a05..97f3b469d65 100644
--- a/src/mongo/db/exec/sort.cpp
+++ b/src/mongo/db/exec/sort.cpp
@@ -121,19 +121,11 @@ PlanStage::StageState SortStage::doWork(WorkingSetID* out) {
         StageState code = child()->work(&id);
 
         if (PlanStage::ADVANCED == code) {
-            // Add it into the map for quick invalidation if it has a valid RecordId.
-            // A RecordId may be invalidated at any time (during a yield).  We need to get into
-            // the WorkingSet as quickly as possible to handle it.
             WorkingSetMember* member = _ws->get(id);
 
             // Planner must put a fetch before we get here.
             verify(member->hasObj());
 
-            // We might be sorting something that was invalidated at some point.
-            if (member->hasRecordId()) {
-                _wsidByRecordId[member->recordId] = id;
-            }
-
             SortableDataItem item;
             item.wsid = id;
 
@@ -177,40 +169,9 @@ PlanStage::StageState SortStage::doWork(WorkingSetID* out) {
     *out = _resultIterator->wsid;
     _resultIterator++;
 
-    // If we're returning something, take it out of our DL -> WSID map so that future
-    // calls to invalidate don't cause us to take action for a DL we're done with.
-    WorkingSetMember* member = _ws->get(*out);
-    if (member->hasRecordId()) {
-        _wsidByRecordId.erase(member->recordId);
-    }
-
     return PlanStage::ADVANCED;
 }
 
-void SortStage::doInvalidate(OperationContext* opCtx, const RecordId& dl, InvalidationType type) {
-    // If we have a deletion, we can fetch and carry on.
-    // If we have a mutation, it's easier to fetch and use the previous document.
-    // So, no matter what, fetch and keep the doc in play.
-
-    // _data contains indices into the WorkingSet, not actual data.  If a WorkingSetMember in
-    // the WorkingSet needs to change state as a result of a RecordId invalidation, it will still
-    // be at the same spot in the WorkingSet.  As such, we don't need to modify _data.
-    DataMap::iterator it = _wsidByRecordId.find(dl);
-
-    // If we're holding on to data that's got the RecordId we're invalidating...
-    if (_wsidByRecordId.end() != it) {
-        // Grab the WSM that we're nuking.
-        WorkingSetMember* member = _ws->get(it->second);
-        verify(member->recordId == dl);
-
-        WorkingSetCommon::fetchAndInvalidateRecordId(opCtx, member, _collection);
-
-        // Remove the RecordId from our set of active DLs.
-        _wsidByRecordId.erase(it);
-        ++_specificStats.forcedFetches;
-    }
-}
-
 unique_ptr<PlanStageStats> SortStage::getStats() {
     _commonStats.isEOF = isEOF();
     const size_t maxBytes = static_cast<size_t>(internalQueryExecMaxBlockingSortBytes.load());
@@ -306,13 +267,10 @@ void SortStage::addToBuffer(const SortableDataItem& item) {
         }
     }
 
-    // If the working set ID is valid, remove from
-    // RecordId invalidation map and free from working set.
+    // There was a buffered result which we can throw out because we are executing a sort with a
+    // limit, and the result is now known not to be in the top k set. Free the working set member
+    // associated with 'wsidToFree'.
     if (wsidToFree != WorkingSet::INVALID_ID) {
-        WorkingSetMember* member = _ws->get(wsidToFree);
-        if (member->hasRecordId()) {
-            _wsidByRecordId.erase(member->recordId);
-        }
         _ws->free(wsidToFree);
     }
 }
diff --git a/src/mongo/db/exec/sort.h b/src/mongo/db/exec/sort.h
index 3418cea9447..e3793b20c62 100644
--- a/src/mongo/db/exec/sort.h
+++ b/src/mongo/db/exec/sort.h
@@ -77,8 +77,6 @@ public:
     bool isEOF() final;
     StageState doWork(WorkingSetID* out) final;
 
-    void doInvalidate(OperationContext* opCtx, const RecordId& dl, InvalidationType type) final;
-
     StageType stageType() const final {
         return STAGE_SORT;
     }
@@ -170,10 +168,6 @@ private:
     // Iterates through _data post-sort returning it.
     std::vector<SortableDataItem>::iterator _resultIterator;
 
-    // We buffer a lot of data and we want to look it up by RecordId quickly upon invalidation.
-    typedef stdx::unordered_map<RecordId, WorkingSetID, RecordId::Hasher> DataMap;
-    DataMap _wsidByRecordId;
-
     SortStats _specificStats;
 
     // The usage in bytes of all buffered data that we're sorting.
diff --git a/src/mongo/db/exec/subplan.cpp b/src/mongo/db/exec/subplan.cpp
index 00c4c5a053c..d6a78a3853e 100644
--- a/src/mongo/db/exec/subplan.cpp
+++ b/src/mongo/db/exec/subplan.cpp
@@ -252,9 +252,9 @@ Status SubplanStage::choosePlanForSubqueries(PlanYieldPolicy* yieldPolicy) {
 
             // We pass the SometimesCache option to the MPS because the SubplanStage currently does
             // not use the CachedPlanStage's eviction mechanism. We therefore are more conservative
-            // about putting a potentially bad plan into the cache in the subplan path.
-            // We temporarily add the MPS to _children to ensure that we pass down all
-            // save/restore/invalidate messages that can be generated if pickBestPlan yields.
+            // about putting a potentially bad plan into the cache in the subplan path.  We
+            // temporarily add the MPS to _children to ensure that we pass down all save/restore
+            // messages that can be generated if pickBestPlan yields.
             invariant(_children.empty());
             _children.emplace_back(
                 stdx::make_unique<MultiPlanStage>(getOpCtx(),
diff --git a/src/mongo/db/exec/text_or.cpp b/src/mongo/db/exec/text_or.cpp
index 19873825342..b4070bb3a3a 100644
--- a/src/mongo/db/exec/text_or.cpp
+++ b/src/mongo/db/exec/text_or.cpp
@@ -104,17 +104,6 @@ void TextOrStage::doReattachToOperationContext() {
         _recordCursor->reattachToOperationContext(getOpCtx());
 }
 
-void TextOrStage::doInvalidate(OperationContext* opCtx, const RecordId& dl, InvalidationType type) {
-    // Remove the RecordID from the ScoreMap.
-    ScoreMap::iterator scoreIt = _scores.find(dl);
-    if (scoreIt != _scores.end()) {
-        if (scoreIt == _scoreIterator) {
-            _scoreIterator++;
-        }
-        _scores.erase(scoreIt);
-    }
-}
-
 std::unique_ptr<PlanStageStats> TextOrStage::getStats() {
     _commonStats.isEOF = isEOF();
 
diff --git a/src/mongo/db/exec/text_or.h b/src/mongo/db/exec/text_or.h
index 4df4563aefd..41bc808b880 100644
--- a/src/mongo/db/exec/text_or.h
+++ b/src/mongo/db/exec/text_or.h
@@ -87,7 +87,6 @@ public:
     void doRestoreState() final;
     void doDetachFromOperationContext() final;
     void doReattachToOperationContext() final;
-    void doInvalidate(OperationContext* opCtx, const RecordId& dl, InvalidationType type) final;
 
     StageType stageType() const final {
         return STAGE_TEXT_OR;
diff --git a/src/mongo/db/exec/update.cpp b/src/mongo/db/exec/update.cpp
index b97d3209e80..cac39a29729 100644
--- a/src/mongo/db/exec/update.cpp
+++ b/src/mongo/db/exec/update.cpp
@@ -569,11 +569,7 @@ PlanStage::StageState UpdateStage::doWork(WorkingSetID* out) {
         // it.
         ScopeGuard memberFreer = MakeGuard(&WorkingSet::free, _ws, id);
 
-        if (!member->hasRecordId()) {
-            // We expect to be here because of an invalidation causing a force-fetch.
-            ++_specificStats.nInvalidateSkips;
-            return PlanStage::NEED_TIME;
-        }
+        invariant(member->hasRecordId());
         recordId = member->recordId;
 
         // Updates can't have projections. This means that covering analysis will always add
diff --git a/src/mongo/db/exec/working_set.cpp b/src/mongo/db/exec/working_set.cpp
index a66a184e440..0882328c285 100644
--- a/src/mongo/db/exec/working_set.cpp
+++ b/src/mongo/db/exec/working_set.cpp
@@ -157,7 +157,7 @@ bool WorkingSetMember::hasOwnedObj() const {
 }
 
 void WorkingSetMember::makeObjOwnedIfNeeded() {
-    if (supportsDocLocking() && _state == RID_AND_OBJ && !obj.value().isOwned()) {
+    if (_state == RID_AND_OBJ && !obj.value().isOwned()) {
         obj.setValue(obj.value().getOwned());
     }
 }
diff --git a/src/mongo/db/exec/working_set.h b/src/mongo/db/exec/working_set.h
index a2a719208bb..9cc70750638 100644
--- a/src/mongo/db/exec/working_set.h
+++ b/src/mongo/db/exec/working_set.h
@@ -232,8 +232,9 @@ public:
         // BSONObj might be owned or unowned.
         RID_AND_OBJ,
 
-        // RecordId has been invalidated, or the obj doesn't correspond to an on-disk document
-        // anymore (e.g. is a computed expression).
+        // The WSM doesn't correspond to an on-disk document anymore (e.g. is a computed
+        // expression). Since it doesn't correspond to a stored document, a WSM in this state has an
+        // owned BSONObj, but no record id.
         OWNED_OBJ,
     };
 
@@ -265,7 +266,8 @@ public:
      * Ensures that 'obj' of a WSM in the RID_AND_OBJ state is owned BSON. It is a no-op if the WSM
      * is in a different state or if 'obj' is already owned.
      *
-     * It is also a no-op if the active storage engine doesn't support document-level concurrency.
+     * It is illegal for unowned BSON to survive a yield, so this must be called on any working set
+     * members which may stay alive across yield points.
      */
     void makeObjOwnedIfNeeded();
 
diff --git a/src/mongo/db/exec/working_set_common.cpp b/src/mongo/db/exec/working_set_common.cpp
index cdd4b2227eb..4439af31ba8 100644
--- a/src/mongo/db/exec/working_set_common.cpp
+++ b/src/mongo/db/exec/working_set_common.cpp
@@ -39,38 +39,7 @@
 
 namespace mongo {
 
-// static
-bool WorkingSetCommon::fetchAndInvalidateRecordId(OperationContext* opCtx,
-                                                  WorkingSetMember* member,
-                                                  const Collection* collection) {
-    // Already in our desired state.
-    if (member->getState() == WorkingSetMember::OWNED_OBJ) {
-        return true;
-    }
-
-    // We can't do anything without a RecordId.
-    if (!member->hasRecordId()) {
-        return false;
-    }
-
-    // Do the fetch, invalidate the DL.
-    member->obj = collection->docFor(opCtx, member->recordId);
-    member->obj.setValue(member->obj.value().getOwned());
-    member->recordId = RecordId();
-    member->transitionToOwnedObj();
-
-    return true;
-}
-
 void WorkingSetCommon::prepareForSnapshotChange(WorkingSet* workingSet) {
-    if (!supportsDocLocking()) {
-        // Non doc-locking storage engines use invalidations, so we don't need to examine the
-        // buffered working set ids. But we do need to clear the set of ids in order to keep our
-        // memory utilization in check.
-        workingSet->getAndClearYieldSensitiveIds();
-        return;
-    }
-
     for (auto id : workingSet->getAndClearYieldSensitiveIds()) {
         if (workingSet->isFree(id)) {
             continue;
diff --git a/src/mongo/db/exec/working_set_common.h b/src/mongo/db/exec/working_set_common.h
index 61c0e04af15..5f35dffb878 100644
--- a/src/mongo/db/exec/working_set_common.h
+++ b/src/mongo/db/exec/working_set_common.h
@@ -41,15 +41,6 @@ class SeekableRecordCursor;
 class WorkingSetCommon {
 public:
     /**
-     * Get an owned copy of the BSONObj the WSM refers to.
-     * Requires either a valid BSONObj or valid RecordId.
-     * Returns true if the fetch and invalidate succeeded, false otherwise.
-     */
-    static bool fetchAndInvalidateRecordId(OperationContext* opCtx,
-                                           WorkingSetMember* member,
-                                           const Collection* collection);
-
-    /**
      * This must be called as part of "saveState" operations after all nodes in the tree save their
      * state.
      *
diff --git a/src/mongo/db/exec/write_stage_common.cpp b/src/mongo/db/exec/write_stage_common.cpp
index 8d48801f2db..570e1c3ec4f 100644
--- a/src/mongo/db/exec/write_stage_common.cpp
+++ b/src/mongo/db/exec/write_stage_common.cpp
@@ -46,8 +46,13 @@ bool ensureStillMatches(const Collection* collection,
                         const CanonicalQuery* cq) {
     // If the snapshot changed, then we have to make sure we have the latest copy of the doc and
     // that it still matches.
+    //
+    // Storage engines that don't support document-level concurrency also do not track snapshot ids.
+    // Those storage engines always need to check whether the document still matches, as the
+    // document we are planning to delete may have already been deleted or updated during yield.
     WorkingSetMember* member = ws->get(id);
-    if (opCtx->recoveryUnit()->getSnapshotId() != member->obj.snapshotId()) {
+    if (!supportsDocLocking() ||
+        opCtx->recoveryUnit()->getSnapshotId() != member->obj.snapshotId()) {
         std::unique_ptr<SeekableRecordCursor> cursor(collection->getCursor(opCtx));
 
         if (!WorkingSetCommon::fetch(opCtx, ws, id, cursor)) {