SERVER-4400 don't record query plan if a client cursor yield recovery fails; this patch violates the QueryOp abstraction a bit, but we are replacing that code soon anyway

3 files changed, 49 insertions, 5 deletions

diff --git a/db/ops/query.cpp b/db/ops/query.cpp
index cf4dc98a649..36f25367163 100644
--- a/db/ops/query.cpp
+++ b/db/ops/query.cpp
@@ -221,7 +221,8 @@ namespace mongo {
             _skip( spec["skip"].numberLong() ),
             _limit( spec["limit"].numberLong() ),
             _nscanned(),
-            _bc() {
+            _bc(),
+            _yieldRecoveryFailed() {
         }
 
         virtual void _init() {
@@ -251,6 +252,7 @@ namespace mongo {
 
         virtual void recoverFromYield() {
             if ( _cc && !ClientCursor::recoverFromYield( _yieldData ) ) {
+                _yieldRecoveryFailed = true;
                 _c.reset();
                 _cc.reset();
 
@@ -309,7 +311,7 @@ namespace mongo {
         }
         long long count() const { return _count; }
         virtual bool mayRecordPlan() const {
-            return ( _myCount > _limit / 2 ) || ( complete() && !stopRequested() );
+            return !_yieldRecoveryFailed && ( ( _myCount > _limit / 2 ) || ( complete() && !stopRequested() ) );
         }
     private:
 
@@ -343,6 +345,7 @@ namespace mongo {
 
         ClientCursor::CleanupPointer _cc;
         ClientCursor::YieldData _yieldData;
+        bool _yieldRecoveryFailed;
     };
 
     /* { count: "collectionname"[, query: <query>] }
@@ -474,7 +477,8 @@ namespace mongo {
             _oplogReplay( pq.hasOption( QueryOption_OplogReplay) ),
             _response( response ),
             _eb( eb ),
-            _curop( curop )
+            _curop( curop ),
+            _yieldRecoveryFailed()
         {}
 
         virtual void _init() {
@@ -531,6 +535,7 @@ namespace mongo {
                 _findingStartCursor->recoverFromYield();
             }
             else if ( _cc && !ClientCursor::recoverFromYield( _yieldData ) ) {
+                _yieldRecoveryFailed = true;
                 _c.reset();
                 _cc.reset();
                 _so.reset();
@@ -723,7 +728,7 @@ namespace mongo {
         }
 
         virtual bool mayRecordPlan() const {
-            return ( _pq.getNumToReturn() != 1 ) && ( ( _n > _pq.getNumToReturn() / 2 ) || ( complete() && !stopRequested() ) );
+            return !_yieldRecoveryFailed && ( _pq.getNumToReturn() != 1 ) && ( ( _n > _pq.getNumToReturn() / 2 ) || ( complete() && !stopRequested() ) );
         }
 
         virtual QueryOp *_createChild() const {
@@ -791,6 +796,8 @@ namespace mongo {
         ExplainBuilder &_eb;
         CurOp &_curop;
         OpTime _slaveReadTill;
+
+        bool _yieldRecoveryFailed;
     };
 
     /* run a query -- includes checking for and running a Command \
diff --git a/db/queryoptimizercursor.cpp b/db/queryoptimizercursor.cpp
index 92608895dcf..80041dcc92d 100644
--- a/db/queryoptimizercursor.cpp
+++ b/db/queryoptimizercursor.cpp
@@ -35,7 +35,9 @@ namespace mongo {
          * @param aggregateNscanned - shared int counting total nscanned for
          * query ops for all cursors.
          */
-        QueryOptimizerCursorOp( long long &aggregateNscanned ) : _matchCount(), _mustAdvance(), _nscanned(), _aggregateNscanned( aggregateNscanned ) {}
+        QueryOptimizerCursorOp( long long &aggregateNscanned ) :
+        _matchCount(), _mustAdvance(), _nscanned(), _capped(),
+        _aggregateNscanned( aggregateNscanned ), _yieldRecoveryFailed() {}
         
         virtual void _init() {
             if ( qp().scanAndOrderRequired() ) {
@@ -64,6 +66,7 @@ namespace mongo {
         
         virtual void recoverFromYield() {
             if ( _cc && !ClientCursor::recoverFromYield( _yieldData ) ) {
+                _yieldRecoveryFailed = true;
                 _c.reset();
                 _cc.reset();
                 
@@ -134,6 +137,7 @@ namespace mongo {
         DiskLoc _posBeforeYield;
         ClientCursor::YieldData _yieldData;
         long long &_aggregateNscanned;
+        bool _yieldRecoveryFailed;
     };
     
     /**
diff --git a/jstests/queryoptimizer3.js b/jstests/queryoptimizer3.js
new file mode 100644
index 00000000000..76bc5b6be30
--- /dev/null
+++ b/jstests/queryoptimizer3.js
@@ -0,0 +1,33 @@
+// Check cases where index scans are aborted due to the collection being dropped.
+
+t = db.jstests_queryoptimizer3;
+t.drop();
+
+p = startParallelShell( 'for( i = 0; i < 400; ++i ) { sleep( 50 ); db.jstests_queryoptimizer3.drop(); }' );
+
+for( i = 0; i < 100; ++i ) {
+    t.drop();
+    t.ensureIndex({a:1});
+    t.ensureIndex({b:1});
+    for( j = 0; j < 100; ++j ) {
+        t.save({a:j,b:j});
+    }
+    m = i % 5;
+    if ( m == 0 ) {
+        t.count({a:{$gte:0},b:{$gte:0}});        
+    }
+    else if ( m == 1 ) {
+        t.find({a:{$gte:0},b:{$gte:0}}).itcount();
+    }
+    else if ( m == 2 ) {
+        t.remove({a:{$gte:0},b:{$gte:0}});
+    }
+    else if ( m == 3 ) {
+        t.update({a:{$gte:0},b:{$gte:0}},{});
+    }
+    else if ( m == 4 ) {
+        t.distinct('x',{a:{$gte:0},b:{$gte:0}});
+    }
+}
+
+p();