SERVER-15665 MMAP v1 requests yields during page faults via NEED_FETCH

1 files changed, 12 insertions, 3 deletions

diff --git a/src/mongo/db/exec/near.cpp b/src/mongo/db/exec/near.cpp
index a1c96e80cf4..a8050e7e89f 100644
--- a/src/mongo/db/exec/near.cpp
+++ b/src/mongo/db/exec/near.cpp
@@ -76,7 +76,7 @@ namespace mongo {
             return PlanStage::NEED_TIME;
         }
 
-        invariant(state != PlanStage::ADVANCED);
+        invariant(state != PlanStage::ADVANCED && state != PlanStage::NEED_FETCH);
 
         // Propagate NEED_TIME or errors upward.
         return state;
@@ -105,7 +105,7 @@ namespace mongo {
             nextState = initNext();
         }
         else if (SearchState_Buffering == _searchState) {
-            nextState = bufferNext(&error);
+            nextState = bufferNext(&toReturn, &error);
         }
         else if (SearchState_Advancing == _searchState) {
             nextState = advanceNext(&toReturn);
@@ -126,6 +126,10 @@ namespace mongo {
             *out = toReturn;
             ++_stats->common.advanced;
         }
+        else if (PlanStage::NEED_FETCH == nextState) {
+            *out = toReturn;
+            ++_stats->common.needFetch;
+        }
         else if (PlanStage::NEED_TIME == nextState) {
             ++_stats->common.needTime;
         }
@@ -154,7 +158,8 @@ namespace mongo {
         double distance;
     };
 
-    PlanStage::StageState NearStage::bufferNext(Status* error) {
+    // Set "toReturn" when NEED_FETCH.
+    PlanStage::StageState NearStage::bufferNext(WorkingSetID* toReturn, Status* error) {
 
         //
         // Try to retrieve the next covered member
@@ -199,6 +204,10 @@ namespace mongo {
             *error = WorkingSetCommon::getMemberStatus(*_workingSet->get(nextMemberID));
             return intervalState;
         }
+        else if (PlanStage::NEED_FETCH == intervalState) {
+            *toReturn = nextMemberID;
+            return intervalState;
+        }
         else if (PlanStage::ADVANCED != intervalState) {
             return intervalState;
         }