SERVER-17011 add EnsureSorted stage

Preserves the sort order for 'ntoreturn hack' plans.

1 files changed, 12 insertions, 0 deletions

diff --git a/src/mongo/db/exec/plan_stats.h b/src/mongo/db/exec/plan_stats.h
index 14e07391920..7587aa47da8 100644
--- a/src/mongo/db/exec/plan_stats.h
+++ b/src/mongo/db/exec/plan_stats.h
@@ -298,6 +298,18 @@ struct DistinctScanStats : public SpecificStats {
     BSONObj indexBounds;
 };
 
+struct EnsureSortedStats : public SpecificStats {
+    EnsureSortedStats() : nDropped(0) {}
+
+    SpecificStats* clone() const final {
+        EnsureSortedStats* specific = new EnsureSortedStats(*this);
+        return specific;
+    }
+
+    // The number of out-of-order results that were dropped.
+    long long nDropped;
+};
+
 struct FetchStats : public SpecificStats {
     FetchStats() : alreadyHasObj(0), forcedFetches(0), docsExamined(0) {}