fix exists with index SERVER-708

3 files changed, 26 insertions, 2 deletions

diff --git a/db/matcher.cpp b/db/matcher.cpp
index e5eb3f3cb75..91fff7fcea1 100644
--- a/db/matcher.cpp
+++ b/db/matcher.cpp
@@ -139,8 +139,10 @@ namespace mongo {
     {
         _needRecord = ! ( 
                          _docMatcher.keyMatch() && 
-                         _keyMatcher.jsobj.nFields() == _docMatcher.jsobj.nFields()
+                         _keyMatcher.jsobj.nFields() == _docMatcher.jsobj.nFields() &&
+                         ! _keyMatcher.hasType( BSONObj::opEXISTS )
                           );
+
     }
     
     bool CoveredIndexMatcher::matches(const BSONObj &key, const DiskLoc &recLoc , MatchDetails * details ) {
@@ -148,7 +150,7 @@ namespace mongo {
             details->reset();
         
         if ( _keyMatcher.keyMatch() ) {
-            if ( !_keyMatcher.matches(key) ) {
+            if ( !_keyMatcher.matches(key, details ) ){
                 return false;
             }
         }
@@ -710,6 +712,13 @@ namespace mongo {
         return true;
     }
 
+    bool Matcher::hasType( BSONObj::MatchType type ) const {
+        for ( unsigned i=0; i<basics.size() ; i++ )
+            if ( basics[i].compareOp == type )
+                return true;
+        return false;
+    }
+
     struct JSObj1 js1;
 
 #pragma pack(1)
diff --git a/db/matcher.h b/db/matcher.h
index da68cf4f358..72d6ec59c33 100644
--- a/db/matcher.h
+++ b/db/matcher.h
@@ -140,6 +140,7 @@ namespace mongo {
 
         bool atomic() const { return _atomic; }
 
+        bool hasType( BSONObj::MatchType type ) const;
     private:
         void addBasic(const BSONElement &e, int c, bool isNot) {
             // TODO May want to selectively ignore these element types based on op type.
diff --git a/jstests/exists2.js b/jstests/exists2.js
new file mode 100644
index 00000000000..a9b4d1ed7b3
--- /dev/null
+++ b/jstests/exists2.js
@@ -0,0 +1,14 @@
+
+t = db.exists2;
+t.drop();
+
+t.save( { a : 1 , b : 1 } )
+t.save( { a : 1 , b : 1 , c : 1 } )
+
+assert.eq( 2 , t.find().itcount() , "A1" );
+assert.eq( 2 , t.find( { a : 1 , b : 1 } ).itcount() , "A2" );
+assert.eq( 1 , t.find( { a : 1 , b : 1 , c : { "$exists" : true } } ).itcount() , "A3" );
+
+t.ensureIndex( { a : 1 , b : 1 , c : 1 } )
+assert.eq( 1 , t.find( { a : 1 , b : 1 , c : { "$exists" : true } } ).itcount() , "B1" );
+