Revert "SERVER-2094 distinct only wants the field it's distinct-ing over"

This reverts commit 3b5b31f42d390e9da23f66e78a300d997ae653c4.

2 files changed, 12 insertions, 16 deletions

diff --git a/jstests/distinct_index1.js b/jstests/distinct_index1.js
index e6687d7b762..9e2089858b9 100644
--- a/jstests/distinct_index1.js
+++ b/jstests/distinct_index1.js
@@ -37,11 +37,14 @@ t.ensureIndex( { a : 1 } )
 x = d( "a" );
 assert.eq( 1000 , x.stats.n , "BA1" )
 assert.eq( 1000 , x.stats.nscanned , "BA2" )
+// QUERY_MIGRATION: pending projection support
+//assert.eq( 0 , x.stats.nscannedObjects , "BA3" )
 
 x = d( "a" , { a : { $gt : 5 } } );
 assert.eq( 398 , x.stats.n , "BB1" )
 assert.eq( 398 , x.stats.nscanned , "BB2" )
-assert.eq( 0 , x.stats.nscannedObjects , "BB3" )
+// QUERY_MIGRATION: pending projection support
+// assert.eq( 0 , x.stats.nscannedObjects , "BB3" )
 
 x = d( "b" , { a : { $gt : 5 } } );
 assert.eq( 398 , x.stats.n , "BC1" )
@@ -52,5 +55,10 @@ assert.eq( 398 , x.stats.nscannedObjects , "BC3" )
 t.dropIndexes();
 t.ensureIndex( { a : 1, b : 1 } );
 x = d( "b" , { a : { $gt : 5 }, b : { $gt : 5 } } );
+// QUERY_MIGRATION: we show the actual cursor used
+// assert.eq( "QueryOptimizerCursor", x.stats.cursor );
 assert.eq( 171 , x.stats.n )
-assert.eq( 0 , x.stats.nscannedObjects , "BB3" )
+// QUERY_MIGRATION: our nscanned is lower...
+// assert.eq( 275 , x.stats.nscanned )
+// Disable temporarily - exact value doesn't matter.
+// assert.eq( 266 , x.stats.nscannedObjects )
diff --git a/src/mongo/db/commands/distinct.cpp b/src/mongo/db/commands/distinct.cpp
index 503beedf4dc..f22a407a941 100644
--- a/src/mongo/db/commands/distinct.cpp
+++ b/src/mongo/db/commands/distinct.cpp
@@ -100,15 +100,8 @@ namespace mongo {
             }
 
             CanonicalQuery* cq;
-
-            // We only care about the field that we're projecting over.  Have to drop the _id field
-            // explicitly because those are .find() semantics.
-            //
-            // Applying a projection allows the planner to try to give us covered plans.
-            BSONObj projection = BSON("_id" << 0 << key << 1);
-
-            // Apply a projection of the key.  Empty BSONObj() is for the sort.
-            if (!CanonicalQuery::canonicalize(ns, query, BSONObj(), projection, &cq).isOK()) {
+            // XXX: project out just the field we're distinct-ing.  May be covered...
+            if (!CanonicalQuery::canonicalize(ns, query, &cq).isOK()) {
                 uasserted(17215, "Can't canonicalize query " + query.toString());
                 return 0;
             }
@@ -127,11 +120,6 @@ namespace mongo {
             BSONObj obj;
             Runner::RunnerState state;
             while (Runner::RUNNER_ADVANCED == (state = runner->getNext(&obj, NULL))) {
-                // Distinct expands arrays.
-                //
-                // If our query is covered, each value of the key should be in the index key and
-                // available to us without this.  If a collection scan is providing the data, we may
-                // have to expand an array.
                 BSONElementSet elts;
                 obj.getFieldsDotted(key, elts);