SERVER-13084: remove many cc() calls from query/exec world

64 files changed, 317 insertions, 265 deletions

diff --git a/src/mongo/db/auth/authz_manager_external_state_d.cpp b/src/mongo/db/auth/authz_manager_external_state_d.cpp
index 6263a0d67f0..388644f9bdc 100644
--- a/src/mongo/db/auth/authz_manager_external_state_d.cpp
+++ b/src/mongo/db/auth/authz_manager_external_state_d.cpp
@@ -108,7 +108,7 @@ namespace mongo {
 
         Client::ReadContext ctx(collectionName.ns());
         BSONObj found;
-        if (Helpers::findOne(collectionName.ns(),
+        if (Helpers::findOne(ctx.ctx().db()->getCollection(collectionName),
                              query,
                              found)) {
             *result = found.getOwned();
diff --git a/src/mongo/db/catalog/collection.h b/src/mongo/db/catalog/collection.h
index f633a5444cf..4c84a8370df 100644
--- a/src/mongo/db/catalog/collection.h
+++ b/src/mongo/db/catalog/collection.h
@@ -139,8 +139,9 @@ namespace mongo {
          * canonical to get all would be
          * getIterator( DiskLoc(), false, CollectionScanParams::FORWARD )
          */
-        RecordIterator* getIterator( const DiskLoc& start, bool tailable,
-                                     const CollectionScanParams::Direction& dir) const;
+        RecordIterator* getIterator( const DiskLoc& start = DiskLoc(),
+                                     bool tailable = false,
+                                     const CollectionScanParams::Direction& dir = CollectionScanParams::FORWARD ) const;
 
 
         /**
diff --git a/src/mongo/db/catalog/database.cpp b/src/mongo/db/catalog/database.cpp
index 5f8e530202d..ece0e04db27 100644
--- a/src/mongo/db/catalog/database.cpp
+++ b/src/mongo/db/catalog/database.cpp
@@ -308,33 +308,32 @@ namespace mongo {
     void Database::clearTmpCollections() {
 
         Lock::assertWriteLocked( _name );
-        Client::Context ctx( _name );
-
-        string systemNamespaces =  _name + ".system.namespaces";
 
         // Note: we build up a toDelete vector rather than dropping the collection inside the loop
         // to avoid modifying the system.namespaces collection while iterating over it since that
         // would corrupt the cursor.
         vector<string> toDelete;
-        auto_ptr<Runner> runner(InternalPlanner::collectionScan(systemNamespaces));
-        BSONObj nsObj;
-        Runner::RunnerState state;
-        while (Runner::RUNNER_ADVANCED == (state = runner->getNext(&nsObj, NULL))) {
-            BSONElement e = nsObj.getFieldDotted( "options.temp" );
-            if ( !e.trueValue() )
-                continue;
+        {
+            Collection* coll = getCollection( _namespacesName );
+            if ( coll ) {
+                scoped_ptr<RecordIterator> it( coll->getIterator() );
+                DiskLoc next;
+                while ( !( next = it->getNext() ).isNull() ) {
+                    BSONObj nsObj = coll->docFor( next );
 
-            string ns = nsObj["name"].String();
+                    BSONElement e = nsObj.getFieldDotted( "options.temp" );
+                    if ( !e.trueValue() )
+                        continue;
 
-            // Do not attempt to drop indexes
-            if ( !NamespaceString::normal(ns.c_str()) )
-                continue;
+                    string ns = nsObj["name"].String();
 
-            toDelete.push_back(ns);
-        }
+                    // Do not attempt to drop indexes
+                    if ( !NamespaceString::normal(ns.c_str()) )
+                        continue;
 
-        if (Runner::RUNNER_EOF != state) {
-            warning() << "Internal error while reading collection " << systemNamespaces << endl;
+                    toDelete.push_back(ns);
+                }
+            }
         }
 
         for (size_t i=0; i < toDelete.size(); i++) {
@@ -509,7 +508,9 @@ namespace mongo {
 
         // move index namespaces
         BSONObj oldIndexSpec;
-        while( Helpers::findOne( _indexesName, BSON( "ns" << fromNS ), oldIndexSpec ) ) {
+        while( Helpers::findOne( getCollection( _indexesName ),
+                                 BSON( "ns" << fromNS ),
+                                 oldIndexSpec ) ) {
             oldIndexSpec = oldIndexSpec.getOwned();
 
             BSONObj newIndexSpec;
@@ -615,7 +616,9 @@ namespace mongo {
         {
 
             BSONObj oldSpec;
-            if ( !Helpers::findOne( _namespacesName, BSON( "name" << fromNS ), oldSpec ) )
+            if ( !Helpers::findOne( getCollection( _namespacesName ),
+                                    BSON( "name" << fromNS ),
+                                    oldSpec ) )
                 return Status( ErrorCodes::InternalError, "can't find system.namespaces entry" );
 
             BSONObjBuilder b;
diff --git a/src/mongo/db/catalog/index_catalog.cpp b/src/mongo/db/catalog/index_catalog.cpp
index 6f900fca99c..6376ea048d7 100644
--- a/src/mongo/db/catalog/index_catalog.cpp
+++ b/src/mongo/db/catalog/index_catalog.cpp
@@ -255,7 +255,8 @@ namespace mongo {
 
         fassert(16737, dfh->versionMinor == PDFILE_VERSION_MINOR_22_AND_OLDER);
 
-        auto_ptr<Runner> runner( InternalPlanner::collectionScan( db->_indexesName ) );
+        auto_ptr<Runner> runner( InternalPlanner::collectionScan( db->_indexesName,
+                                                                  db->getCollection( db->_indexesName ) ) );
 
         BSONObj index;
         Runner::RunnerState state;
diff --git a/src/mongo/db/catalog/index_create.cpp b/src/mongo/db/catalog/index_create.cpp
index 744ed46d96d..44e1fa157c8 100644
--- a/src/mongo/db/catalog/index_create.cpp
+++ b/src/mongo/db/catalog/index_create.cpp
@@ -104,7 +104,7 @@ namespace mongo {
         unsigned long long n = 0;
         unsigned long long numDropped = 0;
 
-        auto_ptr<Runner> runner(InternalPlanner::collectionScan(ns));
+        auto_ptr<Runner> runner(InternalPlanner::collectionScan(ns,collection));
 
         // We're not delegating yielding to the runner because we need to know when a yield
         // happens.
diff --git a/src/mongo/db/commands/collection_to_capped.cpp b/src/mongo/db/commands/collection_to_capped.cpp
index e1fe3c6c1c6..d7304afc31d 100644
--- a/src/mongo/db/commands/collection_to_capped.cpp
+++ b/src/mongo/db/commands/collection_to_capped.cpp
@@ -81,6 +81,7 @@ namespace mongo {
                                     ( toCollection->storageSize() * 2 ) );
 
         scoped_ptr<Runner> runner( InternalPlanner::collectionScan(fromNs,
+                                                                   fromCollection,
                                                                    InternalPlanner::FORWARD ) );
 
 
diff --git a/src/mongo/db/commands/dbhash.cpp b/src/mongo/db/commands/dbhash.cpp
index 227473dabd8..61e75e61e61 100644
--- a/src/mongo/db/commands/dbhash.cpp
+++ b/src/mongo/db/commands/dbhash.cpp
@@ -98,7 +98,8 @@ namespace mongo {
                                                     InternalPlanner::IXSCAN_FETCH));
         }
         else if ( collection->details()->isCapped() ) {
-            runner.reset(InternalPlanner::collectionScan(fullCollectionName));
+            runner.reset(InternalPlanner::collectionScan(fullCollectionName,
+                                                         collection));
         }
         else {
             log() << "can't find _id index for: " << fullCollectionName << endl;
diff --git a/src/mongo/db/commands/find_and_modify.cpp b/src/mongo/db/commands/find_and_modify.cpp
index 6ec6f6f87c5..072bb2d8000 100644
--- a/src/mongo/db/commands/find_and_modify.cpp
+++ b/src/mongo/db/commands/find_and_modify.cpp
@@ -139,6 +139,7 @@ namespace mongo {
             
             Lock::DBWrite lk( ns );
             Client::Context cx( ns );
+            Collection* collection = cx.db()->getCollection( ns );
 
             BSONObj doc;
             bool found = false;
@@ -149,7 +150,7 @@ namespace mongo {
 
                 Runner* rawRunner;
                 massert(17384, "Could not get runner for query " + queryOriginal.toString(),
-                        getRunner(cq, &rawRunner, QueryPlannerParams::DEFAULT).isOK());
+                        getRunner(collection, cq, &rawRunner, QueryPlannerParams::DEFAULT).isOK());
 
                 auto_ptr<Runner> runner(rawRunner);
 
@@ -255,6 +256,10 @@ namespace mongo {
                     UpdateLifecycleImpl updateLifecycle(false, requestNs);
                     request.setLifecycle(&updateLifecycle);
                     UpdateResult res = mongo::update(request, &cc().curop()->debug());
+                    if ( !collection ) {
+                        // collection created by an upsert
+                        collection = cx.db()->getCollection( ns );
+                    }
 
                     LOG(3) << "update result: "  << res ;
                     if ( returnNew ) {
@@ -270,7 +275,7 @@ namespace mongo {
                         }
 
                         LOG(3) << "using modified query to return the new doc: " << queryModified;
-                        if ( ! Helpers::findOne( ns.c_str() , queryModified , doc ) ) {
+                        if ( ! Helpers::findOne( collection, queryModified, doc ) ) {
                             errmsg = str::stream() << "can't find object after modification  " 
                                                    << " ns: " << ns 
                                                    << " queryModified: " << queryModified 
diff --git a/src/mongo/db/commands/geonear.cpp b/src/mongo/db/commands/geonear.cpp
index 135b861005c..1df9385c43e 100644
--- a/src/mongo/db/commands/geonear.cpp
+++ b/src/mongo/db/commands/geonear.cpp
@@ -177,7 +177,7 @@ namespace mongo {
             }
 
             Runner* rawRunner;
-            if (!getRunner(cq, &rawRunner, 0).isOK()) {
+            if (!getRunner(collection, cq, &rawRunner, 0).isOK()) {
                 errmsg = "can't get query runner";
                 return false;
             }
diff --git a/src/mongo/db/commands/group.cpp b/src/mongo/db/commands/group.cpp
index b431853eb05..e0e28264b13 100644
--- a/src/mongo/db/commands/group.cpp
+++ b/src/mongo/db/commands/group.cpp
@@ -144,7 +144,7 @@ namespace mongo {
                 }
 
                 Runner* rawRunner;
-                if (!getRunner(cq, &rawRunner).isOK()) {
+                if (!getRunner(collection, cq, &rawRunner).isOK()) {
                     uasserted(17213, "Can't get runner for query " + query.toString());
                     return 0;
                 }
diff --git a/src/mongo/db/commands/mr.cpp b/src/mongo/db/commands/mr.cpp
index 9306256f631..1f72e6648a2 100644
--- a/src/mongo/db/commands/mr.cpp
+++ b/src/mongo/db/commands/mr.cpp
@@ -591,7 +591,8 @@ namespace mongo {
                     bool found;
                     {
                         Client::Context tx( _config.outputOptions.finalNamespace );
-                        found = Helpers::findOne(_config.outputOptions.finalNamespace.c_str(),
+                        Collection* coll = tx.db()->getCollection( _config.outputOptions.finalNamespace );
+                        found = Helpers::findOne(coll,
                                                  temp["_id"].wrap(),
                                                  old,
                                                  true);
@@ -958,7 +959,8 @@ namespace mongo {
             verify(CanonicalQuery::canonicalize(_config.incLong, BSONObj(), sortKey, BSONObj(), &cq).isOK());
 
             Runner* rawRunner;
-            verify(getRunner(cq, &rawRunner, QueryPlannerParams::NO_TABLE_SCAN).isOK());
+            verify(getRunner(ctx.ctx().db()->getCollection(_config.incLong),
+                             cq, &rawRunner, QueryPlannerParams::NO_TABLE_SCAN).isOK());
 
             auto_ptr<Runner> runner(rawRunner);
             const ScopedRunnerRegistration safety(runner.get());
@@ -1297,7 +1299,7 @@ namespace mongo {
                         }
 
                         Runner* rawRunner;
-                        if (!getRunner(cq, &rawRunner).isOK()) {
+                        if (!getRunner(ctx.db()->getCollection( config.ns), cq, &rawRunner).isOK()) {
                             uasserted(17239, "Can't get runner for query " + config.filter.toString());
                             return 0;
                         }
diff --git a/src/mongo/db/commands/pipeline_command.cpp b/src/mongo/db/commands/pipeline_command.cpp
index a0902a3cab2..3cf66336dfc 100644
--- a/src/mongo/db/commands/pipeline_command.cpp
+++ b/src/mongo/db/commands/pipeline_command.cpp
@@ -319,7 +319,9 @@ namespace {
 
                 // This does mongod-specific stuff like creating the input Runner and adding to the
                 // front of the pipeline if needed.
-                boost::shared_ptr<Runner> input = PipelineD::prepareCursorSource(pPipeline, pCtx);
+                boost::shared_ptr<Runner> input = PipelineD::prepareCursorSource(collection,
+                                                                                 pPipeline,
+                                                                                 pCtx);
                 pPipeline->stitch();
 
                 runnerHolder.reset(new PipelineRunner(pPipeline, input));
diff --git a/src/mongo/db/commands/test_commands.cpp b/src/mongo/db/commands/test_commands.cpp
index ffbb052e1fb..0553f314a12 100644
--- a/src/mongo/db/commands/test_commands.cpp
+++ b/src/mongo/db/commands/test_commands.cpp
@@ -146,6 +146,7 @@ namespace mongo {
             massert( 13417, "captrunc collection not found or empty", collection);
 
             boost::scoped_ptr<Runner> runner(InternalPlanner::collectionScan(nss.ns(),
+                                                                             collection,
                                                                              InternalPlanner::BACKWARD));
             DiskLoc end;
             // We remove 'n' elements so the start is one past that
diff --git a/src/mongo/db/db.cpp b/src/mongo/db/db.cpp
index 795d36094b3..5fc8ed61c86 100644
--- a/src/mongo/db/db.cpp
+++ b/src/mongo/db/db.cpp
@@ -414,8 +414,9 @@ namespace mongo {
                 }
             }
             else {
-                const string systemIndexes = cc().database()->name() + ".system.indexes";
-                auto_ptr<Runner> runner(InternalPlanner::collectionScan(systemIndexes));
+                const string systemIndexes = ctx.db()->name() + ".system.indexes";
+                Collection* coll = ctx.db()->getCollection( systemIndexes );
+                auto_ptr<Runner> runner(InternalPlanner::collectionScan(systemIndexes,coll));
                 BSONObj index;
                 Runner::RunnerState state;
                 while (Runner::RUNNER_ADVANCED == (state = runner->getNext(&index, NULL))) {
diff --git a/src/mongo/db/dbcommands.cpp b/src/mongo/db/dbcommands.cpp
index e8dd0904832..fdedbb125a1 100644
--- a/src/mongo/db/dbcommands.cpp
+++ b/src/mongo/db/dbcommands.cpp
@@ -808,10 +808,6 @@ namespace mongo {
         bool run(const string& dbname, BSONObj& jsobj, int, string& errmsg, BSONObjBuilder& result, bool fromRepl ) {
             const std::string ns = parseNs(dbname, jsobj);
 
-            // Check shard version at startup.
-            // This will throw before we've done any work if shard version is outdated
-            Client::ReadContext ctx(ns);
-
             md5digest d;
             md5_state_t st;
             md5_init(&st);
@@ -837,6 +833,11 @@ namespace mongo {
             BSONObj query = BSON( "files_id" << jsobj["filemd5"] << "n" << GTE << n );
             BSONObj sort = BSON( "files_id" << 1 << "n" << 1 );
 
+            // Check shard version at startup.
+            // This will throw before we've done any work if shard version is outdated
+            Client::ReadContext ctx(ns);
+            Collection* coll = ctx.ctx().db()->getCollection(ns);
+
             CanonicalQuery* cq;
             if (!CanonicalQuery::canonicalize(ns, query, sort, BSONObj(), &cq).isOK()) {
                 uasserted(17240, "Can't canonicalize query " + query.toString());
@@ -844,7 +845,7 @@ namespace mongo {
             }
 
             Runner* rawRunner;
-            if (!getRunner(cq, &rawRunner, QueryPlannerParams::NO_TABLE_SCAN).isOK()) {
+            if (!getRunner(coll, cq, &rawRunner, QueryPlannerParams::NO_TABLE_SCAN).isOK()) {
                 uasserted(17241, "Can't get runner for query " + query.toString());
                 return 0;
             }
@@ -989,7 +990,7 @@ namespace mongo {
                     result.append( "millis" , timer.millis() );
                     return 1;
                 }
-                runner.reset(InternalPlanner::collectionScan(ns));
+                runner.reset(InternalPlanner::collectionScan(ns,collection));
             }
             else if ( min.isEmpty() || max.isEmpty() ) {
                 errmsg = "only one of min or max specified";
diff --git a/src/mongo/db/dbhelpers.cpp b/src/mongo/db/dbhelpers.cpp
index 9808c7e7f7c..6ffaaf6c2fc 100644
--- a/src/mongo/db/dbhelpers.cpp
+++ b/src/mongo/db/dbhelpers.cpp
@@ -89,8 +89,8 @@ namespace mongo {
     /* fetch a single object from collection ns that matches query
        set your db SavedContext first
     */
-    bool Helpers::findOne(const StringData& ns, const BSONObj &query, BSONObj& result, bool requireIndex) {
-        DiskLoc loc = findOne( ns, query, requireIndex );
+    bool Helpers::findOne(Collection* collection, const BSONObj &query, BSONObj& result, bool requireIndex) {
+        DiskLoc loc = findOne( collection, query, requireIndex );
         if ( loc.isNull() )
             return false;
         result = loc.obj();
@@ -100,15 +100,18 @@ namespace mongo {
     /* fetch a single object from collection ns that matches query
        set your db SavedContext first
     */
-    DiskLoc Helpers::findOne(const StringData& ns, const BSONObj &query, bool requireIndex) {
+    DiskLoc Helpers::findOne(Collection* collection, const BSONObj &query, bool requireIndex) {
+        if ( !collection )
+            return DiskLoc();
+
         CanonicalQuery* cq;
         massert(17244, "Could not canonicalize " + query.toString(),
-                CanonicalQuery::canonicalize(ns.toString(), query, &cq).isOK());
+                CanonicalQuery::canonicalize(collection->ns(), query, &cq).isOK());
 
         Runner* rawRunner;
         size_t options = requireIndex ? QueryPlannerParams::NO_TABLE_SCAN : QueryPlannerParams::DEFAULT;
         massert(17245, "Could not get runner for query " + query.toString(),
-                getRunner(cq, &rawRunner, options).isOK());
+                getRunner(collection, cq, &rawRunner, options).isOK());
 
         auto_ptr<Runner> runner(rawRunner);
         Runner::RunnerState state;
@@ -174,7 +177,7 @@ namespace mongo {
 
         Runner* rawRunner;
         uassert(17237, "Could not get runner for query " + query.toString(),
-                getRunner(cq, &rawRunner).isOK());
+                getRunner(ctx.db()->getCollection( ns ), cq, &rawRunner).isOK());
 
         vector<BSONObj> all;
 
@@ -190,7 +193,8 @@ namespace mongo {
 
     bool Helpers::isEmpty(const char *ns) {
         Client::Context context(ns, storageGlobalParams.dbpath);
-        auto_ptr<Runner> runner(InternalPlanner::collectionScan(ns));
+        auto_ptr<Runner> runner(InternalPlanner::collectionScan(ns,
+                                                                context.db()->getCollection(ns)));
         return Runner::RUNNER_EOF == runner->getNext(NULL, NULL);
     }
 
@@ -201,7 +205,8 @@ namespace mongo {
     */
     bool Helpers::getSingleton(const char *ns, BSONObj& result) {
         Client::Context context(ns);
-        auto_ptr<Runner> runner(InternalPlanner::collectionScan(ns));
+        auto_ptr<Runner> runner(InternalPlanner::collectionScan(ns,
+                                                                context.db()->getCollection(ns)));
         Runner::RunnerState state = runner->getNext(&result, NULL);
         context.getClient()->curop()->done();
         return Runner::RUNNER_ADVANCED == state;
@@ -209,7 +214,10 @@ namespace mongo {
 
     bool Helpers::getLast(const char *ns, BSONObj& result) {
         Client::Context ctx(ns);
-        auto_ptr<Runner> runner(InternalPlanner::collectionScan(ns, InternalPlanner::BACKWARD));
+        Collection* coll = ctx.db()->getCollection( ns );
+        auto_ptr<Runner> runner(InternalPlanner::collectionScan(ns,
+                                                                coll,
+                                                                InternalPlanner::BACKWARD));
         Runner::RunnerState state = runner->getNext(&result, NULL);
         return Runner::RUNNER_ADVANCED == state;
     }
diff --git a/src/mongo/db/dbhelpers.h b/src/mongo/db/dbhelpers.h
index a8aebc58c25..15aa8d96e77 100644
--- a/src/mongo/db/dbhelpers.h
+++ b/src/mongo/db/dbhelpers.h
@@ -80,8 +80,10 @@ namespace mongo {
 
            @return true if object found
         */
-        static bool findOne(const StringData& ns, const BSONObj &query, BSONObj& result, bool requireIndex = false);
-        static DiskLoc findOne(const StringData& ns, const BSONObj &query, bool requireIndex);
+        static bool findOne(Collection* collection, const BSONObj &query,
+                            BSONObj& result, bool requireIndex = false);
+        static DiskLoc findOne(Collection* collection, const BSONObj &query,
+                               bool requireIndex);
 
         /**
          * have to be locked already
diff --git a/src/mongo/db/exec/2d.cpp b/src/mongo/db/exec/2d.cpp
index 7c5da3f4141..0d9a4b301c4 100644
--- a/src/mongo/db/exec/2d.cpp
+++ b/src/mongo/db/exec/2d.cpp
@@ -38,7 +38,8 @@ namespace mongo {
 
     TwoD::TwoD(const TwoDParams& params, WorkingSet* ws)
         : _params(params), _workingSet(ws), _initted(false),
-          _descriptor(NULL), _am(NULL) { }
+          _descriptor(NULL), _am(NULL) {
+    }
 
     TwoD::~TwoD() { }
 
@@ -52,19 +53,16 @@ namespace mongo {
         if (!_initted) {
             _initted = true;
 
-            Database* database = cc().database();
-            if ( !database )
+            if ( !_params.collection )
                 return PlanStage::IS_EOF;
 
-            Collection* collection = database->getCollection( _params.ns );
-            if ( !collection )
-                return PlanStage::IS_EOF;
+            IndexCatalog* indexCatalog = _params.collection->getIndexCatalog();
 
-            _descriptor = collection->getIndexCatalog()->findIndexByKeyPattern(_params.indexKeyPattern);
+            _descriptor = indexCatalog->findIndexByKeyPattern(_params.indexKeyPattern);
             if ( _descriptor == NULL )
                 return PlanStage::IS_EOF;
 
-            _am = static_cast<TwoDAccessMethod*>( collection->getIndexCatalog()->getIndex( _descriptor ) );
+            _am = static_cast<TwoDAccessMethod*>( indexCatalog->getIndex( _descriptor ) );
             verify( _am );
 
             if (NULL != _params.gq.getGeometry()._cap.get()) {
diff --git a/src/mongo/db/exec/2d.h b/src/mongo/db/exec/2d.h
index ae8cdfd2595..0f0cdd111de 100644
--- a/src/mongo/db/exec/2d.h
+++ b/src/mongo/db/exec/2d.h
@@ -35,11 +35,11 @@
 namespace mongo {
 
     struct TwoDParams {
-        TwoDParams() : filter(NULL) { }
+        TwoDParams() : filter(NULL), collection(NULL) { }
         GeoQuery gq;
         MatchExpression* filter;
         BSONObj indexKeyPattern;
-        string ns;
+        Collection* collection; // not owned
     };
 
     class TwoD : public PlanStage {
diff --git a/src/mongo/db/exec/2dnear.cpp b/src/mongo/db/exec/2dnear.cpp
index d739c4ca8b7..3f62aeefac9 100644
--- a/src/mongo/db/exec/2dnear.cpp
+++ b/src/mongo/db/exec/2dnear.cpp
@@ -54,17 +54,15 @@ namespace mongo {
         if (!_initted) {
             _initted = true;
 
-            Database* db = cc().database();
-            if ( !db )
-                return PlanStage::IS_EOF;
-            Collection* collection = db->getCollection( _params.ns );
-            if ( !collection )
+            if ( !_params.collection )
                 return PlanStage::IS_EOF;
 
-            IndexDescriptor* desc = collection->getIndexCatalog()->findIndexByKeyPattern(_params.indexKeyPattern);
+            IndexCatalog* indexCatalog = _params.collection->getIndexCatalog();
+
+            IndexDescriptor* desc = indexCatalog->findIndexByKeyPattern(_params.indexKeyPattern);
             if ( desc == NULL )
                 return PlanStage::IS_EOF;
-            TwoDAccessMethod* am = static_cast<TwoDAccessMethod*>( collection->getIndexCatalog()->getIndex( desc ) );
+            TwoDAccessMethod* am = static_cast<TwoDAccessMethod*>( indexCatalog->getIndex( desc ) );
 
             auto_ptr<twod_exec::GeoSearch> search;
             search.reset(new twod_exec::GeoSearch(am,
diff --git a/src/mongo/db/exec/2dnear.h b/src/mongo/db/exec/2dnear.h
index 7b8a8b66fa4..9768ebb90c4 100644
--- a/src/mongo/db/exec/2dnear.h
+++ b/src/mongo/db/exec/2dnear.h
@@ -41,7 +41,7 @@ namespace mongo {
 
     struct TwoDNearParams {
         NearQuery nearQuery;
-        string ns;
+        Collection* collection; // not owned
         BSONObj indexKeyPattern;
         MatchExpression* filter;
         int numWanted;
diff --git a/src/mongo/db/exec/collection_scan.cpp b/src/mongo/db/exec/collection_scan.cpp
index e652099faa5..b74682c47c4 100644
--- a/src/mongo/db/exec/collection_scan.cpp
+++ b/src/mongo/db/exec/collection_scan.cpp
@@ -79,15 +79,14 @@ namespace mongo {
 
         // Do some init if we haven't already.
         if (NULL == _iter) {
-            Collection* collection = cc().database()->getCollection( _params.ns );
-            if ( collection == NULL ) {
+            if ( _params.collection == NULL ) {
                 _nsDropped = true;
                 return PlanStage::DEAD;
             }
 
-            _iter.reset( collection->getIterator( _params.start,
-                                                  _params.tailable,
-                                                  _params.direction ) );
+            _iter.reset( _params.collection->getIterator( _params.start,
+                                                          _params.tailable,
+                                                          _params.direction ) );
 
             ++_commonStats.needTime;
             return PlanStage::NEED_TIME;
diff --git a/src/mongo/db/exec/collection_scan.h b/src/mongo/db/exec/collection_scan.h
index 0b1a63bf9ab..05b38df9d52 100644
--- a/src/mongo/db/exec/collection_scan.h
+++ b/src/mongo/db/exec/collection_scan.h
@@ -58,7 +58,6 @@ namespace mongo {
         virtual void recoverFromYield();
 
         virtual PlanStageStats* getStats();
-
     private:
         /**
          * Returns true if the record 'loc' references is in memory, false otherwise.
diff --git a/src/mongo/db/exec/collection_scan_common.h b/src/mongo/db/exec/collection_scan_common.h
index 9c88e7653f6..92a3c19fbbc 100644
--- a/src/mongo/db/exec/collection_scan_common.h
+++ b/src/mongo/db/exec/collection_scan_common.h
@@ -32,19 +32,23 @@
 
 namespace mongo {
 
+    class Collection;
+
     struct CollectionScanParams {
         enum Direction {
             FORWARD = 1,
             BACKWARD = -1,
         };
 
-        CollectionScanParams() : start(DiskLoc()),
+        CollectionScanParams() : collection(NULL),
+                                 start(DiskLoc()),
                                  direction(FORWARD),
                                  tailable(false),
                                  maxScan(0) { }
 
         // What collection?
-        string ns;
+        // not owned
+        Collection* collection;
 
         // isNull by default.  If you specify any value for this, you're responsible for the DiskLoc
         // not being invalidated before the first call to work(...).
diff --git a/src/mongo/db/exec/oplogstart.cpp b/src/mongo/db/exec/oplogstart.cpp
index f6754d42670..15f0036c563 100644
--- a/src/mongo/db/exec/oplogstart.cpp
+++ b/src/mongo/db/exec/oplogstart.cpp
@@ -38,13 +38,14 @@
 namespace mongo {
 
     // Does not take ownership.
-    OplogStart::OplogStart(const string& ns, MatchExpression* filter, WorkingSet* ws)
+    OplogStart::OplogStart(Collection* collection, MatchExpression* filter, WorkingSet* ws)
         : _needInit(true),
           _backwardsScanning(false),
           _extentHopping(false),
           _done(false),
+          _collection(collection),
+          _nsd(NULL),
           _workingSet(ws),
-          _ns(ns),
           _filter(filter) { }
 
     OplogStart::~OplogStart() { }
@@ -53,11 +54,10 @@ namespace mongo {
         // We do our (heavy) init in a work(), where work is expected.
         if (_needInit) {
             CollectionScanParams params;
-            params.ns = _ns;
+            params.collection = _collection;
             params.direction = CollectionScanParams::BACKWARD;
             _cs.reset(new CollectionScan(params, _workingSet, NULL));
-            Collection* collection = cc().database()->getCollection( _ns );
-            _nsd = collection->details();
+            _nsd = _collection->details();
             _needInit = false;
             _backwardsScanning = true;
             _timer.reset();
diff --git a/src/mongo/db/exec/oplogstart.h b/src/mongo/db/exec/oplogstart.h
index 1fce80218d4..f2a0b76c478 100644
--- a/src/mongo/db/exec/oplogstart.h
+++ b/src/mongo/db/exec/oplogstart.h
@@ -61,7 +61,7 @@ namespace mongo {
     class OplogStart : public PlanStage {
     public:
         // Does not take ownership.
-        OplogStart(const string& ns, MatchExpression* filter, WorkingSet* ws);
+        OplogStart(Collection* collection, MatchExpression* filter, WorkingSet* ws);
         virtual ~OplogStart();
 
         virtual StageState work(WorkingSetID* out);
@@ -107,6 +107,7 @@ namespace mongo {
         // Our final state: done.
         bool _done;
 
+        Collection* _collection;
         const NamespaceDetails* _nsd;
 
         // We only go backwards via a collscan for a few seconds.
@@ -116,7 +117,7 @@ namespace mongo {
         WorkingSet* _workingSet;
 
         string _ns;
-        
+
         MatchExpression* _filter;
 
         static int _backwardsScanTime;
diff --git a/src/mongo/db/exec/plan_stage.h b/src/mongo/db/exec/plan_stage.h
index 6797841971e..304baf50bf5 100644
--- a/src/mongo/db/exec/plan_stage.h
+++ b/src/mongo/db/exec/plan_stage.h
@@ -34,6 +34,7 @@
 
 namespace mongo {
 
+    class Collection;
     class DiskLoc;
 
     /**
@@ -220,6 +221,7 @@ namespace mongo {
          * Caller owns returned pointer.
          */
         virtual PlanStageStats* getStats() = 0;
+
     };
 
 }  // namespace mongo
diff --git a/src/mongo/db/exec/s2near.cpp b/src/mongo/db/exec/s2near.cpp
index 8ad0c2bd9eb..2af9b6259a7 100644
--- a/src/mongo/db/exec/s2near.cpp
+++ b/src/mongo/db/exec/s2near.cpp
@@ -80,19 +80,13 @@ namespace mongo {
         _outerRadiusInclusive = false;
 
         // Grab the IndexDescriptor.
-        Database* db = cc().database();
-        if (!db) {
+        if ( !_params.collection ) {
             _failed = true;
             return;
         }
 
-        Collection* collection = db->getCollection(_params.ns);
-        if (!collection) {
-            _failed = true;
-            return;
-        }
-
-        _descriptor = collection->getIndexCatalog()->findIndexByKeyPattern(_params.indexKeyPattern);
+        _descriptor =
+            _params.collection->getIndexCatalog()->findIndexByKeyPattern(_params.indexKeyPattern);
         if (NULL == _descriptor) {
             _failed = true;
             return;
diff --git a/src/mongo/db/exec/s2near.h b/src/mongo/db/exec/s2near.h
index 054b4cce16f..add9cf6ef29 100644
--- a/src/mongo/db/exec/s2near.h
+++ b/src/mongo/db/exec/s2near.h
@@ -44,7 +44,8 @@
 namespace mongo {
 
     struct S2NearParams {
-        string ns;
+        S2NearParams() : collection(NULL) { }
+        Collection* collection;
         BSONObj indexKeyPattern;
         NearQuery nearQuery;
         IndexBounds baseBounds;
diff --git a/src/mongo/db/exec/sort.cpp b/src/mongo/db/exec/sort.cpp
index db7b6a5777d..f9119cd1a72 100644
--- a/src/mongo/db/exec/sort.cpp
+++ b/src/mongo/db/exec/sort.cpp
@@ -44,7 +44,10 @@ namespace mongo {
 
     const size_t kMaxBytes = 32 * 1024 * 1024;
 
-    SortStageKeyGenerator::SortStageKeyGenerator(const BSONObj& sortSpec, const BSONObj& queryObj) {
+    SortStageKeyGenerator::SortStageKeyGenerator(Collection* collection,
+                                                 const BSONObj& sortSpec,
+                                                 const BSONObj& queryObj) {
+        _collection = collection;
         _hasBounds = false;
         _sortHasMeta = false;
         _rawSortSpec = sortSpec;
@@ -275,7 +278,8 @@ namespace mongo {
     }
 
     SortStage::SortStage(const SortStageParams& params, WorkingSet* ws, PlanStage* child)
-        : _ws(ws),
+        : _collection(params.collection),
+          _ws(ws),
           _child(child),
           _pattern(params.pattern),
           _query(params.query),
@@ -298,7 +302,7 @@ namespace mongo {
 
         if (NULL == _sortKeyGen) {
             // This is heavy and should be done as part of work().
-            _sortKeyGen.reset(new SortStageKeyGenerator(_pattern, _query));
+            _sortKeyGen.reset(new SortStageKeyGenerator(_collection, _pattern, _query));
             _sortKeyComparator.reset(new WorkingSetComparator(_sortKeyGen->getSortComparator()));
             // If limit > 1, we need to initialize _dataSet here to maintain ordered
             // set of data items while fetching from the child stage.
diff --git a/src/mongo/db/exec/sort.h b/src/mongo/db/exec/sort.h
index 91fbb0826f4..e67305504ba 100644
--- a/src/mongo/db/exec/sort.h
+++ b/src/mongo/db/exec/sort.h
@@ -47,7 +47,9 @@ namespace mongo {
     // Parameters that must be provided to a SortStage
     class SortStageParams {
     public:
-        SortStageParams() : limit(0) { }
+        SortStageParams() : collection( NULL), limit(0) { }
+
+        Collection* collection;
 
         // How we're sorting.
         BSONObj pattern;
@@ -71,12 +73,15 @@ namespace mongo {
          * ensure that the value we select to sort by is within bounds generated by
          * executing 'queryObj' using the virtual index with key pattern 'sortSpec'.
          */
-        SortStageKeyGenerator(const BSONObj& sortSpec, const BSONObj& queryObj);
+        SortStageKeyGenerator(Collection* collection,
+                              const BSONObj& sortSpec,
+                              const BSONObj& queryObj);
 
         /**
          * Returns the key used to sort 'member'.
          */
-        Status getSortKey(const WorkingSetMember& member, BSONObj* objOut) const;
+        Status getSortKey(const WorkingSetMember& member,
+                          BSONObj* objOut) const;
 
         /**
          * Passed to std::sort and used to sort the keys that are returned from getSortKey.
@@ -96,7 +101,10 @@ namespace mongo {
          *
          * Populates _hasBounds and _bounds.
          */
-        void getBoundsForSort(const BSONObj& queryObj, const BSONObj& sortObj);
+        void getBoundsForSort(const BSONObj& queryObj,
+                              const BSONObj& sortObj);
+
+        Collection* _collection;
 
         // The object that we use to call woCompare on our resulting key.  Is equal to _rawSortSpec
         // unless we have some $meta expressions.  Each $meta expression has a default sort order.
@@ -152,6 +160,8 @@ namespace mongo {
         // Query Stage
         //
 
+        Collection* _collection;
+
         // Not owned by us.
         WorkingSet* _ws;
 
diff --git a/src/mongo/db/exec/stagedebug_cmd.cpp b/src/mongo/db/exec/stagedebug_cmd.cpp
index 5d4f36d31da..f2af118dc6d 100644
--- a/src/mongo/db/exec/stagedebug_cmd.cpp
+++ b/src/mongo/db/exec/stagedebug_cmd.cpp
@@ -295,9 +295,9 @@ namespace mongo {
                 CollectionScanParams params;
 
                 // What collection?
-                params.ns = dbname + "." + nodeArgs["name"].String();
-                uassert(16962, "Can't find collection " + nodeArgs["name"].String(),
-                        NULL != cc().database()->getCollection(params.ns));
+                string ns = dbname + "." + nodeArgs["name"].String();
+                params.collection = cc().database()->getCollection(ns);
+                uassert(16962, "Can't find collection " + ns, NULL != params.collection );
 
                 // What direction?
                 uassert(16963, "Direction argument must be specified and be a number",
@@ -364,7 +364,6 @@ namespace mongo {
                 FTSAccessMethod* fam =
                     dynamic_cast<FTSAccessMethod*>( collection->getIndexCatalog()->getIndex( index ) );
                 TextStageParams params(fam->getSpec());
-                params.ns = ns;
                 params.index = index;
 
                 // TODO: Deal with non-empty filters.  This is a hack to put in covering information
diff --git a/src/mongo/db/exec/text.h b/src/mongo/db/exec/text.h
index 932e0de2e7c..29c1210deab 100644
--- a/src/mongo/db/exec/text.h
+++ b/src/mongo/db/exec/text.h
@@ -55,9 +55,6 @@ namespace mongo {
     struct TextStageParams {
         TextStageParams(const FTSSpec& s) : spec(s) {}
 
-        // Namespace.
-        string ns;
-
         // Text index descriptor.  IndexCatalog owns this.
         IndexDescriptor* index;
 
diff --git a/src/mongo/db/fts/fts_command_mongod.cpp b/src/mongo/db/fts/fts_command_mongod.cpp
index 7240d587a7c..695a6e937e5 100644
--- a/src/mongo/db/fts/fts_command_mongod.cpp
+++ b/src/mongo/db/fts/fts_command_mongod.cpp
@@ -31,6 +31,7 @@
 #include <string>
 
 #include "mongo/db/client.h"
+#include "mongo/db/catalog/database.h"
 #include "mongo/db/fts/fts_command.h"
 #include "mongo/db/fts/fts_util.h"
 #include "mongo/db/pdfile.h"
@@ -103,7 +104,7 @@ namespace mongo {
             }
 
             Runner* rawRunner;
-            Status getRunnerStatus = getRunner(cq, &rawRunner, 0);
+            Status getRunnerStatus = getRunner(ctx.ctx().db()->getCollection(ns), cq, &rawRunner);
             if (!getRunnerStatus.isOK()) {
                 errmsg = getRunnerStatus.reason();
                 return false;
diff --git a/src/mongo/db/pipeline/pipeline_d.cpp b/src/mongo/db/pipeline/pipeline_d.cpp
index 15615a4cbe5..73e011e7065 100644
--- a/src/mongo/db/pipeline/pipeline_d.cpp
+++ b/src/mongo/db/pipeline/pipeline_d.cpp
@@ -65,6 +65,7 @@ namespace {
 }
 
     boost::shared_ptr<Runner> PipelineD::prepareCursorSource(
+            Collection* collection,
             const intrusive_ptr<Pipeline>& pPipeline,
             const intrusive_ptr<ExpressionContext>& pExpCtx) {
         // get the full "namespace" name
@@ -162,7 +163,7 @@ namespace {
                                              projectionForQuery,
                                              &cq);
             Runner* rawRunner;
-            if (status.isOK() && getRunner(cq, &rawRunner, runnerOptions).isOK()) {
+            if (status.isOK() && getRunner(collection, cq, &rawRunner, runnerOptions).isOK()) {
                 // success: The Runner will handle sorting for us using an index.
                 runner.reset(rawRunner);
                 sortInRunner = true;
@@ -186,7 +187,7 @@ namespace {
                                              &cq));
 
             Runner* rawRunner;
-            uassertStatusOK(getRunner(cq, &rawRunner, runnerOptions));
+            uassertStatusOK(getRunner(collection, cq, &rawRunner, runnerOptions));
             runner.reset(rawRunner);
         }
 
diff --git a/src/mongo/db/pipeline/pipeline_d.h b/src/mongo/db/pipeline/pipeline_d.h
index 98ea7537be3..b6b34e6f378 100644
--- a/src/mongo/db/pipeline/pipeline_d.h
+++ b/src/mongo/db/pipeline/pipeline_d.h
@@ -71,6 +71,7 @@ namespace mongo {
          * @param pExpCtx the expression context for this pipeline
          */
         static boost::shared_ptr<Runner> prepareCursorSource(
+            Collection* collection,
             const intrusive_ptr<Pipeline> &pPipeline,
             const intrusive_ptr<ExpressionContext> &pExpCtx);
 
diff --git a/src/mongo/db/query/cached_plan_runner.cpp b/src/mongo/db/query/cached_plan_runner.cpp
index 18cc3d3af71..08c944b9b8d 100644
--- a/src/mongo/db/query/cached_plan_runner.cpp
+++ b/src/mongo/db/query/cached_plan_runner.cpp
@@ -181,14 +181,15 @@ namespace mongo {
             return;
         }
 
-        Database* db = cc().database();
-
         // We need to check db and collection for NULL because updateCache() is called upon destruction of
         // the CachedPlanRunner. In some cases, the db or collection could be dropped without kill()
         // being called on the runner (for example, timeout of a ClientCursor holding the runner).
+        // XXX - this whole thing is odd
+        Database* db = cc().database();
         if (NULL == db) { return; }
         Collection* collection = db->getCollection(_canonicalQuery->ns());
         if (NULL == collection) { return; }
+        invariant( collection == _collection );
         PlanCache* cache = collection->infoCache()->getPlanCache();
 
         std::auto_ptr<PlanCacheEntryFeedback> feedback(new PlanCacheEntryFeedback());
diff --git a/src/mongo/db/query/get_runner.cpp b/src/mongo/db/query/get_runner.cpp
index f062fbe578e..d817b218259 100644
--- a/src/mongo/db/query/get_runner.cpp
+++ b/src/mongo/db/query/get_runner.cpp
@@ -85,21 +85,6 @@ namespace mongo {
         temp.swap(*indexEntries);
     }
 
-    /**
-     * For a given query, get a runner.  The runner could be a SingleSolutionRunner, a
-     * CachedQueryRunner, or a MultiPlanRunner, depending on the cache/query solver/etc.
-     */
-    Status getRunner(CanonicalQuery* rawCanonicalQuery,
-                     Runner** out, size_t plannerOptions) {
-        verify(rawCanonicalQuery);
-        Database* db = cc().database();
-        verify(db);
-        return getRunner(db->getCollection(rawCanonicalQuery->ns()),
-                         rawCanonicalQuery,
-                         out,
-                         plannerOptions);
-    }
-
     Status getRunner(Collection* collection,
                      const std::string& ns,
                      const BSONObj& unparsedQuery,
@@ -240,7 +225,7 @@ namespace mongo {
 
                 WorkingSet* ws;
                 PlanStage* root;
-                verify(StageBuilder::build(*qs, &root, &ws));
+                verify(StageBuilder::build(collection, *qs, &root, &ws));
                 *out = new SingleSolutionRunner(collection,
                                                 canonicalQuery, qs, root, ws);
                 if (NULL != backupQs) {
@@ -256,7 +241,7 @@ namespace mongo {
 
         WorkingSet* ws;
         PlanStage* root;
-        verify(StageBuilder::build(*qs, &root, &ws));
+        verify(StageBuilder::build(collection, *qs, &root, &ws));
         CachedPlanRunner* cpr = new CachedPlanRunner(collection,
                                                      canonicalQuery,
                                                      qs,
@@ -267,7 +252,7 @@ namespace mongo {
         if (NULL != backupQs) {
             WorkingSet* backupWs;
             PlanStage* backupRoot;
-            verify(StageBuilder::build(*backupQs, &backupRoot, &backupWs));
+            verify(StageBuilder::build(collection, *backupQs, &backupRoot, &backupWs));
             cpr->setBackupPlan(backupQs, backupRoot, backupWs);
         }
 
@@ -397,7 +382,7 @@ namespace mongo {
                     // We're not going to cache anything that's fast count.
                     WorkingSet* ws;
                     PlanStage* root;
-                    verify(StageBuilder::build(*solutions[i], &root, &ws));
+                    verify(StageBuilder::build(collection, *solutions[i], &root, &ws));
                     *out = new SingleSolutionRunner(collection,
                                                     canonicalQuery.release(),
                                                     solutions[i],
@@ -416,7 +401,7 @@ namespace mongo {
             // Only one possible plan.  Run it.  Build the stages from the solution.
             WorkingSet* ws;
             PlanStage* root;
-            verify(StageBuilder::build(*solutions[0], &root, &ws));
+            verify(StageBuilder::build(collection, *solutions[0], &root, &ws));
 
             // And, run the plan.
             *out = new SingleSolutionRunner(collection,
@@ -436,7 +421,7 @@ namespace mongo {
                 if (solutions[i]->cacheData.get()) {
                     solutions[i]->cacheData->indexFilterApplied = plannerParams.indexFiltersApplied;
                 }
-                verify(StageBuilder::build(*solutions[i], &root, &ws));
+                verify(StageBuilder::build(collection, *solutions[i], &root, &ws));
                 // Takes ownership of all arguments.
                 mpr->addPlan(solutions[i], root, ws);
             }
@@ -750,7 +735,7 @@ namespace mongo {
             }
 
             // Takes ownership of cq.
-            return getRunner(cq, out);
+            return getRunner(collection, cq, out);
         }
 
         //
@@ -796,7 +781,7 @@ namespace mongo {
 
             WorkingSet* ws;
             PlanStage* root;
-            verify(StageBuilder::build(*soln, &root, &ws));
+            verify(StageBuilder::build(collection, *soln, &root, &ws));
             *out = new SingleSolutionRunner(collection, cq, soln, root, ws);
             return Status::OK();
         }
@@ -805,7 +790,7 @@ namespace mongo {
         vector<QuerySolution*> solutions;
         status = QueryPlanner::plan(*cq, plannerParams, &solutions);
         if (!status.isOK()) {
-            return getRunner(cq, out);
+            return getRunner(collection, cq, out);
         }
 
         // We look for a solution that has an ixscan we can turn into a distinctixscan
@@ -824,7 +809,7 @@ namespace mongo {
                 // Build and return the SSR over solutions[i].
                 WorkingSet* ws;
                 PlanStage* root;
-                verify(StageBuilder::build(*solutions[i], &root, &ws));
+                verify(StageBuilder::build(collection, *solutions[i], &root, &ws));
                 *out = new SingleSolutionRunner(collection, cq, solutions[i], root, ws);
                 return Status::OK();
             }
@@ -849,7 +834,7 @@ namespace mongo {
         }
 
         // Takes ownership of cq.
-        return getRunner(cq, out);
+        return getRunner(collection, cq, out);
     }
 
     ScopedRunnerRegistration::ScopedRunnerRegistration(Runner* runner)
diff --git a/src/mongo/db/query/get_runner.h b/src/mongo/db/query/get_runner.h
index 18f7c7235f1..9360478e278 100644
--- a/src/mongo/db/query/get_runner.h
+++ b/src/mongo/db/query/get_runner.h
@@ -61,17 +61,6 @@ namespace mongo {
      * If the query cannot be executed, returns a Status indicating why.  Deletes
      * rawCanonicalQuery.
      */
-    Status getRunner(CanonicalQuery* rawCanonicalQuery,
-                     Runner** out,
-                     size_t plannerOptions = 0);
-
-    /**
-     * Get a runner for a query.  Takes ownership of rawCanonicalQuery.
-     *
-     * As 'getRunner' above, but takes a Collection* as the first argument, for cases where the
-     * work to obtain the Collection has already been done by the caller. The 'collection'
-     * argument may be NULL.
-     */
     Status getRunner(Collection* collection,
                      CanonicalQuery* rawCanonicalQuery,
                      Runner** out,
diff --git a/src/mongo/db/query/internal_plans.h b/src/mongo/db/query/internal_plans.h
index fa5597dfbc1..a36b7478714 100644
--- a/src/mongo/db/query/internal_plans.h
+++ b/src/mongo/db/query/internal_plans.h
@@ -62,14 +62,18 @@ namespace mongo {
         /**
          * Return a collection scan.  Caller owns pointer.
          */
-        static Runner* collectionScan(const StringData& ns, // TODO: make this a Collection*
+        static Runner* collectionScan(const StringData& ns,
+                                      Collection* collection,
                                       const Direction direction = FORWARD,
                                       const DiskLoc startLoc = DiskLoc()) {
-            Collection* collection = cc().database()->getCollection(ns);
-            if (NULL == collection) { return new EOFRunner(NULL, ns.toString()); }
+            if (NULL == collection) {
+                return new EOFRunner(NULL, ns.toString());
+            }
+
+            dassert( ns == collection->ns().ns() );
 
             CollectionScanParams params;
-            params.ns = ns.toString();
+            params.collection = collection;
             params.start = startLoc;
 
             if (FORWARD == direction) {
diff --git a/src/mongo/db/query/new_find.cpp b/src/mongo/db/query/new_find.cpp
index 3205eb3f45c..25ffb9b042d 100644
--- a/src/mongo/db/query/new_find.cpp
+++ b/src/mongo/db/query/new_find.cpp
@@ -363,7 +363,7 @@ namespace mongo {
 
         // Make an oplog start finding stage.
         WorkingSet* oplogws = new WorkingSet();
-        OplogStart* stage = new OplogStart(cq->ns(), tsExpr, oplogws);
+        OplogStart* stage = new OplogStart(collection, tsExpr, oplogws);
 
         // Takes ownership of ws and stage.
         auto_ptr<InternalRunner> runner(new InternalRunner(collection, stage, oplogws));
@@ -374,7 +374,7 @@ namespace mongo {
         Runner::RunnerState state = runner->getNext(NULL, &startLoc);
 
         // This is normal.  The start of the oplog is the beginning of the collection.
-        if (Runner::RUNNER_EOF == state) { return getRunner(cq, runnerOut); }
+        if (Runner::RUNNER_EOF == state) { return getRunner(collection, cq, runnerOut); }
 
         // This is not normal.  An error was encountered.
         if (Runner::RUNNER_ADVANCED != state) {
@@ -386,7 +386,7 @@ namespace mongo {
 
         // Build our collection scan...
         CollectionScanParams params;
-        params.ns = cq->ns();
+        params.collection = collection;
         params.start = startLoc;
         params.direction = CollectionScanParams::FORWARD;
         params.tailable = cq->getParsed().hasOption(QueryOption_CursorTailable);
@@ -495,7 +495,7 @@ namespace mongo {
             if (shardingState.needCollectionMetadata(pq.ns())) {
                 options |= QueryPlannerParams::INCLUDE_SHARD_FILTER;
             }
-            status = getRunner(cq, &rawRunner, options);
+            status = getRunner(collection, cq, &rawRunner, options);
         }
 
         if (!status.isOK()) {
diff --git a/src/mongo/db/query/planner_analysis.cpp b/src/mongo/db/query/planner_analysis.cpp
index 24441a7a811..a6339e4121e 100644
--- a/src/mongo/db/query/planner_analysis.cpp
+++ b/src/mongo/db/query/planner_analysis.cpp
@@ -465,12 +465,11 @@ namespace mongo {
 
     // static
     QuerySolution* QueryPlannerAnalysis::analyzeDataAccess(const CanonicalQuery& query,
-                                                   const QueryPlannerParams& params,
-                                                   QuerySolutionNode* solnRoot) {
+                                                           const QueryPlannerParams& params,
+                                                           QuerySolutionNode* solnRoot) {
         auto_ptr<QuerySolution> soln(new QuerySolution());
         soln->filterData = query.getQueryObj();
         verify(soln->filterData.isOwned());
-        soln->ns = query.ns();
         soln->indexFilterApplied = params.indexFiltersApplied;
 
         solnRoot->computeProperties();
diff --git a/src/mongo/db/query/planner_analysis.h b/src/mongo/db/query/planner_analysis.h
index 22237c1afcc..4dcf9dd2aea 100644
--- a/src/mongo/db/query/planner_analysis.h
+++ b/src/mongo/db/query/planner_analysis.h
@@ -34,6 +34,8 @@
 
 namespace mongo {
 
+    class Collection;
+
     class QueryPlannerAnalysis {
     public:
 
diff --git a/src/mongo/db/query/query_planner.cpp b/src/mongo/db/query/query_planner.cpp
index 92d8a04674e..94bb3eece90 100644
--- a/src/mongo/db/query/query_planner.cpp
+++ b/src/mongo/db/query/query_planner.cpp
@@ -271,7 +271,9 @@ namespace mongo {
         if (SolutionCacheData::WHOLE_IXSCAN_SOLN == cacheData.solnType) {
             // The solution can be constructed by a scan over the entire index.
             QuerySolution* soln = buildWholeIXSoln(*cacheData.tree->entry,
-                query, params, cacheData.wholeIXSolnDir);
+                                                   query,
+                                                   params,
+                                                   cacheData.wholeIXSolnDir);
             if (soln == NULL) {
                 return Status(ErrorCodes::BadValue,
                               "plan cache error: soln that uses index to provide sort");
@@ -331,7 +333,9 @@ namespace mongo {
 
         if (NULL != solnRoot) {
             // Takes ownership of 'solnRoot'.
-            QuerySolution* soln = QueryPlannerAnalysis::analyzeDataAccess(query, params, solnRoot);
+            QuerySolution* soln = QueryPlannerAnalysis::analyzeDataAccess(query,
+                                                                          params,
+                                                                          solnRoot);
             if (NULL != soln) {
                 QLOG() << "Planner: solution constructed from the cache:\n" << soln->toString() << endl;
                 *out = soln;
@@ -369,7 +373,8 @@ namespace mongo {
 
         if (cachedSoln.backupSoln) {
             SolutionCacheData* backupCacheData = cachedSoln.plannerData[*cachedSoln.backupSoln];
-            Status backupStatus = planFromCache(query, params, *backupCacheData, backupOut);
+            Status backupStatus = planFromCache(query, params,
+                                                *backupCacheData, backupOut);
             if (!backupStatus.isOK()) {
                 return backupStatus;
             }
@@ -653,7 +658,9 @@ namespace mongo {
                 // only be first for gnNode.
                 tag->first.erase(tag->first.begin() + i);
 
-                QuerySolution* soln = QueryPlannerAnalysis::analyzeDataAccess(query, params, solnRoot);
+                QuerySolution* soln = QueryPlannerAnalysis::analyzeDataAccess(query,
+                                                                              params,
+                                                                              solnRoot);
 
                 if (NULL != soln) {
                     out->push_back(soln);
@@ -743,7 +750,9 @@ namespace mongo {
 
                 if (NULL == solnRoot) { continue; }
 
-                QuerySolution* soln = QueryPlannerAnalysis::analyzeDataAccess(query, params, solnRoot);
+                QuerySolution* soln = QueryPlannerAnalysis::analyzeDataAccess(query,
+                                                                              params,
+                                                                              solnRoot);
                 if (NULL != soln) {
                     QLOG() << "Planner: adding solution:" << endl << soln->toString();
                     if (indexTreeStatus.isOK()) {
@@ -780,7 +789,8 @@ namespace mongo {
         // desired behavior when an index is hinted that is not relevant to the query.
         if (!hintIndex.isEmpty()) {
             if (0 == out->size()) {
-                QuerySolution* soln = buildWholeIXSoln(params.indices[hintIndexNumber], query, params);
+                QuerySolution* soln = buildWholeIXSoln(params.indices[hintIndexNumber],
+                                                       query, params);
                 verify(NULL != soln);
                 QLOG() << "Planner: outputting soln that uses hinted index as scan." << endl;
                 out->push_back(soln);
@@ -816,7 +826,8 @@ namespace mongo {
                     if (providesSort(query, kp)) {
                         QLOG() << "Planner: outputting soln that uses index to provide sort."
                                << endl;
-                        QuerySolution* soln = buildWholeIXSoln(params.indices[i], query, params);
+                        QuerySolution* soln = buildWholeIXSoln(params.indices[i],
+                                                               query, params);
                         if (NULL != soln) {
                             PlanCacheIndexTree* indexTree = new PlanCacheIndexTree();
                             indexTree->setIndexEntry(params.indices[i]);
@@ -833,7 +844,8 @@ namespace mongo {
                     if (providesSort(query, QueryPlannerCommon::reverseSortObj(kp))) {
                         QLOG() << "Planner: outputting soln that uses (reverse) index "
                                << "to provide sort." << endl;
-                        QuerySolution* soln = buildWholeIXSoln(params.indices[i], query, params, -1);
+                        QuerySolution* soln = buildWholeIXSoln(params.indices[i], query,
+                                                               params, -1);
                         if (NULL != soln) {
                             PlanCacheIndexTree* indexTree = new PlanCacheIndexTree();
                             indexTree->setIndexEntry(params.indices[i]);
diff --git a/src/mongo/db/query/query_planner.h b/src/mongo/db/query/query_planner.h
index a8534c69f62..e314e1f132c 100644
--- a/src/mongo/db/query/query_planner.h
+++ b/src/mongo/db/query/query_planner.h
@@ -35,6 +35,7 @@
 namespace mongo {
 
     class CachedSolution;
+    class Collection;
 
     /**
      * QueryPlanner's job is to provide an entry point to the query planning and optimization
diff --git a/src/mongo/db/query/query_solution.h b/src/mongo/db/query/query_solution.h
index 7721e718f83..45908539398 100644
--- a/src/mongo/db/query/query_solution.h
+++ b/src/mongo/db/query/query_solution.h
@@ -180,8 +180,6 @@ namespace mongo {
         // Any filters in root or below point into this object.  Must be owned.
         BSONObj filterData;
 
-        string ns;
-
         // There are two known scenarios in which a query solution might potentially block:
         //
         // Sort stage:
diff --git a/src/mongo/db/query/stage_builder.cpp b/src/mongo/db/query/stage_builder.cpp
index 6e71b1db934..da4005cd4d1 100644
--- a/src/mongo/db/query/stage_builder.cpp
+++ b/src/mongo/db/query/stage_builder.cpp
@@ -55,11 +55,14 @@
 
 namespace mongo {
 
-    PlanStage* buildStages(const QuerySolution& qsol, const QuerySolutionNode* root, WorkingSet* ws) {
+    PlanStage* buildStages(Collection* collection,
+                           const QuerySolution& qsol,
+                           const QuerySolutionNode* root,
+                           WorkingSet* ws) {
         if (STAGE_COLLSCAN == root->getType()) {
             const CollectionScanNode* csn = static_cast<const CollectionScanNode*>(root);
             CollectionScanParams params;
-            params.ns = csn->name;
+            params.collection = collection;
             params.tailable = csn->tailable;
             params.direction = (csn->direction == 1) ? CollectionScanParams::FORWARD
                                                      : CollectionScanParams::BACKWARD;
@@ -69,19 +72,18 @@ namespace mongo {
         else if (STAGE_IXSCAN == root->getType()) {
             const IndexScanNode* ixn = static_cast<const IndexScanNode*>(root);
 
-            Database* db = cc().database();
-            Collection* collection = db ? db->getCollection(qsol.ns) : NULL;
             if (NULL == collection) {
-                warning() << "Can't ixscan null namespace " << qsol.ns << endl;
+                warning() << "Can't ixscan null namespace";
                 return NULL;
             }
 
             IndexScanParams params;
 
-            params.descriptor = collection->getIndexCatalog()->findIndexByKeyPattern( ixn->indexKeyPattern );
+            params.descriptor =
+                collection->getIndexCatalog()->findIndexByKeyPattern( ixn->indexKeyPattern );
             if ( params.descriptor == NULL ) {
                 warning() << "Can't find index " << ixn->indexKeyPattern.toString()
-                          << "in namespace " << qsol.ns << endl;
+                          << "in namespace " << collection->ns() << endl;
                 return NULL;
             }
 
@@ -93,13 +95,13 @@ namespace mongo {
         }
         else if (STAGE_FETCH == root->getType()) {
             const FetchNode* fn = static_cast<const FetchNode*>(root);
-            PlanStage* childStage = buildStages(qsol, fn->children[0], ws);
+            PlanStage* childStage = buildStages(collection, qsol, fn->children[0], ws);
             if (NULL == childStage) { return NULL; }
             return new FetchStage(ws, childStage, fn->filter.get());
         }
         else if (STAGE_SORT == root->getType()) {
             const SortNode* sn = static_cast<const SortNode*>(root);
-            PlanStage* childStage = buildStages(qsol, sn->children[0], ws);
+            PlanStage* childStage = buildStages(collection, qsol, sn->children[0], ws);
             if (NULL == childStage) { return NULL; }
             SortStageParams params;
             params.pattern = sn->pattern;
@@ -109,7 +111,7 @@ namespace mongo {
         }
         else if (STAGE_PROJECTION == root->getType()) {
             const ProjectionNode* pn = static_cast<const ProjectionNode*>(root);
-            PlanStage* childStage = buildStages(qsol, pn->children[0], ws);
+            PlanStage* childStage = buildStages(collection, qsol, pn->children[0], ws);
             if (NULL == childStage) { return NULL; }
             ProjectionStageParams params;
             params.projObj = pn->projection;
@@ -133,13 +135,13 @@ namespace mongo {
         }
         else if (STAGE_LIMIT == root->getType()) {
             const LimitNode* ln = static_cast<const LimitNode*>(root);
-            PlanStage* childStage = buildStages(qsol, ln->children[0], ws);
+            PlanStage* childStage = buildStages(collection, qsol, ln->children[0], ws);
             if (NULL == childStage) { return NULL; }
             return new LimitStage(ln->limit, ws, childStage);
         }
         else if (STAGE_SKIP == root->getType()) {
             const SkipNode* sn = static_cast<const SkipNode*>(root);
-            PlanStage* childStage = buildStages(qsol, sn->children[0], ws);
+            PlanStage* childStage = buildStages(collection, qsol, sn->children[0], ws);
             if (NULL == childStage) { return NULL; }
             return new SkipStage(sn->skip, ws, childStage);
         }
@@ -147,7 +149,7 @@ namespace mongo {
             const AndHashNode* ahn = static_cast<const AndHashNode*>(root);
             auto_ptr<AndHashStage> ret(new AndHashStage(ws, ahn->filter.get()));
             for (size_t i = 0; i < ahn->children.size(); ++i) {
-                PlanStage* childStage = buildStages(qsol, ahn->children[i], ws);
+                PlanStage* childStage = buildStages(collection, qsol, ahn->children[i], ws);
                 if (NULL == childStage) { return NULL; }
                 ret->addChild(childStage);
             }
@@ -157,7 +159,7 @@ namespace mongo {
             const OrNode * orn = static_cast<const OrNode*>(root);
             auto_ptr<OrStage> ret(new OrStage(ws, orn->dedup, orn->filter.get()));
             for (size_t i = 0; i < orn->children.size(); ++i) {
-                PlanStage* childStage = buildStages(qsol, orn->children[i], ws);
+                PlanStage* childStage = buildStages(collection, qsol, orn->children[i], ws);
                 if (NULL == childStage) { return NULL; }
                 ret->addChild(childStage);
             }
@@ -167,7 +169,7 @@ namespace mongo {
             const AndSortedNode* asn = static_cast<const AndSortedNode*>(root);
             auto_ptr<AndSortedStage> ret(new AndSortedStage(ws, asn->filter.get()));
             for (size_t i = 0; i < asn->children.size(); ++i) {
-                PlanStage* childStage = buildStages(qsol, asn->children[i], ws);
+                PlanStage* childStage = buildStages(collection, qsol, asn->children[i], ws);
                 if (NULL == childStage) { return NULL; }
                 ret->addChild(childStage);
             }
@@ -180,7 +182,7 @@ namespace mongo {
             params.pattern = msn->sort;
             auto_ptr<MergeSortStage> ret(new MergeSortStage(params, ws));
             for (size_t i = 0; i < msn->children.size(); ++i) {
-                PlanStage* childStage = buildStages(qsol, msn->children[i], ws);
+                PlanStage* childStage = buildStages(collection, qsol, msn->children[i], ws);
                 if (NULL == childStage) { return NULL; }
                 ret->addChild(childStage);
             }
@@ -192,14 +194,14 @@ namespace mongo {
             params.gq = node->gq;
             params.filter = node->filter.get();
             params.indexKeyPattern = node->indexKeyPattern;
-            params.ns = qsol.ns;
+            params.collection = collection;
             return new TwoD(params, ws);
         }
         else if (STAGE_GEO_NEAR_2D == root->getType()) {
             const GeoNear2DNode* node = static_cast<const GeoNear2DNode*>(root);
             TwoDNearParams params;
             params.nearQuery = node->nq;
-            params.ns = qsol.ns;
+            params.collection = collection;
             params.indexKeyPattern = node->indexKeyPattern;
             params.filter = node->filter.get();
             params.numWanted = node->numWanted;
@@ -210,7 +212,7 @@ namespace mongo {
         else if (STAGE_GEO_NEAR_2DSPHERE == root->getType()) {
             const GeoNear2DSphereNode* node = static_cast<const GeoNear2DSphereNode*>(root);
             S2NearParams params;
-            params.ns = qsol.ns;
+            params.collection = collection;
             params.indexKeyPattern = node->indexKeyPattern;
             params.nearQuery = node->nq;
             params.baseBounds = node->baseBounds;
@@ -222,8 +224,6 @@ namespace mongo {
         else if (STAGE_TEXT == root->getType()) {
             const TextNode* node = static_cast<const TextNode*>(root);
 
-            Database* db = cc().database();
-            Collection* collection = db ? db->getCollection(qsol.ns) : NULL;
             if (NULL == collection) {
                 warning() << "Null collection for text";
                 return NULL;
@@ -239,7 +239,7 @@ namespace mongo {
                 static_cast<FTSAccessMethod*>( collection->getIndexCatalog()->getIndex( index ) );
             TextStageParams params(fam->getSpec());
 
-            params.ns = qsol.ns;
+            //params.collection = collection;
             params.index = index;
             params.spec = fam->getSpec();
             params.indexPrefix = node->indexPrefix;
@@ -258,23 +258,22 @@ namespace mongo {
         }
         else if (STAGE_SHARDING_FILTER == root->getType()) {
             const ShardingFilterNode* fn = static_cast<const ShardingFilterNode*>(root);
-            PlanStage* childStage = buildStages(qsol, fn->children[0], ws);
+            PlanStage* childStage = buildStages(collection, qsol, fn->children[0], ws);
             if (NULL == childStage) { return NULL; }
-            return new ShardFilterStage(shardingState.getCollectionMetadata(qsol.ns), ws, childStage);
+            return new ShardFilterStage(shardingState.getCollectionMetadata(collection->ns()),
+                                        ws, childStage);
         }
         else if (STAGE_KEEP_MUTATIONS == root->getType()) {
             const KeepMutationsNode* km = static_cast<const KeepMutationsNode*>(root);
-            PlanStage* childStage = buildStages(qsol, km->children[0], ws);
+            PlanStage* childStage = buildStages(collection, qsol, km->children[0], ws);
             if (NULL == childStage) { return NULL; }
             return new KeepMutationsStage(km->filter.get(), ws, childStage);
         }
         else if (STAGE_DISTINCT == root->getType()) {
             const DistinctNode* dn = static_cast<const DistinctNode*>(root);
 
-            Database* db = cc().database();
-            Collection* collection = db ? db->getCollection(qsol.ns) : NULL;
             if (NULL == collection) {
-                warning() << "Can't distinct-scan null namespace " << qsol.ns << endl;
+                warning() << "Can't distinct-scan null namespace";
                 return NULL;
             }
 
@@ -290,15 +289,8 @@ namespace mongo {
         else if (STAGE_COUNT == root->getType()) {
             const CountNode* cn = static_cast<const CountNode*>(root);
 
-            Database* db = cc().database();
-            if (NULL == db) {
-                warning() << "Can't fast-count null namespace (database null)" << qsol.ns << endl;
-                return NULL;
-            }
-
-            Collection* collection = db ? db->getCollection(qsol.ns) : NULL;
             if (NULL == collection) {
-                warning() << "Can't fast-count null namespace (collection null)" << qsol.ns << endl;
+                warning() << "Can't fast-count null namespace (collection null)";
                 return NULL;
             }
 
@@ -323,13 +315,15 @@ namespace mongo {
     }
 
     // static
-    bool StageBuilder::build(const QuerySolution& solution, PlanStage** rootOut,
+    bool StageBuilder::build(Collection* collection,
+                             const QuerySolution& solution,
+                             PlanStage** rootOut,
                              WorkingSet** wsOut) {
         QuerySolutionNode* root = solution.root.get();
         if (NULL == root) { return false; }
 
         auto_ptr<WorkingSet> ws(new WorkingSet());
-        PlanStage* stageRoot = buildStages(solution, root, ws.get());
+        PlanStage* stageRoot = buildStages(collection, solution, root, ws.get());
 
         if (NULL != stageRoot) {
             *rootOut = stageRoot;
diff --git a/src/mongo/db/query/stage_builder.h b/src/mongo/db/query/stage_builder.h
index c352fd1b9b6..4f3c5be8831 100644
--- a/src/mongo/db/query/stage_builder.h
+++ b/src/mongo/db/query/stage_builder.h
@@ -48,7 +48,10 @@ namespace mongo {
          *
          * Returns false otherwise.  *rootOut and *wsOut are invalid.
          */
-        static bool build(const QuerySolution& solution, PlanStage** rootOut, WorkingSet** wsOut);
+        static bool build(Collection* collection,
+                          const QuerySolution& solution,
+                          PlanStage** rootOut,
+                          WorkingSet** wsOut);
     };
 
 }  // namespace mongo
diff --git a/src/mongo/db/query/subplan_runner.cpp b/src/mongo/db/query/subplan_runner.cpp
index 8c9566b7f15..82d100bc0d1 100644
--- a/src/mongo/db/query/subplan_runner.cpp
+++ b/src/mongo/db/query/subplan_runner.cpp
@@ -249,7 +249,7 @@ namespace mongo {
                 for (size_t i = 0; i < solutions.size(); ++i) {
                     WorkingSet* ws;
                     PlanStage* root;
-                    verify(StageBuilder::build(*solutions[i], &root, &ws));
+                    verify(StageBuilder::build(_collection, *solutions[i], &root, &ws));
                     // Takes ownership of all arguments.
                     mpr->addPlan(solutions[i], root, ws);
                 }
@@ -336,7 +336,7 @@ namespace mongo {
         MultiPlanRunner* mpr = new MultiPlanRunner(_collection, _query.release());
         WorkingSet* ws;
         PlanStage* root;
-        verify(StageBuilder::build(*soln, &root, &ws));
+        verify(StageBuilder::build(_collection, *soln, &root, &ws));
         // Takes ownership of all arguments.
         mpr->addPlan(soln, root, ws);
 
diff --git a/src/mongo/db/repl/master_slave.cpp b/src/mongo/db/repl/master_slave.cpp
index 78b5cc8195c..83e1527ebcc 100644
--- a/src/mongo/db/repl/master_slave.cpp
+++ b/src/mongo/db/repl/master_slave.cpp
@@ -227,7 +227,8 @@ namespace mongo {
        and cursor in effect.
     */
     void ReplSource::loadAll(SourceVector &v) {
-        Client::Context ctx("local.sources");
+        const char* localSources = "local.sources";
+        Client::Context ctx(localSources);
         SourceVector old = v;
         v.clear();
 
@@ -236,7 +237,8 @@ namespace mongo {
             // check that no items are in sources other than that
             // add if missing
             int n = 0;
-            auto_ptr<Runner> runner(InternalPlanner::collectionScan("local.sources"));
+            auto_ptr<Runner> runner(InternalPlanner::collectionScan(localSources,
+                                                                    ctx.db()->getCollection(localSources)));
             BSONObj obj;
             Runner::RunnerState state;
             while (Runner::RUNNER_ADVANCED == (state = runner->getNext(&obj, NULL))) {
@@ -278,7 +280,8 @@ namespace mongo {
             }
         }
 
-        auto_ptr<Runner> runner(InternalPlanner::collectionScan("local.sources"));
+        auto_ptr<Runner> runner(InternalPlanner::collectionScan(localSources,
+                                                                ctx.db()->getCollection(localSources)));
         BSONObj obj;
         Runner::RunnerState state;
         while (Runner::RUNNER_ADVANCED == (state = runner->getNext(&obj, NULL))) {
diff --git a/src/mongo/db/repl/oplog.cpp b/src/mongo/db/repl/oplog.cpp
index 716bd8c7c83..c1308a85e43 100644
--- a/src/mongo/db/repl/oplog.cpp
+++ b/src/mongo/db/repl/oplog.cpp
@@ -625,7 +625,7 @@ namespace mongo {
                         if (collection == NULL ||
                             (indexCatalog->haveIdIndex() && Helpers::findById(collection, updateCriteria).isNull()) ||
                             // capped collections won't have an _id index
-                            (!indexCatalog->haveIdIndex() && Helpers::findOne(ns, updateCriteria, false).isNull())) {
+                            (!indexCatalog->haveIdIndex() && Helpers::findOne(collection, updateCriteria, false).isNull())) {
                             failedUpdate = true;
                             log() << "replication couldn't find doc: " << op.toString() << endl;
                         }
diff --git a/src/mongo/db/repl/replication_server_status.cpp b/src/mongo/db/repl/replication_server_status.cpp
index ff220122500..14164a2a63b 100644
--- a/src/mongo/db/repl/replication_server_status.cpp
+++ b/src/mongo/db/repl/replication_server_status.cpp
@@ -86,8 +86,10 @@ namespace mongo {
             int n = 0;
             list<BSONObj> src;
             {
-                Client::ReadContext ctx("local.sources", storageGlobalParams.dbpath);
-                auto_ptr<Runner> runner(InternalPlanner::collectionScan("local.sources"));
+                const char* localSources = "local.sources";
+                Client::ReadContext ctx(localSources, storageGlobalParams.dbpath);
+                auto_ptr<Runner> runner(InternalPlanner::collectionScan(localSources,
+                                                                        ctx.ctx().db()->getCollection(localSources)));
                 BSONObj obj;
                 Runner::RunnerState state;
                 while (Runner::RUNNER_ADVANCED == (state = runner->getNext(&obj, NULL))) {
diff --git a/src/mongo/db/repl/rs_rollback.cpp b/src/mongo/db/repl/rs_rollback.cpp
index 4c3c69e912c..250c55b0a71 100644
--- a/src/mongo/db/repl/rs_rollback.cpp
+++ b/src/mongo/db/repl/rs_rollback.cpp
@@ -229,8 +229,9 @@ namespace mongo {
         verify( Lock::isLocked() );
         Client::Context c(rsoplog);
 
-        boost::scoped_ptr<Runner> runner(
-            InternalPlanner::collectionScan(rsoplog, InternalPlanner::BACKWARD));
+        boost::scoped_ptr<Runner> runner(InternalPlanner::collectionScan(rsoplog,
+                                                                         c.db()->getCollection(rsoplog),
+                                                                         InternalPlanner::BACKWARD));
 
         BSONObj ourObj;
         DiskLoc ourLoc;
@@ -496,7 +497,7 @@ namespace mongo {
 
                 // Add the doc to our rollback file
                 BSONObj obj;
-                bool found = Helpers::findOne(d.ns, pattern, obj, false);
+                bool found = Helpers::findOne(c.db()->getCollection(d.ns), pattern, obj, false);
                 if ( found ) {
                     rs->goingToDelete( obj );
                 } else {
@@ -517,7 +518,7 @@ namespace mongo {
                                 /** todo: IIRC cappedTruncateAfter does not handle completely empty.  todo. */
                                 // this will crazy slow if no _id index.
                                 long long start = Listener::getElapsedTimeMillis();
-                                DiskLoc loc = Helpers::findOne(d.ns, pattern, false);
+                                DiskLoc loc = Helpers::findOne(collection, pattern, false);
                                 if( Listener::getElapsedTimeMillis() - start > 200 )
                                     log() << "replSet warning roll back slow no _id index for " << d.ns << " perhaps?" << rsLog;
                                 //would be faster but requires index: DiskLoc loc = Helpers::findById(nsd, pattern);
diff --git a/src/mongo/db/structure/catalog/namespace_details.cpp b/src/mongo/db/structure/catalog/namespace_details.cpp
index e369a477405..5acd5d98585 100644
--- a/src/mongo/db/structure/catalog/namespace_details.cpp
+++ b/src/mongo/db/structure/catalog/namespace_details.cpp
@@ -413,11 +413,11 @@ namespace mongo {
         Lock::assertWriteLocked( ns );
 
         string system_namespaces = nsToDatabaseSubstring(ns).toString() + ".system.namespaces";
+        Collection* coll = cc().database()->getCollection( system_namespaces );
 
-        DiskLoc oldLocation = Helpers::findOne( system_namespaces, BSON( "name" << ns ), false );
+        DiskLoc oldLocation = Helpers::findOne( coll, BSON( "name" << ns ), false );
         fassert( 17247, !oldLocation.isNull() );
 
-        Collection* coll = cc().database()->getCollection( system_namespaces );
         BSONObj oldEntry = coll->docFor( oldLocation );
 
         BSONObj newEntry = applyUpdateOperators( oldEntry , BSON( "$set" << BSON( "options.flags" << userFlags() ) ) );
diff --git a/src/mongo/dbtests/documentsourcetests.cpp b/src/mongo/dbtests/documentsourcetests.cpp
index 06ce6475e34..607ee1001c0 100644
--- a/src/mongo/dbtests/documentsourcetests.cpp
+++ b/src/mongo/dbtests/documentsourcetests.cpp
@@ -169,7 +169,7 @@ namespace DocumentSourceTests {
                 CanonicalQuery* cq;
                 uassertStatusOK(CanonicalQuery::canonicalize(ns, /*query=*/BSONObj(), &cq));
                 Runner* runnerBare;
-                uassertStatusOK(getRunner(cq, &runnerBare));
+                uassertStatusOK(getRunner(ctx.ctx().db()->getCollection(ns), cq, &runnerBare));
 
                 _runner.reset(runnerBare);
                 _runner->setYieldPolicy(Runner::YIELD_AUTO);
diff --git a/src/mongo/dbtests/namespacetests.cpp b/src/mongo/dbtests/namespacetests.cpp
index 2b2f69e3f4f..687d26776b6 100644
--- a/src/mongo/dbtests/namespacetests.cpp
+++ b/src/mongo/dbtests/namespacetests.cpp
@@ -1658,14 +1658,16 @@ namespace NamespaceTests {
 
                 DiskLoc last, first;
                 {
-                    auto_ptr<Runner> runner(
-                        InternalPlanner::collectionScan(ns(), InternalPlanner::BACKWARD));
+                    auto_ptr<Runner> runner(InternalPlanner::collectionScan(ns(),
+                                                                            collection(),
+                                                                            InternalPlanner::BACKWARD));
                     runner->getNext(NULL, &last);
                     ASSERT( !last.isNull() );
                 }
                 {
-                    auto_ptr<Runner> runner(
-                        InternalPlanner::collectionScan(ns(), InternalPlanner::FORWARD));
+                    auto_ptr<Runner> runner(InternalPlanner::collectionScan(ns(),
+                                                                            collection(),
+                                                                            InternalPlanner::FORWARD));
                     runner->getNext(NULL, &first);
                     ASSERT( !first.isNull() );
                     ASSERT( first != last ) ;
@@ -1676,14 +1678,16 @@ namespace NamespaceTests {
 
                 {
                     DiskLoc loc;
-                    auto_ptr<Runner> runner(
-                        InternalPlanner::collectionScan(ns(), InternalPlanner::FORWARD));
+                    auto_ptr<Runner> runner(InternalPlanner::collectionScan(ns(),
+                                                                            collection(),
+                                                                            InternalPlanner::FORWARD));
                     runner->getNext(NULL, &loc);
                     ASSERT( first == loc);
                 }
                 {
-                    auto_ptr<Runner> runner(
-                        InternalPlanner::collectionScan(ns(), InternalPlanner::BACKWARD));
+                    auto_ptr<Runner> runner(InternalPlanner::collectionScan(ns(),
+                                                                            collection(),
+                                                                            InternalPlanner::BACKWARD));
                     DiskLoc loc;
                     runner->getNext(NULL, &loc);
                     ASSERT( last != loc );
diff --git a/src/mongo/dbtests/oplogstarttests.cpp b/src/mongo/dbtests/oplogstarttests.cpp
index 3f4c725521d..0b8a168ae36 100644
--- a/src/mongo/dbtests/oplogstarttests.cpp
+++ b/src/mongo/dbtests/oplogstarttests.cpp
@@ -73,6 +73,10 @@ namespace OplogStartTests {
             return "oplogstarttests";
         }
 
+        Collection* collection() {
+            return _context.db()->getCollection( ns() );
+        }
+
         DBDirectClient *client() const { return &_client; }
 
         void setupFromQuery(const BSONObj& query) {
@@ -81,7 +85,7 @@ namespace OplogStartTests {
             ASSERT(s.isOK());
             _cq.reset(cq);
             _oplogws.reset(new WorkingSet());
-            _stage.reset(new OplogStart(_cq->ns(), _cq->root(), _oplogws.get()));
+            _stage.reset(new OplogStart(collection(), _cq->root(), _oplogws.get()));
         }
 
         void assertWorkingSetMemberHasId(WorkingSetID id, int expectedId) {
diff --git a/src/mongo/dbtests/plan_ranking.cpp b/src/mongo/dbtests/plan_ranking.cpp
index 991ffc6d316..df47ba579f1 100644
--- a/src/mongo/dbtests/plan_ranking.cpp
+++ b/src/mongo/dbtests/plan_ranking.cpp
@@ -111,7 +111,7 @@ namespace PlanRankingTests {
             for (size_t i = 0; i < solutions.size(); ++i) {
                 WorkingSet* ws;
                 PlanStage* root;
-                ASSERT(StageBuilder::build(*solutions[i], &root, &ws));
+                ASSERT(StageBuilder::build(collection, *solutions[i], &root, &ws));
                 // Takes ownership of all arguments.
                 _mpr->addPlan(solutions[i], root, ws);
             }
diff --git a/src/mongo/dbtests/query_multi_plan_runner.cpp b/src/mongo/dbtests/query_multi_plan_runner.cpp
index fadc0347a50..717035c5ce1 100644
--- a/src/mongo/dbtests/query_multi_plan_runner.cpp
+++ b/src/mongo/dbtests/query_multi_plan_runner.cpp
@@ -114,7 +114,7 @@ namespace QueryMultiPlanRunner {
 
             // Plan 1: CollScan with matcher.
             CollectionScanParams csparams;
-            csparams.ns = ns();
+            csparams.collection = ctx.ctx().db()->getCollection( ns() );
             csparams.direction = CollectionScanParams::FORWARD;
             auto_ptr<WorkingSet> secondWs(new WorkingSet());
             // Make the filter.
diff --git a/src/mongo/dbtests/query_single_solution_runner.cpp b/src/mongo/dbtests/query_single_solution_runner.cpp
index b11bc35aaed..2d6064b90d7 100644
--- a/src/mongo/dbtests/query_single_solution_runner.cpp
+++ b/src/mongo/dbtests/query_single_solution_runner.cpp
@@ -80,7 +80,7 @@ namespace QuerySingleSolutionRunner {
         SingleSolutionRunner* makeCollScanRunner(Client::Context& ctx,
                                                  BSONObj& filterObj) {
             CollectionScanParams csparams;
-            csparams.ns = ns();
+            csparams.collection = ctx.db()->getCollection( ns() );
             csparams.direction = CollectionScanParams::FORWARD;
             auto_ptr<WorkingSet> ws(new WorkingSet());
             // Parse the filter.
diff --git a/src/mongo/dbtests/query_stage_collscan.cpp b/src/mongo/dbtests/query_stage_collscan.cpp
index 04e5b64015c..47360cdf9a7 100644
--- a/src/mongo/dbtests/query_stage_collscan.cpp
+++ b/src/mongo/dbtests/query_stage_collscan.cpp
@@ -68,7 +68,7 @@ namespace QueryStageCollectionScan {
             insertTestData();
 
             CollectionScanParams params;
-            params.ns = ns();
+            params.collection = collection();
             params.direction = CollectionScanParams::FORWARD;
             params.tailable = false;
             params.start = DiskLoc();
@@ -321,7 +321,7 @@ namespace QueryStageCollectionScan {
 
             // Configure the scan.
             CollectionScanParams params;
-            params.ns = ns();
+            params.collection = ctx.ctx().db()->getCollection( ns() );
             params.direction = direction;
             params.tailable = false;
 
@@ -341,11 +341,13 @@ namespace QueryStageCollectionScan {
             return count;
         }
 
-        void getLocs(CollectionScanParams::Direction direction, vector<DiskLoc>* out) {
+        void getLocs(Collection* collection,
+                     CollectionScanParams::Direction direction,
+                     vector<DiskLoc>* out) {
             WorkingSet ws;
 
             CollectionScanParams params;
-            params.ns = ns();
+            params.collection = collection;
             params.direction = direction;
             params.tailable = false;
 
@@ -427,7 +429,7 @@ namespace QueryStageCollectionScan {
 
             // Configure the scan.
             CollectionScanParams params;
-            params.ns = ns();
+            params.collection = ctx.ctx().db()->getCollection( ns() );
             params.direction = CollectionScanParams::FORWARD;
             params.tailable = false;
 
@@ -457,7 +459,7 @@ namespace QueryStageCollectionScan {
             Client::ReadContext ctx(ns());
 
             CollectionScanParams params;
-            params.ns = ns();
+            params.collection = ctx.ctx().db()->getCollection( ns() );
             params.direction = CollectionScanParams::BACKWARD;
             params.tailable = false;
 
@@ -485,13 +487,15 @@ namespace QueryStageCollectionScan {
         void run() {
             Client::WriteContext ctx(ns());
 
+            Collection* coll = ctx.ctx().db()->getCollection( ns() );
+
             // Get the DiskLocs that would be returned by an in-order scan.
             vector<DiskLoc> locs;
-            getLocs(CollectionScanParams::FORWARD, &locs);
+            getLocs(coll, CollectionScanParams::FORWARD, &locs);
 
             // Configure the scan.
             CollectionScanParams params;
-            params.ns = ns();
+            params.collection = coll;
             params.direction = CollectionScanParams::FORWARD;
             params.tailable = false;
 
@@ -544,14 +548,15 @@ namespace QueryStageCollectionScan {
     public:
         void run() {
             Client::WriteContext ctx(ns());
+            Collection* coll = ctx.ctx().db()->getCollection(ns());
 
             // Get the DiskLocs that would be returned by an in-order scan.
             vector<DiskLoc> locs;
-            getLocs(CollectionScanParams::BACKWARD, &locs);
+            getLocs(coll, CollectionScanParams::BACKWARD, &locs);
 
             // Configure the scan.
             CollectionScanParams params;
-            params.ns = ns();
+            params.collection = coll;
             params.direction = CollectionScanParams::BACKWARD;
             params.tailable = false;
 
@@ -599,6 +604,7 @@ namespace QueryStageCollectionScan {
     public:
         void run() {
             Client::WriteContext ctx(ns());
+            Collection* coll = ctx.ctx().db()->getCollection(ns());
 
             // We want every result from our collscan to NOT be in memory, at least
             // the first time around.
@@ -609,11 +615,11 @@ namespace QueryStageCollectionScan {
 
             // Get the DiskLocs that would be returned by an in-order scan.
             vector<DiskLoc> locs;
-            getLocs(CollectionScanParams::FORWARD, &locs);
+            getLocs(coll, CollectionScanParams::FORWARD, &locs);
 
             // Configure the scan.
             CollectionScanParams params;
-            params.ns = ns();
+            params.collection = coll;
             params.direction = CollectionScanParams::FORWARD;
             params.tailable = false;
 
diff --git a/src/mongo/dbtests/query_stage_keep.cpp b/src/mongo/dbtests/query_stage_keep.cpp
index 8e4699950e8..46a990146f1 100644
--- a/src/mongo/dbtests/query_stage_keep.cpp
+++ b/src/mongo/dbtests/query_stage_keep.cpp
@@ -127,7 +127,7 @@ namespace QueryStageKeep {
 
             // Create a collscan to provide the 10 objects in the collection.
             CollectionScanParams params;
-            params.ns = ns();
+            params.collection = coll;
             params.direction = CollectionScanParams::FORWARD;
             params.tailable = false;
             params.start = DiskLoc();
diff --git a/src/mongo/dbtests/querytests.cpp b/src/mongo/dbtests/querytests.cpp
index 8c53cc324b7..82454857fab 100644
--- a/src/mongo/dbtests/querytests.cpp
+++ b/src/mongo/dbtests/querytests.cpp
@@ -115,10 +115,10 @@ namespace QueryTests {
             BSONObj query = fromjson( "{$or:[{b:2},{c:3}]}" );
             BSONObj ret;
             // Check findOne() returning object.
-            ASSERT( Helpers::findOne( ns(), query, ret, true ) );
+            ASSERT( Helpers::findOne( _collection, query, ret, true ) );
             ASSERT_EQUALS( string( "b" ), ret.firstElement().fieldName() );
             // Cross check with findOne() returning location.
-            ASSERT_EQUALS( ret, Helpers::findOne( ns(), query, true ).obj() );
+            ASSERT_EQUALS( ret, Helpers::findOne( _collection, query, true ).obj() );
         }
     };
     
@@ -130,20 +130,20 @@ namespace QueryTests {
             BSONObj ret;
 
             // Check findOne() returning object, allowing unindexed scan.
-            ASSERT( Helpers::findOne( ns(), query, ret, false ) );
+            ASSERT( Helpers::findOne( _collection, query, ret, false ) );
             // Check findOne() returning location, allowing unindexed scan.
-            ASSERT_EQUALS( ret, Helpers::findOne( ns(), query, false ).obj() );
+            ASSERT_EQUALS( ret, Helpers::findOne( _collection, query, false ).obj() );
             
             // Check findOne() returning object, requiring indexed scan without index.
-            ASSERT_THROWS( Helpers::findOne( ns(), query, ret, true ), MsgAssertionException );
+            ASSERT_THROWS( Helpers::findOne( _collection, query, ret, true ), MsgAssertionException );
             // Check findOne() returning location, requiring indexed scan without index.
-            ASSERT_THROWS( Helpers::findOne( ns(), query, true ), MsgAssertionException );
+            ASSERT_THROWS( Helpers::findOne( _collection, query, true ), MsgAssertionException );
 
             addIndex( BSON( "b" << 1 ) );
             // Check findOne() returning object, requiring indexed scan with index.
-            ASSERT( Helpers::findOne( ns(), query, ret, true ) );
+            ASSERT( Helpers::findOne( _collection, query, ret, true ) );
             // Check findOne() returning location, requiring indexed scan with index.
-            ASSERT_EQUALS( ret, Helpers::findOne( ns(), query, true ).obj() );
+            ASSERT_EQUALS( ret, Helpers::findOne( _collection, query, true ).obj() );
         }
     };
     
@@ -171,9 +171,9 @@ namespace QueryTests {
             insert( BSONObj() );
             BSONObj query;
             BSONObj ret;
-            ASSERT( Helpers::findOne( ns(), query, ret, false ) );
+            ASSERT( Helpers::findOne( _collection, query, ret, false ) );
             ASSERT( ret.isEmpty() );
-            ASSERT_EQUALS( ret, Helpers::findOne( ns(), query, false ).obj() );
+            ASSERT_EQUALS( ret, Helpers::findOne( _collection, query, false ).obj() );
         }
     };
     
@@ -1226,7 +1226,8 @@ namespace QueryTests {
             ASSERT_EQUALS( 50 , count() );
 
             BSONObj res;
-            ASSERT( Helpers::findOne( ns() , BSON( "_id" << 20 ) , res , true ) );
+            ASSERT( Helpers::findOne( ctx.ctx().db()->getCollection( ns() ),
+                                      BSON( "_id" << 20 ) , res , true ) );
             ASSERT_EQUALS( 40 , res["x"].numberInt() );
 
             ASSERT( Helpers::findById( cc(), ns() , BSON( "_id" << 20 ) , res ) );
@@ -1241,7 +1242,8 @@ namespace QueryTests {
             {
                 Timer t;
                 for ( int i=0; i<n; i++ ) {
-                    ASSERT( Helpers::findOne( ns() , BSON( "_id" << 20 ) , res , true ) );
+                    ASSERT( Helpers::findOne( ctx.ctx().db()->getCollection(ns()),
+                                              BSON( "_id" << 20 ), res, true ) );
                 }
                 slow = t.micros();
             }
diff --git a/src/mongo/dbtests/runner_registry.cpp b/src/mongo/dbtests/runner_registry.cpp
index 5e4bc4645dd..4a079fb1b93 100644
--- a/src/mongo/dbtests/runner_registry.cpp
+++ b/src/mongo/dbtests/runner_registry.cpp
@@ -63,7 +63,7 @@ namespace RunnerRegistry {
         Runner* getCollscan() {
             auto_ptr<WorkingSet> ws(new WorkingSet());
             CollectionScanParams params;
-            params.ns = ns();
+            params.collection = collection();
             params.direction = CollectionScanParams::FORWARD;
             params.tailable = false;
             auto_ptr<CollectionScan> scan(new CollectionScan(params, ws.get(), NULL));
@@ -87,6 +87,10 @@ namespace RunnerRegistry {
 
         int N() { return 50; }
 
+        Collection* collection() {
+            return _ctx->ctx().db()->getCollection( ns() );
+        }
+
         static const char* ns() { return "unittests.RunnerRegistryDiskLocInvalidation"; }
         static DBDirectClient _client;
         auto_ptr<Client::WriteContext> _ctx;