SERVER-13084: remove Client::database and make many things not use thread local versions

54 files changed, 206 insertions, 212 deletions

diff --git a/src/mongo/db/catalog/database.cpp b/src/mongo/db/catalog/database.cpp
index ece0e04db27..19bb36e66b3 100644
--- a/src/mongo/db/catalog/database.cpp
+++ b/src/mongo/db/catalog/database.cpp
@@ -359,8 +359,6 @@ namespace mongo {
             return true;
         }
 
-        verify( cc().database() == this );
-
         if (!getOrCreateProfileCollection(this, true, &errmsg))
             return false;
 
diff --git a/src/mongo/db/client.h b/src/mongo/db/client.h
index 8f3e5817c25..2ebfce97d2b 100644
--- a/src/mongo/db/client.h
+++ b/src/mongo/db/client.h
@@ -94,7 +94,6 @@ namespace mongo {
         string clientAddress(bool includePort=false) const;
         CurOp* curop() const { return _curOp; }
         Context* getContext() const { return _context; }
-        Database* database() const {  return _context ? _context->db() : 0; }
         const StringData desc() const { return _desc; }
         void setLastOp( OpTime op ) { _lastOp = op; }
         OpTime getLastOp() const { return _lastOp; }
diff --git a/src/mongo/db/cloner.cpp b/src/mongo/db/cloner.cpp
index 06a6a37a312..aa37056f340 100644
--- a/src/mongo/db/cloner.cpp
+++ b/src/mongo/db/cloner.cpp
@@ -84,7 +84,7 @@ namespace mongo {
        we need to fix up the value in the "ns" parameter so that the name prefix is correct on a
        copy to a new name.
     */
-    BSONObj fixindex(BSONObj o) {
+    BSONObj fixindex(const string& newDbName, BSONObj o) {
         BSONObjBuilder b;
         BSONObjIterator i(o);
         while ( i.moreWithEOO() ) {
@@ -101,7 +101,7 @@ namespace mongo {
                 uassert( 10024 , "bad ns field for index during dbcopy", e.type() == String);
                 const char *p = strchr(e.valuestr(), '.');
                 uassert( 10025 , "bad ns field for index during dbcopy [2]", p);
-                string newname = cc().database()->name() + p;
+                string newname = newDbName + p;
                 b.append("ns", newname);
             }
             else
@@ -174,7 +174,7 @@ namespace mongo {
                 BSONObj js = tmp;
                 if ( isindex ) {
                     verify(nsToCollectionSubstring(from_collection) == "system.indexes");
-                    js = fixindex(tmp);
+                    js = fixindex(context.db()->name(), tmp);
                     indexesToBuild->push_back( js.getOwned() );
                     continue;
                 }
@@ -315,7 +315,7 @@ namespace mongo {
         string temp = ctx.ctx().db()->name() + ".system.namespaces";
         BSONObj config = _conn->findOne(temp , BSON("name" << ns));
         if (config["options"].isABSONObj()) {
-            Status status = userCreateNS(ns.c_str(), config["options"].Obj(), logForRepl, 0);
+            Status status = userCreateNS(ctx.ctx().db(), ns, config["options"].Obj(), logForRepl, 0);
             if ( !status.isOK() ) {
                 errmsg = status.toString();
                 return false;
@@ -351,13 +351,13 @@ namespace mongo {
         }
         massert( 10289 ,  "useReplAuth is not written to replication log", !opts.useReplAuth || !opts.logForRepl );
 
-        string todb = cc().database()->name();
+        string todb = context.db()->name();
         stringstream a,b;
         a << "localhost:" << serverGlobalParams.port;
         b << "127.0.0.1:" << serverGlobalParams.port;
         bool masterSameProcess = ( a.str() == masterHost || b.str() == masterHost );
         if ( masterSameProcess ) {
-            if (opts.fromDB == todb && cc().database()->path() == storageGlobalParams.dbpath) {
+            if (opts.fromDB == todb && context.db()->path() == storageGlobalParams.dbpath) {
                 // guard against an "infinite" loop
                 /* if you are replicating, the local.sources config may be wrong if you get this */
                 errmsg = "can't clone from self (localhost).";
@@ -469,7 +469,7 @@ namespace mongo {
 
             {
                 /* we defer building id index for performance - building it in batch is much faster */
-                userCreateNS(to_name, options, opts.logForRepl, false);
+                userCreateNS(context.db(), to_name, options, opts.logForRepl, false);
             }
             LOG(1) << "\t\t cloning " << from_name << " -> " << to_name << endl;
             Query q;
@@ -485,7 +485,7 @@ namespace mongo {
                 bool old = inDBRepair;
                 try {
                     inDBRepair = true;
-                    Collection* c = cc().database()->getCollection( to_name );
+                    Collection* c = context.db()->getCollection( to_name );
                     if ( c )
                         c->getIndexCatalog()->ensureHaveIdIndex();
                     inDBRepair = old;
diff --git a/src/mongo/db/commands/apply_ops.cpp b/src/mongo/db/commands/apply_ops.cpp
index 9e2a18a1bf8..828fb61aa69 100644
--- a/src/mongo/db/commands/apply_ops.cpp
+++ b/src/mongo/db/commands/apply_ops.cpp
@@ -126,7 +126,7 @@ namespace mongo {
                 invariant(Lock::nested());
 
                 Client::Context ctx(ns);
-                bool failed = applyOperation_inlock(temp, false, alwaysUpsert);
+                bool failed = applyOperation_inlock(ctx.db(), temp, false, alwaysUpsert);
                 ab.append(!failed);
                 if ( failed )
                     errors++;
diff --git a/src/mongo/db/commands/collection_to_capped.cpp b/src/mongo/db/commands/collection_to_capped.cpp
index d7304afc31d..6e9c1f64056 100644
--- a/src/mongo/db/commands/collection_to_capped.cpp
+++ b/src/mongo/db/commands/collection_to_capped.cpp
@@ -66,7 +66,7 @@ namespace mongo {
             if ( temp )
                 spec.appendBool( "temp", true );
 
-            Status status = userCreateNS( toNs.c_str(), spec.done(), logForReplication );
+            Status status = userCreateNS( ctx.db(), toNs, spec.done(), logForReplication );
             if ( !status.isOK() )
                 return status;
         }
@@ -154,7 +154,7 @@ namespace mongo {
             Lock::DBWrite dbXLock(dbname);
             Client::Context ctx(dbname);
 
-            Status status = cloneCollectionAsCapped( cc().database(), from, to, size, temp, true );
+            Status status = cloneCollectionAsCapped( ctx.db(), from, to, size, temp, true );
             return appendCommandStatus( result, status );
         }
     } cmdCloneCollectionAsCapped;
@@ -200,7 +200,7 @@ namespace mongo {
             Lock::GlobalWrite globalWriteLock;
             Client::Context ctx(dbname);
 
-            Database* db = cc().database();
+            Database* db = ctx.db();
 
             stopIndexBuilds(db, jsobj);
             BackgroundOperation::assertNoBgOpInProgForDb(dbname.c_str());
diff --git a/src/mongo/db/commands/dbhash.cpp b/src/mongo/db/commands/dbhash.cpp
index 61e75e61e61..1b6936c6877 100644
--- a/src/mongo/db/commands/dbhash.cpp
+++ b/src/mongo/db/commands/dbhash.cpp
@@ -67,7 +67,7 @@ namespace mongo {
         out->push_back(Privilege(ResourcePattern::forDatabaseName(dbname), actions));
     }
 
-    string DBHashCmd::hashCollection( const string& fullCollectionName, bool* fromCache ) {
+    string DBHashCmd::hashCollection( Database* db, const string& fullCollectionName, bool* fromCache ) {
 
         scoped_ptr<scoped_lock> cachedHashedLock;
 
@@ -81,7 +81,7 @@ namespace mongo {
         }
 
         *fromCache = false;
-        Collection* collection = cc().database()->getCollection( fullCollectionName );
+        Collection* collection = db->getCollection( fullCollectionName );
         if ( !collection )
             return "";
 
@@ -147,11 +147,11 @@ namespace mongo {
             }
         }
 
+        list<string> colls;
         const string ns = parseNs(dbname, cmdObj);
-        Client::ReadContext ctx(ns);
 
-        list<string> colls;
-        Database* db = cc().database();
+        Client::ReadContext ctx(ns);
+        Database* db = ctx.ctx().db();
         if ( db )
             db->namespaceIndex().getNamespaces( colls );
         colls.sort();
@@ -181,7 +181,7 @@ namespace mongo {
                 continue;
 
             bool fromCache = false;
-            string hash = hashCollection( fullCollectionName, &fromCache );
+            string hash = hashCollection( db, fullCollectionName, &fromCache );
 
             bb.append( shortCollectionName, hash );
 
diff --git a/src/mongo/db/commands/dbhash.h b/src/mongo/db/commands/dbhash.h
index 175c5df100e..3853d5532e1 100644
--- a/src/mongo/db/commands/dbhash.h
+++ b/src/mongo/db/commands/dbhash.h
@@ -59,7 +59,7 @@ namespace mongo {
 
         bool isCachable( const StringData& ns ) const;
 
-        string hashCollection( const string& fullCollectionName, bool* fromCache );
+        string hashCollection( Database* db, const string& fullCollectionName, bool* fromCache );
 
         map<string,string> _cachedHashed;
         mutex _cachedHashedMutex;
diff --git a/src/mongo/db/commands/distinct.cpp b/src/mongo/db/commands/distinct.cpp
index 9e52a41074a..236867d4a1f 100644
--- a/src/mongo/db/commands/distinct.cpp
+++ b/src/mongo/db/commands/distinct.cpp
@@ -92,7 +92,7 @@ namespace mongo {
 
             Client::ReadContext ctx(ns);
 
-            Collection* collection = cc().database()->getCollection( ns );
+            Collection* collection = ctx.ctx().db()->getCollection( ns );
 
             if (!collection) {
                 result.appendArray( "values" , BSONObj() );
diff --git a/src/mongo/db/commands/drop_indexes.cpp b/src/mongo/db/commands/drop_indexes.cpp
index 27e01a7da5a..1936a6e9e07 100644
--- a/src/mongo/db/commands/drop_indexes.cpp
+++ b/src/mongo/db/commands/drop_indexes.cpp
@@ -102,14 +102,15 @@ namespace mongo {
 
             Lock::DBWrite dbXLock(dbname);
             Client::Context ctx(toDeleteNs);
+            Database* db = ctx.db();
 
-            Collection* collection = cc().database()->getCollection( toDeleteNs );
+            Collection* collection = db->getCollection( toDeleteNs );
             if ( ! collection ) {
                 errmsg = "ns not found";
                 return false;
             }
 
-            stopIndexBuilds(cc().database(), jsobj);
+            stopIndexBuilds(db, jsobj);
 
             IndexCatalog* indexCatalog = collection->getIndexCatalog();
             anObjBuilder.appendNumber("nIndexesWas", indexCatalog->numIndexesTotal() );
@@ -214,7 +215,7 @@ namespace mongo {
             Lock::DBWrite dbXLock(dbname);
             Client::Context ctx(toDeleteNs);
 
-            Collection* collection = cc().database()->getCollection( toDeleteNs );
+            Collection* collection = ctx.db()->getCollection( toDeleteNs );
 
             if ( !collection ) {
                 errmsg = "ns not found";
@@ -223,7 +224,7 @@ namespace mongo {
 
             BackgroundOperation::assertNoBgOpInProgForNs( toDeleteNs );
 
-            std::vector<BSONObj> indexesInProg = stopIndexBuilds(cc().database(), jsobj);
+            std::vector<BSONObj> indexesInProg = stopIndexBuilds(ctx.db(), jsobj);
 
             list<BSONObj> all;
             auto_ptr<DBClientCursor> i = db.query( dbname + ".system.indexes" , BSON( "ns" << toDeleteNs ) , 0 , 0 , 0 , QueryOption_SlaveOk );
diff --git a/src/mongo/db/commands/geonear.cpp b/src/mongo/db/commands/geonear.cpp
index 1df9385c43e..1fbd03524df 100644
--- a/src/mongo/db/commands/geonear.cpp
+++ b/src/mongo/db/commands/geonear.cpp
@@ -79,7 +79,7 @@ namespace mongo {
 
             Client::ReadContext ctx(ns);
 
-            Database* db = cc().database();
+            Database* db = ctx.ctx().db();
             if ( !db ) {
                 errmsg = "can't find ns";
                 return false;
diff --git a/src/mongo/db/commands/group.cpp b/src/mongo/db/commands/group.cpp
index e0e28264b13..95059c64380 100644
--- a/src/mongo/db/commands/group.cpp
+++ b/src/mongo/db/commands/group.cpp
@@ -87,7 +87,7 @@ namespace mongo {
             return obj.extractFields( keyPattern , true ).getOwned();
         }
 
-        bool group( const std::string& realdbname,
+        bool group( Database* db,
                     const std::string& ns,
                     const BSONObj& query,
                     BSONObj keyPattern,
@@ -101,7 +101,7 @@ namespace mongo {
 
             const string userToken = ClientBasic::getCurrent()->getAuthorizationSession()
                                                               ->getAuthenticatedUserNamesToken();
-            auto_ptr<Scope> s = globalScriptEngine->getPooledScope(realdbname, "group" + userToken);
+            auto_ptr<Scope> s = globalScriptEngine->getPooledScope(db->name(), "group" + userToken);
 
             if ( reduceScope )
                 s->init( reduceScope );
@@ -131,7 +131,7 @@ namespace mongo {
             double keysize = keyPattern.objsize() * 3;
             double keynum = 1;
 
-            Collection* collection = cc().database()->getCollection( ns );
+            Collection* collection = db->getCollection( ns );
 
             map<BSONObj,int,BSONObjCmp> map;
             list<BSONObj> blah;
@@ -255,7 +255,7 @@ namespace mongo {
             const string ns = parseNs(dbname, jsobj);
             Client::ReadContext ctx(ns);
 
-            return group( dbname , ns , q ,
+            return group( ctx.ctx().db() , ns , q ,
                           key , keyf , reduce._asCode() , reduce.type() != CodeWScope ? 0 : reduce.codeWScopeScopeDataUnsafe() ,
                           initial.embeddedObject() , finalize ,
                           errmsg , result );
diff --git a/src/mongo/db/commands/index_stats.cpp b/src/mongo/db/commands/index_stats.cpp
index 3ebf31b58e9..92bb1a944da 100644
--- a/src/mongo/db/commands/index_stats.cpp
+++ b/src/mongo/db/commands/index_stats.cpp
@@ -500,7 +500,7 @@ namespace mongo {
 
             Client::ReadContext ctx(nss.ns());
 
-            const Collection* collection = cc().database()->getCollection( nss.ns() );
+            const Collection* collection = ctx.ctx().db()->getCollection( nss.ns() );
             if (!collection) {
                 errmsg = "ns not found";
                 return false;
diff --git a/src/mongo/db/commands/parallel_collection_scan.cpp b/src/mongo/db/commands/parallel_collection_scan.cpp
index 32196ceff4b..57302169ae8 100644
--- a/src/mongo/db/commands/parallel_collection_scan.cpp
+++ b/src/mongo/db/commands/parallel_collection_scan.cpp
@@ -190,7 +190,7 @@ namespace mongo {
 
             Client::ReadContext ctx(ns.ns());
 
-            Database* db = cc().database();
+            Database* db = ctx.ctx().db();
             Collection* collection = db->getCollection( ns );
 
             if ( !collection )
diff --git a/src/mongo/db/commands/rename_collection.cpp b/src/mongo/db/commands/rename_collection.cpp
index ba90f5120a5..e7cc87a2a13 100644
--- a/src/mongo/db/commands/rename_collection.cpp
+++ b/src/mongo/db/commands/rename_collection.cpp
@@ -182,7 +182,7 @@ namespace mongo {
                         return false;
                     }
 
-                    Status s = cc().database()->dropCollection( target );
+                    Status s = ctx.db()->dropCollection( target );
                     if ( !s.isOK() ) {
                         errmsg = s.toString();
                         restoreIndexBuildsOnSource( indexesInProg, source );
diff --git a/src/mongo/db/commands/test_commands.cpp b/src/mongo/db/commands/test_commands.cpp
index 0553f314a12..a3560d6c15d 100644
--- a/src/mongo/db/commands/test_commands.cpp
+++ b/src/mongo/db/commands/test_commands.cpp
@@ -187,10 +187,11 @@ namespace mongo {
             NamespaceString nss( dbname, coll );
 
             Client::WriteContext ctx( nss.ns() );
-            Collection* collection = ctx.ctx().db()->getCollection( nss.ns() );
+            Database* db = ctx.ctx().db();
+            Collection* collection = db->getCollection( nss.ns() );
             massert( 13429, "emptycapped no such collection", collection );
 
-            std::vector<BSONObj> indexes = stopIndexBuilds(cc().database(), cmdObj);
+            std::vector<BSONObj> indexes = stopIndexBuilds(db, cmdObj);
 
             Status status = collection->truncate();
             if ( !status.isOK() )
diff --git a/src/mongo/db/commands/validate.cpp b/src/mongo/db/commands/validate.cpp
index a416085d32f..2cb7c623a0b 100644
--- a/src/mongo/db/commands/validate.cpp
+++ b/src/mongo/db/commands/validate.cpp
@@ -77,8 +77,7 @@ namespace mongo {
             }
 
             Client::ReadContext ctx(ns_string.ns());
-
-            Database* db = cc().database();
+            Database* db = ctx.ctx().db();
             if ( !db ) {
                 errmsg = "database not found";
                 return false;
diff --git a/src/mongo/db/dbcommands.cpp b/src/mongo/db/dbcommands.cpp
index fdedbb125a1..00dfa9179fa 100644
--- a/src/mongo/db/dbcommands.cpp
+++ b/src/mongo/db/dbcommands.cpp
@@ -214,7 +214,7 @@ namespace mongo {
 
                 Client::Context context(dbname);
                 stopIndexBuilds(context.db(), cmdObj);
-                dropDatabase(dbname);
+                dropDatabase(context.db());
 
                 log() << "dropDatabase " << dbname << " finished";
             }
@@ -358,7 +358,7 @@ namespace mongo {
             Client::Context ctx(dbname);
 
             BSONElement e = cmdObj.firstElement();
-            result.append("was", cc().database()->getProfilingLevel());
+            result.append("was", ctx.db()->getProfilingLevel());
             result.append("slowms", serverGlobalParams.slowMS);
 
             int p = (int) e.number();
@@ -367,7 +367,7 @@ namespace mongo {
             if ( p == -1 )
                 ok = true;
             else if ( p >= 0 && p <= 2 ) {
-                ok = cc().database()->setProfilingLevel( p , errmsg );
+                ok = ctx.db()->setProfilingLevel( p , errmsg );
             }
 
             BSONElement slow = cmdObj["slowms"];
@@ -482,8 +482,9 @@ namespace mongo {
 
             Lock::DBWrite dbXLock(dbname);
             Client::Context ctx(nsToDrop);
+            Database* db = ctx.db();
 
-            Collection* coll = cc().database()->getCollection( nsToDrop );
+            Collection* coll = db->getCollection( nsToDrop );
             // If collection does not exist, short circuit and return.
             if ( !coll ) {
                 errmsg = "ns not found";
@@ -492,12 +493,12 @@ namespace mongo {
 
             int numIndexes = coll->getIndexCatalog()->numIndexesTotal();
 
-            stopIndexBuilds(cc().database(), cmdObj);
+            stopIndexBuilds(db, cmdObj);
 
             result.append( "ns", nsToDrop );
             result.append( "nIndexesWas", numIndexes );
 
-            Status s = cc().database()->dropCollection( nsToDrop );
+            Status s = db->dropCollection( nsToDrop );
 
             if ( s.isOK() )
                 return true;
@@ -649,7 +650,7 @@ namespace mongo {
 
             // Create collection.
             return appendCommandStatus( result,
-                                        userCreateNS(ns.c_str(), options, !fromRepl) );
+                                        userCreateNS(ctx.db(), ns.c_str(), options, !fromRepl) );
         }
     } cmdCreate;
 
@@ -1339,10 +1340,10 @@ namespace mongo {
             }
 
             const string ns = parseNs(dbname, jsobj);
-            Client::ReadContext ctx(ns);
-
             list<string> collections;
-            Database* d = cc().database();
+
+            Client::ReadContext ctx(ns);
+            Database* d = ctx.ctx().db();
 
             if ( d && ( d->isEmpty() || d->getExtentManager().numFiles() == 0 ) )
                 d = NULL;
diff --git a/src/mongo/db/dbhelpers.cpp b/src/mongo/db/dbhelpers.cpp
index 6ffaaf6c2fc..91a433cef4a 100644
--- a/src/mongo/db/dbhelpers.cpp
+++ b/src/mongo/db/dbhelpers.cpp
@@ -60,17 +60,6 @@ namespace mongo {
 
     const BSONObj reverseNaturalObj = BSON( "$natural" << -1 );
 
-    void Helpers::ensureIndex(const char *ns, BSONObj keyPattern, bool unique, const char *name) {
-        Database* db = cc().database();
-        verify(db);
-
-        Collection* collection = db->getCollection( ns );
-        if ( !collection )
-            return;
-
-        ensureIndex( collection, keyPattern, unique, name );
-    }
-
     void Helpers::ensureIndex(Collection* collection,
                               BSONObj keyPattern, bool unique, const char *name) {
         BSONObjBuilder b;
@@ -122,11 +111,10 @@ namespace mongo {
         return DiskLoc();
     }
 
-    bool Helpers::findById(Client& c, const char *ns, BSONObj query, BSONObj& result ,
+    bool Helpers::findById(Database* database, const char *ns, BSONObj query, BSONObj& result ,
                            bool* nsFound , bool* indexFound ) {
         Lock::assertAtLeastReadLocked(ns);
-        Database *database = c.database();
-        verify( database );
+        invariant( database );
 
         Collection* collection = database->getCollection( ns );
         if ( !collection ) {
@@ -295,11 +283,11 @@ namespace mongo {
         return kpBuilder.obj();
     }
 
-    bool findShardKeyIndexPattern_inlock( const string& ns,
-                                          const BSONObj& shardKeyPattern,
-                                          BSONObj* indexPattern ) {
-        verify( Lock::isLocked() );
-        Collection* collection = cc().database()->getCollection( ns );
+    bool findShardKeyIndexPattern( const string& ns,
+                                   const BSONObj& shardKeyPattern,
+                                   BSONObj* indexPattern ) {
+        Client::ReadContext context( ns );
+        Collection* collection = context.ctx().db()->getCollection( ns );
         if ( !collection )
             return false;
 
@@ -316,13 +304,6 @@ namespace mongo {
         return true;
     }
 
-    bool findShardKeyIndexPattern( const string& ns,
-                                   const BSONObj& shardKeyPattern,
-                                   BSONObj* indexPattern ) {
-        Client::ReadContext context( ns );
-        return findShardKeyIndexPattern_inlock( ns, shardKeyPattern, indexPattern );
-    }
-
     long long Helpers::removeRange( const KeyRange& range,
                                     bool maxInclusive,
                                     bool secondaryThrottle,
@@ -372,7 +353,8 @@ namespace mongo {
             {
                 Client::WriteContext ctx(ns);
                 Collection* collection = ctx.ctx().db()->getCollection( ns );
-                if ( !collection ) break;
+                if ( !collection )
+                    break;
 
                 IndexDescriptor* desc =
                     collection->getIndexCatalog()->findIndexByKeyPattern( indexKeyPattern.toBSON() );
@@ -383,7 +365,6 @@ namespace mongo {
                                                                    InternalPlanner::IXSCAN_FETCH));
 
                 runner->setYieldPolicy(Runner::YIELD_AUTO);
-
                 DiskLoc rloc;
                 BSONObj obj;
                 Runner::RunnerState state;
@@ -422,12 +403,11 @@ namespace mongo {
                         break;
                     }
                 }
-
                 if ( callback )
                     callback->goingToDelete( obj );
 
                 logOp("d", ns.c_str(), obj["_id"].wrap(), 0, 0, fromMigrate);
-                c.database()->getCollection( ns )->deleteDocument( rloc );
+                collection->deleteDocument( rloc );
                 numDeleted++;
             }
 
diff --git a/src/mongo/db/dbhelpers.h b/src/mongo/db/dbhelpers.h
index 15aa8d96e77..86a40682ced 100644
--- a/src/mongo/db/dbhelpers.h
+++ b/src/mongo/db/dbhelpers.h
@@ -63,9 +63,6 @@ namespace mongo {
 
            Note: does nothing if collection does not yet exist.
         */
-        static void ensureIndex(const char *ns, BSONObj keyPattern, bool unique, const char *name);
-
-        // same as other ensureIndex
         static void ensureIndex(Collection* collection,
                                 BSONObj keyPattern, bool unique, const char *name);
 
@@ -94,8 +91,8 @@ namespace mongo {
          * @param foundIndex if passed in will be set to 1 if ns and index found
          * @return true if object found
          */
-        static bool findById(Client&, const char *ns, BSONObj query, BSONObj& result ,
-                             bool * nsFound = 0 , bool * indexFound = 0 );
+        static bool findById(Database* db, const char *ns, BSONObj query, BSONObj& result,
+                             bool* nsFound = 0, bool* indexFound = 0 );
 
         /* TODO: should this move into Collection?
          * uasserts if no _id index.
diff --git a/src/mongo/db/exec/stagedebug_cmd.cpp b/src/mongo/db/exec/stagedebug_cmd.cpp
index f2af118dc6d..c0596bc16c1 100644
--- a/src/mongo/db/exec/stagedebug_cmd.cpp
+++ b/src/mongo/db/exec/stagedebug_cmd.cpp
@@ -114,10 +114,9 @@ namespace mongo {
             OwnedPointerVector<MatchExpression> exprs;
             auto_ptr<WorkingSet> ws(new WorkingSet());
 
-            const string ns = parseNs(dbname, cmdObj);
-            Client::ReadContext ctx(ns);
+            Client::ReadContext ctx(dbname);
 
-            PlanStage* userRoot = parseQuery(dbname, argObj, ws.get(), &exprs);
+            PlanStage* userRoot = parseQuery(ctx.ctx().db(), argObj, ws.get(), &exprs);
             uassert(16911, "Couldn't parse plan from " + argObj.toString(), NULL != userRoot);
 
             // Add a fetch at the top for the user so we can get obj back for sure.
@@ -136,7 +135,7 @@ namespace mongo {
             return true;
         }
 
-        PlanStage* parseQuery(const string& dbname, BSONObj obj, WorkingSet* workingSet,
+        PlanStage* parseQuery(Database* db, BSONObj obj, WorkingSet* workingSet,
                               OwnedPointerVector<MatchExpression>* exprs) {
             BSONElement firstElt = obj.firstElement();
             if (!firstElt.isABSONObj()) { return NULL; }
@@ -176,8 +175,7 @@ namespace mongo {
 
             if ("ixscan" == nodeName) {
 
-                Database* db = cc().database();
-                Collection* collection = db->getCollection( dbname + "." + nodeArgs["name"].String() );
+                Collection* collection = db->getCollection( db->name() + "." + nodeArgs["name"].String() );
                 uassert(16913, "Can't find collection " + nodeArgs["name"].String(), collection);
 
                 IndexDescriptor* desc =
@@ -207,7 +205,7 @@ namespace mongo {
                     uassert(16922, "node of AND isn't an obj?: " + e.toString(),
                             e.isABSONObj());
 
-                    PlanStage* subNode = parseQuery(dbname, e.Obj(), workingSet, exprs);
+                    PlanStage* subNode = parseQuery(db, e.Obj(), workingSet, exprs);
                     uassert(16923, "Can't parse sub-node of AND: " + e.Obj().toString(),
                             NULL != subNode);
                     // takes ownership
@@ -233,7 +231,7 @@ namespace mongo {
                     uassert(16925, "node of AND isn't an obj?: " + e.toString(),
                             e.isABSONObj());
 
-                    PlanStage* subNode = parseQuery(dbname, e.Obj(), workingSet, exprs);
+                    PlanStage* subNode = parseQuery(db, e.Obj(), workingSet, exprs);
                     uassert(16926, "Can't parse sub-node of AND: " + e.Obj().toString(),
                             NULL != subNode);
                     // takes ownership
@@ -256,7 +254,7 @@ namespace mongo {
                 while (it.more()) {
                     BSONElement e = it.next();
                     if (!e.isABSONObj()) { return NULL; }
-                    PlanStage* subNode = parseQuery(dbname, e.Obj(), workingSet, exprs);
+                    PlanStage* subNode = parseQuery(db, e.Obj(), workingSet, exprs);
                     uassert(16936, "Can't parse sub-node of OR: " + e.Obj().toString(),
                             NULL != subNode);
                     // takes ownership
@@ -268,7 +266,7 @@ namespace mongo {
             else if ("fetch" == nodeName) {
                 uassert(16929, "Node argument must be provided to fetch",
                         nodeArgs["node"].isABSONObj());
-                PlanStage* subNode = parseQuery(dbname, nodeArgs["node"].Obj(), workingSet, exprs);
+                PlanStage* subNode = parseQuery(db, nodeArgs["node"].Obj(), workingSet, exprs);
                 return new FetchStage(workingSet, subNode, matcher);
             }
             else if ("limit" == nodeName) {
@@ -278,7 +276,7 @@ namespace mongo {
                         nodeArgs["node"].isABSONObj());
                 uassert(16931, "Num argument must be provided to limit",
                         nodeArgs["num"].isNumber());
-                PlanStage* subNode = parseQuery(dbname, nodeArgs["node"].Obj(), workingSet, exprs);
+                PlanStage* subNode = parseQuery(db, nodeArgs["node"].Obj(), workingSet, exprs);
                 return new LimitStage(nodeArgs["num"].numberInt(), workingSet, subNode);
             }
             else if ("skip" == nodeName) {
@@ -288,15 +286,15 @@ namespace mongo {
                         nodeArgs["node"].isABSONObj());
                 uassert(16933, "Num argument must be provided to skip",
                         nodeArgs["num"].isNumber());
-                PlanStage* subNode = parseQuery(dbname, nodeArgs["node"].Obj(), workingSet, exprs);
+                PlanStage* subNode = parseQuery(db, nodeArgs["node"].Obj(), workingSet, exprs);
                 return new SkipStage(nodeArgs["num"].numberInt(), workingSet, subNode);
             }
             else if ("cscan" == nodeName) {
                 CollectionScanParams params;
 
                 // What collection?
-                string ns = dbname + "." + nodeArgs["name"].String();
-                params.collection = cc().database()->getCollection(ns);
+                string ns = db->name() + "." + nodeArgs["name"].String();
+                params.collection = db->getCollection(ns);
                 uassert(16962, "Can't find collection " + ns, NULL != params.collection );
 
                 // What direction?
@@ -318,7 +316,7 @@ namespace mongo {
                         nodeArgs["node"].isABSONObj());
                 uassert(16970, "Pattern argument must be provided to sort",
                         nodeArgs["pattern"].isABSONObj());
-                PlanStage* subNode = parseQuery(dbname, nodeArgs["node"].Obj(), workingSet, exprs);
+                PlanStage* subNode = parseQuery(db, nodeArgs["node"].Obj(), workingSet, exprs);
                 SortStageParams params;
                 params.pattern = nodeArgs["pattern"].Obj();
                 return new SortStage(params, workingSet, subNode);
@@ -342,7 +340,7 @@ namespace mongo {
                     uassert(16973, "node of mergeSort isn't an obj?: " + e.toString(),
                             e.isABSONObj());
 
-                    PlanStage* subNode = parseQuery(dbname, e.Obj(), workingSet, exprs);
+                    PlanStage* subNode = parseQuery(db, e.Obj(), workingSet, exprs);
                     uassert(16974, "Can't parse sub-node of mergeSort: " + e.Obj().toString(),
                             NULL != subNode);
                     // takes ownership
@@ -353,7 +351,6 @@ namespace mongo {
             else if ("text" == nodeName) {
                 string ns = nodeArgs["name"].String();
                 string search = nodeArgs["search"].String();
-                Database* db = cc().database();
                 Collection* collection = db->getCollection( ns );
                 uassert(17193, "Can't find namespace " + ns, collection);
                 vector<IndexDescriptor*> idxMatches;
diff --git a/src/mongo/db/geo/haystack.cpp b/src/mongo/db/geo/haystack.cpp
index b8250ee1a30..7b8699533cb 100644
--- a/src/mongo/db/geo/haystack.cpp
+++ b/src/mongo/db/geo/haystack.cpp
@@ -73,7 +73,7 @@ namespace mongo {
             const string ns = dbname + "." + cmdObj.firstElement().valuestr();
             Client::ReadContext ctx(ns);
 
-            Database* db = cc().database();
+            Database* db = ctx.ctx().db();
             if ( !db ) {
                 errmsg = "can't find ns";
                 return false;
diff --git a/src/mongo/db/index_rebuilder.cpp b/src/mongo/db/index_rebuilder.cpp
index 734b7bf75b2..35969190807 100644
--- a/src/mongo/db/index_rebuilder.cpp
+++ b/src/mongo/db/index_rebuilder.cpp
@@ -62,7 +62,7 @@ namespace mongo {
                  dbName < dbNames.end();
                  dbName++) {
                 Client::ReadContext ctx(*dbName);
-                Database* db = cc().database();
+                Database* db = ctx.ctx().db();
                 db->namespaceIndex().getNamespaces(collNames, /* onlyCollections */ true);
             }
             checkNS(collNames);
diff --git a/src/mongo/db/introspect.cpp b/src/mongo/db/introspect.cpp
index 9d466d51249..4f18011d2fb 100644
--- a/src/mongo/db/introspect.cpp
+++ b/src/mongo/db/introspect.cpp
@@ -79,9 +79,9 @@ namespace {
     }
 } // namespace
 
-    static void _profile(const Client& c, CurOp& currentOp, BufBuilder& profileBufBuilder) {
-        Database *db = c.database();
-        DEV verify( db );
+    static void _profile(const Client& c, Database* db,
+                         CurOp& currentOp, BufBuilder& profileBufBuilder) {
+        dassert( db );
 
         // build object
         BSONObjBuilder b(profileBufBuilder);
@@ -137,7 +137,8 @@ namespace {
             Lock::DBWrite lk( currentOp.getNS() );
             if (dbHolder()._isLoaded(nsToDatabase(currentOp.getNS()), storageGlobalParams.dbpath)) {
                 Client::Context cx(currentOp.getNS(), storageGlobalParams.dbpath, false);
-                _profile(c, currentOp, profileBufBuilder);
+                _profile(c, cx.db(),
+                         currentOp, profileBufBuilder);
             }
             else {
                 mongo::log() << "note: not profiling because db went away - probably a close on: "
diff --git a/src/mongo/db/ops/delete_executor.cpp b/src/mongo/db/ops/delete_executor.cpp
index c5afe38374a..a7007e8df2c 100644
--- a/src/mongo/db/ops/delete_executor.cpp
+++ b/src/mongo/db/ops/delete_executor.cpp
@@ -101,12 +101,14 @@ namespace mongo {
             }
         }
 
+        Database* db = currentClient.get()->getContext()->db();
+
         massert(17418,
                 mongoutils::str::stream() <<
-                "dbname = " << currentClient.get()->database()->name() <<
+                "dbname = " << db->name() <<
                 "; ns = " << ns.ns(),
-                currentClient.get()->database()->name() == nsToDatabaseSubstring(ns.ns()));
-        Collection* collection = currentClient.get()->database()->getCollection(ns.ns());
+                db->name() == nsToDatabaseSubstring(ns.ns()));
+        Collection* collection = db->getCollection(ns.ns());
         if (NULL == collection) {
             return 0;
         }
diff --git a/src/mongo/db/ops/update.cpp b/src/mongo/db/ops/update.cpp
index 8bdb532e860..50ff3a30379 100644
--- a/src/mongo/db/ops/update.cpp
+++ b/src/mongo/db/ops/update.cpp
@@ -405,7 +405,7 @@ namespace mongo {
             }
 
             Collection* oldCollection = collection;
-            collection = cc().database()->getCollection(nsString.ns());
+            collection = cc().getContext()->db()->getCollection(nsString.ns());
 
             // We should not get a new pointer to the same collection...
             if (oldCollection && (oldCollection != collection))
@@ -500,7 +500,7 @@ namespace mongo {
         const NamespaceString& nsString = request.getNamespaceString();
         UpdateLifecycle* lifecycle = request.getLifecycle();
         const CurOp* curOp = cc().curop();
-        Collection* collection = cc().database()->getCollection(nsString.ns());
+        Collection* collection = cc().getContext()->db()->getCollection(nsString.ns());
 
         validateUpdate(nsString.ns().c_str(), request.getUpdates(), request.getQuery());
 
@@ -874,9 +874,10 @@ namespace mongo {
 
         // Only create the collection if the doc will be inserted.
         if (!collection) {
-            collection = cc().database()->getCollection(request.getNamespaceString().ns());
+            Database* db = cc().getContext()->db();
+            collection = db->getCollection(request.getNamespaceString().ns());
             if (!collection) {
-                collection = cc().database()->createCollection(request.getNamespaceString().ns());
+                collection = db->createCollection(request.getNamespaceString().ns());
             }
         }
 
diff --git a/src/mongo/db/pdfile.cpp b/src/mongo/db/pdfile.cpp
index 655c1a6041e..4cc0552ebc0 100644
--- a/src/mongo/db/pdfile.cpp
+++ b/src/mongo/db/pdfile.cpp
@@ -106,19 +106,20 @@ namespace mongo {
      * @param createDefaultIndexes - if false, defers id (and other) index creation.
      * @return true if successful
     */
-    Status userCreateNS( const StringData& ns,
+    Status userCreateNS( Database* db,
+                         const StringData& ns,
                          BSONObj options,
                          bool logForReplication,
                          bool createDefaultIndexes ) {
 
+        invariant( db );
+
         LOG(1) << "create collection " << ns << ' ' << options;
 
         if ( !NamespaceString::validCollectionComponent(ns) )
             return Status( ErrorCodes::InvalidNamespace,
                            str::stream() << "invalid ns: " << ns );
 
-        Database* db = cc().database();
-
         Collection* collection = db->getCollection( ns );
 
         if ( collection )
@@ -156,21 +157,22 @@ namespace mongo {
         for( vector<string>::iterator i = n.begin(); i != n.end(); i++ ) {
             if( *i != "local" ) {
                 Client::Context ctx(*i);
-                dropDatabase(*i);
+                dropDatabase(ctx.db());
             }
         }
     }
 
-    void dropDatabase(const std::string& db) {
-        LOG(1) << "dropDatabase " << db << endl;
-        Lock::assertWriteLocked(db);
-        Database *d = cc().database();
-        verify( d );
-        verify( d->name() == db );
+    void dropDatabase(Database* db ) {
+        invariant( db );
+
+        string name = db->name(); // just to have safe
+        LOG(1) << "dropDatabase " << name << endl;
+
+        Lock::assertWriteLocked( name );
 
-        BackgroundOperation::assertNoBgOpInProgForDb(d->name().c_str());
+        BackgroundOperation::assertNoBgOpInProgForDb(name.c_str());
 
-        audit::logDropDatabase( currentClient.get(), db );
+        audit::logDropDatabase( currentClient.get(), name );
 
         // Not sure we need this here, so removed.  If we do, we need to move it down
         // within other calls both (1) as they could be called from elsewhere and
@@ -181,10 +183,10 @@ namespace mongo {
 
         getDur().syncDataAndTruncateJournal();
 
-        Database::closeDatabase( d->name(), d->path() );
-        d = 0; // d is now deleted
+        Database::closeDatabase( name, db->path() );
+        db = 0; // d is now deleted
 
-        _deleteDataFiles( db );
+        _deleteDataFiles( name );
     }
 
 } // namespace mongo
diff --git a/src/mongo/db/pdfile.h b/src/mongo/db/pdfile.h
index ca89b1586da..0d347d09e64 100644
--- a/src/mongo/db/pdfile.h
+++ b/src/mongo/db/pdfile.h
@@ -44,9 +44,12 @@
 
 namespace mongo {
 
-    void dropDatabase(const std::string& db);
+    class Database;
 
-    Status userCreateNS( const StringData& ns,
+    void dropDatabase(Database* db);
+
+    Status userCreateNS( Database* db,
+                         const StringData& ns,
                          BSONObj options,
                          bool logForReplication,
                          bool createDefaultIndexes = true );
diff --git a/src/mongo/db/prefetch.cpp b/src/mongo/db/prefetch.cpp
index ee1646288e8..fdcd3bc2c75 100644
--- a/src/mongo/db/prefetch.cpp
+++ b/src/mongo/db/prefetch.cpp
@@ -56,7 +56,7 @@ namespace mongo {
                                                     &prefetchDocStats );
 
     // prefetch for an oplog operation
-    void prefetchPagesForReplicatedOp(const BSONObj& op) {
+    void prefetchPagesForReplicatedOp(Database* db, const BSONObj& op) {
         const char *opField;
         const char *opType = op.getStringField("op");
         switch (*opType) {
@@ -75,10 +75,6 @@ namespace mongo {
         BSONObj obj = op.getObjectField(opField);
         const char *ns = op.getStringField("ns");
 
-        Database* db = cc().database();
-        if ( !db )
-            return;
-
         Collection* collection = db->getCollection( ns );
         if ( !collection )
             return;
@@ -185,12 +181,12 @@ namespace mongo {
                 // we can probably use Client::Context here instead of ReadContext as we
                 // have locked higher up the call stack already
                 Client::ReadContext ctx( ns );
-                if( Helpers::findById(cc(), ns, builder.done(), result) ) {
+                if( Helpers::findById(ctx.ctx().db(), ns, builder.done(), result) ) {
                     // do we want to use Record::touch() here?  it's pretty similar.
                     volatile char _dummy_char = '\0';
                     // Touch the first word on every page in order to fault it into memory
-                    for (int i = 0; i < result.objsize(); i += g_minOSPageSizeBytes) {                        
-                        _dummy_char += *(result.objdata() + i); 
+                    for (int i = 0; i < result.objsize(); i += g_minOSPageSizeBytes) {
+                        _dummy_char += *(result.objdata() + i);
                     }
                     // hit the last page, in case we missed it above
                     _dummy_char += *(result.objdata() + result.objsize() - 1);
diff --git a/src/mongo/db/prefetch.h b/src/mongo/db/prefetch.h
index d70a662a754..3e97753da23 100644
--- a/src/mongo/db/prefetch.h
+++ b/src/mongo/db/prefetch.h
@@ -32,8 +32,10 @@
 
 namespace mongo {
     class Collection;
+    class Database;
+
     // page in both index and data pages for an op from the oplog
-    void prefetchPagesForReplicatedOp(const BSONObj& op);
+    void prefetchPagesForReplicatedOp(Database* db, const BSONObj& op);
 
     // page in pages needed for all index lookups on a given object
     void prefetchIndexPages(Collection *nsd, const BSONObj& obj);
diff --git a/src/mongo/db/query/cached_plan_runner.cpp b/src/mongo/db/query/cached_plan_runner.cpp
index 08c944b9b8d..60d72b4aa12 100644
--- a/src/mongo/db/query/cached_plan_runner.cpp
+++ b/src/mongo/db/query/cached_plan_runner.cpp
@@ -185,7 +185,7 @@ namespace mongo {
         // 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();
+        Database* db = cc().getContext()->db();
         if (NULL == db) { return; }
         Collection* collection = db->getCollection(_canonicalQuery->ns());
         if (NULL == collection) { return; }
diff --git a/src/mongo/db/query/multi_plan_runner.cpp b/src/mongo/db/query/multi_plan_runner.cpp
index 4547b92e3e2..316fddc7689 100644
--- a/src/mongo/db/query/multi_plan_runner.cpp
+++ b/src/mongo/db/query/multi_plan_runner.cpp
@@ -293,7 +293,7 @@ namespace mongo {
             // cached plan runner to fall back on a different solution
             // if the best solution fails. Alternatively we could try to
             // defer cache insertion to be after the first produced result.
-            Database* db = cc().database();
+            Database* db = cc().getContext()->db();
             verify(NULL != db);
             Collection* collection = db->getCollection(_query->ns());
             verify(NULL != collection);
@@ -397,7 +397,7 @@ namespace mongo {
         const PlanStageStats* bestStats = _ranking->stats.vector()[0];
         if (PlanCache::shouldCacheQuery(*_query)
             && (!_alreadyProduced.empty() || bestStats->common.isEOF)) {
-            Database* db = cc().database();
+            Database* db = cc().getContext()->db();
             verify(NULL != db);
             Collection* collection = db->getCollection(_query->ns());
             verify(NULL != collection);
diff --git a/src/mongo/db/repair_database.cpp b/src/mongo/db/repair_database.cpp
index b28859b5237..31db42f7fa3 100644
--- a/src/mongo/db/repair_database.cpp
+++ b/src/mongo/db/repair_database.cpp
@@ -279,9 +279,6 @@ namespace mongo {
 
         log() << "repairDatabase " << dbName << endl;
 
-        invariant( cc().database()->name() == dbName );
-        invariant( cc().database()->path() == storageGlobalParams.dbpath );
-
         BackgroundOperation::assertNoBgOpInProgForDb(dbName);
 
         getDur().syncDataAndTruncateJournal(); // Must be done before and after repair
diff --git a/src/mongo/db/repl/is_master.h b/src/mongo/db/repl/is_master.h
index 7457364bb60..93d7047357e 100644
--- a/src/mongo/db/repl/is_master.h
+++ b/src/mongo/db/repl/is_master.h
@@ -74,11 +74,15 @@ namespace mongo {
         if( _isMaster() )
             return true;
         if ( ! dbname ) {
-            Database *database = cc().database();
-            verify( database );
-            dbname = database->name().c_str();
+            // XXX: remove this magic and make dbname required?
+            if ( cc().getContext() ) {
+                Database *database = cc().getContext()->db();
+                if ( database ) {
+                    dbname = database->name().c_str();
+                }
+            }
         }
-        return strcmp( dbname , "local" ) == 0;
+        return strcmp( dbname, "local" ) == 0;
     }
     inline bool isMasterNs( const char *ns ) {
         if ( _isMaster() )
diff --git a/src/mongo/db/repl/master_slave.cpp b/src/mongo/db/repl/master_slave.cpp
index 83e1527ebcc..fb83eb842c5 100644
--- a/src/mongo/db/repl/master_slave.cpp
+++ b/src/mongo/db/repl/master_slave.cpp
@@ -354,7 +354,7 @@ namespace mongo {
     void ReplSource::resyncDrop( const string& db ) {
         log() << "resync: dropping database " << db;
         Client::Context ctx(db);
-        dropDatabase(db);
+        dropDatabase(ctx.db());
     }
 
     /* grab initial copy of a database from the master */
@@ -489,7 +489,7 @@ namespace mongo {
             incompleteCloneDbs.erase(*i);
             addDbNextPass.erase(*i);
             Client::Context ctx(*i);
-            dropDatabase(*i);
+            dropDatabase(ctx.db());
         }
         
         massert( 14034, "Duplicate database names present after attempting to delete duplicates",
@@ -497,13 +497,15 @@ namespace mongo {
         return true;
     }
 
-    void ReplSource::applyOperation(const BSONObj& op) {
+    void ReplSource::applyOperation(Database* db, const BSONObj& op) {
         try {
-            bool failedUpdate = applyOperation_inlock( op );
+            bool failedUpdate = applyOperation_inlock( db, op );
             if (failedUpdate) {
                 Sync sync(hostName);
                 if (sync.shouldRetry(op)) {
-                    uassert(15914, "Failure retrying initial sync update", !applyOperation_inlock(op));
+                    uassert(15914,
+                            "Failure retrying initial sync update",
+                            !applyOperation_inlock(db, op));
                 }
             }
         }
@@ -611,7 +613,7 @@ namespace mongo {
         // always apply admin command command
         // this is a bit hacky -- the semantics of replication/commands aren't well specified
         if ( strcmp( clientName, "admin" ) == 0 && *op.getStringField( "op" ) == 'c' ) {
-            applyOperation( op );
+            applyOperation( ctx.db(), op );
             return;
         }
 
@@ -640,7 +642,7 @@ namespace mongo {
             save();
         }
         else {
-            applyOperation( op );
+            applyOperation( ctx.db(), op );
             addDbNextPass.erase( clientName );
         }
     }
@@ -1254,7 +1256,7 @@ namespace mongo {
                     b.append(_id);
                     BSONObj result;
                     Client::Context ctx( ns );
-                    if( Helpers::findById(cc(), ns, b.done(), result) )
+                    if( Helpers::findById(ctx.db(), ns, b.done(), result) )
                         _dummy_z += result.objsize(); // touch
                 }
             }
@@ -1288,7 +1290,7 @@ namespace mongo {
                 b.append(_id);
                 BSONObj result;
                 Client::ReadContext ctx( ns );
-                if( Helpers::findById(cc(), ns, b.done(), result) )
+                if( Helpers::findById(ctx.ctx().db(), ns, b.done(), result) )
                     _dummy_z += result.objsize(); // touch
             }
         }
diff --git a/src/mongo/db/repl/master_slave.h b/src/mongo/db/repl/master_slave.h
index 66f21eeb53d..24279627ab2 100644
--- a/src/mongo/db/repl/master_slave.h
+++ b/src/mongo/db/repl/master_slave.h
@@ -41,6 +41,8 @@
 
 namespace mongo {
 
+    class Database;
+
     // Main entry point for master/slave at startup time.
     void startMasterSlave();
 
@@ -117,7 +119,7 @@ namespace mongo {
     public:
         OplogReader oplogReader;
 
-        void applyOperation(const BSONObj& op);
+        void applyOperation(Database* db, const BSONObj& op);
         string hostName;    // ip addr or hostname plus optionally, ":<port>"
         string _sourceName;  // a logical source name.
         string sourceName() const { return _sourceName.empty() ? "main" : _sourceName; }
diff --git a/src/mongo/db/repl/oplog.cpp b/src/mongo/db/repl/oplog.cpp
index c1308a85e43..e90542808ca 100644
--- a/src/mongo/db/repl/oplog.cpp
+++ b/src/mongo/db/repl/oplog.cpp
@@ -466,7 +466,8 @@ namespace mongo {
     /** @param fromRepl false if from ApplyOpsCmd
         @return true if was and update should have happened and the document DNE.  see replset initial sync code.
      */
-    bool applyOperation_inlock(const BSONObj& op, bool fromRepl, bool convertUpdateToUpsert) {
+    bool applyOperation_inlock(Database* db, const BSONObj& op,
+                               bool fromRepl, bool convertUpdateToUpsert) {
         LOG(3) << "applying op: " << op << endl;
         bool failedUpdate = false;
 
@@ -495,7 +496,7 @@ namespace mongo {
 
         Lock::assertWriteLocked(ns);
 
-        Collection* collection = cc().database()->getCollection( ns );
+        Collection* collection = db->getCollection( ns );
         IndexCatalog* indexCatalog = collection == NULL ? NULL : collection->getIndexCatalog();
 
         // operation type -- see logOp() comments for types
diff --git a/src/mongo/db/repl/oplog.h b/src/mongo/db/repl/oplog.h
index 7e788f36bb3..bf32e1e062c 100644
--- a/src/mongo/db/repl/oplog.h
+++ b/src/mongo/db/repl/oplog.h
@@ -90,7 +90,8 @@ namespace mongo {
      * @param convertUpdateToUpsert convert some updates to upserts for idempotency reasons
      * Returns if the op was an update that could not be applied (true on failure)
      */
-    bool applyOperation_inlock(const BSONObj& op, 
-                               bool fromRepl = true, 
+    bool applyOperation_inlock(Database* db,
+                               const BSONObj& op,
+                               bool fromRepl = true,
                                bool convertUpdateToUpsert = false);
 }
diff --git a/src/mongo/db/repl/rs.cpp b/src/mongo/db/repl/rs.cpp
index 0e733b7f489..9a6c79fbd5f 100644
--- a/src/mongo/db/repl/rs.cpp
+++ b/src/mongo/db/repl/rs.cpp
@@ -124,7 +124,7 @@ namespace {
                 continue;
 
             Client::Context ctx(*it);
-            cc().database()->clearTmpCollections();
+            ctx.db()->clearTmpCollections();
         }
     }
 }
diff --git a/src/mongo/db/repl/rs_rollback.cpp b/src/mongo/db/repl/rs_rollback.cpp
index 250c55b0a71..3a22f7a07bb 100644
--- a/src/mongo/db/repl/rs_rollback.cpp
+++ b/src/mongo/db/repl/rs_rollback.cpp
@@ -553,12 +553,12 @@ namespace mongo {
                         // did we just empty the collection?  if so let's check if it even exists on the source.
                         if( collection->numRecords() == 0 ) {
                             try {
-                                string sys = cc().database()->name() + ".system.namespaces";
+                                string sys = c.db()->name() + ".system.namespaces";
                                 bo o = them->findOne(sys, QUERY("name"<<d.ns));
                                 if( o.isEmpty() ) {
                                     // we should drop
                                     try {
-                                        cc().database()->dropCollection(d.ns);
+                                        c.db()->dropCollection(d.ns);
                                     }
                                     catch(...) {
                                         log() << "replset error rolling back collection " << d.ns << rsLog;
diff --git a/src/mongo/db/repl/rs_sync.cpp b/src/mongo/db/repl/rs_sync.cpp
index 88275b981d2..31ac2902f89 100644
--- a/src/mongo/db/repl/rs_sync.cpp
+++ b/src/mongo/db/repl/rs_sync.cpp
@@ -128,7 +128,7 @@ namespace replset {
         ctx.getClient()->curop()->reset();
         // For non-initial-sync, we convert updates to upserts
         // to suppress errors when replaying oplog entries.
-        bool ok = !applyOperation_inlock(op, true, convertUpdateToUpsert);
+        bool ok = !applyOperation_inlock(ctx.db(), op, true, convertUpdateToUpsert);
         opsAppliedStats.increment();
         getDur().commitIfNeeded();
 
@@ -219,7 +219,7 @@ namespace replset {
                 // one possible tweak here would be to stay in the read lock for this database 
                 // for multiple prefetches if they are for the same database.
                 Client::ReadContext ctx(ns);
-                prefetchPagesForReplicatedOp(op);
+                prefetchPagesForReplicatedOp(ctx.ctx().db(), op);
             }
             catch (const DBException& e) {
                 LOG(2) << "ignoring exception in prefetchOp(): " << e.what() << endl;
@@ -786,7 +786,7 @@ namespace replset {
         changeState(MemberState::RS_RECOVERING);
 
         Client::Context ctx("local");
-        cc().database()->dropCollection("local.oplog.rs");
+        ctx.db()->dropCollection("local.oplog.rs");
         {
             boost::unique_lock<boost::mutex> lock(theReplSet->initialSyncMutex);
             theReplSet->initialSyncRequested = true;
diff --git a/src/mongo/db/repl/sync.cpp b/src/mongo/db/repl/sync.cpp
index f09d06355a5..87380803105 100644
--- a/src/mongo/db/repl/sync.cpp
+++ b/src/mongo/db/repl/sync.cpp
@@ -47,12 +47,12 @@ namespace mongo {
         hn = hostname;
     }
 
-    BSONObj Sync::getMissingDoc(const BSONObj& o) {
+    BSONObj Sync::getMissingDoc(Database* db, const BSONObj& o) {
         OplogReader missingObjReader; // why are we using OplogReader to run a non-oplog query?
         const char *ns = o.getStringField("ns");
 
         // capped collections
-        Collection* collection = cc().database()->getCollection(ns);
+        Collection* collection = db->getCollection(ns);
         if ( collection && collection->isCapped() ) {
             log() << "replication missing doc, but this is okay for a capped collection (" << ns << ")" << endl;
             return BSONObj();
@@ -113,7 +113,7 @@ namespace mongo {
         // we don't have the object yet, which is possible on initial sync.  get it.
         log() << "replication info adding missing object" << endl; // rare enough we can log
 
-        BSONObj missingObj = getMissingDoc(o);
+        BSONObj missingObj = getMissingDoc(ctx.db(), o);
 
         if( missingObj.isEmpty() ) {
             log() << "replication missing object not found on source. presumably deleted later in oplog" << endl;
diff --git a/src/mongo/db/repl/sync.h b/src/mongo/db/repl/sync.h
index cf11dfbb7c2..9edca0b585b 100644
--- a/src/mongo/db/repl/sync.h
+++ b/src/mongo/db/repl/sync.h
@@ -32,7 +32,9 @@
 
 #include "mongo/db/jsobj.h"
 
-namespace mongo { 
+namespace mongo {
+
+    class Database;
 
     class Sync {
     protected:
@@ -40,7 +42,7 @@ namespace mongo {
     public:
         Sync(const string& hostname) : hn(hostname) {}
         virtual ~Sync() {}
-        virtual BSONObj getMissingDoc(const BSONObj& o);
+        virtual BSONObj getMissingDoc(Database* db, const BSONObj& o);
 
         /**
          * If applyOperation_inlock should be called again after an update fails.
diff --git a/src/mongo/db/storage/record.cpp b/src/mongo/db/storage/record.cpp
index 2db9815902d..9da02d5d6c4 100644
--- a/src/mongo/db/storage/record.cpp
+++ b/src/mongo/db/storage/record.cpp
@@ -526,12 +526,12 @@ namespace mongo {
     Record* DiskLoc::rec() const {
         // XXX-ERH
         verify(a() != -1);
-        return cc().database()->getExtentManager().recordFor( *this );
+        return cc().getContext()->db()->getExtentManager().recordFor( *this );
     }
 
     Extent* DiskLoc::ext() const {
         verify( a() != -1 );
-        return cc().database()->getExtentManager().getExtent(*this);
+        return cc().getContext()->db()->getExtentManager().getExtent(*this);
     }
 
     BSONObj DiskLoc::obj() const {
@@ -543,7 +543,7 @@ namespace mongo {
             return;
 
         const Client& client = cc();
-        Database* db = client.database();
+        Database* db = client.getContext()->db();
         
         recordStats.accessesNotInMemory.fetchAndAdd(1);
         if ( db )
diff --git a/src/mongo/db/structure/catalog/namespace_details.cpp b/src/mongo/db/structure/catalog/namespace_details.cpp
index 5acd5d98585..b9d25980541 100644
--- a/src/mongo/db/structure/catalog/namespace_details.cpp
+++ b/src/mongo/db/structure/catalog/namespace_details.cpp
@@ -413,7 +413,7 @@ namespace mongo {
         Lock::assertWriteLocked( ns );
 
         string system_namespaces = nsToDatabaseSubstring(ns).toString() + ".system.namespaces";
-        Collection* coll = cc().database()->getCollection( system_namespaces );
+        Collection* coll = cc().getContext()->db()->getCollection( system_namespaces );
 
         DiskLoc oldLocation = Helpers::findOne( coll, BSON( "name" << ns ), false );
         fassert( 17247, !oldLocation.isNull() );
diff --git a/src/mongo/dbtests/indexupdatetests.cpp b/src/mongo/dbtests/indexupdatetests.cpp
index 2160975eb70..a1d594fb201 100644
--- a/src/mongo/dbtests/indexupdatetests.cpp
+++ b/src/mongo/dbtests/indexupdatetests.cpp
@@ -475,7 +475,7 @@ namespace IndexUpdateTests {
             // Request an interrupt.
             killCurrentOp.killAll();
             // The call is not interrupted.
-            Helpers::ensureIndex( _ns, BSON( "a" << 1 ), false, "a_1" );
+            Helpers::ensureIndex( collection(), BSON( "a" << 1 ), false, "a_1" );
             // only want to interrupt the index build
             killCurrentOp.reset();
             // The new index is listed in system.indexes because the index build completed.
diff --git a/src/mongo/dbtests/namespacetests.cpp b/src/mongo/dbtests/namespacetests.cpp
index 687d26776b6..039f8a6651f 100644
--- a/src/mongo/dbtests/namespacetests.cpp
+++ b/src/mongo/dbtests/namespacetests.cpp
@@ -1041,12 +1041,12 @@ namespace NamespaceTests {
             virtual ~Base() {
                 if ( !nsd() )
                     return;
-                cc().database()->dropCollection( ns() );
+                _context.db()->dropCollection( ns() );
             }
         protected:
             void create() {
                 Lock::GlobalWrite lk;
-                ASSERT( userCreateNS( ns(), fromjson( spec() ), false ).isOK() );
+                ASSERT( userCreateNS( db(), ns(), fromjson( spec() ), false ).isOK() );
             }
             virtual string spec() const {
                 return "{\"capped\":true,\"size\":512,\"$nExtents\":1}";
diff --git a/src/mongo/dbtests/query_multi_plan_runner.cpp b/src/mongo/dbtests/query_multi_plan_runner.cpp
index 717035c5ce1..8f3d36f0cfe 100644
--- a/src/mongo/dbtests/query_multi_plan_runner.cpp
+++ b/src/mongo/dbtests/query_multi_plan_runner.cpp
@@ -63,8 +63,8 @@ namespace QueryMultiPlanRunner {
             _client.ensureIndex(ns(), obj);
         }
 
-        IndexDescriptor* getIndex(const BSONObj& obj) {
-            Collection* collection = cc().database()->getCollection( ns() );
+        IndexDescriptor* getIndex(Database* db, const BSONObj& obj) {
+            Collection* collection = db->getCollection( ns() );
             return collection->getIndexCatalog()->findIndexByKeyPattern(obj);
         }
 
@@ -102,7 +102,7 @@ namespace QueryMultiPlanRunner {
             // Every call to work() returns something so this should clearly win (by current scoring
             // at least).
             IndexScanParams ixparams;
-            ixparams.descriptor = getIndex(BSON("foo" << 1));
+            ixparams.descriptor = getIndex(ctx.ctx().db(), BSON("foo" << 1));
             ixparams.bounds.isSimpleRange = true;
             ixparams.bounds.startKey = BSON("" << 7);
             ixparams.bounds.endKey = BSON("" << 7);
diff --git a/src/mongo/dbtests/query_single_solution_runner.cpp b/src/mongo/dbtests/query_single_solution_runner.cpp
index 2d6064b90d7..beae1e0ec7e 100644
--- a/src/mongo/dbtests/query_single_solution_runner.cpp
+++ b/src/mongo/dbtests/query_single_solution_runner.cpp
@@ -120,7 +120,7 @@ namespace QuerySingleSolutionRunner {
                                                   BSONObj& indexSpec, int start, int end) {
             // Build the index scan stage.
             IndexScanParams ixparams;
-            ixparams.descriptor = getIndex(indexSpec);
+            ixparams.descriptor = getIndex(context.db(), indexSpec);
             ixparams.bounds.isSimpleRange = true;
             ixparams.bounds.startKey = BSON("" << start);
             ixparams.bounds.endKey = BSON("" << end);
@@ -163,8 +163,8 @@ namespace QuerySingleSolutionRunner {
         }
 
     private:
-        IndexDescriptor* getIndex(const BSONObj& obj) {
-            Collection* collection = cc().database()->getCollection( ns() );
+        IndexDescriptor* getIndex(Database* db, const BSONObj& obj) {
+            Collection* collection = db->getCollection( ns() );
             return collection->getIndexCatalog()->findIndexByKeyPattern(obj);
         }
 
diff --git a/src/mongo/dbtests/query_stage_collscan.cpp b/src/mongo/dbtests/query_stage_collscan.cpp
index 47360cdf9a7..b6ff997e914 100644
--- a/src/mongo/dbtests/query_stage_collscan.cpp
+++ b/src/mongo/dbtests/query_stage_collscan.cpp
@@ -62,7 +62,7 @@ namespace QueryStageCollectionScan {
             stringstream spec;
             spec << "{\"capped\":true,\"size\":2000,\"$nExtents\":" << nExtents() << "}";
 
-            ASSERT( userCreateNS( ns(), fromjson( spec.str() ), false ).isOK() );
+            ASSERT( userCreateNS( db(), ns(), fromjson( spec.str() ), false ).isOK() );
 
             // Tell the test to add data/extents/etc.
             insertTestData();
diff --git a/src/mongo/dbtests/querytests.cpp b/src/mongo/dbtests/querytests.cpp
index 82454857fab..c8634a6c6b1 100644
--- a/src/mongo/dbtests/querytests.cpp
+++ b/src/mongo/dbtests/querytests.cpp
@@ -1044,7 +1044,7 @@ namespace QueryTests {
             Lock::GlobalWrite lk;
             Client::Context ctx( "unittests.DirectLocking" );
             client().remove( "a.b", BSONObj() );
-            ASSERT_EQUALS( "unittests", cc().database()->name() );
+            ASSERT_EQUALS( "unittests", ctx.db()->name() );
         }
         const char *ns;
     };
@@ -1171,7 +1171,8 @@ namespace QueryTests {
             Client::WriteContext ctx( "unittests" );
 
             // note that extents are always at least 4KB now - so this will get rounded up a bit.
-            ASSERT( userCreateNS( ns(), fromjson( "{ capped : true, size : 2000 }" ), false ).isOK() );
+            ASSERT( userCreateNS( ctx.ctx().db(), ns(),
+                                  fromjson( "{ capped : true, size : 2000 }" ), false ).isOK() );
             for ( int i=0; i<200; i++ ) {
                 insertNext();
 //                cout << count() << endl;
@@ -1230,10 +1231,10 @@ namespace QueryTests {
                                       BSON( "_id" << 20 ) , res , true ) );
             ASSERT_EQUALS( 40 , res["x"].numberInt() );
 
-            ASSERT( Helpers::findById( cc(), ns() , BSON( "_id" << 20 ) , res ) );
+            ASSERT( Helpers::findById( ctx.ctx().db(), ns() , BSON( "_id" << 20 ) , res ) );
             ASSERT_EQUALS( 40 , res["x"].numberInt() );
 
-            ASSERT( ! Helpers::findById( cc(), ns() , BSON( "_id" << 200 ) , res ) );
+            ASSERT( ! Helpers::findById( ctx.ctx().db(), ns() , BSON( "_id" << 200 ) , res ) );
 
             unsigned long long slow , fast;
 
@@ -1250,7 +1251,7 @@ namespace QueryTests {
             {
                 Timer t;
                 for ( int i=0; i<n; i++ ) {
-                    ASSERT( Helpers::findById( cc(), ns() , BSON( "_id" << 20 ) , res ) );
+                    ASSERT( Helpers::findById( ctx.ctx().db(), ns() , BSON( "_id" << 20 ) , res ) );
                 }
                 fast = t.micros();
             }
@@ -1278,7 +1279,7 @@ namespace QueryTests {
 
             BSONObj res;
             for ( int i=0; i<1000; i++ ) {
-                bool found = Helpers::findById( cc(), ns() , BSON( "_id" << i ) , res );
+                bool found = Helpers::findById( ctx.ctx().db(), ns() , BSON( "_id" << i ) , res );
                 ASSERT_EQUALS( i % 2 , int(found) );
             }
 
diff --git a/src/mongo/dbtests/queryutiltests.cpp b/src/mongo/dbtests/queryutiltests.cpp
index ae0ebdd48dc..8b75aa21b41 100644
--- a/src/mongo/dbtests/queryutiltests.cpp
+++ b/src/mongo/dbtests/queryutiltests.cpp
@@ -1587,7 +1587,7 @@ namespace QueryUtilTests {
             Client::Context _ctx;
         public:
             IndexBase() : _lk(ns()), _ctx( ns() ) , indexNum_( 0 ) {
-                userCreateNS( ns(), BSONObj(), false );
+                userCreateNS( _ctx.db(), ns(), BSONObj(), false );
             }
             ~IndexBase() {
                 if ( !nsd() )
diff --git a/src/mongo/dbtests/replsettests.cpp b/src/mongo/dbtests/replsettests.cpp
index f334cc2f3b1..e1779e2465d 100644
--- a/src/mongo/dbtests/replsettests.cpp
+++ b/src/mongo/dbtests/replsettests.cpp
@@ -316,7 +316,7 @@ namespace ReplSetTests {
 
         void create() {
             Client::Context c(_cappedNs);
-            ASSERT( userCreateNS( _cappedNs, fromjson( spec() ), false ).isOK() );
+            ASSERT( userCreateNS( c.db(), _cappedNs, fromjson( spec() ), false ).isOK() );
         }
 
         void dropCapped() {
@@ -359,7 +359,7 @@ namespace ReplSetTests {
         bool apply(const BSONObj& op) {
             Client::Context ctx( _cappedNs );
             // in an annoying twist of api, returns true on failure
-            return !applyOperation_inlock(op, true);
+            return !applyOperation_inlock(ctx.db(), op, true);
         }
 
         void run() {
diff --git a/src/mongo/dbtests/repltests.cpp b/src/mongo/dbtests/repltests.cpp
index 10c08845122..2dfa2f99fbc 100644
--- a/src/mongo/dbtests/repltests.cpp
+++ b/src/mongo/dbtests/repltests.cpp
@@ -172,7 +172,7 @@ namespace ReplTests {
                     if ( 0 ) {
                         mongo::unittest::log() << "op: " << *i << endl;
                     }
-                    a.applyOperation( *i );
+                    a.applyOperation( ctx.db(), *i );
                 }
             }
         }
@@ -244,6 +244,9 @@ namespace ReplTests {
             b.appendElements( fromjson( json ) );
             return b.obj();
         }
+        Database* db() {
+            return _context.db();
+        }
     private:
         static DBDirectClient client_;
     };
@@ -1384,7 +1387,7 @@ namespace ReplTests {
         bool returnEmpty;
         SyncTest() : Sync(""), returnEmpty(false) {}
         virtual ~SyncTest() {}
-        virtual BSONObj getMissingDoc(const BSONObj& o) {
+        virtual BSONObj getMissingDoc(Database* db, const BSONObj& o) {
             if (returnEmpty) {
                 BSONObj o;
                 return o;
@@ -1402,7 +1405,7 @@ namespace ReplTests {
             // this should fail because we can't connect
             try {
                 Sync badSource("localhost:123");
-                badSource.getMissingDoc(o);
+                badSource.getMissingDoc(db(), o);
             }
             catch (DBException&) {
                 threw = true;
diff --git a/src/mongo/s/d_migrate.cpp b/src/mongo/s/d_migrate.cpp
index 0f5088fbc66..4a789d3067f 100644
--- a/src/mongo/s/d_migrate.cpp
+++ b/src/mongo/s/d_migrate.cpp
@@ -320,7 +320,8 @@ namespace mongo {
                 break;
 
             case 'u':
-                if ( ! Helpers::findById( cc() , _ns.c_str() , ide.wrap() , it ) ) {
+                Client::Context ctx( _ns );
+                if ( ! Helpers::findById( ctx.db(), _ns.c_str(), ide.wrap(), it ) ) {
                     warning() << "logOpForSharding couldn't find: " << ide << " even though should have" << migrateLog;
                     return;
                 }
@@ -335,7 +336,7 @@ namespace mongo {
             _memoryUsed += ide.size() + 5;
         }
 
-        void xfer( list<BSONObj> * l , BSONObjBuilder& b , const char * name , long long& size , bool explode ) {
+        void xfer( Database* db, list<BSONObj> * l , BSONObjBuilder& b , const char * name , long long& size , bool explode ) {
             const long long maxSize = 1024 * 1024;
 
             if ( l->size() == 0 || size > maxSize )
@@ -349,7 +350,7 @@ namespace mongo {
                 BSONObj t = *i;
                 if ( explode ) {
                     BSONObj it;
-                    if ( Helpers::findById( cc() , _ns.c_str() , t, it ) ) {
+                    if ( Helpers::findById( db , _ns.c_str() , t, it ) ) {
                         arr.append( it );
                         size += it.objsize();
                     }
@@ -379,8 +380,8 @@ namespace mongo {
             {
                 Client::ReadContext cx( _ns );
 
-                xfer( &_deleted , b , "deleted" , size , false );
-                xfer( &_reload , b , "reload" , size , true );
+                xfer( cx.ctx().db(), &_deleted, b, "deleted", size, false );
+                xfer( cx.ctx().db(), &_reload, b, "reload", size, true );
             }
 
             b.append( "size" , size );
@@ -1652,7 +1653,7 @@ namespace mongo {
                     string system_namespaces = nsToDatabase(ns) + ".system.namespaces";
                     BSONObj entry = conn->findOne( system_namespaces, BSON( "name" << ns ) );
                     if ( entry["options"].isABSONObj() ) {
-                        Status status = userCreateNS( ns, entry["options"].Obj(), true, 0 );
+                        Status status = userCreateNS( db, ns, entry["options"].Obj(), true, 0 );
                         if ( !status.isOK() ) {
                             warning() << "failed to create collection [" << ns << "] "
                                       << " with options: " << status;
@@ -1778,7 +1779,7 @@ namespace mongo {
                                     Client::WriteContext cx( ns );
 
                                     BSONObj localDoc;
-                                    if ( willOverrideLocalId( o, &localDoc ) ) {
+                                    if ( willOverrideLocalId( cx.ctx().db(), o, &localDoc ) ) {
                                         string errMsg =
                                             str::stream() << "cannot migrate chunk, local document "
                                                           << localDoc
@@ -1981,7 +1982,7 @@ namespace mongo {
 
                     // do not apply deletes if they do not belong to the chunk being migrated
                     BSONObj fullObj;
-                    if ( Helpers::findById( cc() , ns.c_str() , id, fullObj ) ) {
+                    if ( Helpers::findById( cx.ctx().db(), ns.c_str(), id, fullObj ) ) {
                         if ( ! isInRange( fullObj , min , max , shardKeyPattern ) ) {
                             log() << "not applying out of range deletion: " << fullObj << migrateLog;
 
@@ -2014,7 +2015,7 @@ namespace mongo {
                     BSONObj it = i.next().Obj();
 
                     BSONObj localDoc;
-                    if ( willOverrideLocalId( it, &localDoc ) ) {
+                    if ( willOverrideLocalId( cx.ctx().db(), it, &localDoc ) ) {
                         string errMsg =
                             str::stream() << "cannot migrate chunk, local document "
                                           << localDoc
@@ -2044,10 +2045,10 @@ namespace mongo {
          * Must be in WriteContext to avoid races and DBHelper errors.
          * TODO: Could optimize this check out if sharding on _id.
          */
-        bool willOverrideLocalId( BSONObj remoteDoc, BSONObj* localDoc ) {
+        bool willOverrideLocalId( Database* db, BSONObj remoteDoc, BSONObj* localDoc ) {
 
             *localDoc = BSONObj();
-            if ( Helpers::findById( cc(), ns.c_str(), remoteDoc, *localDoc ) ) {
+            if ( Helpers::findById( db, ns.c_str(), remoteDoc, *localDoc ) ) {
                 return !isInRange( *localDoc , min , max , shardKeyPattern );
             }