SERVER-13961 Pass LockState to DBWrite and DBRead directly

This is part of the changes to move LockState be part of OperationContext
and not retrieved from TLS.

25 files changed, 294 insertions, 231 deletions

diff --git a/src/mongo/dbtests/clienttests.cpp b/src/mongo/dbtests/clienttests.cpp
index e47e67ea4ea..194cc048046 100644
--- a/src/mongo/dbtests/clienttests.cpp
+++ b/src/mongo/dbtests/clienttests.cpp
@@ -1,3 +1,5 @@
+// client.cpp
+
 /*
  *    Copyright (C) 2010 10gen Inc.
  *
@@ -26,16 +28,13 @@
  *    then also delete it in the license file.
  */
 
-// client.cpp
-
-#include "mongo/pch.h"
-
 #include "mongo/client/dbclientcursor.h"
 #include "mongo/db/catalog/collection.h"
 #include "mongo/db/catalog/database.h"
-#include "mongo/db/d_concurrency.h"
+#include "mongo/db/operation_context_noop.h"
 #include "mongo/dbtests/dbtests.h"
 
+
 namespace ClientTests {
 
     class Base {
@@ -123,8 +122,8 @@ namespace ClientTests {
     public:
         BuildIndex() : Base("buildIndex") {}
         void run() {
-            Lock::DBWrite lock(ns());
-            Client::WriteContext ctx(ns());
+            OperationContextNoop txn;
+            Client::WriteContext ctx(&txn, ns());
 
             db.insert(ns(), BSON("x" << 1 << "y" << 2));
             db.insert(ns(), BSON("x" << 2 << "y" << 2));
diff --git a/src/mongo/dbtests/counttests.cpp b/src/mongo/dbtests/counttests.cpp
index 1ff84d735f8..729443e2835 100644
--- a/src/mongo/dbtests/counttests.cpp
+++ b/src/mongo/dbtests/counttests.cpp
@@ -41,13 +41,16 @@
 namespace CountTests {
 
     class Base {
+        OperationContextImpl _txn;
         Lock::DBWrite lk;
+
         Client::Context _context;
+
         Database* _database;
         Collection* _collection;
-        OperationContextImpl _txn;
+
     public:
-        Base() : lk(ns()), _context( ns() ) {
+        Base() : lk(_txn.lockState(), ns()), _context( ns() ) {
             _database = _context.db();
             _collection = _database->getCollection( ns() );
             if ( _collection ) {
diff --git a/src/mongo/dbtests/dbhelper_tests.cpp b/src/mongo/dbtests/dbhelper_tests.cpp
index 535dab6124d..0cee60de170 100644
--- a/src/mongo/dbtests/dbhelper_tests.cpp
+++ b/src/mongo/dbtests/dbhelper_tests.cpp
@@ -58,8 +58,9 @@ namespace mongo {
             {
                 // Remove _id range [_min, _max).
                 OperationContextImpl txn;
-                Lock::DBWrite lk( ns );
+                Lock::DBWrite lk(txn.lockState(), ns);
                 Client::Context ctx( ns );
+
                 KeyRange range( ns,
                                 BSON( "_id" << _min ),
                                 BSON( "_id" << _max ),
@@ -112,6 +113,8 @@ namespace mongo {
     TEST(DBHelperTests, FindDiskLocs) {
 
         DBDirectClient client;
+        OperationContextImpl txn;
+
         // Some unique tag we can use to make sure we're pulling back the right data
         OID tag = OID::gen();
         client.remove( ns, BSONObj() );
@@ -128,14 +131,15 @@ namespace mongo {
         long long estSizeBytes;
         {
             // search _id range (0, 10)
-            Lock::DBRead lk( ns );
+            Lock::DBRead lk(txn.lockState(), ns);
 
             KeyRange range( ns,
                             BSON( "_id" << 0 ),
                             BSON( "_id" << numDocsInserted ),
                             BSON( "_id" << 1 ) );
 
-            Status result = Helpers::getLocsInRange( range,
+            Status result = Helpers::getLocsInRange( &txn,
+                                                     range,
                                                      maxSizeBytes,
                                                      &locs,
                                                      &numDocsFound,
@@ -164,6 +168,8 @@ namespace mongo {
     TEST(DBHelperTests, FindDiskLocsNoIndex) {
 
         DBDirectClient client;
+        OperationContextImpl txn;
+
         client.remove( ns, BSONObj() );
         client.insert( ns, BSON( "_id" << OID::gen() ) );
 
@@ -173,7 +179,7 @@ namespace mongo {
         long long numDocsFound;
         long long estSizeBytes;
         {
-            Lock::DBRead lk( ns );
+            Lock::DBRead lk(txn.lockState(), ns);
             Client::Context ctx( ns );
 
             // search invalid index range
@@ -182,7 +188,8 @@ namespace mongo {
                             BSON( "badIndex" << 10 ),
                             BSON( "badIndex" << 1 ) );
 
-            Status result = Helpers::getLocsInRange( range,
+            Status result = Helpers::getLocsInRange( &txn,
+                                                     range,
                                                      maxSizeBytes,
                                                      &locs,
                                                      &numDocsFound,
@@ -203,6 +210,8 @@ namespace mongo {
     TEST(DBHelperTests, FindDiskLocsTooBig) {
 
         DBDirectClient client;
+        OperationContextImpl txn;
+
         client.remove( ns, BSONObj() );
 
         int numDocsInserted = 10;
@@ -217,14 +226,15 @@ namespace mongo {
         long long numDocsFound;
         long long estSizeBytes;
         {
-            Lock::DBRead lk( ns );
+            Lock::DBRead lk(txn.lockState(), ns);
             Client::Context ctx( ns );
             KeyRange range( ns,
                             BSON( "_id" << 0 ),
                             BSON( "_id" << numDocsInserted ),
                             BSON( "_id" << 1 ) );
 
-            Status result = Helpers::getLocsInRange( range,
+            Status result = Helpers::getLocsInRange( &txn,
+                                                     range,
                                                      maxSizeBytes,
                                                      &locs,
                                                      &numDocsFound,
diff --git a/src/mongo/dbtests/documentsourcetests.cpp b/src/mongo/dbtests/documentsourcetests.cpp
index 593c310eb93..652958c2efe 100644
--- a/src/mongo/dbtests/documentsourcetests.cpp
+++ b/src/mongo/dbtests/documentsourcetests.cpp
@@ -166,7 +166,7 @@ namespace DocumentSourceTests {
                 _registration.reset();
                 _runner.reset();
 
-                Client::WriteContext ctx (ns);
+                Client::WriteContext ctx(&_opCtx, ns);
                 CanonicalQuery* cq;
                 uassertStatusOK(CanonicalQuery::canonicalize(ns, /*query=*/BSONObj(), &cq));
                 Runner* runnerBare;
diff --git a/src/mongo/dbtests/indexcatalogtests.cpp b/src/mongo/dbtests/indexcatalogtests.cpp
index 8afba25af39..bf9b61cf5d3 100644
--- a/src/mongo/dbtests/indexcatalogtests.cpp
+++ b/src/mongo/dbtests/indexcatalogtests.cpp
@@ -31,22 +31,25 @@ namespace IndexCatalogTests {
     class IndexIteratorTests {
     public:
         IndexIteratorTests() {
-            Client::WriteContext ctx(_ns);
             OperationContextImpl txn;
+            Client::WriteContext ctx(&txn, _ns);
+
             _db = ctx.ctx().db();
             _coll = _db->createCollection(&txn, _ns);
             _catalog = _coll->getIndexCatalog();
         }
 
         ~IndexIteratorTests() {
-            Client::WriteContext ctx(_ns);
             OperationContextImpl txn;
+            Client::WriteContext ctx(&txn, _ns);
+
             _db->dropCollection(&txn, _ns);
         }
 
         void run() {
-            Client::WriteContext ctx(_ns);
             OperationContextImpl txn;
+            Client::WriteContext ctx(&txn, _ns);
+
             int numFinishedIndexesStart = _catalog->numIndexesReady();
 
             BSONObjBuilder b1;
diff --git a/src/mongo/dbtests/indexupdatetests.cpp b/src/mongo/dbtests/indexupdatetests.cpp
index 7c2f03662f6..792c1071d3e 100644
--- a/src/mongo/dbtests/indexupdatetests.cpp
+++ b/src/mongo/dbtests/indexupdatetests.cpp
@@ -55,7 +55,7 @@ namespace IndexUpdateTests {
     class IndexBuildBase {
     public:
         IndexBuildBase() :
-            _ctx( _ns ) {
+            _ctx(&_txn, _ns) {
             _client.createCollection( _ns );
         }
         ~IndexBuildBase() {
@@ -91,8 +91,9 @@ namespace IndexUpdateTests {
             return collection()->getIndexCatalog()->findIndexByName( "a_1" );
         }
 #endif
-        Client::WriteContext _ctx;
+
         OperationContextImpl _txn;
+        Client::WriteContext _ctx;
     };
 
     /** addKeysToPhaseOne() adds keys from a collection's documents to an external sorter. */
diff --git a/src/mongo/dbtests/matchertests.cpp b/src/mongo/dbtests/matchertests.cpp
index 5bee238cda6..67bff7ef74b 100644
--- a/src/mongo/dbtests/matchertests.cpp
+++ b/src/mongo/dbtests/matchertests.cpp
@@ -33,6 +33,7 @@
 
 #include "mongo/db/json.h"
 #include "mongo/db/matcher/matcher.h"
+#include "mongo/db/operation_context_impl.h"
 #include "mongo/dbtests/dbtests.h"
 #include "mongo/util/timer.h"
 
@@ -216,7 +217,9 @@ namespace MatcherTests {
     class WhereSimple1 {
     public:
         void run() {
-            Client::ReadContext ctx( "unittests.matchertests" );
+            OperationContextImpl txn;
+            Client::ReadContext ctx(&txn, "unittests.matchertests");
+
             M m(BSON("$where" << "function(){ return this.a == 1; }"),
                 WhereCallbackReal(StringData("unittests")));
             ASSERT( m.matches( BSON( "a" << 1 ) ) );
diff --git a/src/mongo/dbtests/pdfiletests.cpp b/src/mongo/dbtests/pdfiletests.cpp
index 59d5f1bc483..5ef98e0b08b 100644
--- a/src/mongo/dbtests/pdfiletests.cpp
+++ b/src/mongo/dbtests/pdfiletests.cpp
@@ -164,7 +164,8 @@ namespace PdfileTests {
         void run() {
             SmallFilesControl c;
 
-            Client::ReadContext ctx( "local" );
+            OperationContextImpl txn;
+            Client::ReadContext ctx(&txn, "local");
             Database* db = ctx.ctx().db();
             ExtentManager* em = db->getExtentManager();
 
diff --git a/src/mongo/dbtests/plan_ranking.cpp b/src/mongo/dbtests/plan_ranking.cpp
index 970e59a97ca..02939707de3 100644
--- a/src/mongo/dbtests/plan_ranking.cpp
+++ b/src/mongo/dbtests/plan_ranking.cpp
@@ -37,6 +37,7 @@
 #include "mongo/db/index/index_descriptor.h"
 #include "mongo/db/instance.h"
 #include "mongo/db/json.h"
+#include "mongo/db/operation_context_impl.h"
 #include "mongo/db/query/get_runner.h"
 #include "mongo/db/query/qlog.h"
 #include "mongo/db/query/query_knobs.h"
@@ -45,6 +46,7 @@
 #include "mongo/db/query/stage_builder.h"
 #include "mongo/dbtests/dbtests.h"
 
+
 namespace mongo {
 
     // How we access the external setParameter testing bool.
@@ -59,7 +61,7 @@ namespace PlanRankingTests {
     class PlanRankingTestBase {
     public:
         PlanRankingTestBase() : _internalQueryForceIntersectionPlans(internalQueryForceIntersectionPlans) {
-            Client::WriteContext ctx(ns);
+            Client::WriteContext ctx(&_txn, ns);
             _client.dropCollection(ns);
         }
 
@@ -69,12 +71,12 @@ namespace PlanRankingTests {
         }
 
         void insert(const BSONObj& obj) {
-            Client::WriteContext ctx(ns);
+            Client::WriteContext ctx(&_txn, ns);
             _client.insert(ns, obj);
         }
 
         void addIndex(const BSONObj& obj) {
-            Client::WriteContext ctx(ns);
+            Client::WriteContext ctx(&_txn, ns);
             _client.ensureIndex(ns, obj);
         }
 
@@ -85,7 +87,7 @@ namespace PlanRankingTests {
          * Takes ownership of 'cq'.  Caller DOES NOT own the returned QuerySolution*.
          */
         QuerySolution* pickBestPlan(CanonicalQuery* cq) {
-            Client::ReadContext ctx(ns);
+            Client::ReadContext ctx(&_txn, ns);
             Collection* collection = ctx.ctx().db()->getCollection(ns);
 
             QueryPlannerParams plannerParams;
@@ -135,16 +137,17 @@ namespace PlanRankingTests {
         // determining the number of documents in the tests below.
         static const int N;
 
+        OperationContextImpl _txn;
+
     private:
-        static DBDirectClient _client;
+
+        DBDirectClient _client;
         scoped_ptr<MultiPlanStage> _mps;
         // Holds the value of global "internalQueryForceIntersectionPlans" setParameter flag.
         // Restored at end of test invocation regardless of test result.
         bool _internalQueryForceIntersectionPlans;
     };
 
-    DBDirectClient PlanRankingTestBase::_client;
-
     // static
     const int PlanRankingTestBase::N = internalQueryPlanEvaluationWorks + 1000;
 
diff --git a/src/mongo/dbtests/query_multi_plan_runner.cpp b/src/mongo/dbtests/query_multi_plan_runner.cpp
index bc853298488..99d1f61d172 100644
--- a/src/mongo/dbtests/query_multi_plan_runner.cpp
+++ b/src/mongo/dbtests/query_multi_plan_runner.cpp
@@ -38,6 +38,7 @@
 #include "mongo/db/instance.h"
 #include "mongo/db/json.h"
 #include "mongo/db/matcher/expression_parser.h"
+#include "mongo/db/operation_context_impl.h"
 #include "mongo/db/catalog/collection.h"
 #include "mongo/dbtests/dbtests.h"
 
@@ -92,7 +93,8 @@ namespace QueryMultiPlanRunner {
     class MPRCollectionScanVsHighlySelectiveIXScan : public MultiPlanRunnerBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            OperationContextImpl txn;
+            Client::WriteContext ctx(&txn, ns());
 
             const int N = 5000;
             for (int i = 0; i < N; ++i) {
diff --git a/src/mongo/dbtests/query_single_solution_runner.cpp b/src/mongo/dbtests/query_single_solution_runner.cpp
index 30d7ca0535f..3e2e1330323 100644
--- a/src/mongo/dbtests/query_single_solution_runner.cpp
+++ b/src/mongo/dbtests/query_single_solution_runner.cpp
@@ -39,6 +39,7 @@
 #include "mongo/db/query/query_solution.h"
 #include "mongo/db/query/single_solution_runner.h"
 #include "mongo/db/catalog/collection.h"
+#include "mongo/db/operation_context_impl.h"
 #include "mongo/dbtests/dbtests.h"
 
 namespace QuerySingleSolutionRunner {
@@ -147,7 +148,7 @@ namespace QuerySingleSolutionRunner {
         static const char* ns() { return "unittests.QueryStageSingleSolutionRunner"; }
 
         size_t numCursors() {
-            Client::ReadContext ctx( ns() );
+            Client::ReadContext ctx(&_txn, ns() );
             Collection* collection = ctx.ctx().db()->getCollection( ns() );
             if ( !collection )
                 return 0;
@@ -155,28 +156,29 @@ namespace QuerySingleSolutionRunner {
         }
 
         void registerRunner( Runner* runner ) {
-            Client::ReadContext ctx( ns() );
+            Client::ReadContext ctx(&_txn, ns());
             Collection* collection = ctx.ctx().db()->getOrCreateCollection( ns() );
             return collection->cursorCache()->registerRunner( runner );
         }
 
         void deregisterRunner( Runner* runner ) {
-            Client::ReadContext ctx( ns() );
+            Client::ReadContext ctx(&_txn, ns());
             Collection* collection = ctx.ctx().db()->getOrCreateCollection( ns() );
             return collection->cursorCache()->deregisterRunner( runner );
         }
 
+    protected:
+        OperationContextImpl _txn;
+
     private:
         IndexDescriptor* getIndex(Database* db, const BSONObj& obj) {
             Collection* collection = db->getCollection( ns() );
             return collection->getIndexCatalog()->findIndexByKeyPattern(obj);
         }
 
-        static DBDirectClient _client;
+        DBDirectClient _client;
     };
 
-    DBDirectClient SingleSolutionRunnerBase::_client;
-
     /**
      * Test dropping the collection while the
      * SingleSolutionRunner is doing a collection scan.
@@ -184,7 +186,7 @@ namespace QuerySingleSolutionRunner {
     class DropCollScan : public SingleSolutionRunnerBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             insert(BSON("_id" << 1));
             insert(BSON("_id" << 2));
 
@@ -212,7 +214,7 @@ namespace QuerySingleSolutionRunner {
     class DropIndexScan : public SingleSolutionRunnerBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             insert(BSON("_id" << 1 << "a" << 6));
             insert(BSON("_id" << 2 << "a" << 7));
             insert(BSON("_id" << 3 << "a" << 8));
@@ -283,7 +285,7 @@ namespace QuerySingleSolutionRunner {
     class SnapshotControl : public SnapshotBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             setupCollection();
 
             BSONObj filterObj = fromjson("{a: {$gte: 2}}");
@@ -308,7 +310,7 @@ namespace QuerySingleSolutionRunner {
     class SnapshotTest : public SnapshotBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             setupCollection();
             BSONObj indexSpec = BSON("_id" << 1);
             addIndex(indexSpec);
@@ -339,7 +341,7 @@ namespace QuerySingleSolutionRunner {
         class Invalidate : public SingleSolutionRunnerBase {
         public:
             void run() {
-                Client::WriteContext ctx(ns());
+                Client::WriteContext ctx(&_txn, ns());
                 insert(BSON("a" << 1 << "b" << 1));
 
                 BSONObj filterObj = fromjson("{_id: {$gt: 0}, b: {$gt: 0}}");
@@ -364,7 +366,7 @@ namespace QuerySingleSolutionRunner {
         class InvalidatePinned : public SingleSolutionRunnerBase {
         public:
             void run() {
-                Client::WriteContext ctx(ns());
+                Client::WriteContext ctx(&_txn, ns());
                 insert(BSON("a" << 1 << "b" << 1));
 
                 Collection* collection = ctx.ctx().db()->getCollection(ns());
@@ -402,12 +404,12 @@ namespace QuerySingleSolutionRunner {
         public:
             void run() {
                 {
-                    Client::WriteContext ctx(ns());
+                    Client::WriteContext ctx(&_txn, ns());
                     insert(BSON("a" << 1 << "b" << 1));
                 }
 
                 {
-                    Client::ReadContext ctx(ns());
+                    Client::ReadContext ctx(&_txn, ns());
                     Collection* collection = ctx.ctx().db()->getCollection(ns());
 
                     BSONObj filterObj = fromjson("{_id: {$gt: 0}, b: {$gt: 0}}");
@@ -420,7 +422,7 @@ namespace QuerySingleSolutionRunner {
                 // There should be one cursor before timeout,
                 // and zero cursors after timeout.
                 ASSERT_EQUALS(1U, numCursors());
-                CollectionCursorCache::timeoutCursorsGlobal(600001);
+                CollectionCursorCache::timeoutCursorsGlobal(&_txn, 600001);
                 ASSERT_EQUALS(0U, numCursors());
             }
         };
diff --git a/src/mongo/dbtests/query_stage_and.cpp b/src/mongo/dbtests/query_stage_and.cpp
index 3f9d3526f2e..f1d33ff7fb8 100644
--- a/src/mongo/dbtests/query_stage_and.cpp
+++ b/src/mongo/dbtests/query_stage_and.cpp
@@ -109,12 +109,13 @@ namespace QueryStageAnd {
 
         static const char* ns() { return "unittests.QueryStageAnd"; }
 
+    protected:
+        OperationContextImpl _txn;
+
     private:
-        static DBDirectClient _client;
+        DBDirectClient _client;
     };
 
-    DBDirectClient QueryStageAndBase::_client;
-
     //
     // Hash AND tests
     //
@@ -126,12 +127,12 @@ namespace QueryStageAnd {
     class QueryStageAndHashInvalidation : public QueryStageAndBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
             Collection* coll = db->getCollection(ns());
             if (!coll) {
-                coll = db->createCollection(&txn, ns());
+                coll = db->createCollection(&_txn, ns());
             }
 
             for (int i = 0; i < 50; ++i) {
@@ -228,12 +229,12 @@ namespace QueryStageAnd {
     class QueryStageAndHashInvalidateLookahead : public QueryStageAndBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
             Collection* coll = db->getCollection(ns());
             if (!coll) {
-                coll = db->createCollection(&txn, ns());
+                coll = db->createCollection(&_txn, ns());
             }
 
             for (int i = 0; i < 50; ++i) {
@@ -314,12 +315,12 @@ namespace QueryStageAnd {
     class QueryStageAndHashTwoLeaf : public QueryStageAndBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
             Collection* coll = db->getCollection(ns());
             if (!coll) {
-                coll = db->createCollection(&txn, ns());
+                coll = db->createCollection(&_txn, ns());
             }
 
             for (int i = 0; i < 50; ++i) {
@@ -363,12 +364,12 @@ namespace QueryStageAnd {
     class QueryStageAndHashTwoLeafFirstChildLargeKeys : public QueryStageAndBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
             Collection* coll = db->getCollection(ns());
             if (!coll) {
-                coll = db->createCollection(&txn, ns());
+                coll = db->createCollection(&_txn, ns());
             }
 
             // Generate large keys for {foo: 1, big: 1} index.
@@ -415,12 +416,12 @@ namespace QueryStageAnd {
     class QueryStageAndHashTwoLeafLastChildLargeKeys : public QueryStageAndBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
             Collection* coll = db->getCollection(ns());
             if (!coll) {
-                coll = db->createCollection(&txn, ns());
+                coll = db->createCollection(&_txn, ns());
             }
 
             // Generate large keys for {baz: 1, big: 1} index.
@@ -466,12 +467,12 @@ namespace QueryStageAnd {
     class QueryStageAndHashThreeLeaf : public QueryStageAndBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
             Collection* coll = db->getCollection(ns());
             if (!coll) {
-                coll = db->createCollection(&txn, ns());
+                coll = db->createCollection(&_txn, ns());
             }
 
             for (int i = 0; i < 50; ++i) {
@@ -527,12 +528,12 @@ namespace QueryStageAnd {
     class QueryStageAndHashThreeLeafMiddleChildLargeKeys : public QueryStageAndBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
             Collection* coll = db->getCollection(ns());
             if (!coll) {
-                coll = db->createCollection(&txn, ns());
+                coll = db->createCollection(&_txn, ns());
             }
 
             // Generate large keys for {bar: 1, big: 1} index.
@@ -586,12 +587,12 @@ namespace QueryStageAnd {
     class QueryStageAndHashWithNothing : public QueryStageAndBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
             Collection* coll = db->getCollection(ns());
             if (!coll) {
-                coll = db->createCollection(&txn, ns());
+                coll = db->createCollection(&_txn, ns());
             }
 
             for (int i = 0; i < 50; ++i) {
@@ -645,12 +646,12 @@ namespace QueryStageAnd {
     class QueryStageAndHashProducesNothing : public QueryStageAndBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
             Collection* coll = db->getCollection(ns());
             if (!coll) {
-                coll = db->createCollection(&txn, ns());
+                coll = db->createCollection(&_txn, ns());
             }
 
             for (int i = 0; i < 10; ++i) {
@@ -693,12 +694,12 @@ namespace QueryStageAnd {
     class QueryStageAndHashWithMatcher : public QueryStageAndBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
             Collection* coll = db->getCollection(ns());
             if (!coll) {
-                coll = db->createCollection(&txn, ns());
+                coll = db->createCollection(&_txn, ns());
             }
 
             for (int i = 0; i < 50; ++i) {
@@ -749,12 +750,12 @@ namespace QueryStageAnd {
     class QueryStageAndSortedInvalidation : public QueryStageAndBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
             Collection* coll = db->getCollection(ns());
             if (!coll) {
-                coll = db->createCollection(&txn, ns());
+                coll = db->createCollection(&_txn, ns());
             }
 
             // Insert a bunch of data
@@ -866,12 +867,12 @@ namespace QueryStageAnd {
     class QueryStageAndSortedThreeLeaf : public QueryStageAndBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
             Collection* coll = db->getCollection(ns());
             if (!coll) {
-                coll = db->createCollection(&txn, ns());
+                coll = db->createCollection(&_txn, ns());
             }
 
             // Insert a bunch of data
@@ -919,12 +920,12 @@ namespace QueryStageAnd {
     class QueryStageAndSortedWithNothing : public QueryStageAndBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
             Collection* coll = db->getCollection(ns());
             if (!coll) {
-                coll = db->createCollection(&txn, ns());
+                coll = db->createCollection(&_txn, ns());
             }
 
 
@@ -964,12 +965,12 @@ namespace QueryStageAnd {
     class QueryStageAndSortedProducesNothing : public QueryStageAndBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
             Collection* coll = db->getCollection(ns());
             if (!coll) {
-                coll = db->createCollection(&txn, ns());
+                coll = db->createCollection(&_txn, ns());
             }
 
             for (int i = 0; i < 50; ++i) {
@@ -1012,12 +1013,12 @@ namespace QueryStageAnd {
     class QueryStageAndSortedWithMatcher : public QueryStageAndBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
             Collection* coll = db->getCollection(ns());
             if (!coll) {
-                coll = db->createCollection(&txn, ns());
+                coll = db->createCollection(&_txn, ns());
             }
 
             for (int i = 0; i < 50; ++i) {
@@ -1057,12 +1058,12 @@ namespace QueryStageAnd {
     class QueryStageAndSortedByLastChild : public QueryStageAndBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
             Collection* coll = db->getCollection(ns());
             if (!coll) {
-                coll = db->createCollection(&txn, ns());
+                coll = db->createCollection(&_txn, ns());
             }
 
             for (int i = 0; i < 50; ++i) {
diff --git a/src/mongo/dbtests/query_stage_collscan.cpp b/src/mongo/dbtests/query_stage_collscan.cpp
index aa0fb3a2e65..fc30e82ad99 100644
--- a/src/mongo/dbtests/query_stage_collscan.cpp
+++ b/src/mongo/dbtests/query_stage_collscan.cpp
@@ -315,7 +315,7 @@ namespace QueryStageCollectionScan {
     class QueryStageCollectionScanBase {
     public:
         QueryStageCollectionScanBase() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
 
             for (int i = 0; i < numObj(); ++i) {
                 BSONObjBuilder bob;
@@ -325,7 +325,7 @@ namespace QueryStageCollectionScan {
         }
 
         virtual ~QueryStageCollectionScanBase() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             _client.dropCollection(ns());
         }
 
@@ -334,7 +334,7 @@ namespace QueryStageCollectionScan {
         }
 
         int countResults(CollectionScanParams::Direction direction, const BSONObj& filterObj) {
-            Client::ReadContext ctx(ns());
+            Client::ReadContext ctx(&_txn, ns());
 
             // Configure the scan.
             CollectionScanParams params;
@@ -384,11 +384,13 @@ namespace QueryStageCollectionScan {
 
         static const char* ns() { return "unittests.QueryStageCollectionScan"; }
 
+    protected:
+        OperationContextImpl _txn;
+
     private:
-        static DBDirectClient _client;
+        DBDirectClient _client;
     };
 
-    DBDirectClient QueryStageCollectionScanBase::_client;
 
     //
     // Go forwards, get everything.
@@ -442,7 +444,7 @@ namespace QueryStageCollectionScan {
     class QueryStageCollscanObjectsInOrderForward : public QueryStageCollectionScanBase {
     public:
         void run() {
-            Client::ReadContext ctx(ns());
+            Client::ReadContext ctx(&_txn, ns());
 
             // Configure the scan.
             CollectionScanParams params;
@@ -473,7 +475,7 @@ namespace QueryStageCollectionScan {
     class QueryStageCollscanObjectsInOrderBackward : public QueryStageCollectionScanBase {
     public:
         void run() {
-            Client::ReadContext ctx(ns());
+            Client::ReadContext ctx(&_txn, ns());
 
             CollectionScanParams params;
             params.collection = ctx.ctx().db()->getCollection( ns() );
@@ -502,7 +504,7 @@ namespace QueryStageCollectionScan {
     class QueryStageCollscanInvalidateUpcomingObject : public QueryStageCollectionScanBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
 
             Collection* coll = ctx.ctx().db()->getCollection( ns() );
 
@@ -564,7 +566,7 @@ namespace QueryStageCollectionScan {
     class QueryStageCollscanInvalidateUpcomingObjectBackward : public QueryStageCollectionScanBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             Collection* coll = ctx.ctx().db()->getCollection(ns());
 
             // Get the DiskLocs that would be returned by an in-order scan.
diff --git a/src/mongo/dbtests/query_stage_count.cpp b/src/mongo/dbtests/query_stage_count.cpp
index 090bf068f63..0d0dcbc0673 100644
--- a/src/mongo/dbtests/query_stage_count.cpp
+++ b/src/mongo/dbtests/query_stage_count.cpp
@@ -37,6 +37,7 @@
 #include "mongo/db/instance.h"
 #include "mongo/db/json.h"
 #include "mongo/db/matcher/expression_parser.h"
+#include "mongo/db/operation_context_impl.h"
 #include "mongo/db/pdfile.h"
 #include "mongo/db/catalog/collection.h"
 #include "mongo/dbtests/dbtests.h"
@@ -51,7 +52,7 @@ namespace QueryStageCount {
         CountBase() { }
 
         virtual ~CountBase() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             _client.dropCollection(ns());
         }
 
@@ -92,11 +93,13 @@ namespace QueryStageCount {
 
         static const char* ns() { return "unittests.QueryStageCount"; }
 
+    protected:
+        OperationContextImpl _txn;
+
     private:
-        static DBDirectClient _client;
+        DBDirectClient _client;
     };
-    
-    DBDirectClient CountBase::_client;
+   
 
     //
     // Check that dups are properly identified
@@ -104,7 +107,7 @@ namespace QueryStageCount {
     class QueryStageCountDups : public CountBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
 
             // Insert some docs
             insert(BSON("a" << BSON_ARRAY(5 << 7)));
@@ -136,7 +139,7 @@ namespace QueryStageCount {
     class QueryStageCountInclusiveBounds : public CountBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
 
             // Insert some docs
             for (int i = 0; i < 10; ++i) {
@@ -168,7 +171,7 @@ namespace QueryStageCount {
     class QueryStageCountExclusiveBounds : public CountBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
 
             // Insert some docs
             for (int i = 0; i < 10; ++i) {
@@ -200,7 +203,7 @@ namespace QueryStageCount {
     class QueryStageCountLowerBound : public CountBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
 
             // Insert doc, add index
             insert(BSON("a" << 2));
@@ -228,7 +231,7 @@ namespace QueryStageCount {
     class QueryStageCountNothingInInterval : public CountBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
 
             // Insert documents, add index
             insert(BSON("a" << 2));
@@ -258,7 +261,7 @@ namespace QueryStageCount {
     class QueryStageCountNothingInIntervalFirstMatchTooHigh : public CountBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
 
             // Insert some documents, add index
             insert(BSON("a" << 2));
@@ -288,7 +291,7 @@ namespace QueryStageCount {
     class QueryStageCountNoChangeDuringYield : public CountBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
 
             // Insert documents, add index
             for (int i = 0; i < 10; ++i) {
@@ -339,7 +342,7 @@ namespace QueryStageCount {
     class QueryStageCountDeleteDuringYield : public CountBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
 
             // Insert documents, add index
             for (int i = 0; i < 10; ++i) {
@@ -393,7 +396,7 @@ namespace QueryStageCount {
     class QueryStageCountInsertNewDocsDuringYield : public CountBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
 
             // Insert documents, add index
             for (int i = 0; i < 10; ++i) {
@@ -450,7 +453,7 @@ namespace QueryStageCount {
     class QueryStageCountBecomesMultiKeyDuringYield : public CountBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
 
             // Insert documents, add index
             for (int i = 0; i < 10; ++i) {
@@ -503,7 +506,7 @@ namespace QueryStageCount {
     class QueryStageCountUnusedKeys : public CountBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
 
             // Insert docs, add index
             for (int i = 0; i < 10; ++i) {
@@ -538,7 +541,7 @@ namespace QueryStageCount {
     class QueryStageCountUnusedEndKey : public CountBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
 
             // Insert docs, add index
             for (int i = 0; i < 10; ++i) {
@@ -571,7 +574,7 @@ namespace QueryStageCount {
     class QueryStageCountKeyBecomesUnusedDuringYield : public CountBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
 
             // Insert documents, add index
             for (int i = 0; i < 10; ++i) {
diff --git a/src/mongo/dbtests/query_stage_distinct.cpp b/src/mongo/dbtests/query_stage_distinct.cpp
index 37a0a6473b1..ecbbbaf5561 100644
--- a/src/mongo/dbtests/query_stage_distinct.cpp
+++ b/src/mongo/dbtests/query_stage_distinct.cpp
@@ -32,6 +32,7 @@
 #include "mongo/db/exec/plan_stage.h"
 #include "mongo/db/instance.h"
 #include "mongo/db/json.h"
+#include "mongo/db/operation_context_impl.h"
 #include "mongo/db/query/index_bounds_builder.h"
 #include "mongo/db/query/plan_executor.h"
 #include "mongo/db/catalog/collection.h"
@@ -48,22 +49,22 @@ namespace QueryStageDistinct {
         DistinctBase() { }
 
         virtual ~DistinctBase() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             _client.dropCollection(ns());
         }
 
         void addIndex(const BSONObj& obj) {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             _client.ensureIndex(ns(), obj);
         }
 
         void insert(const BSONObj& obj) {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             _client.insert(ns(), obj);
         }
 
         IndexDescriptor* getIndex(const BSONObj& obj) {
-            Client::ReadContext ctx(ns());
+            Client::ReadContext ctx(&_txn, ns());
             Collection* collection = ctx.ctx().db()->getCollection( ns() );
             return collection->getIndexCatalog()->findIndexByKeyPattern( obj );
         }
@@ -96,11 +97,13 @@ namespace QueryStageDistinct {
 
         static const char* ns() { return "unittests.QueryStageDistinct"; }
 
+    protected:
+        OperationContextImpl _txn;
+
     private:
-        static DBDirectClient _client;
+        DBDirectClient _client;
     };
 
-    DBDirectClient DistinctBase::_client;
 
     // Tests distinct with single key indices.
     class QueryStageDistinctBasic : public DistinctBase {
@@ -121,7 +124,7 @@ namespace QueryStageDistinct {
             // Make an index on a:1
             addIndex(BSON("a" << 1));
 
-            Client::ReadContext ctx(ns());
+            Client::ReadContext ctx(&_txn, ns());
 
             // Set up the distinct stage.
             DistinctParams params;
@@ -184,7 +187,7 @@ namespace QueryStageDistinct {
             // Make an index on a:1
             addIndex(BSON("a" << 1));
 
-            Client::ReadContext ctx(ns());
+            Client::ReadContext ctx(&_txn, ns());
 
             // Set up the distinct stage.
             DistinctParams params;
diff --git a/src/mongo/dbtests/query_stage_fetch.cpp b/src/mongo/dbtests/query_stage_fetch.cpp
index 4aaaa2657b7..b99a95b1d87 100644
--- a/src/mongo/dbtests/query_stage_fetch.cpp
+++ b/src/mongo/dbtests/query_stage_fetch.cpp
@@ -87,8 +87,9 @@ namespace QueryStageFetch {
     class FetchStageAlreadyFetched : public QueryStageFetchBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
             OperationContextImpl txn;
+            Client::WriteContext ctx(&txn, ns());
+
             Database* db = ctx.ctx().db();
             Collection* coll = db->getCollection(ns());
             if (!coll) {
@@ -145,8 +146,9 @@ namespace QueryStageFetch {
     class FetchStageFilter : public QueryStageFetchBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
             OperationContextImpl txn;
+            Client::WriteContext ctx(&txn, ns());
+
             Database* db = ctx.ctx().db();
             Collection* coll = db->getCollection(ns());
             if (!coll) {
diff --git a/src/mongo/dbtests/query_stage_keep.cpp b/src/mongo/dbtests/query_stage_keep.cpp
index c030387ff09..5ea488a37f2 100644
--- a/src/mongo/dbtests/query_stage_keep.cpp
+++ b/src/mongo/dbtests/query_stage_keep.cpp
@@ -104,8 +104,9 @@ namespace QueryStageKeep {
     class KeepStageBasic : public QueryStageKeepBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
             OperationContextImpl txn;
+            Client::WriteContext ctx(&txn, ns());
+
             Database* db = ctx.ctx().db();
             Collection* coll = db->getCollection(ns());
             if (!coll) {
diff --git a/src/mongo/dbtests/query_stage_merge_sort.cpp b/src/mongo/dbtests/query_stage_merge_sort.cpp
index 6ddf69290e5..43319528bb2 100644
--- a/src/mongo/dbtests/query_stage_merge_sort.cpp
+++ b/src/mongo/dbtests/query_stage_merge_sort.cpp
@@ -50,7 +50,7 @@ namespace QueryStageMergeSortTests {
         QueryStageMergeSortTestBase() { }
 
         virtual ~QueryStageMergeSortTestBase() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             _client.dropCollection(ns());
         }
 
@@ -95,23 +95,25 @@ namespace QueryStageMergeSortTests {
         }
 
         static const char* ns() { return "unittests.QueryStageMergeSort"; }
+
+    protected:
+        OperationContextImpl _txn;
+
     private:
-        static DBDirectClient _client;
+        DBDirectClient _client;
     };
 
-    DBDirectClient QueryStageMergeSortTestBase::_client;
-
     // SERVER-1205:
     // find($or[{a:1}, {b:1}]).sort({c:1}) with indices {a:1, c:1} and {b:1, c:1}.
     class QueryStageMergeSortPrefixIndex : public QueryStageMergeSortTestBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
             Collection* coll = db->getCollection(ns());
             if (!coll) {
-                coll = db->createCollection(&txn, ns());
+                coll = db->createCollection(&_txn, ns());
             }
 
             const int N = 50;
@@ -170,12 +172,12 @@ namespace QueryStageMergeSortTests {
     class QueryStageMergeSortDups : public QueryStageMergeSortTestBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
             Collection* coll = db->getCollection(ns());
             if (!coll) {
-                coll = db->createCollection(&txn, ns());
+                coll = db->createCollection(&_txn, ns());
             }
 
             const int N = 50;
@@ -233,12 +235,12 @@ namespace QueryStageMergeSortTests {
     class QueryStageMergeSortDupsNoDedup : public QueryStageMergeSortTestBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
             Collection* coll = db->getCollection(ns());
             if (!coll) {
-                coll = db->createCollection(&txn, ns());
+                coll = db->createCollection(&_txn, ns());
             }
 
             const int N = 50;
@@ -297,12 +299,12 @@ namespace QueryStageMergeSortTests {
     class QueryStageMergeSortPrefixIndexReverse : public QueryStageMergeSortTestBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
             Collection* coll = db->getCollection(ns());
             if (!coll) {
-                coll = db->createCollection(&txn, ns());
+                coll = db->createCollection(&_txn, ns());
             }
 
             const int N = 50;
@@ -362,12 +364,12 @@ namespace QueryStageMergeSortTests {
     class QueryStageMergeSortOneStageEOF : public QueryStageMergeSortTestBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
             Collection* coll = db->getCollection(ns());
             if (!coll) {
-                coll = db->createCollection(&txn, ns());
+                coll = db->createCollection(&_txn, ns());
             }
 
             const int N = 50;
@@ -425,12 +427,12 @@ namespace QueryStageMergeSortTests {
     class QueryStageMergeSortManyShort : public QueryStageMergeSortTestBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
             Collection* coll = db->getCollection(ns());
             if (!coll) {
-                coll = db->createCollection(&txn, ns());
+                coll = db->createCollection(&_txn, ns());
             }
 
             WorkingSet* ws = new WorkingSet();
@@ -478,12 +480,12 @@ namespace QueryStageMergeSortTests {
     class QueryStageMergeSortInvalidation : public QueryStageMergeSortTestBase {
     public:
         void run() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
             Collection* coll = db->getCollection(ns());
             if (!coll) {
-                coll = db->createCollection(&txn, ns());
+                coll = db->createCollection(&_txn, ns());
             }
 
             WorkingSet ws;
diff --git a/src/mongo/dbtests/query_stage_sort.cpp b/src/mongo/dbtests/query_stage_sort.cpp
index f0605a7abbc..2440f67948f 100644
--- a/src/mongo/dbtests/query_stage_sort.cpp
+++ b/src/mongo/dbtests/query_stage_sort.cpp
@@ -169,10 +169,9 @@ namespace QueryStageSortTests {
 
         static const char* ns() { return "unittests.QueryStageSort"; }
     private:
-        static DBDirectClient _client;
+        DBDirectClient _client;
     };
 
-    DBDirectClient QueryStageSortTestBase::_client;
 
     // Sort some small # of results in increasing order.
     class QueryStageSortInc: public QueryStageSortTestBase {
@@ -180,8 +179,9 @@ namespace QueryStageSortTests {
         virtual int numObj() { return 100; }
 
         void run() {
-            Client::WriteContext ctx(ns());
             OperationContextImpl txn;
+            Client::WriteContext ctx(&txn, ns());
+
             Database* db = ctx.ctx().db();
             Collection* coll = db->getCollection(ns());
             if (!coll) {
@@ -199,8 +199,9 @@ namespace QueryStageSortTests {
         virtual int numObj() { return 100; }
 
         void run() {
-            Client::WriteContext ctx(ns());
             OperationContextImpl txn;
+            Client::WriteContext ctx(&txn, ns());
+
             Database* db = ctx.ctx().db();
             Collection* coll = db->getCollection(ns());
             if (!coll) {
@@ -227,8 +228,9 @@ namespace QueryStageSortTests {
         virtual int numObj() { return 10000; }
 
         void run() {
-            Client::WriteContext ctx(ns());
             OperationContextImpl txn;
+            Client::WriteContext ctx(&txn, ns());
+
             Database* db = ctx.ctx().db();
             Collection* coll = db->getCollection(ns());
             if (!coll) {
@@ -246,8 +248,9 @@ namespace QueryStageSortTests {
         virtual int numObj() { return 2000; }
 
         void run() {
-            Client::WriteContext ctx(ns());
             OperationContextImpl txn;
+            Client::WriteContext ctx(&txn, ns());
+            
             Database* db = ctx.ctx().db();
             Collection* coll = db->getCollection(ns());
             if (!coll) {
@@ -336,8 +339,9 @@ namespace QueryStageSortTests {
         virtual int numObj() { return 100; }
 
         void run() {
-            Client::WriteContext ctx(ns());
             OperationContextImpl txn;
+            Client::WriteContext ctx(&txn, ns());
+            
             Database* db = ctx.ctx().db();
             Collection* coll = db->getCollection(ns());
             if (!coll) {
diff --git a/src/mongo/dbtests/query_stage_tests.cpp b/src/mongo/dbtests/query_stage_tests.cpp
index 3bf9b0ca31f..7e0b0f20c6e 100644
--- a/src/mongo/dbtests/query_stage_tests.cpp
+++ b/src/mongo/dbtests/query_stage_tests.cpp
@@ -33,6 +33,7 @@
 #include "mongo/db/instance.h"
 #include "mongo/db/json.h"
 #include "mongo/db/matcher/expression_parser.h"
+#include "mongo/db/operation_context_impl.h"
 #include "mongo/db/query/plan_executor.h"
 #include "mongo/db/catalog/collection.h"
 #include "mongo/dbtests/dbtests.h"
@@ -46,7 +47,7 @@ namespace QueryStageTests {
     class IndexScanBase {
     public:
         IndexScanBase() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
 
             for (int i = 0; i < numObj(); ++i) {
                 BSONObjBuilder bob;
@@ -61,17 +62,17 @@ namespace QueryStageTests {
         }
 
         virtual ~IndexScanBase() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             _client.dropCollection(ns());
         }
 
         void addIndex(const BSONObj& obj) {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
             _client.ensureIndex(ns(), obj);
         }
 
         int countResults(const IndexScanParams& params, BSONObj filterObj = BSONObj()) {
-            Client::ReadContext ctx(ns());
+            Client::ReadContext ctx(&_txn, ns());
 
             StatusWithMatchExpression swme = MatchExpressionParser::parse(filterObj);
             verify(swme.isOK());
@@ -91,7 +92,7 @@ namespace QueryStageTests {
         }
 
         void makeGeoData() {
-            Client::WriteContext ctx(ns());
+            Client::WriteContext ctx(&_txn, ns());
 
             for (int i = 0; i < numObj(); ++i) {
                 double lat = double(rand()) / RAND_MAX;
@@ -101,7 +102,7 @@ namespace QueryStageTests {
         }
 
         IndexDescriptor* getIndex(const BSONObj& obj) {
-            Client::ReadContext ctx(ns());
+            Client::ReadContext ctx(&_txn, ns());
             Collection* collection = ctx.ctx().db()->getCollection( ns() );
             return collection->getIndexCatalog()->findIndexByKeyPattern( obj );
         }
@@ -109,12 +110,13 @@ namespace QueryStageTests {
         static int numObj() { return 50; }
         static const char* ns() { return "unittests.IndexScan"; }
 
+    protected:
+        OperationContextImpl _txn;
+
     private:
-        static DBDirectClient _client;
+        DBDirectClient _client;
     };
 
-    DBDirectClient IndexScanBase::_client;
-
     class QueryStageIXScanBasic : public IndexScanBase {
     public:
         virtual ~QueryStageIXScanBasic() { }
diff --git a/src/mongo/dbtests/querytests.cpp b/src/mongo/dbtests/querytests.cpp
index 0f834d1d50c..0e73c01e3b5 100644
--- a/src/mongo/dbtests/querytests.cpp
+++ b/src/mongo/dbtests/querytests.cpp
@@ -157,14 +157,13 @@ namespace QueryTests {
             // an empty object (one might be allowed inside a reserved namespace at some point).
             Lock::GlobalWrite lk;
             Client::Context ctx( "unittests.querytests" );
-            OperationContextImpl txn;
 
             Database* db = ctx.db();
             if ( db->getCollection( ns() ) ) {
                 _collection = NULL;
-                db->dropCollection( &txn, ns() );
+                db->dropCollection( &_txn, ns() );
             }
-            _collection = db->createCollection( &txn, ns(), CollectionOptions(), true, false );
+            _collection = db->createCollection( &_txn, ns(), CollectionOptions(), true, false );
             ASSERT( _collection );
 
             DBDirectClient cl;
@@ -189,21 +188,25 @@ namespace QueryTests {
         ~ClientBase() {
             //mongo::lastError.release();
         }
+
     protected:
-        static void insert( const char *ns, BSONObj o ) {
+        void insert( const char *ns, BSONObj o ) {
             client_.insert( ns, o );
         }
-        static void update( const char *ns, BSONObj q, BSONObj o, bool upsert = 0 ) {
+        void update( const char *ns, BSONObj q, BSONObj o, bool upsert = 0 ) {
             client_.update( ns, Query( q ), o, upsert );
         }
-        static bool error() {
+        bool error() {
             return !client_.getPrevError().getField( "err" ).isNull();
         }
-        DBDirectClient &client() const { return client_; }
 
-        static DBDirectClient client_;
+        const DBDirectClient& client() const { return client_; }
+        DBDirectClient& client() { return client_; }
+
+        DBDirectClient client_;
+
+        OperationContextImpl _txn;
     };
-    DBDirectClient ClientBase::client_;
 
     class BoundedKey : public ClientBase {
     public:
@@ -239,7 +242,7 @@ namespace QueryTests {
 
             {
                 // Check internal server handoff to getmore.
-                Lock::DBWrite lk(ns);
+                Lock::DBWrite lk(_txn.lockState(), ns);
                 Client::Context ctx( ns );
                 ClientCursorPin clientCursor( ctx.db()->getCollection(ns), cursorId );
                 // pq doesn't exist if it's a runner inside of the clientcursor.
@@ -252,6 +255,9 @@ namespace QueryTests {
             ASSERT( cursor->more() );
             ASSERT_EQUALS( 3, cursor->next().getIntField( "a" ) );
         }
+
+    protected:
+        OperationContextImpl _txn;
     };
 
     /**
@@ -294,10 +300,11 @@ namespace QueryTests {
 
             // Check that the cursor has been removed.
             {
-                Client::ReadContext ctx( ns );
+                Client::ReadContext ctx(&_txn, ns);
                 ASSERT( 0 == ctx.ctx().db()->getCollection( ns )->cursorCache()->numCursors() );
             }
-            ASSERT_FALSE( CollectionCursorCache::eraseCursorGlobal( cursorId ) );
+
+            ASSERT_FALSE(CollectionCursorCache::eraseCursorGlobal(&_txn, cursorId));
 
             // Check that a subsequent get more fails with the cursor removed.
             ASSERT_THROWS( client().getMore( ns, cursorId ), UserException );
@@ -343,7 +350,7 @@ namespace QueryTests {
 
             // Check that the cursor still exists
             {
-                Client::ReadContext ctx( ns );
+                Client::ReadContext ctx(&_txn, ns);
                 ASSERT( 1 == ctx.ctx().db()->getCollection( ns )->cursorCache()->numCursors() );
                 ASSERT( ctx.ctx().db()->getCollection( ns )->cursorCache()->find( cursorId, false ) );
             }
@@ -583,7 +590,7 @@ namespace QueryTests {
         }
         void run() {
             const char *ns = "unittests.querytests.OplogReplaySlaveReadTill";
-            Lock::DBWrite lk(ns);
+            Lock::DBWrite lk(_txn.lockState(), ns);
             Client::Context ctx( ns );
             
             BSONObj info;
@@ -654,7 +661,7 @@ namespace QueryTests {
             count( 2 );
         }
     private:
-        void count( unsigned long long c ) const {
+        void count( unsigned long long c ) {
             ASSERT_EQUALS( c, client().count( "unittests.querytests.BasicCount", BSON( "a" << 4 ) ) );
         }
     };
@@ -749,8 +756,8 @@ namespace QueryTests {
         }
         static const char *ns() { return "unittests.querytests.AutoResetIndexCache"; }
         static const char *idxNs() { return "unittests.system.indexes"; }
-        void index() const { ASSERT( !client().findOne( idxNs(), BSON( "name" << NE << "_id_" ) ).isEmpty() ); }
-        void noIndex() const {
+        void index() { ASSERT( !client().findOne( idxNs(), BSON( "name" << NE << "_id_" ) ).isEmpty() ); }
+        void noIndex() {
             BSONObj o = client().findOne( idxNs(), BSON( "name" << NE << "_id_" ) );
             if( !o.isEmpty() ) {
                 cout << o.toString() << endl;
@@ -1130,7 +1137,7 @@ namespace QueryTests {
         }
 
         size_t numCursorsOpen() {
-            Client::ReadContext ctx( _ns );
+            Client::ReadContext ctx(&_txn, _ns);
             Collection* collection = ctx.ctx().db()->getCollection( _ns );
             if ( !collection )
                 return 0;
@@ -1172,16 +1179,13 @@ namespace QueryTests {
         }
         void run() {
             string err;
-
-            Client::WriteContext ctx( "unittests" );
-            OperationContextImpl txn;
+            Client::WriteContext ctx(&_txn,  "unittests" );
 
             // note that extents are always at least 4KB now - so this will get rounded up a bit.
-            ASSERT( userCreateNS( &txn, ctx.ctx().db(), ns(),
+            ASSERT( userCreateNS( &_txn, ctx.ctx().db(), ns(),
                                   fromjson( "{ capped : true, size : 2000 }" ), false ).isOK() );
             for ( int i=0; i<200; i++ ) {
                 insertNext();
-//                cout << count() << endl;
                 ASSERT( count() < 90 );
             }
 
@@ -1224,7 +1228,7 @@ namespace QueryTests {
         }
 
         void run() {
-            Client::WriteContext ctx( "unittests" );
+            Client::WriteContext ctx(&_txn,  "unittests" );
 
             for ( int i=0; i<50; i++ ) {
                 insert( ns() , BSON( "_id" << i << "x" << i * 2 ) );
@@ -1275,7 +1279,7 @@ namespace QueryTests {
         }
 
         void run() {
-            Client::WriteContext ctx( "unittests" );
+            Client::WriteContext ctx(&_txn,  "unittests" );
 
             for ( int i=0; i<1000; i++ ) {
                 insert( ns() , BSON( "_id" << i << "x" << i * 2 ) );
@@ -1298,7 +1302,7 @@ namespace QueryTests {
         }
 
         void run() {
-            Client::WriteContext ctx( "unittests" );
+            Client::WriteContext ctx(&_txn,  "unittests" );
 
             for ( int i=0; i<1000; i++ ) {
                 insert( ns() , BSON( "_id" << i << "x" << i * 2 ) );
@@ -1414,7 +1418,7 @@ namespace QueryTests {
     public:
         CollectionInternalBase( const char *nsLeaf ) :
           CollectionBase( nsLeaf ),
-          _lk( ns() ),
+          _lk(_txn.lockState(), ns() ),
           _ctx( ns() ) {
         }
     private:
@@ -1439,8 +1443,7 @@ namespace QueryTests {
             DbMessage dbMessage( message );
             QueryMessage queryMessage( dbMessage );
             Message result;
-            OperationContextImpl txn;
-            string exhaust = newRunQuery( &txn, message, queryMessage, *cc().curop(), result );
+            string exhaust = newRunQuery( &_txn, message, queryMessage, *cc().curop(), result );
             ASSERT( exhaust.size() );
             ASSERT_EQUALS( string( ns() ), exhaust );
         }
@@ -1459,7 +1462,7 @@ namespace QueryTests {
             
             ClientCursor *clientCursor = 0;
             {
-                Client::ReadContext ctx( ns() );
+                Client::ReadContext ctx(&_txn, ns());
                 ClientCursorPin clientCursorPointer( ctx.ctx().db()->getCollection( ns() ),
                                                      cursorId );
                 clientCursor = clientCursorPointer.c();
@@ -1497,10 +1500,11 @@ namespace QueryTests {
             long long cursorId = cursor->getCursorId();
             
             {
-                Client::WriteContext ctx( ns() );
+                Client::WriteContext ctx(&_txn,  ns() );
                 ClientCursorPin pinCursor( ctx.ctx().db()->getCollection( ns() ), cursorId );
-  
-                ASSERT_THROWS( client().killCursor( cursorId ), MsgAssertionException );
+ 
+                ASSERT_THROWS(CollectionCursorCache::eraseCursorGlobal(&_txn, cursorId),
+                              MsgAssertionException);
                 string expectedAssertion =
                         str::stream() << "Cannot kill active cursor " << cursorId;
                 ASSERT_EQUALS( expectedAssertion, client().getLastError() );
diff --git a/src/mongo/dbtests/replsettests.cpp b/src/mongo/dbtests/replsettests.cpp
index fb2a2afdd0a..deb82f41e17 100644
--- a/src/mongo/dbtests/replsettests.cpp
+++ b/src/mongo/dbtests/replsettests.cpp
@@ -147,9 +147,10 @@ namespace ReplSetTests {
         DBDirectClient *client() const { return &client_; }
 
         static void insert( const BSONObj &o, bool god = false ) {
-            Lock::DBWrite lk(ns());
-            Client::Context ctx(ns());
             OperationContextImpl txn;
+            Lock::DBWrite lk(txn.lockState(), ns());
+            Client::Context ctx(ns());
+            
             Database* db = ctx.db();
             Collection* coll = db->getCollection(ns());
             if (!coll) {
@@ -174,8 +175,8 @@ namespace ReplSetTests {
         }
 
         void drop() {
-            Client::WriteContext c(ns());
             OperationContextImpl txn;
+            Client::WriteContext c(&txn, ns());
 
             Database* db = c.ctx().db();
 
@@ -306,6 +307,8 @@ namespace ReplSetTests {
 
     class CappedInitialSync : public Base {
         string _cappedNs;
+
+        OperationContextImpl _txn;
         Lock::DBWrite _lk;
 
         string spec() const {
@@ -342,7 +345,8 @@ namespace ReplSetTests {
             return o;
         }
     public:
-        CappedInitialSync() : _cappedNs("unittests.foo.bar"), _lk(_cappedNs) {
+        CappedInitialSync() : 
+                _cappedNs("unittests.foo.bar"), _lk(_txn.lockState(), _cappedNs) {
             dropCapped();
             create();
         }
@@ -363,7 +367,8 @@ namespace ReplSetTests {
         }
 
         void run() {
-            Lock::DBWrite lk(_cappedNs);
+            OperationContextImpl txn;
+            Lock::DBWrite lk(txn.lockState(), _cappedNs);
 
             BSONObj op = updateFail();
 
diff --git a/src/mongo/dbtests/runner_registry.cpp b/src/mongo/dbtests/runner_registry.cpp
index 8881ff2d4f3..b29088e36d8 100644
--- a/src/mongo/dbtests/runner_registry.cpp
+++ b/src/mongo/dbtests/runner_registry.cpp
@@ -51,7 +51,7 @@ namespace RunnerRegistry {
     class RunnerRegistryBase {
     public:
         RunnerRegistryBase() {
-            _ctx.reset(new Client::WriteContext(ns()));
+            _ctx.reset(new Client::WriteContext(&_opCtx, ns()));
             _client.dropCollection(ns());
 
             for (int i = 0; i < N(); ++i) {
@@ -269,7 +269,7 @@ namespace RunnerRegistry {
             // requires a "global write lock."
             _ctx.reset();
             _client.dropDatabase("somesillydb");
-            _ctx.reset(new Client::WriteContext(ns()));
+            _ctx.reset(new Client::WriteContext(&_opCtx, ns()));
 
             // Unregister and restore state.
             deregisterRunner(run.get());
@@ -285,7 +285,7 @@ namespace RunnerRegistry {
             // Drop our DB.  Once again, must give up the lock.
             _ctx.reset();
             _client.dropDatabase("unittests");
-            _ctx.reset(new Client::WriteContext(ns()));
+            _ctx.reset(new Client::WriteContext(&_opCtx, ns()));
 
             // Unregister and restore state.
             deregisterRunner(run.get());
diff --git a/src/mongo/dbtests/threadedtests.cpp b/src/mongo/dbtests/threadedtests.cpp
index b5537364525..96e6e0df7b4 100644
--- a/src/mongo/dbtests/threadedtests.cpp
+++ b/src/mongo/dbtests/threadedtests.cpp
@@ -35,6 +35,7 @@
 
 #include "mongo/bson/util/atomic_int.h"
 #include "mongo/db/d_concurrency.h"
+#include "mongo/db/operation_context_impl.h"
 #include "mongo/dbtests/dbtests.h"
 #include "mongo/platform/atomic_word.h"
 #include "mongo/stdx/functional.h"
@@ -115,6 +116,8 @@ namespace ThreadedTests {
         }
         virtual void subthread(int tnumber) {
             Client::initThread("mongomutextest");
+            LockState lockState;
+
             sleepmillis(0);
             for( int i = 0; i < N; i++ ) {
                 int x = std::rand();
@@ -169,13 +172,13 @@ namespace ThreadedTests {
                 }
                 else if( i % 7 == 5 ) {
                     {
-                        Lock::DBRead r("foo");
+                        Lock::DBRead r(&lockState, "foo");
                         if( sometimes ) {
                             Lock::TempRelease t;
                         }
                     }
                     {
-                        Lock::DBRead r("bar");
+                        Lock::DBRead r(&lockState, "bar");
                     }
                 }
                 else if( i % 7 == 6 ) {
@@ -183,13 +186,13 @@ namespace ThreadedTests {
                         int q = i % 11;
                         if( q == 0 ) { 
                             char what = 'r';
-                            Lock::DBRead r("foo");
+                            Lock::DBRead r(&lockState, "foo");
                             ASSERT( Lock::isLocked() == what && Lock::atLeastReadLocked("foo") );
                             ASSERT( !Lock::nested() );
-                            Lock::DBRead r2("foo");
+                            Lock::DBRead r2(&lockState, "foo");
                             ASSERT( Lock::nested() );
                             ASSERT( Lock::isLocked() == what && Lock::atLeastReadLocked("foo") );
-                            Lock::DBRead r3("local");
+                            Lock::DBRead r3(&lockState, "local");
                             if( sometimes ) {
                                 Lock::TempRelease t;
                             }
@@ -199,41 +202,48 @@ namespace ThreadedTests {
                         else if( q == 1 ) {
                             // test locking local only -- with no preceeding lock
                             { 
-                                Lock::DBRead x("local"); 
+                                Lock::DBRead x(&lockState, "local");
                                 //Lock::DBRead y("q");
                                 if( sometimes ) {
                                     Lock::TempRelease t; // we don't temprelease (cant=true) here thus this is just a check that nothing weird happens...
                                 }
                             }
-                            { 
-                                Lock::DBWrite x("local"); 
+                            {
+                                OperationContextImpl txn;
+                                Lock::DBWrite x(txn.lockState(), "local");
                                 if( sometimes ) {
                                     Lock::TempRelease t;
                                 }
                             }
                         } else if( q == 1 ) {
-                            { Lock::DBRead  x("admin"); }
-                            { Lock::DBWrite x("admin"); }
+                                { Lock::DBRead  x(&lockState, "admin"); }
+                            { 
+                                OperationContextImpl txn;
+                                Lock::DBWrite x(txn.lockState(), "admin"); 
+                            }
                         } else if( q == 2 ) { 
                             /*Lock::DBWrite x("foo");
                             Lock::DBWrite y("admin");
                             { Lock::TempRelease t; }*/
                         }
                         else if( q == 3 ) {
-                            Lock::DBWrite x("foo");
-                            Lock::DBRead y("admin");
+                            OperationContextImpl txn;
+                            Lock::DBWrite x(txn.lockState(), "foo");
+                            Lock::DBRead y(&lockState, "admin");
                             { Lock::TempRelease t; }
                         } 
                         else if( q == 4 ) { 
-                            Lock::DBRead x("foo2");
-                            Lock::DBRead y("admin");
+                            Lock::DBRead x(&lockState, "foo2");
+                            Lock::DBRead y(&lockState, "admin");
                             { Lock::TempRelease t; }
                         }
                         else if ( q > 4 && q < 8 ) {
                             static const char * const dbnames[] = {
                                 "bar0", "bar1", "bar2", "bar3", "bar4", "bar5",
                                 "bar6", "bar7", "bar8", "bar9", "bar10" };
-                            Lock::DBWrite w(dbnames[q]);
+
+                            OperationContextImpl txn;
+                            Lock::DBWrite w(txn.lockState(), dbnames[q]);
                             {
                                 Lock::UpgradeGlobalLockToExclusive wToX;
                                 if (wToX.gotUpgrade()) {
@@ -245,21 +255,24 @@ namespace ThreadedTests {
                             }
                         }
                         else { 
-                            Lock::DBWrite w("foo");
+                            OperationContextImpl txn;
+                            Lock::DBWrite w(txn.lockState(), "foo");
+
                             {
                                 Lock::TempRelease t;
                             }
-                            Lock::DBRead r2("foo");
-                            Lock::DBRead r3("local");
+
+                            Lock::DBRead r2(&lockState, "foo");
+                            Lock::DBRead r3(&lockState, "local");
                             if( sometimes ) {
                                 Lock::TempRelease t;
                             }
                         }
                     }
                     else { 
-                        Lock::DBRead r("foo");
-                        Lock::DBRead r2("foo");
-                        Lock::DBRead r3("local");
+                        Lock::DBRead r(&lockState, "foo");
+                        Lock::DBRead r2(&lockState, "foo");
+                        Lock::DBRead r3(&lockState, "local");
                     }
                 }
                 pm.hit();
diff --git a/src/mongo/dbtests/updatetests.cpp b/src/mongo/dbtests/updatetests.cpp
index 32e20bd9d01..e89997330cf 100644
--- a/src/mongo/dbtests/updatetests.cpp
+++ b/src/mongo/dbtests/updatetests.cpp
@@ -1060,14 +1060,11 @@ namespace UpdateTests {
 
                 BSONObj result;
                 BSONObj expected;
-                switch ( i ) {
-                default:
-                    client().update( ns(), Query(), getUpdate(i) );
-                    result = client().findOne( ns(), Query() );
-                    expected = fromjson( "{'_id':0,x:[]}" );
-                    ASSERT_EQUALS( result, expected );
-                    break;
-                }
+
+                client().update( ns(), Query(), getUpdate(i) );
+                result = client().findOne( ns(), Query() );
+                expected = fromjson( "{'_id':0,x:[]}" );
+                ASSERT_EQUALS( result, expected );
             }
         }
     };
@@ -1092,14 +1089,11 @@ namespace UpdateTests {
 
                 BSONObj result;
                 BSONObj expected;
-                switch ( i ) {
-                default:
-                    client().update( ns(), Query(), getUpdate(i) );
-                    result = client().findOne( ns(), Query() );
-                    expected = fromjson( "{'_id':0,x:[]}" );
-                    ASSERT_EQUALS( result, expected );
-                    break;
-                }
+
+                client().update( ns(), Query(), getUpdate(i) );
+                result = client().findOne( ns(), Query() );
+                expected = fromjson( "{'_id':0,x:[]}" );
+                ASSERT_EQUALS( result, expected );
             }
         }
     };