added db.<collection>.getResponsibleShard() (#8683)

3rdParty/velocypack/include/velocypack/StringRef.h

@@ -118,16 +118,9 @@ class StringRef {
     return operator[](index);
   }
   
-  size_t find(char c) const {
+  size_t find(char c) const;
-    char const* p =
-        static_cast<char const*>(memchr(static_cast<void const*>(_data), c, _length));
   
-    if (p == nullptr) {
+  size_t rfind(char c) const;
-      return std::string::npos;
-    }
-
-    return (p - _data);
-  }
 
   int compare(std::string const& other) const noexcept {
     int res = memcmp(_data, other.data(), (std::min)(_length, other.size()));

3rdParty/velocypack/src/Builder.cpp

@@ -120,7 +120,11 @@ void Builder::sortObjectIndexLong(uint8_t* objBase,
   }
   VELOCYPACK_ASSERT(_sortEntries.size() == n);
   std::sort(_sortEntries.begin(), _sortEntries.end(), [](SortEntry const& a, 
-                                                         SortEntry const& b) noexcept(checkOverflow(UINT64_MAX)) {
+                                                         SortEntry const& b) 
+#ifdef VELOCYPACK_64BIT
+    noexcept
+#endif
+  {
     // return true iff a < b:
     uint64_t sizea = a.nameSize;
     uint64_t sizeb = b.nameSize;

3rdParty/velocypack/src/StringRef.cpp

@@ -31,6 +31,28 @@
 
 using namespace arangodb::velocypack;
 
+namespace {
+
+void* memrchrSwitch(void const* block, int c, size_t size) {
+#ifdef __linux__
+  return const_cast<void*>(memrchr(block, c, size));
+#else
+/// naive memrchr overlay for Windows or other platforms, which don't implement it
+  if (size) {
+    unsigned char const* p = static_cast<unsigned char const*>(block);
+
+    for (p += size - 1; size; p--, size--) {
+      if (*p == c) {
+        return const_cast<void*>(static_cast<void const*>(p));
+      }
+    }
+  }
+  return nullptr;
+#endif
+}
+
+} // namespace
+  
 StringRef::StringRef(Slice slice) {
   VELOCYPACK_ASSERT(slice.isString());
   ValueLength l;
@@ -47,6 +69,28 @@ StringRef& StringRef::operator=(Slice slice) {
   return *this;
 }
   
+size_t StringRef::find(char c) const {
+  char const* p =
+      static_cast<char const*>(memchr(static_cast<void const*>(_data), c, _length));
+
+  if (p == nullptr) {
+    return std::string::npos;
+  }
+
+  return (p - _data);
+}
+  
+size_t StringRef::rfind(char c) const {
+  char const* p =
+      static_cast<char const*>(::memrchrSwitch(static_cast<void const*>(_data), c, _length));
+
+  if (p == nullptr) {
+    return std::string::npos;
+  }
+
+  return (p - _data);
+}
+
 namespace arangodb {
 namespace velocypack {
 

CHANGELOG

@@ -1,6 +1,10 @@
 devel
 -----
 
+* added function `db.<collection>.getResponsibleShard()` to find out which is the
+  responsible shard for a given document. Note that this function is only available
+  in a cluster coordinator.
+
 * updated bundled version of jemalloc memory allocator to 5.2.0.
 
 * don't create per-database system collection `_frontend` automatically.

Documentation/Books/HTTP/Collection/Getting.md

@@ -13,6 +13,8 @@ Getting Information about a Collection
 <!-- js/actions/api-collection.js -->
 @startDocuBlock get_api_collection_figures
 
+@startDocuBlock get_api_collection_getResponsibleShard
+
 <!-- js/actions/api-collection.js -->
 @startDocuBlock get_api_collection_revision
 

Documentation/Books/Manual/Appendix/References/CollectionObject.md

@@ -10,6 +10,7 @@ The following methods exist on the collection object (returned by *db.name*):
 * [collection.count()](../../DataModeling/Documents/DocumentMethods.md#count)
 * [collection.drop()](../../DataModeling/Collections/CollectionMethods.md#drop)
 * [collection.figures()](../../DataModeling/Collections/CollectionMethods.md#figures)
+* [collection.getResponsibleShard()](../../DataModeling/Collections/CollectionMethods.md#getresponsibleshard)
 * [collection.load()](../../DataModeling/Collections/CollectionMethods.md#load)
 * [collection.properties(options)](../../DataModeling/Collections/CollectionMethods.md#properties)
 * [collection.revision()](../../DataModeling/Collections/CollectionMethods.md#revision)

Documentation/Books/Manual/DataModeling/Collections/CollectionMethods.md

@@ -213,6 +213,21 @@ used as a lower bound approximation of the disk usage.
     @endDocuBlock collectionFigures
 
 
+GetResponsibleShard
+-------------------
+
+<!-- arangod/V8Server/v8-collection.cpp -->
+
+
+returns the responsible shard for the given document.
+`collection.getResponsibleShard(document)`
+
+Returns a string with the responsible shard's ID. Note that the
+returned shard ID is the ID of responsible shard for the document's
+shard key values, and it will be returned even if no such document exists.
+
+**Note**: this function can only be used on a coordinator in a cluster.
+
 
 Load
 ----

Documentation/Books/Manual/ReleaseNotes/NewFeatures35.md

@@ -254,6 +254,8 @@ documents in a single collection at once can be controlled by the startup option
 HTTP API extensions
 -------------------
 
+### Extended index API
+
 The HTTP API for creating indexes at POST `/_api/index` has been extended two-fold:
 
 * to create a TTL (time-to-live) index, it is now possible to specify a value of `ttl`
@@ -263,6 +265,22 @@ The HTTP API for creating indexes at POST `/_api/index` has been extended two-fo
 
 * to create an index in background, the attribute `inBackground` can be set to `true`.
 
+### API for querying the responsible shard
+
+The HTTP API for collections has got an additional route for retrieving the responsible
+shard for a document at PUT `/_api/collection/<name>/responsibleShard`.
+
+When calling this route, the request body is supposed to contain the document for which
+the responsible shard should be determined. The response will contain an attribute `shardId`
+containing the ID of the shard that is responsible for that document.
+
+A method `collection.getResponsibleShard(document)` was added to the JS API as well.
+
+It does not matter if the document actually exists or not, as the shard responsibility 
+is determined from the document's attribute values only. 
+
+Please note that this API is only meaningful and available on a cluster coordinator.
+
 
 Web interface
 -------------
@@ -390,14 +408,18 @@ them as well.
 
 ### Fewer system collections
 
-The system collections `_routing` and `_modules` are not created anymore for new
+The system collections `_frontend`, `_modules` and `_routing` are not created 
-new databases, as both are only needed for legacy functionality.
+anymore for new databases by default. 
 
+`_modules` and `_routing` are only needed for legacy functionality.
 Existing `_routing` collections will not be touched as they may contain user-defined
 entries, and will continue to work.
 
 Existing `_modules` collections will also remain functional.
 
+The `_frontend` collection may still be required for actions triggered by the
+web interface, but it will automatically be created lazily if needed.
+
 ### Named indices
 
 Indices now have an additional `name` field, which allows for more useful

Documentation/DocuBlocks/Rest/Collections/get_api_collection_getResponsibleShard.md

@@ -0,0 +1,35 @@
+
+@startDocuBlock get_api_collection_getResponsibleShard
+@brief Return the responsible shard for a document
+
+@RESTHEADER{PUT /_api/collection/{collection-name}/responsibleShard, Return responsible shard for a document}
+
+@RESTURLPARAMETERS
+
+@RESTURLPARAM{collection-name,string,required}
+The name of the collection.
+
+@RESTDESCRIPTION
+Returns the ID of the shard that is responsible for the given document
+(if the document exists) or that would be responsible if such document
+existed.
+
+The response is a JSON object with a *shardId* attribute, which will 
+contain the ID of the responsible shard.
+
+**Note** : This method is only available in a cluster coordinator.
+
+@RESTRETURNCODES
+
+@RESTRETURNCODE{200}
+Returns the ID of the responsible shard:
+
+@RESTRETURNCODE{400}
+If the *collection-name* is missing, then a *HTTP 400* is
+returned.
+
+@RESTRETURNCODE{404}
+If the *collection-name* is unknown, then an *HTTP 404*
+is returned.
+
+@endDocuBlock

arangod/RestHandler/RestCollectionHandler.cpp

@@ -246,7 +246,7 @@ void RestCollectionHandler::handleCommandGet() {
       skipGenerate = true;
       this->generateError(rest::ResponseCode::NOT_FOUND, TRI_ERROR_HTTP_NOT_FOUND,
                           "expecting one of the resources 'checksum', 'count', "
-                          "'figures', 'properties', 'revision', 'shards'");
+                          "'figures', 'properties', 'responsibleShard', 'revision', 'shards'");
     }
   });
 
@@ -392,6 +392,19 @@ void RestCollectionHandler::handleCommandPut() {
                                  /*showFigures*/ false, /*showCount*/ false,
                                  /*detailedCount*/ true);
       }
+    } else if (sub == "responsibleShard") {
+      if (!ServerState::instance()->isCoordinator()) {
+        res.reset(TRI_ERROR_CLUSTER_ONLY_ON_COORDINATOR);
+      } else {
+        std::string shardId;
+        res = coll->getResponsibleShard(body, false, shardId);
+
+        if (res.ok()) {
+          builder.openObject();
+          builder.add("shardId", VPackValue(shardId));
+          builder.close();
+        }
+      }
     } else if (sub == "truncate") {
       {
         OperationOptions opts;

arangod/RocksDBEngine/RocksDBMethods.cpp

@@ -148,7 +148,7 @@ rocksdb::Status RocksDBReadOnlyMethods::Get(rocksdb::ColumnFamilyHandle* cf,
   TRI_ASSERT(cf != nullptr);
   rocksdb::ReadOptions const& ro = _state->_rocksReadOptions;
   TRI_ASSERT(ro.snapshot != nullptr ||
-             _state->isReadOnlyTransaction() && _state->isSingleOperation());
+             (_state->isReadOnlyTransaction() && _state->isSingleOperation()));
   return _db->Get(ro, cf, key, val);
 }
 
@@ -158,7 +158,7 @@ rocksdb::Status RocksDBReadOnlyMethods::Get(rocksdb::ColumnFamilyHandle* cf,
   TRI_ASSERT(cf != nullptr);
   rocksdb::ReadOptions const& ro = _state->_rocksReadOptions;
   TRI_ASSERT(ro.snapshot != nullptr ||
-             _state->isReadOnlyTransaction() && _state->isSingleOperation());
+             (_state->isReadOnlyTransaction() && _state->isSingleOperation()));
   return _db->Get(ro, cf, key, val);
 }
 

arangod/Sharding/ShardingStrategyDefault.cpp

@@ -69,48 +69,43 @@ template <bool returnNullSlice>
 VPackSlice buildTemporarySlice(VPackSlice const& sub, Part const& part,
                                VPackBuilder& temporaryBuilder, bool splitSlash) {
   if (sub.isString()) {
-    switch (part) {
-      case Part::ALL: {
-        if (splitSlash) {
     arangodb::velocypack::StringRef key(sub);
+    if (splitSlash) {
       size_t pos = key.find('/');
       if (pos != std::string::npos) {
         // We have an _id. Split it.
         key = key.substr(pos + 1);
-            temporaryBuilder.clear();
-            temporaryBuilder.add(VPackValue(key.toString()));
-            return temporaryBuilder.slice();
       }
     }
-        return sub;
+    switch (part) {
+      case Part::ALL: {
+        // by adding the key to the builder, we may invalidate the original key...
+        // however, this is safe here as the original key is not used after we have
+        // added to the builder
+        return VPackSlice(temporaryBuilder.add(VPackValuePair(key.data(), key.size(), VPackValueType::String)));
       }
       case Part::FRONT: {
-        arangodb::velocypack::StringRef prefix(sub);
+        size_t pos = key.find(':');
-        size_t pos;
-        if (splitSlash) {
-          pos = prefix.find('/');
         if (pos != std::string::npos) {
-            // We have an _id. Split it.
+          key = key.substr(0, pos);
-            prefix = prefix.substr(pos + 1);
+          // by adding the key to the builder, we may invalidate the original key...
-          }
+          // however, this is safe here as the original key is not used after we have
-        }
+          // added to the builder
-        pos = prefix.find(':');
+          return VPackSlice(temporaryBuilder.add(VPackValuePair(key.data(), key.size(), VPackValueType::String)));
-        if (pos != std::string::npos) {
-          prefix = prefix.substr(0, pos);
-          temporaryBuilder.clear();
-          temporaryBuilder.add(VPackValue(prefix.toString()));
-          return temporaryBuilder.slice();
         }
+        // fall-through to returning null or original slice
         break;
       }
       case Part::BACK: {
-        std::string prefix = sub.copyString();
+        size_t pos = key.rfind(':');
-        size_t pos = prefix.rfind(':');
         if (pos != std::string::npos) {
-          temporaryBuilder.clear();
+          key = key.substr(pos + 1);
-          temporaryBuilder.add(VPackValue(prefix.substr(pos + 1)));
+          // by adding the key to the builder, we may invalidate the original key...
-          return temporaryBuilder.slice();
+          // however, this is safe here as the original key is not used after we have
+          // added to the builder
+          return VPackSlice(temporaryBuilder.add(VPackValuePair(key.data(), key.size(), VPackValueType::String)));
         }
+        // fall-through to returning null or original slice
         break;
       }
     }
@@ -129,13 +124,16 @@ uint64_t hashByAttributesImpl(VPackSlice slice, std::vector<std::string> const&
   error = TRI_ERROR_NO_ERROR;
   slice = slice.resolveExternal();
   if (slice.isObject()) {
+    VPackBuilder temporaryBuilder;
     for (auto const& attr : attributes) {
+      temporaryBuilder.clear();
+
       arangodb::velocypack::StringRef realAttr;
       ::Part part;
       ::parseAttributeAndPart(attr, realAttr, part);
       VPackSlice sub = slice.get(realAttr).resolveExternal();
-      VPackBuilder temporaryBuilder;
       if (sub.isNone()) {
+        // shard key attribute not present in document
         if (realAttr == StaticStrings::KeyString && !key.empty()) {
           temporaryBuilder.add(VPackValue(key));
           sub = temporaryBuilder.slice();
@@ -147,6 +145,9 @@ uint64_t hashByAttributesImpl(VPackSlice slice, std::vector<std::string> const&
           sub = VPackSlice::nullSlice();
         }
       }
+      // buildTemporarySlice may append data to the builder, which may invalidate
+      // the original "sub" value. however, "sub" is reassigned immediately with
+      // a new value, so it does not matter in reality
       sub = ::buildTemporarySlice<returnNullSlice>(sub, part, temporaryBuilder, false);
       hash = sub.normalizedHash(hash);
     }

arangod/V8Server/v8-collection.cpp

@@ -961,6 +961,42 @@ static void JS_FiguresVocbaseCol(v8::FunctionCallbackInfo<v8::Value> const& args
   TRI_V8_TRY_CATCH_END
 }
 
+static void JS_GetResponsibleShardVocbaseCol(v8::FunctionCallbackInfo<v8::Value> const& args) {
+  TRI_V8_TRY_CATCH_BEGIN(isolate);
+  v8::HandleScope scope(isolate);
+  
+  if (!ServerState::instance()->isCoordinator()) {
+    TRI_V8_THROW_EXCEPTION(TRI_ERROR_CLUSTER_ONLY_ON_COORDINATOR);
+  }
+
+  auto* collection = UnwrapCollection(isolate, args.Holder());
+
+  if (!collection) {
+    TRI_V8_THROW_EXCEPTION_INTERNAL("cannot extract collection");
+  }
+  if (args.Length() < 1) {
+    TRI_V8_THROW_EXCEPTION_USAGE("getResponsibleShard(<data>)");
+  }
+  
+  VPackBuilder builder;      
+  int res = TRI_V8ToVPack(isolate, builder, args[0], false);
+  if (res != TRI_ERROR_NO_ERROR) {
+    TRI_V8_THROW_EXCEPTION(res);
+  }
+
+  std::string shardId;
+  res = collection->getResponsibleShard(builder.slice(), false, shardId);
+
+  if (res != TRI_ERROR_NO_ERROR) {
+    TRI_V8_THROW_EXCEPTION(res);
+  }
+
+  v8::Handle<v8::Value> result = TRI_V8_STD_STRING(isolate, shardId);
+  TRI_V8_RETURN(result);
+
+  TRI_V8_TRY_CATCH_END
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 /// @brief was docuBlock collectionLoad
 ////////////////////////////////////////////////////////////////////////////////
@@ -2481,6 +2517,7 @@ void TRI_InitV8Collections(v8::Handle<v8::Context> context, TRI_vocbase_t* vocba
   TRI_AddMethodVocbase(isolate, rt, TRI_V8_ASCII_STRING(isolate, "drop"), JS_DropVocbaseCol);
   TRI_AddMethodVocbase(isolate, rt, TRI_V8_ASCII_STRING(isolate, "exists"), JS_ExistsVocbaseVPack);
   TRI_AddMethodVocbase(isolate, rt, TRI_V8_ASCII_STRING(isolate, "figures"), JS_FiguresVocbaseCol);
+  TRI_AddMethodVocbase(isolate, rt, TRI_V8_ASCII_STRING(isolate, "getResponsibleShard"), JS_GetResponsibleShardVocbaseCol);
   TRI_AddMethodVocbase(isolate, rt, TRI_V8_ASCII_STRING(isolate, "insert"), JS_InsertVocbaseCol);
   TRI_AddMethodVocbase(isolate, rt,
                        TRI_V8_ASCII_STRING(isolate, "_binaryInsert"),

js/client/modules/@arangodb/arango-collection.js

@@ -431,6 +431,23 @@ ArangoCollection.prototype.figures = function () {
   return requestResult.figures;
 };
 
+// //////////////////////////////////////////////////////////////////////////////
+// / @brief gets the responsible shard for a specific value
+// //////////////////////////////////////////////////////////////////////////////
+
+ArangoCollection.prototype.getResponsibleShard = function (data) {
+  if (data === undefined || data === null) {
+    data = {};
+  } else if (typeof data === 'string' || typeof data === 'number') {
+    data = { _key: String(data) };
+  }
+  var requestResult = this._database._connection.PUT(this._baseurl('responsibleShard'), data);
+
+  arangosh.checkRequestResult(requestResult);
+
+  return requestResult.shardId;
+};
+
 // //////////////////////////////////////////////////////////////////////////////
 // / @brief gets the checksum of a collection
 // //////////////////////////////////////////////////////////////////////////////

tests/js/common/shell/shell-responsibleshard-cluster.js

@@ -0,0 +1,220 @@
+/*jshint globalstrict:false, strict:false */
+/*global assertEqual, assertNotEqual, assertNull, assertTrue, assertUndefined, fail */
+
+////////////////////////////////////////////////////////////////////////////////
+/// DISCLAIMER
+///
+/// Copyright 2014-2018 ArangoDB GmbH, Cologne, Germany
+/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
+///
+/// Licensed under the Apache License, Version 2.0 (the "License");
+/// you may not use this file except in compliance with the License.
+/// You may obtain a copy of the License at
+///
+///     http://www.apache.org/licenses/LICENSE-2.0
+///
+/// Unless required by applicable law or agreed to in writing, software
+/// distributed under the License is distributed on an "AS IS" BASIS,
+/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+/// See the License for the specific language governing permissions and
+/// limitations under the License.
+///
+/// Copyright holder is ArangoDB GmbH, Cologne, Germany
+///
+/// @author Jan Steemann
+////////////////////////////////////////////////////////////////////////////////
+
+let jsunity = require("jsunity");
+let arangodb = require("@arangodb");
+let internal = require("internal");
+let db = arangodb.db;
+
+function ResponsibleShardSuite() {
+  const cn = "UnitTestsCollection1";
+
+  return {
+
+    setUp : function () {
+      db._drop(cn);
+    },
+
+    tearDown : function () {
+      db._drop(cn);
+    },
+    
+    testCheckMissingParameter : function () {
+      let c = db._create(cn, { numberOfShards: 5, shardKeys: ["_key"] });
+
+      let key = c.insert({})._key;
+
+      let shardCounts = c.count(true);
+
+      let total = 0;
+      let expected = null;
+      assertEqual(5, Object.keys(shardCounts).length);
+      Object.keys(shardCounts).forEach(function(key) {
+        let count = shardCounts[key];
+        total += count;
+        if (count > 0) {
+          expected = key;
+        }
+      });
+
+      assertEqual(1, total);
+      assertEqual(expected, c.getResponsibleShard(key));
+      assertEqual(expected, c.getResponsibleShard({ _key: key }));
+    },
+    
+    testCheckBrokenParameter : function () {
+      let c = db._create(cn, { numberOfShards: 5, shardKeys: ["_key"] });
+
+      assertNotEqual("", c.getResponsibleShard(12345));
+    },
+    
+    testCheckKeyNotGiven : function () {
+      let c = db._create(cn, { numberOfShards: 5, shardKeys: ["_key"] });
+
+      try {
+        c.getResponsibleShard({ test: "foo" });
+        fail();
+      } catch (err) {
+        assertEqual(internal.errors.ERROR_CLUSTER_NOT_ALL_SHARDING_ATTRIBUTES_GIVEN.code, err.errorNum);
+      }
+    },
+
+    testCheckWithShardKeyKey : function () {
+      let c = db._create(cn, { numberOfShards: 5, shardKeys: ["_key"] });
+
+      c.insert({ _key: "meow" });
+
+      let shardCounts = c.count(true);
+
+      let total = 0;
+      let expected = null;
+      assertEqual(5, Object.keys(shardCounts).length);
+      Object.keys(shardCounts).forEach(function(key) {
+        let count = shardCounts[key];
+        total += count;
+        if (count > 0) {
+          expected = key;
+        }
+      });
+
+      assertEqual(1, total);
+      assertEqual(expected, c.getResponsibleShard("meow"));
+      assertEqual(expected, c.getResponsibleShard({ _key: "meow" }));
+    },
+    
+    testCheckWithShardKeyOther : function () {
+      let c = db._create(cn, { numberOfShards: 5, shardKeys: ["test"] });
+
+      c.insert({ test: "abc" });
+
+      let shardCounts = c.count(true);
+
+      let total = 0;
+      let expected = null;
+      assertEqual(5, Object.keys(shardCounts).length);
+      Object.keys(shardCounts).forEach(function(key) {
+        let count = shardCounts[key];
+        total += count;
+        if (count > 0) {
+          expected = key;
+        }
+      });
+
+      assertEqual(1, total);
+      assertEqual(expected, c.getResponsibleShard({ test: "abc" }));
+
+      try {
+        c.getResponsibleShard({});
+        fail();
+      } catch (err) {
+        assertEqual(internal.errors.ERROR_CLUSTER_NOT_ALL_SHARDING_ATTRIBUTES_GIVEN.code, err.errorNum);
+      }
+    },
+    
+    testCheckWithShardKeysMultiple : function () {
+      let c = db._create(cn, { numberOfShards: 5, shardKeys: ["test1", "test2"] });
+
+      c.insert({ test1: "abc", test2: "nnsn" });
+
+      let shardCounts = c.count(true);
+
+      let total = 0;
+      let expected = null;
+      assertEqual(5, Object.keys(shardCounts).length);
+      Object.keys(shardCounts).forEach(function(key) {
+        let count = shardCounts[key];
+        total += count;
+        if (count > 0) {
+          expected = key;
+        }
+      });
+
+      assertEqual(1, total);
+      assertEqual(expected, c.getResponsibleShard({ test1: "abc", test2: "nnsn" }));
+    },
+    
+    testCheckWithShardKeysPartial : function () {
+      let c = db._create(cn, { numberOfShards: 5, shardKeys: ["test1", "test2"] });
+
+      c.insert({ test1: "abc" });
+
+      let shardCounts = c.count(true);
+
+      let total = 0;
+      let expected = null;
+      assertEqual(5, Object.keys(shardCounts).length);
+      Object.keys(shardCounts).forEach(function(key) {
+        let count = shardCounts[key];
+        total += count;
+        if (count > 0) {
+          expected = key;
+        }
+      });
+
+      assertEqual(1, total);
+      assertEqual(expected, c.getResponsibleShard({ test1: "abc", test2: null }));
+      try {
+        c.getResponsibleShard({ test1: "abc" });
+        fail();
+      } catch (err) {
+        assertEqual(internal.errors.ERROR_CLUSTER_NOT_ALL_SHARDING_ATTRIBUTES_GIVEN.code, err.errorNum);
+      }
+    },
+    
+    testCheckWithShardKeysPartialOther : function () {
+      let c = db._create(cn, { numberOfShards: 5, shardKeys: ["test1", "test2"] });
+
+      c.insert({ test2: "abc", test1: null });
+
+      let shardCounts = c.count(true);
+
+      let total = 0;
+      let expected = null;
+      assertEqual(5, Object.keys(shardCounts).length);
+      Object.keys(shardCounts).forEach(function(key) {
+        let count = shardCounts[key];
+        total += count;
+        if (count > 0) {
+          expected = key;
+        }
+      });
+
+      assertEqual(1, total);
+      assertEqual(expected, c.getResponsibleShard({ test2: "abc", test1: null }));
+      try {
+        c.getResponsibleShard({ test2: "abc" });
+        fail();
+      } catch (err) {
+        assertEqual(internal.errors.ERROR_CLUSTER_NOT_ALL_SHARDING_ATTRIBUTES_GIVEN.code, err.errorNum);
+      }
+    },
+
+  };
+}
+
+jsunity.run(ResponsibleShardSuite);
+
+return jsunity.done();