Process read requests without raft

src/Common/ZooKeeper/ZooKeeperCommon.cpp

@@ -326,6 +326,12 @@ void ZooKeeperMultiRequest::readImpl(ReadBuffer & in)
     }
 }
 
+bool ZooKeeperMultiRequest::isReadRequest() const
+{
+    /// Possibly we can do better
+    return false;
+}
+
 void ZooKeeperMultiResponse::readImpl(ReadBuffer & in)
 {
     for (auto & response : responses)

src/Common/ZooKeeper/ZooKeeperCommon.h

@@ -60,6 +60,7 @@ struct ZooKeeperRequest : virtual Request
     static std::shared_ptr<ZooKeeperRequest> read(ReadBuffer & in);
 
     virtual ZooKeeperResponsePtr makeResponse() const = 0;
+    virtual bool isReadRequest() const = 0;
 };
 
 using ZooKeeperRequestPtr = std::shared_ptr<ZooKeeperRequest>;
@@ -71,6 +72,7 @@ struct ZooKeeperHeartbeatRequest final : ZooKeeperRequest
     void writeImpl(WriteBuffer &) const override {}
     void readImpl(ReadBuffer &) override {}
     ZooKeeperResponsePtr makeResponse() const override;
+    bool isReadRequest() const override { return true; }
 };
 
 struct ZooKeeperHeartbeatResponse final : ZooKeeperResponse
@@ -104,6 +106,7 @@ struct ZooKeeperAuthRequest final : ZooKeeperRequest
     void readImpl(ReadBuffer & in) override;
 
     ZooKeeperResponsePtr makeResponse() const override;
+    bool isReadRequest() const override { return false; }
 };
 
 struct ZooKeeperAuthResponse final : ZooKeeperResponse
@@ -122,6 +125,7 @@ struct ZooKeeperCloseRequest final : ZooKeeperRequest
     void readImpl(ReadBuffer &) override {}
 
     ZooKeeperResponsePtr makeResponse() const override;
+    bool isReadRequest() const override { return false; }
 };
 
 struct ZooKeeperCloseResponse final : ZooKeeperResponse
@@ -146,6 +150,7 @@ struct ZooKeeperCreateRequest final : public CreateRequest, ZooKeeperRequest
     void readImpl(ReadBuffer & in) override;
 
     ZooKeeperResponsePtr makeResponse() const override;
+    bool isReadRequest() const override { return false; }
 };
 
 struct ZooKeeperCreateResponse final : CreateResponse, ZooKeeperResponse
@@ -167,6 +172,7 @@ struct ZooKeeperRemoveRequest final : RemoveRequest, ZooKeeperRequest
     void readImpl(ReadBuffer & in) override;
 
     ZooKeeperResponsePtr makeResponse() const override;
+    bool isReadRequest() const override { return false; }
 };
 
 struct ZooKeeperRemoveResponse final : RemoveResponse, ZooKeeperResponse
@@ -183,6 +189,7 @@ struct ZooKeeperExistsRequest final : ExistsRequest, ZooKeeperRequest
     void readImpl(ReadBuffer & in) override;
 
     ZooKeeperResponsePtr makeResponse() const override;
+    bool isReadRequest() const override { return !has_watch; }
 };
 
 struct ZooKeeperExistsResponse final : ExistsResponse, ZooKeeperResponse
@@ -199,6 +206,7 @@ struct ZooKeeperGetRequest final : GetRequest, ZooKeeperRequest
     void readImpl(ReadBuffer & in) override;
 
     ZooKeeperResponsePtr makeResponse() const override;
+    bool isReadRequest() const override { return !has_watch; }
 };
 
 struct ZooKeeperGetResponse final : GetResponse, ZooKeeperResponse
@@ -217,6 +225,7 @@ struct ZooKeeperSetRequest final : SetRequest, ZooKeeperRequest
     void writeImpl(WriteBuffer & out) const override;
     void readImpl(ReadBuffer & in) override;
     ZooKeeperResponsePtr makeResponse() const override;
+    bool isReadRequest() const override { return false; }
 };
 
 struct ZooKeeperSetResponse final : SetResponse, ZooKeeperResponse
@@ -232,6 +241,7 @@ struct ZooKeeperListRequest : ListRequest, ZooKeeperRequest
     void writeImpl(WriteBuffer & out) const override;
     void readImpl(ReadBuffer & in) override;
     ZooKeeperResponsePtr makeResponse() const override;
+    bool isReadRequest() const override { return !has_watch; }
 };
 
 struct ZooKeeperSimpleListRequest final : ZooKeeperListRequest
@@ -261,6 +271,7 @@ struct ZooKeeperCheckRequest final : CheckRequest, ZooKeeperRequest
     void readImpl(ReadBuffer & in) override;
 
     ZooKeeperResponsePtr makeResponse() const override;
+    bool isReadRequest() const override { return !has_watch; }
 };
 
 struct ZooKeeperCheckResponse final : CheckResponse, ZooKeeperResponse
@@ -290,6 +301,7 @@ struct ZooKeeperMultiRequest final : MultiRequest, ZooKeeperRequest
     void readImpl(ReadBuffer & in) override;
 
     ZooKeeperResponsePtr makeResponse() const override;
+    bool isReadRequest() const override;
 };
 
 struct ZooKeeperMultiResponse final : MultiResponse, ZooKeeperResponse

src/Coordination/NuKeeperServer.cpp

@@ -146,34 +146,41 @@ TestKeeperStorage::ResponsesForSessions NuKeeperServer::readZooKeeperResponses(n
 
 TestKeeperStorage::ResponsesForSessions NuKeeperServer::putRequests(const TestKeeperStorage::RequestsForSessions & requests)
 {
-    std::vector<nuraft::ptr<nuraft::buffer>> entries;
+    if (requests.size() == 1 && requests[0].request->isReadRequest())
-    for (const auto & [session_id, request] : requests)
     {
-        ops_mapping[session_id][request->xid] = request->makeResponse();
+        return state_machine->processReadRequest(requests[0]);
-        entries.push_back(getZooKeeperLogEntry(session_id, request));
     }
-
+    else
-    auto result = raft_instance->append_entries(entries);
-    if (!result->get_accepted())
-        throw Exception(ErrorCodes::RAFT_ERROR, "Cannot send requests to RAFT, mostly because we are not leader, code {}, message: '{}'", result->get_result_code(), result->get_result_str());
-
-    if (result->get_result_code() == nuraft::cmd_result_code::TIMEOUT)
     {
-        TestKeeperStorage::ResponsesForSessions responses;
+        std::vector<nuraft::ptr<nuraft::buffer>> entries;
         for (const auto & [session_id, request] : requests)
         {
-            auto response = request->makeResponse();
+            ops_mapping[session_id][request->xid] = request->makeResponse();
-            response->xid = request->xid;
+            entries.push_back(getZooKeeperLogEntry(session_id, request));
-            response->zxid = 0; /// FIXME what we can do with it?
-            response->error = Coordination::Error::ZOPERATIONTIMEOUT;
-            responses.push_back(DB::TestKeeperStorage::ResponseForSession{session_id, response});
         }
-        return responses;
-    }
-    else if (result->get_result_code() != nuraft::cmd_result_code::OK)
-        throw Exception(ErrorCodes::RAFT_ERROR, "Requests result failed with code {} and message: '{}'", result->get_result_code(), result->get_result_str());
 
-    return readZooKeeperResponses(result->get());
+        auto result = raft_instance->append_entries(entries);
+        if (!result->get_accepted())
+            throw Exception(ErrorCodes::RAFT_ERROR, "Cannot send requests to RAFT, mostly because we are not leader, code {}, message: '{}'", result->get_result_code(), result->get_result_str());
+
+        if (result->get_result_code() == nuraft::cmd_result_code::TIMEOUT)
+        {
+            TestKeeperStorage::ResponsesForSessions responses;
+            for (const auto & [session_id, request] : requests)
+            {
+                auto response = request->makeResponse();
+                response->xid = request->xid;
+                response->zxid = 0; /// FIXME what we can do with it?
+                response->error = Coordination::Error::ZOPERATIONTIMEOUT;
+                responses.push_back(DB::TestKeeperStorage::ResponseForSession{session_id, response});
+            }
+            return responses;
+        }
+        else if (result->get_result_code() != nuraft::cmd_result_code::OK)
+            throw Exception(ErrorCodes::RAFT_ERROR, "Requests result failed with code {} and message: '{}'", result->get_result_code(), result->get_result_str());
+
+        return readZooKeeperResponses(result->get());
+    }
 }
 
 

src/Coordination/NuKeeperStateMachine.cpp

@@ -223,4 +223,10 @@ int NuKeeperStateMachine::read_logical_snp_obj(
     return 0;
 }
 
+TestKeeperStorage::ResponsesForSessions NuKeeperStateMachine::processReadRequest(const TestKeeperStorage::RequestForSession & request_for_session)
+{
+    std::lock_guard lock(storage_lock);
+    return storage.processRequest(request_for_session.request, request_for_session.session_id);
+}
+
 }

src/Coordination/NuKeeperStateMachine.h

@@ -47,6 +47,8 @@ public:
         return storage;
     }
 
+    TestKeeperStorage::ResponsesForSessions processReadRequest(const TestKeeperStorage::RequestForSession & requests);
+
 private:
     struct StorageSnapshot
     {