diff --git a/lib/inc/drogon/HttpAppFramework.h b/lib/inc/drogon/HttpAppFramework.h
index b054840e..1ac2aa6a 100644
--- a/lib/inc/drogon/HttpAppFramework.h
+++ b/lib/inc/drogon/HttpAppFramework.h
@@ -910,6 +910,22 @@ class HttpAppFramework : public trantor::NonCopyable
     /// Return true is drogon supports SSL(https)
     virtual bool supportSSL() const = 0;
 
+    /**
+     * @brief Get the Current Thread Index whose range is [0, the total number
+     * of IO threads]
+     *
+     * @return size_t If the current thread is the main thread, the number of
+     * the IO threads is returned. If the current thread is a network IO thread,
+     * the index of it in the range [0, the number of IO threads) is returned.
+     * otherwise the maximum value of type size_t is returned.
+     *
+     * @note Basically this method is used for storing thread-related various in
+     * an array and users can use indexes returned by this method to access
+     * them. This is much faster than using a map. If the array is properly
+     * initialized at the beginning, users can access it without locks.
+     */
+    virtual size_t getCurrentThreadIndex() const = 0;
+
   private:
     virtual void registerHttpController(
         const std::string &pathPattern,
diff --git a/lib/src/DbClientManager.h b/lib/src/DbClientManager.h
index a5b6bfb7..0f17a256 100644
--- a/lib/src/DbClientManager.h
+++ b/lib/src/DbClientManager.h
@@ -15,6 +15,7 @@
 #pragma once
 
 #include <drogon/orm/DbClient.h>
+#include <drogon/HttpAppFramework.h>
 #include <trantor/utils/NonCopyable.h>
 #include <trantor/net/EventLoop.h>
 #include <string>
@@ -35,11 +36,11 @@ class DbClientManager : public trantor::NonCopyable
 
     DbClientPtr getFastDbClient(const std::string &name)
     {
-        assert(_dbFastClientsMap[name].find(
-                   trantor::EventLoop::getEventLoopOfCurrentThread()) !=
-               _dbFastClientsMap[name].end());
-        return _dbFastClientsMap
-            [name][trantor::EventLoop::getEventLoopOfCurrentThread()];
+        auto index = drogon::app().getCurrentThreadIndex();
+        auto iter = _dbFastClientsMap.find(name);
+        assert(iter != _dbFastClientsMap.end());
+        assert(index < iter->second.size());
+        return iter->second[index];
     }
     void createDbClient(const std::string &dbType,
                         const std::string &host,
@@ -63,8 +64,7 @@ class DbClientManager : public trantor::NonCopyable
         size_t _connectionNumber;
     };
     std::vector<DbInfo> _dbInfos;
-    std::map<std::string, std::map<trantor::EventLoop *, orm::DbClientPtr>>
-        _dbFastClientsMap;
+    std::map<std::string, std::vector<orm::DbClientPtr>> _dbFastClientsMap;
 };
 }  // namespace orm
 }  // namespace drogon
diff --git a/lib/src/HttpAppFrameworkImpl.cc b/lib/src/HttpAppFrameworkImpl.cc
index 97c24436..a21ae10a 100644
--- a/lib/src/HttpAppFrameworkImpl.cc
+++ b/lib/src/HttpAppFrameworkImpl.cc
@@ -397,8 +397,14 @@ void HttpAppFrameworkImpl::run()
         _sslKeyPath,
         _threadNum,
         _syncAdvices);
-    // A fast database client instance should be created in the main event loop,
-    // so put the main loop into ioLoops.
+    assert(ioLoops.size() == _threadNum);
+    for (size_t i=0; i < _threadNum; ++i)
+    {
+        ioLoops[i]->setIndex(i);
+    }
+    getLoop()->setIndex(_threadNum);
+    // A fast database client instance should be created in the main event
+    // loop, so put the main loop into ioLoops.
     ioLoops.push_back(getLoop());
     _dbClientManagerPtr->createDbClients(ioLoops);
     ioLoops.pop_back();
diff --git a/lib/src/HttpAppFrameworkImpl.h b/lib/src/HttpAppFrameworkImpl.h
index d9bf3971..3a9b3af5 100644
--- a/lib/src/HttpAppFrameworkImpl.h
+++ b/lib/src/HttpAppFrameworkImpl.h
@@ -23,6 +23,7 @@
 #include <string>
 #include <vector>
 #include <functional>
+#include <limits>
 
 namespace drogon
 {
@@ -392,6 +393,16 @@ class HttpAppFrameworkImpl : public HttpAppFramework
         return false;
     }
 
+    virtual size_t getCurrentThreadIndex() const override
+    {
+        auto *loop = trantor::EventLoop::getEventLoopOfCurrentThread();
+        if (loop)
+        {
+            return loop->index();
+        }
+        return std::numeric_limits<size_t>::max();
+    }
+
   private:
     virtual void registerHttpController(
         const std::string &pathPattern,
diff --git a/lib/src/HttpControllersRouter.cc b/lib/src/HttpControllersRouter.cc
index 87777e0f..059f597c 100644
--- a/lib/src/HttpControllersRouter.cc
+++ b/lib/src/HttpControllersRouter.cc
@@ -54,11 +54,7 @@ void HttpControllersRouter::init(
             {
                 binder->_filters =
                     filters_function::createFilters(binder->_filterNames);
-                for (auto ioloop : ioLoops)
-                {
-                    binder->_responsePtrMap[ioloop] =
-                        std::shared_ptr<HttpResponse>();
-                }
+                binder->_responseCache.resize(ioLoops.size());
             }
         }
     }
@@ -344,7 +340,7 @@ void HttpControllersRouter::doControllerHandler(
     if (ctrlBinderPtr->_hasCachedResponse)
     {
         HttpResponsePtr &responsePtr =
-            ctrlBinderPtr->_responsePtrMap[req->getLoop()];
+            ctrlBinderPtr->_responseCache[req->getLoop()->index()];
         if (responsePtr &&
             (responsePtr->expiredTime() == 0 ||
              (trantor::Date::now() <
@@ -405,13 +401,13 @@ void HttpControllersRouter::doControllerHandler(
                 auto loop = req->getLoop();
                 if (loop->isInLoopThread())
                 {
-                    ctrlBinderPtr->_responsePtrMap[loop] = resp;
+                    ctrlBinderPtr->_responseCache[loop->index()] = resp;
                     ctrlBinderPtr->_hasCachedResponse = true;
                 }
                 else
                 {
                     req->getLoop()->queueInLoop([loop, resp, ctrlBinderPtr]() {
-                        ctrlBinderPtr->_responsePtrMap[loop] = resp;
+                        ctrlBinderPtr->_responseCache[loop->index()] = resp;
                         ctrlBinderPtr->_hasCachedResponse = true;
                     });
                 }
diff --git a/lib/src/HttpControllersRouter.h b/lib/src/HttpControllersRouter.h
index 9a6b7d60..a77ca936 100644
--- a/lib/src/HttpControllersRouter.h
+++ b/lib/src/HttpControllersRouter.h
@@ -78,8 +78,7 @@ class HttpControllersRouter : public trantor::NonCopyable
         std::vector<std::shared_ptr<HttpFilterBase>> _filters;
         std::vector<size_t> _parameterPlaces;
         std::map<std::string, size_t> _queryParametersPlaces;
-        std::map<trantor::EventLoop *, std::shared_ptr<HttpResponse>>
-            _responsePtrMap;
+        std::vector<std::shared_ptr<HttpResponse>> _responseCache;
         bool _isCORS = false;
         bool _hasCachedResponse = false;
     };
diff --git a/lib/src/HttpSimpleControllersRouter.cc b/lib/src/HttpSimpleControllersRouter.cc
index a8d975c6..b89c929d 100644
--- a/lib/src/HttpSimpleControllersRouter.cc
+++ b/lib/src/HttpSimpleControllersRouter.cc
@@ -197,7 +197,7 @@ void HttpSimpleControllersRouter::doControllerHandler(
         if (ctrlBinderPtr->_hasCachedResponse)
         {
             HttpResponsePtr &responsePtr =
-                ctrlBinderPtr->_responsePtrMap[req->getLoop()];
+                ctrlBinderPtr->_responseCache[req->getLoop()->index()];
             if (responsePtr &&
                 (responsePtr->expiredTime() == 0 ||
                  (trantor::Date::now() < responsePtr->creationDate().after(
@@ -224,13 +224,14 @@ void HttpSimpleControllersRouter::doControllerHandler(
 
                     if (loop->isInLoopThread())
                     {
-                        ctrlBinderPtr->_responsePtrMap[loop] = resp;
+                        ctrlBinderPtr->_responseCache[loop->index()] = resp;
                         ctrlBinderPtr->_hasCachedResponse = true;
                     }
                     else
                     {
                         loop->queueInLoop([loop, resp, &ctrlBinderPtr]() {
-                            ctrlBinderPtr->_responsePtrMap[loop] = resp;
+                            ctrlBinderPtr->_responseCache[loop->index()] =
+                                resp;
                             ctrlBinderPtr->_hasCachedResponse = true;
                         });
                     }
@@ -284,10 +285,7 @@ void HttpSimpleControllersRouter::init(
             {
                 binder->_filters =
                     filters_function::createFilters(binder->_filterNames);
-                for (auto ioloop : ioLoops)
-                {
-                    binder->_responsePtrMap[ioloop] = nullptr;
-                }
+                binder->_responseCache.resize(ioLoops.size());
             }
         }
     }
diff --git a/lib/src/HttpSimpleControllersRouter.h b/lib/src/HttpSimpleControllersRouter.h
index 6bd8e8b2..0cc3bebe 100644
--- a/lib/src/HttpSimpleControllersRouter.h
+++ b/lib/src/HttpSimpleControllersRouter.h
@@ -94,8 +94,7 @@ class HttpSimpleControllersRouter : public trantor::NonCopyable
         std::string _controllerName;
         std::vector<std::string> _filterNames;
         std::vector<std::shared_ptr<HttpFilterBase>> _filters;
-        std::map<trantor::EventLoop *, std::shared_ptr<HttpResponse>>
-            _responsePtrMap;
+        std::vector<std::shared_ptr<HttpResponse>> _responseCache;
         bool _isCORS = false;
         bool _hasCachedResponse = false;
     };
diff --git a/lib/src/Utilities.cc b/lib/src/Utilities.cc
index 6c6c9140..26c674c0 100644
--- a/lib/src/Utilities.cc
+++ b/lib/src/Utilities.cc
@@ -778,8 +778,8 @@ std::string gzipDecompress(const char *data, const size_t ndata)
 
 char *getHttpFullDate(const trantor::Date &date)
 {
-    static __thread int64_t lastSecond = 0;
-    static __thread char lastTimeString[128] = {0};
+    static thread_local int64_t lastSecond = 0;
+    static thread_local char lastTimeString[128] = {0};
     auto nowSecond = date.microSecondsSinceEpoch() / MICRO_SECONDS_PRE_SEC;
     if (nowSecond == lastSecond)
     {
diff --git a/orm_lib/src/DbClientManager.cc b/orm_lib/src/DbClientManager.cc
index 3426d7e9..d30c7a8f 100644
--- a/orm_lib/src/DbClientManager.cc
+++ b/orm_lib/src/DbClientManager.cc
@@ -15,6 +15,7 @@
 #include "../../lib/src/DbClientManager.h"
 #include "DbClientLockFree.h"
 #include <drogon/config.h>
+#include <drogon/HttpAppFramework.h>
 #include <drogon/utils/Utilities.h>
 #include <algorithm>
 
@@ -30,6 +31,7 @@ void DbClientManager::createDbClients(
     {
         if (dbInfo._isFast)
         {
+            _dbFastClientsMap[dbInfo._name].resize(ioloops.size());
             for (auto *loop : ioloops)
             {
                 if (dbInfo._dbType == drogon::orm::ClientType::Sqlite3)
@@ -40,7 +42,7 @@ void DbClientManager::createDbClients(
                 if (dbInfo._dbType == drogon::orm::ClientType::PostgreSQL ||
                     dbInfo._dbType == drogon::orm::ClientType::Mysql)
                 {
-                    _dbFastClientsMap[dbInfo._name][loop] =
+                    _dbFastClientsMap[dbInfo._name][loop->index()] =
                         std::shared_ptr<drogon::orm::DbClient>(
                             new drogon::orm::DbClientLockFree(
                                 dbInfo._connectionInfo,
diff --git a/trantor b/trantor
index e95f82d3..99ba85bd 160000
--- a/trantor
+++ b/trantor
@@ -1 +1 @@
-Subproject commit e95f82d3090f81b4f5b7610b4e0e6e609c734509
+Subproject commit 99ba85bd4c252b7003e73eef50c862d51c23e4e0