fix mysql scoped connection concurrency issue

Former-commit-id: ecb3cf07b5f49f2f87e3972a126452ec2950caf8

cpp/cmake/ThirdPartyPackages.cmake

@@ -271,7 +271,7 @@ endif()
 if(DEFINED ENV{MILVUS_MYSQLPP_URL})
     set(MYSQLPP_SOURCE_URL "$ENV{MILVUS_MYSQLPP_URL}")
 else()
-    set(MYSQLPP_SOURCE_URL "https://github.com/youny626/mysqlpp.git")
+    set(MYSQLPP_SOURCE_URL "https://tangentsoft.com/mysqlpp/releases/mysql++-${MYSQLPP_VERSION}.tar.gz")
 endif()
 
 if (DEFINED ENV{MILVUS_OPENBLAS_URL})
@@ -1095,18 +1095,18 @@ macro(build_mysqlpp)
             "LDFLAGS=-pthread")
 
     externalproject_add(mysqlpp_ep
-#            URL
-#            ${MYSQLPP_SOURCE_URL}
-            GIT_REPOSITORY
+            URL
             ${MYSQLPP_SOURCE_URL}
-            GIT_TAG
-            ${MYSQLPP_VERSION}
-            GIT_SHALLOW
-            TRUE
+#            GIT_REPOSITORY
+#            ${MYSQLPP_SOURCE_URL}
+#            GIT_TAG
+#            ${MYSQLPP_VERSION}
+#            GIT_SHALLOW
+#            TRUE
             ${EP_LOG_OPTIONS}
             CONFIGURE_COMMAND
-            "./bootstrap"
-            COMMAND
+#            "./bootstrap"
+#            COMMAND
             "./configure"
             ${MYSQLPP_CONFIGURE_ARGS}
             BUILD_COMMAND

cpp/conf/server_config.yaml

@@ -10,7 +10,7 @@ db_config:
   db_path: /tmp/milvus
   #URI format: dialect://username:password@host:port/database
   #All parts except dialect are optional, but you MUST include the delimiters
-  db_backend_url: sqlite://:@:/
+  db_backend_url: mysql://root:1234@:/test
   index_building_threshold: 1024          #build index file when raw data file size larger than this value, unit: MB
 
 metric_config:

cpp/src/CMakeLists.txt

@@ -183,7 +183,10 @@ endif ()
 
 install(TARGETS milvus_server DESTINATION bin)
 
-install(FILES ${CMAKE_BINARY_DIR}/mysqlpp_ep-prefix/src/mysqlpp_ep/lib/${CMAKE_SHARED_LIBRARY_PREFIX}mysqlpp${CMAKE_SHARED_LIBRARY_SUFFIX}
+install(FILES
+        ${CMAKE_BINARY_DIR}/mysqlpp_ep-prefix/src/mysqlpp_ep/lib/${CMAKE_SHARED_LIBRARY_PREFIX}mysqlpp${CMAKE_SHARED_LIBRARY_SUFFIX}
+        ${CMAKE_BINARY_DIR}/mysqlpp_ep-prefix/src/mysqlpp_ep/lib/${CMAKE_SHARED_LIBRARY_PREFIX}mysqlpp${CMAKE_SHARED_LIBRARY_SUFFIX}.3
+        ${CMAKE_BINARY_DIR}/mysqlpp_ep-prefix/src/mysqlpp_ep/lib/${CMAKE_SHARED_LIBRARY_PREFIX}mysqlpp${CMAKE_SHARED_LIBRARY_SUFFIX}.3.2.4
         DESTINATION bin) #need to copy libmysqlpp.so
 
 add_subdirectory(sdk)

cpp/src/db/MySQLConnectionPool.h

@@ -3,6 +3,8 @@
 #include <string>
 #include <unistd.h>
 
+#include "Log.h"
+
 class MySQLConnectionPool : public mysqlpp::ConnectionPool {
 
 public:
@@ -43,6 +45,7 @@ public:
             sleep(1);
         }
 
+        ENGINE_LOG_DEBUG << "conns_in_use_ in grab: " << conns_in_use_ << std::endl;
         ++conns_in_use_;
         return mysqlpp::ConnectionPool::grab();
     }
@@ -50,7 +53,11 @@ public:
     // Other half of in-use conn count limit
     void release(const mysqlpp::Connection* pc) override {
         mysqlpp::ConnectionPool::release(pc);
+        ENGINE_LOG_DEBUG << "conns_in_use_ in release: " << conns_in_use_ << std::endl;
         --conns_in_use_;
+        if (conns_in_use_ < 0) {
+            ENGINE_LOG_DEBUG << "conns_in_use_ in release < 0: " << conns_in_use_ << std::endl;
+        }
     }
 
     void set_max_idle_time(int max_idle) {

cpp/thirdparty/versions.txt

@@ -7,7 +7,7 @@ GTEST_VERSION=1.8.1
 JSONCONS_VERSION=0.126.0
 LAPACK_VERSION=v3.8.0
 LZ4_VERSION=v1.9.1
-MYSQLPP_VERSION=zilliz
+MYSQLPP_VERSION=3.2.4
 OPENBLAS_VERSION=v0.3.6
 PROMETHEUS_VERSION=v0.7.0
 ROCKSDB_VERSION=v6.0.2