MDEV-10384 Windows : Refactor threading in mysqld startup.

Remove threads that are doing nothing but wait
- main thread now handles the connections
(if threadpool is used, also threadpool threads would wait for connections)
- thread for socket and pipe connections are removed
- shutdown thread is now removed, we wait for shutdown
notification in main thread as well
- kill_server() is also called inside the main thread, after connection
loop finished.

sql/CMakeLists.txt

@@ -152,6 +152,7 @@ IF (CMAKE_SYSTEM_NAME MATCHES "Linux" OR
  ADD_DEFINITIONS(-DHAVE_POOL_OF_THREADS)
  IF(WIN32)
    SET(SQL_SOURCE ${SQL_SOURCE} threadpool_win.cc)
+   SET(SQL_SOURCE ${SQL_SOURCE} handle_connections_win.cc)
  ENDIF()
  SET(SQL_SOURCE ${SQL_SOURCE} threadpool_generic.cc)
 

sql/handle_connections_win.h

+/* Copyright (c) 2018 MariaDB Corporation.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA */
+
+/**
+  Handles incoming socket and pipe connections, on Windows.
+  Creates new (THD) connections..
+*/
+extern void handle_connections_win();

sql/init.h

@@ -17,6 +17,6 @@
 #define INIT_INCLUDED
 
 void unireg_init(ulong options);
-ATTRIBUTE_NORETURN void unireg_end(void);
+void unireg_end(void);
 
 #endif /* INIT_INCLUDED */

sql/mysqld.h

@@ -24,6 +24,7 @@
 #include "mysql_com.h"                     /* SERVER_VERSION_LENGTH */
 #include "my_atomic.h"
 #include "mysql/psi/mysql_file.h"          /* MYSQL_FILE */
+#include "mysql/psi/mysql_socket.h"        /* MYSQL_SOCKET */
 #include "sql_list.h"                      /* I_List */
 #include "sql_cmd.h"
 #include <my_rnd.h>
@@ -92,6 +93,8 @@ void refresh_status(THD *thd);
 bool is_secure_file_path(char *path);
 void dec_connection_count(scheduler_functions *scheduler);
 extern void init_net_server_extension(THD *thd);
+extern void handle_accepted_socket(MYSQL_SOCKET new_sock, MYSQL_SOCKET sock);
+extern void create_new_thread(CONNECT *connect);
 
 extern "C" MYSQL_PLUGIN_IMPORT CHARSET_INFO *system_charset_info;
 extern MYSQL_PLUGIN_IMPORT CHARSET_INFO *files_charset_info ;
@@ -152,6 +155,7 @@ extern ulong opt_replicate_events_marked_for_skip;
 extern char *default_tz_name;
 extern Time_zone *default_tz;
 extern char *my_bind_addr_str;
+extern int server_socket_ai_family;
 extern char *default_storage_engine, *default_tmp_storage_engine;
 extern char *enforced_storage_engine;
 extern char *gtid_pos_auto_engines;
@@ -759,7 +763,7 @@ enum enum_query_type
 /* query_id */
 extern query_id_t global_query_id;
 
-ATTRIBUTE_NORETURN void unireg_end(void);
+void unireg_end(void);
 
 /* increment query_id and return it.  */
 inline __attribute__((warn_unused_result)) query_id_t next_query_id()

sql/threadpool_win.cc

@@ -70,6 +70,11 @@ static DWORD fls;
 
 static bool skip_completion_port_on_success = false;
 
+PTP_CALLBACK_ENVIRON get_threadpool_win_callback_environ()
+{
+  return pool? &callback_environ: 0;
+}
+
 /*
   Threadpool callbacks.
 
@@ -134,7 +139,15 @@ struct TP_connection *new_TP_connection(CONNECT *connect)
 
 void TP_pool_win::add(TP_connection *c)
 {
-  SubmitThreadpoolWork(((TP_connection_win *)c)->work);
+  if(FlsGetValue(fls))
+  {
+    /* Inside threadpool(), execute callback directly. */
+    tp_callback(c);
+  }
+  else
+  {
+    SubmitThreadpoolWork(((TP_connection_win *)c)->work);
+  }
 }
 
 
@@ -288,14 +301,13 @@ TP_connection_win::~TP_connection_win()
 
 void TP_connection_win::wait_begin(int type)
 {
- 
   /*
     Signal to the threadpool whenever callback can run long. Currently, binlog
     waits are a good candidate, its waits are really long
   */
   if (type == THD_WAIT_BINLOG)
   {
-    if (!long_callback)
+    if (!long_callback && callback_instance)
     {
       CallbackMayRunLong(callback_instance);
       long_callback= true;
@@ -308,12 +320,11 @@ void TP_connection_win::wait_end()
   /* Do we need to do anything ? */
 }
 
-/* 
-  This function should be called first whenever a callback is invoked in the 
+/*
+  This function should be called first whenever a callback is invoked in the
   threadpool, does my_thread_init() if not yet done
 */
-extern ulong thread_created;
-static void pre_callback(PVOID context, PTP_CALLBACK_INSTANCE instance)
+void tp_win_callback_prolog()
 {
   if (FlsGetValue(fls) == NULL)
   {
@@ -323,6 +334,12 @@ static void pre_callback(PVOID context, PTP_CALLBACK_INSTANCE instance)
     InterlockedIncrement((volatile long *)&tp_stats.num_worker_threads);
     my_thread_init();
   }
+}
+
+extern ulong thread_created;
+static void pre_callback(PVOID context, PTP_CALLBACK_INSTANCE instance)
+{
+  tp_win_callback_prolog();
   TP_connection_win *c = (TP_connection_win *)context;
   c->callback_instance = instance;
   c->long_callback = false;