client side implemetation for MDEV-10340:

int STDCALL mysql_reset_connection(MYSQL *mysql)

include/mariadb_com.h

@@ -90,7 +90,9 @@ enum enum_server_command
   COM_STMT_RESET = 26,
   COM_SET_OPTION = 27,
   COM_STMT_FETCH = 28,
-  COM_DAEMON,
+  COM_DAEMON= 29,
+  COM_UNSUPPORTED= 30,
+  COM_RESET_CONNECTION = 31,
   COM_MULTI = 254,
   COM_END
 };

include/mysql.h

@@ -673,6 +673,8 @@ int             STDCALL mysql_read_query_result_start(my_bool *ret,
                                                       MYSQL *mysql);
 int             STDCALL mysql_read_query_result_cont(my_bool *ret,
                                                      MYSQL *mysql, int status);
+int             STDCALL mysql_reset_connection_start(int *ret, MYSQL *mysql);
+int             STDCALL mysql_reset_connection_cont(int *ret, MYSQL *mysql, int status);
 int STDCALL mysql_session_track_get_next(MYSQL *mysql, enum enum_session_state_type type, const char **data, size_t *length);
 int STDCALL mysql_session_track_get_first(MYSQL *mysql, enum enum_session_state_type type, const char **data, size_t *length);
 int STDCALL mysql_stmt_prepare_start(int *ret, MYSQL_STMT *stmt,const char *query, size_t length);
@@ -696,6 +698,7 @@ int STDCALL mysql_stmt_send_long_data_start(my_bool *ret, MYSQL_STMT *stmt,
                                             size_t len);
 int STDCALL mysql_stmt_send_long_data_cont(my_bool *ret, MYSQL_STMT *stmt,
                                            int status);
+int STDCALL mysql_reset_connection(MYSQL *mysql);
 
 /* API function calls (used by dynmic plugins) */
 struct st_mariadb_api {
@@ -813,6 +816,7 @@ struct st_mariadb_api {
   int (STDCALL *mysql_stmt_next_result)(MYSQL_STMT *stmt);
   my_bool (STDCALL *mysql_stmt_more_results)(MYSQL_STMT *stmt);
   int (STDCALL *mariadb_stmt_execute_direct)(MYSQL_STMT *stmt, const char *stmtstr, size_t length);
+  int (STDCALL *mysql_reset_connection)(MYSQL *mysql);
 };
   
 /* these methods can be overwritten by db plugins */

include/mysql/client_plugin.h

@@ -100,6 +100,7 @@ typedef struct st_ma_connection_plugin
   int (*set_connection)(MYSQL *mysql,enum enum_server_command command, const char *arg,
                         size_t length, my_bool skipp_check, void *opt_arg);
   my_bool (*reconnect)(MYSQL *mysql);
+  int (*reset)(MYSQL *mysql);
 } MARIADB_CONNECTION_PLUGIN;
 
 #define MARIADB_DB_DRIVER(a) ((a)->ext_db)

libmariadb/CMakeLists.txt

@@ -90,6 +90,7 @@ SET(MARIADB_LIB_SYMBOLS
  mysql_real_escape_string
  mysql_real_query
  mysql_refresh
+ mysql_reset_connection
  mysql_rollback
  mysql_row_seek
  mysql_row_tell
@@ -201,6 +202,8 @@ SET(MARIADB_NONBLOCK_SYMBOLS
  mysql_next_result_start
  mysql_ping_cont
  mysql_ping_start
+ mysql_reset_connection_start
+ mysql_reset_connection_cont
  mysql_query_cont
  mysql_query_start
  mysql_read_query_result_cont

libmariadb/mariadb_lib.c

@@ -2258,6 +2258,10 @@ mysql_fetch_row(MYSQL_RES *res)
 {
   if (!res)
     return 0;
+  if (res->handle)
+    if (res->handle->status != MYSQL_STATUS_USE_RESULT &&
+        res->handle->status != MYSQL_STATUS_GET_RESULT)
+      return 0;
   if (!res->data)
   {						/* Unbufferred fetch */
     if (!res->eof)
@@ -3873,6 +3877,44 @@ mysql_get_parameters(void)
   return &mariadb_internal_parameters;
 }
 
+int STDCALL mysql_reset_connection(MYSQL *mysql)
+{
+  int rc;
+
+  /* check if connection handler is active */
+  if (IS_CONNHDLR_ACTIVE(mysql))
+  {
+    if (mysql->extension->conn_hdlr->plugin && mysql->extension->conn_hdlr->plugin->reset)
+      return(mysql->extension->conn_hdlr->plugin->reset(mysql));
+  }
+
+  /* skip result sets */
+  if (mysql->status == MYSQL_STATUS_USE_RESULT ||
+      mysql->status == MYSQL_STATUS_GET_RESULT ||
+      mysql->status & SERVER_MORE_RESULTS_EXIST)
+  {
+    mthd_my_skip_result(mysql);
+    mysql->status= MYSQL_STATUS_READY;
+  }
+
+  rc= ma_simple_command(mysql, COM_RESET_CONNECTION, 0, 0, 0, 0);
+  if (rc && mysql->options.reconnect)
+  {
+    /* There is no big sense in resetting but we need reconnect */
+    rc= ma_simple_command(mysql, COM_RESET_CONNECTION,0,0,0,0);
+  }
+  if (rc)
+    return 1;
+
+  /* reset the connection in all active statements */
+  ma_invalidate_stmts(mysql, "mysql_reset_connection()");
+  free_old_query(mysql);
+  mysql->status= MYSQL_STATUS_READY;
+  mysql->affected_rows= ~(my_ulonglong)0;
+  mysql->insert_id= 0;
+  return 0;
+}
+
 #undef STDCALL
 /* API functions for usage in dynamic plugins */
 struct st_mariadb_api MARIADB_API=
@@ -3990,7 +4032,8 @@ struct st_mariadb_api MARIADB_API=
   mysql_stmt_field_count,
   mysql_stmt_next_result,
   mysql_stmt_more_results,
-  mariadb_stmt_execute_direct
+  mariadb_stmt_execute_direct,
+  mysql_reset_connection
 };
 
 /*

plugins/connection/aurora.c

@@ -76,7 +76,8 @@ MARIADB_CONNECTION_PLUGIN _mysql_client_plugin_declaration_ =
   aurora_close,
   NULL,
   aurora_command,
-  aurora_reconnect
+  aurora_reconnect,
+  NULL
 };
 
 struct st_mariadb_api *mariadb_api= NULL;

plugins/connection/replication.c

@@ -69,6 +69,7 @@ MARIADB_CONNECTION_PLUGIN _mysql_client_plugin_declaration_ =
   repl_close,
   repl_set_options,
   repl_command,
+  NULL,
   NULL
 };
 

unittest/libmariadb/connection.c

@@ -1006,7 +1006,57 @@ static int test_unix_socket_close(MYSQL *unused __attribute__((unused)))
   return OK;
 }
 
+static int test_reset(MYSQL *mysql)
+{
+  int rc;
+  MYSQL_RES *res;
+
+  rc= mysql_query(mysql, "DROP TABLE IF EXISTS t1");
+  check_mysql_rc(rc, mysql);
+
+  rc= mysql_query(mysql, "CREATE TABLE t1 (a int)");
+  check_mysql_rc(rc, mysql);
+
+  rc= mysql_query(mysql, "INSERT INTO t1 VALUES (1),(2),(3)");
+  check_mysql_rc(rc, mysql);
+
+  FAIL_IF(mysql_affected_rows(mysql) != 3, "Expected 3 rows");
+
+  rc= mysql_reset_connection(mysql);
+  check_mysql_rc(rc, mysql);
+
+  FAIL_IF(mysql_affected_rows(mysql) != ~(unsigned long)0, "Expected 0 rows");
+
+  rc= mysql_query(mysql, "SELECT a FROM t1");
+  check_mysql_rc(rc, mysql);
+
+  rc= mysql_query(mysql, "SELECT 1 FROM DUAL");
+  FAIL_IF(!rc, "Error expected"); 
+
+  rc= mysql_reset_connection(mysql);
+  check_mysql_rc(rc, mysql);
+
+  res= mysql_store_result(mysql);
+  FAIL_IF(res, "expected no result");
+
+  rc= mysql_query(mysql, "SELECT a FROM t1");
+  check_mysql_rc(rc, mysql);
+
+  res= mysql_use_result(mysql);
+  FAIL_IF(!res, "expected result");
+
+  rc= mysql_reset_connection(mysql);
+  check_mysql_rc(rc, mysql);
+
+  FAIL_IF(mysql_fetch_row(res), "expected error");
+
+  mysql_free_result(res);
+
+  return OK;
+}
+
 struct my_tests_st my_tests[] = {
+  {"test_reset", test_reset, TEST_CONNECTION_DEFAULT, 0, NULL,  NULL},
   {"test_unix_socket_close", test_unix_socket_close, TEST_CONNECTION_NONE, 0, NULL,  NULL},
   {"test_sess_track_db", test_sess_track_db, TEST_CONNECTION_DEFAULT, 0, NULL,  NULL},
   {"test_get_options", test_get_options, TEST_CONNECTION_DEFAULT, 0, NULL,  NULL},

unittest/libmariadb/misc.c

@@ -1180,8 +1180,84 @@ static int test_server_status(MYSQL *mysql)
   return OK;
 }
 
-struct my_tests_st my_tests[] = {
+static int test_wl6797(MYSQL *mysql)
+{
+  MYSQL_STMT *stmt;
+  int        rc;
+  const char *stmt_text;
+  my_ulonglong res;
 
+  if (mysql_get_server_version(mysql) < 50703 ||
+      (mariadb_connection(mysql) && mysql_get_server_version(mysql) < 100203))
+  {
+    diag("Skipping test_wl6797: "
+            "tested feature does not exist in versions before MySQL 5.7.3 and MariaDB 10.2\n");
+    return OK;
+  }
+  /* clean up the session */
+  rc= mysql_reset_connection(mysql);
+  FAIL_UNLESS(rc == 0, "");
+
+  /* do prepare of a query */
+  mysql_query(mysql, "use test");
+  mysql_query(mysql, "DROP TABLE IF EXISTS t1");
+  mysql_query(mysql, "CREATE TABLE t1 (a int)");
+
+  stmt= mysql_stmt_init(mysql);
+  stmt_text= "INSERT INTO t1 VALUES (1), (2)";
+
+  rc= mysql_stmt_prepare(stmt, stmt_text, (ulong)strlen(stmt_text));
+  check_mysql_rc(rc, mysql);
+
+  /* Execute the insert statement */
+  rc= mysql_stmt_execute(stmt);
+  check_mysql_rc(rc, mysql);
+
+  /*
+   clean the session this should remove the prepare statement
+   from the cache.
+  */
+  rc= mysql_reset_connection(mysql);
+  FAIL_UNLESS(rc == 0, "");
+
+  /* this below stmt should report error */
+  rc= mysql_stmt_execute(stmt);
+  FAIL_IF(rc == 0, "");
+
+  /*
+   bug#17653288: MYSQL_RESET_CONNECTION DOES NOT RESET LAST_INSERT_ID
+  */
+
+  mysql_query(mysql, "DROP TABLE IF EXISTS t2");
+  rc= mysql_query(mysql, "CREATE TABLE t2 (a int NOT NULL PRIMARY KEY"\
+                         " auto_increment)");
+  check_mysql_rc(rc, mysql);
+  rc= mysql_query(mysql, "INSERT INTO t2 VALUES (null)");
+  check_mysql_rc(rc, mysql);
+  res= mysql_insert_id(mysql);
+  FAIL_UNLESS(res == 1, "");
+  rc= mysql_reset_connection(mysql);
+  FAIL_UNLESS(rc == 0, "");
+  res= mysql_insert_id(mysql);
+  FAIL_UNLESS(res == 0, "");
+
+  rc= mysql_query(mysql, "INSERT INTO t2 VALUES (last_insert_id(100))");
+  check_mysql_rc(rc, mysql);
+  res= mysql_insert_id(mysql);
+  FAIL_UNLESS(res == 100, "");
+  rc= mysql_reset_connection(mysql);
+  FAIL_UNLESS(rc == 0, "");
+  res= mysql_insert_id(mysql);
+  FAIL_UNLESS(res == 0, "");
+
+  mysql_query(mysql, "DROP TABLE IF EXISTS t1");
+  mysql_query(mysql, "DROP TABLE IF EXISTS t2");
+  mysql_stmt_close(stmt);
+  return OK;
+}
+
+struct my_tests_st my_tests[] = {
+  {"test_wl6797", test_wl6797, TEST_CONNECTION_DEFAULT, 0, NULL, NULL},
   {"test_server_status", test_server_status, TEST_CONNECTION_DEFAULT, 0, NULL, NULL},
   {"test_read_timeout", test_read_timeout, TEST_CONNECTION_DEFAULT, 0, NULL, NULL},
   {"test_zerofill", test_zerofill, TEST_CONNECTION_DEFAULT, 0, NULL, NULL},

unittest/libmariadb/ps_bugs.c

@@ -4501,7 +4501,36 @@ static int test_conc217(MYSQL *mysql)
   return OK;
 }
 
+static int test_conc208(MYSQL *mysql)
+{
+  MYSQL_STMT *stmt= mysql_stmt_init(mysql);
+  int rc;
+  int data;
+  MYSQL_BIND bind;
+
+  rc= mysql_stmt_prepare(stmt, "SELECT \"100\" UNION SELECT \"88\" UNION SELECT \"389789\"", -1);
+  check_stmt_rc(rc, stmt);
+
+  memset(&bind, 0, sizeof(MYSQL_BIND));
+  bind.buffer_type= MYSQL_TYPE_LONG;
+  bind.buffer= (void *)&data;
+
+  rc= mysql_stmt_execute(stmt);
+  check_stmt_rc(rc, stmt);
+
+  rc= mysql_stmt_bind_result(stmt, &bind);
+
+  while (mysql_stmt_fetch(stmt) != MYSQL_NO_DATA)
+  {
+    diag("data=%d", data);
+    FAIL_IF(data != 100 && data != 88 && data != 389789, "Wrong value");
+  }
+  mysql_stmt_close(stmt);
+  return OK;
+}
+
 struct my_tests_st my_tests[] = {
+  {"test_conc208", test_conc208, TEST_CONNECTION_DEFAULT, 0, NULL, NULL},
   {"test_conc217", test_conc217, TEST_CONNECTION_DEFAULT, 0, NULL, NULL},
   {"test_conc205", test_conc205, TEST_CONNECTION_DEFAULT, 0, NULL, NULL},
   {"test_conc198", test_conc198, TEST_CONNECTION_DEFAULT, 0, NULL, NULL},