MDEV-9058: protocol: COM_MULTI command (part 2)

simple COM_MULTI support (no prepared statements chain yet).

include/mysql_com.h

@@ -235,6 +235,8 @@ enum enum_server_command
 #define MARIADB_CLIENT_FLAGS_MASK 0xffffffff00000000ULL
 /* Client support progress indicator */
 #define MARIADB_CLIENT_PROGRESS (1ULL << 32)
+/* support COM_MULTI */
+#define MARIADB_CLIENT_COM_MULTI (1ULL << 33)
 
 #ifdef HAVE_COMPRESS
 #define CAN_CLIENT_COMPRESS CLIENT_COMPRESS
@@ -271,7 +273,8 @@ enum enum_server_command
                            MARIADB_CLIENT_PROGRESS | \
                            CLIENT_PLUGIN_AUTH | \
                            CLIENT_PLUGIN_AUTH_LENENC_CLIENT_DATA | \
-                           CLIENT_CONNECT_ATTRS)
+                           CLIENT_CONNECT_ATTRS |\
+                           MARIADB_CLIENT_COM_MULTI)
 
 /*
   To be added later:

libmysqld/lib_sql.cc

@@ -165,7 +165,7 @@ emb_advanced_command(MYSQL *mysql, enum enum_server_command command,
     arg_length= header_length;
   }
 
-  result= dispatch_command(command, thd, (char *) arg, arg_length);
+  result= dispatch_command(command, thd, (char *) arg, arg_length, FALSE);
   thd->cur_data= 0;
   thd->mysys_var= NULL;
 

sql/log_event.cc

@@ -4429,7 +4429,8 @@ int Query_log_event::do_apply_event(rpl_group_info *rgi,
           thd->m_digest->reset(thd->m_token_array, max_digest_length);
 
         thd->enable_slow_log= thd->variables.sql_log_slow;
-        mysql_parse(thd, thd->query(), thd->query_length(), &parser_state);
+        mysql_parse(thd, thd->query(), thd->query_length(), &parser_state,
+                    FALSE);
         /* Finalize server status flags after executing a statement. */
         thd->update_server_status();
         log_slow_statement(thd);

sql/net_serv.cc

@@ -121,6 +121,8 @@ extern my_bool thd_net_is_killed();
 
 static my_bool net_write_buff(NET *, const uchar *, ulong);
 
+my_bool net_allocate_new_packet(NET *net, void *thd, uint my_flags);
+
 /** Init with packet info. */
 
 my_bool my_net_init(NET *net, Vio *vio, void *thd, uint my_flags)
@@ -129,14 +131,12 @@ my_bool my_net_init(NET *net, Vio *vio, void *thd, uint my_flags)
   DBUG_PRINT("enter", ("my_flags: %u", my_flags));
   net->vio = vio;
   my_net_local_init(net);			/* Set some limits */
-  if (!(net->buff=(uchar*) my_malloc((size_t) net->max_packet+
+
-				     NET_HEADER_SIZE + COMP_HEADER_SIZE +1,
+  if (net_allocate_new_packet(net, thd, my_flags))
-				     MYF(MY_WME | my_flags))))
     DBUG_RETURN(1);
-  net->buff_end=net->buff+net->max_packet;
+
   net->error=0; net->return_status=0;
   net->pkt_nr=net->compress_pkt_nr=0;
-  net->write_pos=net->read_pos = net->buff;
   net->last_error[0]=0;
   net->compress=0; net->reading_or_writing=0;
   net->where_b = net->remain_in_buf=0;
@@ -165,6 +165,18 @@ my_bool my_net_init(NET *net, Vio *vio, void *thd, uint my_flags)
   DBUG_RETURN(0);
 }
 
+my_bool net_allocate_new_packet(NET *net, void *thd, uint my_flags)
+{
+  DBUG_ENTER("net_allocate_new_packet");
+  if (!(net->buff=(uchar*) my_malloc((size_t) net->max_packet+
+				     NET_HEADER_SIZE + COMP_HEADER_SIZE +1,
+				     MYF(MY_WME | my_flags))))
+    DBUG_RETURN(1);
+  net->buff_end=net->buff+net->max_packet;
+  net->write_pos=net->read_pos = net->buff;
+  DBUG_RETURN(0);
+}
+
 
 void net_end(NET *net)
 {

sql/share/errmsg-utf8.txt

@@ -7139,3 +7139,10 @@ ER_KILL_QUERY_DENIED_ERROR
 ER_NO_EIS_FOR_FIELD
         eng "Engine-independent statistics are not collected for column '%s'"
         ukr "Незалежна від типу таблиці статистика не збирається для стовбця '%s'"
+ER_COMMULTI_BADCONTEXT 0A000
+        eng "COM_MULTI can't return a result set in the given context"
+        ger "COM_MULTI kann im gegebenen Kontext keine Ergebnismenge zurückgeben"
+        ukr "COM_MULTI не може повернути результати у цьому контексті"
+ER_BAD_COMMAND_IN_MULTI
+        eng "Command '%s' is not allowed for COM_MULTI"
+        ukr "Команда '%s' не дозволена для COM_MULTI"

sql/sql_class.h

@@ -5365,6 +5365,10 @@ public:
   Do not check that wsrep snapshot is ready before allowing this command
 */
 #define CF_SKIP_WSREP_CHECK     (1U << 2)
+/**
+  Do not allow it for COM_MULTI batch
+*/
+#define CF_NO_COM_MULTI         (1U << 3)
 
 /* Inline functions */
 

sql/sql_parse.cc

@@ -110,7 +110,7 @@
 #include "wsrep_thd.h"
 
 static void wsrep_mysql_parse(THD *thd, char *rawbuf, uint length,
-                              Parser_state *parser_state);
+                              Parser_state *parser_state, bool is_next_command);
 
 /**
   @defgroup Runtime_Environment Runtime Environment
@@ -494,7 +494,7 @@ void init_update_queries(void)
   memset(server_command_flags, 0, sizeof(server_command_flags));
 
   server_command_flags[COM_STATISTICS]= CF_SKIP_QUERY_ID | CF_SKIP_QUESTIONS | CF_SKIP_WSREP_CHECK;
-  server_command_flags[COM_PING]=       CF_SKIP_QUERY_ID | CF_SKIP_QUESTIONS | CF_SKIP_WSREP_CHECK;
+  server_command_flags[COM_PING]=       CF_SKIP_QUERY_ID | CF_SKIP_QUESTIONS | CF_SKIP_WSREP_CHECK | CF_NO_COM_MULTI;
 
   server_command_flags[COM_QUIT]= CF_SKIP_WSREP_CHECK;
   server_command_flags[COM_PROCESS_INFO]= CF_SKIP_WSREP_CHECK;
@@ -519,7 +519,7 @@ void init_update_queries(void)
   server_command_flags[COM_STMT_RESET]= CF_SKIP_QUESTIONS | CF_SKIP_WSREP_CHECK;
   server_command_flags[COM_STMT_EXECUTE]= CF_SKIP_WSREP_CHECK;
   server_command_flags[COM_STMT_SEND_LONG_DATA]= CF_SKIP_WSREP_CHECK;
-  server_command_flags[COM_MULTI]= CF_SKIP_WSREP_CHECK;
+  server_command_flags[COM_MULTI]= CF_SKIP_WSREP_CHECK | CF_NO_COM_MULTI;
 
   /* Initialize the sql command flags array. */
   memset(sql_command_flags, 0, sizeof(sql_command_flags));
@@ -903,7 +903,7 @@ void execute_init_command(THD *thd, LEX_STRING *init_command,
   */
   save_vio= thd->net.vio;
   thd->net.vio= 0;
-  dispatch_command(COM_QUERY, thd, buf, len);
+  dispatch_command(COM_QUERY, thd, buf, len, FALSE, FALSE);
   thd->client_capabilities= save_client_capabilities;
   thd->net.vio= save_vio;
 
@@ -1021,7 +1021,7 @@ static void handle_bootstrap_impl(THD *thd)
       break;
     }
 
-    mysql_parse(thd, thd->query(), length, &parser_state);
+    mysql_parse(thd, thd->query(), length, &parser_state, FALSE);
 
     bootstrap_error= thd->is_error();
     thd->protocol->end_statement();
@@ -1119,6 +1119,23 @@ void cleanup_items(Item *item)
   DBUG_VOID_RETURN;
 }
 
+static enum enum_server_command fetch_command(THD *thd, char *packet)
+{
+  enum enum_server_command
+    command= (enum enum_server_command) (uchar) packet[0];
+  NET *net= &thd->net;
+  DBUG_ENTER("fetch_command");
+
+  if (command >= COM_END ||
+      (command >= COM_MDB_GAP_BEG && command <= COM_MDB_GAP_END))
+    command= COM_END;				// Wrong command
+
+  DBUG_PRINT("info",("Command on %s = %d (%s)",
+                     vio_description(net->vio), command,
+                     command_name[command].str));
+  DBUG_RETURN(command);
+}
+
 
 #ifndef EMBEDDED_LIBRARY
 
@@ -1307,15 +1324,8 @@ bool do_command(THD *thd)
   /* Do not rely on my_net_read, extra safety against programming errors. */
   packet[packet_length]= '\0';                  /* safety */
 
-  command= (enum enum_server_command) (uchar) packet[0];
 
-  if (command >= COM_END ||
+  command= fetch_command(thd, packet);
-      (command >= COM_MDB_GAP_BEG && command <= COM_MDB_GAP_END))
-    command= COM_END;				// Wrong command
-
-  DBUG_PRINT("info",("Command on %s = %d (%s)",
-                     vio_description(net->vio), command,
-                     command_name[command].str));
 
 #ifdef WITH_WSREP
   /*
@@ -1341,7 +1351,8 @@ bool do_command(THD *thd)
 
   DBUG_ASSERT(packet_length);
   DBUG_ASSERT(!thd->apc_target.is_enabled());
-  return_value= dispatch_command(command, thd, packet+1, (uint) (packet_length-1));
+  return_value= dispatch_command(command, thd, packet+1,
+                                 (uint) (packet_length-1), FALSE, FALSE);
 #ifdef WITH_WSREP
   if (WSREP(thd))
   {
@@ -1359,7 +1370,7 @@ bool do_command(THD *thd)
                    my_charset_latin1.csname);
       }
       return_value= dispatch_command(command, thd, thd->wsrep_retry_query,
-                                     thd->wsrep_retry_query_len);
+                                     thd->wsrep_retry_query_len, FALSE, FALSE);
       thd->variables.character_set_client = current_charset;
     }
 
@@ -1450,6 +1461,44 @@ static my_bool deny_updates_if_read_only_option(THD *thd,
 }
 
 
+/**
+  check COM_MULTI packet
+
+  @param thd             thread handle
+  @param packet          pointer on the packet of commands
+  @param packet_length   length of this packet
+
+  @retval 0 - Error
+  @retval # - Number of commands in the batch
+*/
+
+uint maria_multi_check(THD *thd, char *packet, uint packet_length)
+{
+  uint counter= 0;
+  DBUG_ENTER("maria_multi_check");
+  while (packet_length)
+  {
+    // length of command + 3 bytes where that length was stored
+    uint subpacket_length= (uint3korr(packet) + 3);
+    DBUG_PRINT("info", ("sub-packet length: %d  command: %x",
+                        subpacket_length, packet[3]));
+
+    if (subpacket_length == 3 ||
+        subpacket_length > packet_length)
+    {
+      my_message(ER_UNKNOWN_COM_ERROR, ER_THD(thd, ER_UNKNOWN_COM_ERROR),
+                 MYF(0));
+      DBUG_RETURN(0);
+    }
+
+    counter++;
+    packet+= subpacket_length;
+    packet_length-= subpacket_length;
+  }
+  DBUG_RETURN(counter);
+}
+
+
 /**
   Perform one connection-level (COM_XXXX) command.
 
@@ -1459,6 +1508,8 @@ static my_bool deny_updates_if_read_only_option(THD *thd,
   @param packet_length   length of packet + 1 (to show that data is
                          null-terminated) except for COM_SLEEP, where it
                          can be zero.
+  @param is_com_multi    recursive call from COM_MULTI
+  @param is_next_command there will be more command in the COM_MULTI batch
 
   @todo
     set thd->lex->sql_command to SQLCOM_END here.
@@ -1472,15 +1523,22 @@ static my_bool deny_updates_if_read_only_option(THD *thd,
         COM_QUIT/COM_SHUTDOWN
 */
 bool dispatch_command(enum enum_server_command command, THD *thd,
-		      char* packet, uint packet_length)
+		      char* packet, uint packet_length, bool is_com_multi,
+                      bool is_next_command)
 {
   NET *net= &thd->net;
   bool error= 0;
   bool do_end_of_statement= true;
   DBUG_ENTER("dispatch_command");
-  DBUG_PRINT("info", ("command: %d", command));
+  DBUG_PRINT("info", ("command: %d %s", command,
+                      (command_name[command].str != 0 ?
+                       command_name[command].str :
+                       "<?>")));
+  bool drop_more_results= 0;
+
+  if (!is_com_multi)
+    inc_thread_running();
 
-  inc_thread_running();
   /* keep it withing 1 byte */
   compile_time_assert(COM_END == 255);
 
@@ -1572,6 +1630,13 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
     beginning of each command.
   */
   thd->server_status&= ~SERVER_STATUS_CLEAR_SET;
+  if (is_next_command)
+  {
+    drop_more_results= !MY_TEST(thd->server_status &
+                                SERVER_MORE_RESULTS_EXISTS);
+    thd->server_status|= SERVER_MORE_RESULTS_EXISTS;
+  }
+
   switch (command) {
   case COM_INIT_DB:
   {
@@ -1720,9 +1785,11 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
       break;
 
     if (WSREP_ON)
-      wsrep_mysql_parse(thd, thd->query(), thd->query_length(), &parser_state);
+      wsrep_mysql_parse(thd, thd->query(), thd->query_length(), &parser_state,
+                        is_next_command);
     else
-      mysql_parse(thd, thd->query(), thd->query_length(), &parser_state);
+      mysql_parse(thd, thd->query(), thd->query_length(), &parser_state,
+                  is_next_command);
 
     while (!thd->killed && (parser_state.m_lip.found_semicolon != NULL) &&
            ! thd->is_error())
@@ -1807,9 +1874,11 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
       /* TODO: set thd->lex->sql_command to SQLCOM_END here */
 
       if (WSREP_ON)
-        wsrep_mysql_parse(thd, beginning_of_next_stmt, length, &parser_state);
+        wsrep_mysql_parse(thd, beginning_of_next_stmt, length, &parser_state,
+                          is_next_command);
       else
-        mysql_parse(thd, beginning_of_next_stmt, length, &parser_state);
+        mysql_parse(thd, beginning_of_next_stmt, length, &parser_state,
+                    is_next_command);
 
     }
 
@@ -1861,6 +1930,9 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
     }
     packet= arg_end + 1;
     thd->reset_for_next_command();
+    // thd->reset_for_next_command reset state => restore it
+    if (is_next_command)
+      thd->server_status|= SERVER_MORE_RESULTS_EXISTS;
     lex_start(thd);
     /* Must be before we init the table list. */
     if (lower_case_table_names)
@@ -2139,6 +2211,71 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
     general_log_print(thd, command, NullS);
     my_eof(thd);
     break;
+  case COM_MULTI:
+  {
+    uint counter;
+    uint current_com= 0;
+    DBUG_ASSERT(!is_com_multi);
+    if (!(thd->client_capabilities & CLIENT_MULTI_RESULTS))
+    {
+      /* The client does not support multiple result sets being sent back */
+      my_error(ER_COMMULTI_BADCONTEXT, MYF(0));
+      break;
+    }
+
+    if (!(counter= maria_multi_check(thd, packet, packet_length)))
+      break;
+
+    {
+      /* We have to store next length because it will be destroyed by '\0' */
+      uint next_subpacket_length= uint3korr(packet);
+      unsigned char *readbuff= net->buff;
+      unsigned long readbuff_max_packet= net->max_packet;
+
+      if (net_allocate_new_packet(net, thd, MYF(0)))
+        break;
+
+      while (packet_length)
+      {
+        current_com++;
+        uint subpacket_length= next_subpacket_length + 3;
+        if (subpacket_length < packet_length)
+          next_subpacket_length= uint3korr(packet + subpacket_length);
+        /* safety like in do_command() */
+        packet[subpacket_length]= '\0';
+
+        enum enum_server_command subcommand= fetch_command(thd, (packet + 3));
+
+        if (server_command_flags[subcommand] & CF_NO_COM_MULTI)
+        {
+          my_error(ER_BAD_COMMAND_IN_MULTI, MYF(0), command_name[subcommand]);
+          goto com_multi_end;
+        }
+
+        if (dispatch_command(subcommand, thd, packet + (1 + 3),
+                             subpacket_length - (1 + 3), TRUE,
+                             (current_com != counter)))
+        {
+          DBUG_ASSERT(thd->is_error());
+          goto com_multi_end;
+        }
+
+        DBUG_ASSERT(subpacket_length <= packet_length);
+        packet+= subpacket_length;
+        packet_length-= subpacket_length;
+      }
+
+com_multi_end:
+      /* restore buffer to the original one */
+      DBUG_ASSERT(net->buff == net->write_pos); // nothing to send
+      my_free(net->buff);
+      net->buff= readbuff;
+      net->max_packet= readbuff_max_packet;
+      net->buff_end=net->buff + net->max_packet;
+      net->write_pos=net->read_pos = net->buff;
+    }
+    break;
+  }
   case COM_SLEEP:
   case COM_CONNECT:				// Impossible here
   case COM_TIME:				// Impossible from client
@@ -2175,9 +2312,14 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
     thd_proc_info(thd, "updating status");
     /* Finalize server status flags after executing a command. */
     thd->update_server_status();
-    thd->protocol->end_statement();
+    if (command != COM_MULTI)
-    query_cache_end_of_result(thd);
+    {
+      thd->protocol->end_statement();
+      query_cache_end_of_result(thd);
+    }
   }
+  if (drop_more_results)
+    thd->server_status&= ~SERVER_MORE_RESULTS_EXISTS;
 
   if (!thd->is_error() && !thd->killed_errno())
     mysql_audit_general(thd, MYSQL_AUDIT_GENERAL_RESULT, 0, 0);
@@ -2201,8 +2343,11 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
   thd->m_statement_psi= NULL;
   thd->m_digest= NULL;
 
-  dec_thread_running();
+  if (!is_com_multi)
-  thd->packet.shrink(thd->variables.net_buffer_length);	// Reclaim some memory
+  {
+    dec_thread_running();
+    thd->packet.shrink(thd->variables.net_buffer_length); // Reclaim some memory
+  }
   free_root(thd->mem_root,MYF(MY_KEEP_PREALLOC));
 
 #if defined(ENABLED_PROFILING)
@@ -7388,7 +7533,7 @@ void mysql_init_multi_delete(LEX *lex)
 }
 
 static void wsrep_mysql_parse(THD *thd, char *rawbuf, uint length,
-                              Parser_state *parser_state)
+                              Parser_state *parser_state, bool is_next_command)
 {
 #ifdef WITH_WSREP
   bool is_autocommit=
@@ -7407,7 +7552,7 @@ static void wsrep_mysql_parse(THD *thd, char *rawbuf, uint length,
       MYSQL_SET_STATEMENT_TEXT(thd->m_statement_psi, thd->query(),
 	                       thd->query_length());
     }
-    mysql_parse(thd, rawbuf, length, parser_state);
+    mysql_parse(thd, rawbuf, length, parser_state, is_next_command);
 
     if (WSREP(thd)) {
       /* wsrep BF abort in query exec phase */
@@ -7505,10 +7650,11 @@ static void wsrep_mysql_parse(THD *thd, char *rawbuf, uint length,
   @param       length  Length of the query text
   @param[out]  found_semicolon For multi queries, position of the character of
                                the next query in the query text.
+  @param is_next_command there will be more command in the COM_MULTI batch
 */
 
 void mysql_parse(THD *thd, char *rawbuf, uint length,
-                 Parser_state *parser_state)
+                 Parser_state *parser_state, bool is_next_command)
 {
   int error __attribute__((unused));
   DBUG_ENTER("mysql_parse");
@@ -7532,6 +7678,8 @@ void mysql_parse(THD *thd, char *rawbuf, uint length,
   */
   lex_start(thd);
   thd->reset_for_next_command();
+  if (is_next_command)
+    thd->server_status|= SERVER_MORE_RESULTS_EXISTS;
 
   if (query_cache_send_result_to_client(thd, rawbuf, length) <= 0)
   {

sql/sql_parse.h

@@ -35,6 +35,7 @@ enum enum_mysql_completiontype {
 
 extern "C" int test_if_data_home_dir(const char *dir);
 int error_if_data_home_dir(const char *path, const char *what);
+my_bool net_allocate_new_packet(NET *net, void *thd, uint my_flags);
 
 bool multi_update_precheck(THD *thd, TABLE_LIST *tables);
 bool multi_delete_precheck(THD *thd, TABLE_LIST *tables);
@@ -87,7 +88,7 @@ bool is_log_table_write_query(enum enum_sql_command command);
 bool alloc_query(THD *thd, const char *packet, uint packet_length);
 void mysql_init_select(LEX *lex);
 void mysql_parse(THD *thd, char *rawbuf, uint length,
-                 Parser_state *parser_state);
+                 Parser_state *parser_state, bool is_com_multi);
 bool mysql_new_select(LEX *lex, bool move_down);
 void create_select_for_variable(const char *var_name);
 void create_table_set_open_action_and_adjust_tables(LEX *lex);
@@ -99,7 +100,8 @@ int mysql_execute_command(THD *thd);
 bool do_command(THD *thd);
 void do_handle_bootstrap(THD *thd);
 bool dispatch_command(enum enum_server_command command, THD *thd,
-		      char* packet, uint packet_length);
+		      char* packet, uint packet_length,
+                      bool is_com_multi, bool is_next_command);
 void log_slow_statement(THD *thd);
 bool append_file_to_dir(THD *thd, const char **filename_ptr,
                         const char *table_name);

sql/wsrep_sst.cc

@@ -907,7 +907,7 @@ static int run_sql_command(THD *thd, const char *query)
     return -1;
   }
 
-  mysql_parse(thd, thd->query(), thd->query_length(), &ps);
+  mysql_parse(thd, thd->query(), thd->query_length(), &ps, FALSE);
   if (thd->is_error())
   {
     int const err= thd->get_stmt_da()->sql_errno();