mysqldump: remove dead and broken code

since 2006 (3840774) mysqldump tried to be smart when dumping
events - it tried to automatically detected a delimiter per event
that was not present in the event body, using ";;" by default.

This never worked, was broken since the first commit. It either used
the default ";;" or failed after trying the same ";;" delimiter
2147483646 times.

All other objects (routines, triggers, etc) used a hard-coded ";;"
for 20 years, which apparently worked fine. Let's remove the old
broken logic and dump events like all other objects,

Author: vuvova

client/mysqldump.cc

@@ -1744,7 +1744,6 @@ static char *my_case_str(const char *str,
 
 static int switch_db_collation(FILE *sql_file,
                                const char *db_name,
-                               const char *delimiter,
                                const char *current_db_cl_name,
                                const char *required_db_cl_name,
                                int *db_cl_altered)
@@ -1760,11 +1759,10 @@ static int switch_db_collation(FILE *sql_file,
       return 1;
 
     fprintf(sql_file,
-            "ALTER DATABASE %s CHARACTER SET %s COLLATE %s %s\n",
+            "ALTER DATABASE %s CHARACTER SET %s COLLATE %s ;\n",
             (const char *) quoted_db_name,
             (const char *) db_cl->cs_name.str,
-            (const char *) db_cl->coll_name.str,
-            (const char *) delimiter);
+            (const char *) db_cl->coll_name.str);
 
     *db_cl_altered= 1;
 
@@ -1779,7 +1777,6 @@ static int switch_db_collation(FILE *sql_file,
 
 static int restore_db_collation(FILE *sql_file,
                                 const char *db_name,
-                                const char *delimiter,
                                 const char *db_cl_name)
 {
   char quoted_db_buf[NAME_LEN * 2 + 3];
@@ -1791,100 +1788,71 @@ static int restore_db_collation(FILE *sql_file,
     return 1;
 
   fprintf(sql_file,
-          "ALTER DATABASE %s CHARACTER SET %s COLLATE %s %s\n",
+          "ALTER DATABASE %s CHARACTER SET %s COLLATE %s ;\n",
           (const char *) quoted_db_name,
           (const char *) db_cl->cs_name.str,
-          (const char *) db_cl->coll_name.str,
-          (const char *) delimiter);
+          (const char *) db_cl->coll_name.str);
 
   return 0;
 }
 
 
 static void switch_cs_variables(FILE *sql_file,
-                                const char *delimiter,
                                 const char *character_set_client,
                                 const char *character_set_results,
                                 const char *collation_connection)
 {
   fprintf(sql_file,
-          "/*!50003 SET @saved_cs_client      = @@character_set_client */ %s\n"
-          "/*!50003 SET @saved_cs_results     = @@character_set_results */ %s\n"
-          "/*!50003 SET @saved_col_connection = @@collation_connection */ %s\n"
-          "/*!50003 SET character_set_client  = %s */ %s\n"
-          "/*!50003 SET character_set_results = %s */ %s\n"
-          "/*!50003 SET collation_connection  = %s */ %s\n",
-          (const char *) delimiter,
-          (const char *) delimiter,
-          (const char *) delimiter,
-
+          "/*!50003 SET @saved_cs_client      = @@character_set_client */ ;\n"
+          "/*!50003 SET @saved_cs_results     = @@character_set_results */ ;\n"
+          "/*!50003 SET @saved_col_connection = @@collation_connection */ ;\n"
+          "/*!50003 SET character_set_client  = %s */ ;\n"
+          "/*!50003 SET character_set_results = %s */ ;\n"
+          "/*!50003 SET collation_connection  = %s */ ;\n",
           (const char *) character_set_client,
-          (const char *) delimiter,
-
           (const char *) character_set_results,
-          (const char *) delimiter,
-
-          (const char *) collation_connection,
-          (const char *) delimiter);
+          (const char *) collation_connection);
 }
 
 
-static void restore_cs_variables(FILE *sql_file,
-                                 const char *delimiter)
+static void restore_cs_variables(FILE *sql_file)
 {
   fprintf(sql_file,
-          "/*!50003 SET character_set_client  = @saved_cs_client */ %s\n"
-          "/*!50003 SET character_set_results = @saved_cs_results */ %s\n"
-          "/*!50003 SET collation_connection  = @saved_col_connection */ %s\n",
-          (const char *) delimiter,
-          (const char *) delimiter,
-          (const char *) delimiter);
+          "/*!50003 SET character_set_client  = @saved_cs_client */ ;\n"
+          "/*!50003 SET character_set_results = @saved_cs_results */ ;\n"
+          "/*!50003 SET collation_connection  = @saved_col_connection */ ;\n");
 }
 
 
-static void switch_sql_mode(FILE *sql_file,
-                            const char *delimiter,
-                            const char *sql_mode)
+static void switch_sql_mode(FILE *sql_file, const char *sql_mode)
 {
   fprintf(sql_file,
-          "/*!50003 SET @saved_sql_mode       = @@sql_mode */ %s\n"
-          "/*!50003 SET sql_mode              = '%s' */ %s\n",
-          (const char *) delimiter,
-
-          (const char *) sql_mode,
-          (const char *) delimiter);
+          "/*!50003 SET @saved_sql_mode       = @@sql_mode */ ;\n"
+          "/*!50003 SET sql_mode              = '%s' */ ;\n",
+          (const char *) sql_mode);
 }
 
 
-static void restore_sql_mode(FILE *sql_file,
-                             const char *delimiter)
+static void restore_sql_mode(FILE *sql_file)
 {
   fprintf(sql_file,
-          "/*!50003 SET sql_mode              = @saved_sql_mode */ %s\n",
-          (const char *) delimiter);
+          "/*!50003 SET sql_mode              = @saved_sql_mode */ ;\n");
 }
 
 
-static void switch_time_zone(FILE *sql_file,
-                             const char *delimiter,
-                             const char *time_zone)
+static void switch_time_zone(FILE *sql_file, const char *time_zone)
 {
   fprintf(sql_file,
-          "/*!50003 SET @saved_time_zone      = @@time_zone */ %s\n"
-          "/*!50003 SET time_zone             = '%s' */ %s\n",
-          (const char *) delimiter,
-
-          (const char *) time_zone,
-          (const char *) delimiter);
+          "/*!50003 SET @saved_time_zone      = @@time_zone */ ;\n"
+          "/*!50003 SET time_zone             = '%s' */ ;\n",
+          (const char *) time_zone);
 }
 
 
-static void restore_time_zone(FILE *sql_file,
-                              const char *delimiter)
+static void restore_time_zone(FILE *sql_file)
 {
   fprintf(sql_file,
-          "/*!50003 SET time_zone             = @saved_time_zone */ %s\n",
-          (const char *) delimiter);
+          "/*!50003 SET time_zone             = @saved_time_zone */ ;\n");
 }
 
 
@@ -2679,44 +2647,6 @@ static void print_comment(FILE *sql_file, my_bool is_error, const char *format,
   print_xml_comment(sql_file, strlen(comment_buff), comment_buff);
 }
 
-/*
- create_delimiter
- Generate a new (null-terminated) string that does not exist in  query 
- and is therefore suitable for use as a query delimiter.  Store this
- delimiter in  delimiter_buff .
- 
- This is quite simple in that it doesn't even try to parse statements as an
- interpreter would.  It merely returns a string that is not in the query, which
- is much more than adequate for constructing a delimiter.
-
- RETURN
-   ptr to the delimiter  on Success
-   NULL                  on Failure
-*/
-static char *create_delimiter(char *query, char *delimiter_buff, 
-                              int delimiter_max_size) 
-{
-  int proposed_length;
-  char *presence;
-
-  delimiter_buff[0]= ';';  /* start with one semicolon, and */
-
-  for (proposed_length= 2; proposed_length < delimiter_max_size; 
-      delimiter_max_size++) {
-
-    delimiter_buff[proposed_length-1]= ';';  /* add semicolons, until */
-    delimiter_buff[proposed_length]= '\0';
-
-    presence = strstr(query, delimiter_buff);
-    if (presence == NULL) { /* the proposed delimiter is not in the query. */
-       return delimiter_buff;
-    }
-
-  }
-  return NULL;  /* but if we run out of space, return nothing at all. */
-}
-
-
 /*
   dump_events_for_db
   -- retrieves list of events for a given db, and prints out
@@ -2731,7 +2661,6 @@ static uint dump_events_for_db(char *db)
   char       query_buff[QUERY_LENGTH];
   char       db_name_buff[NAME_LEN*2+3], name_buff[NAME_LEN*2+3];
   char       *event_name;
-  char       delimiter[QUERY_LENGTH];
   FILE       *sql_file= md_result_file;
   MYSQL_RES  *event_res= NULL, *event_list_res= NULL;
   MYSQL_ROW  row, event_list_row;
@@ -2759,7 +2688,6 @@ static uint dump_events_for_db(char *db)
   if (mysql_query_with_error_report(mysql, &event_list_res, "show events"))
     DBUG_RETURN(0);
 
-  safe_strcpy(delimiter, sizeof(delimiter), ";");
   if (mysql_num_rows(event_list_res) > 0)
   {
     if (opt_xml)
@@ -2805,25 +2733,16 @@ static uint dump_events_for_db(char *db)
           char *query_str;
 
           if (opt_drop)
-            fprintf(sql_file, "/*!50106 DROP EVENT IF EXISTS %s */%s\n", 
-                event_name, delimiter);
-
-          if (create_delimiter(row[3], delimiter, sizeof(delimiter)) == NULL)
-          {
-            fprintf(stderr, "%s: Warning: Can't create delimiter for event '%s'\n",
-                    my_progname_short, event_name);
-            goto err;
-          }
-
-          fprintf(sql_file, "DELIMITER %s\n", delimiter);
+            fprintf(sql_file, "/*!50106 DROP EVENT IF EXISTS %s */;\n", 
+                event_name);
 
           if (mysql_num_fields(event_res) >= 7)
           {
-            if (switch_db_collation(sql_file, db_name_buff, delimiter,
+            if (switch_db_collation(sql_file, db_name_buff,
                                     db_cl_name, row[6], &db_cl_altered))
               goto err;
 
-            switch_cs_variables(sql_file, delimiter,
+            switch_cs_variables(sql_file,
                                 row[4],   /* character_set_client */
                                 row[4],   /* character_set_results */
                                 row[5]);  /* collation_connection */
@@ -2846,32 +2765,31 @@ static uint dump_events_for_db(char *db)
                     "--\n");
           }
 
-          switch_sql_mode(sql_file, delimiter, row[1]);
+          switch_sql_mode(sql_file, row[1]);
 
-          switch_time_zone(sql_file, delimiter, row[2]);
+          switch_time_zone(sql_file, row[2]);
 
           query_str= cover_definer_clause(row[3], strlen(row[3]),
                                           C_STRING_WITH_LEN("50117"),
                                           C_STRING_WITH_LEN("50106"),
                                           C_STRING_WITH_LEN(" EVENT"));
 
-          fprintf(sql_file,
-                  "/*!50106 %s \n*/ %s\n",
-                  (const char *) (query_str != NULL ? query_str : row[3]),
-                  (const char *) delimiter);
+          fprintf(sql_file, "DELIMITER ;;\n"
+                  "/*!50106 %s \n*/ ;;\n"
+                  "DELIMITER ;\n",
+                  (const char *) (query_str != NULL ? query_str : row[3]));
 
           my_free(query_str);
-          restore_time_zone(sql_file, delimiter);
-          restore_sql_mode(sql_file, delimiter);
+          restore_time_zone(sql_file);
+          restore_sql_mode(sql_file);
 
           if (mysql_num_fields(event_res) >= 7)
           {
-            restore_cs_variables(sql_file, delimiter);
+            restore_cs_variables(sql_file);
 
             if (db_cl_altered)
             {
-              if (restore_db_collation(sql_file, db_name_buff, delimiter,
-                                       db_cl_name))
+              if (restore_db_collation(sql_file, db_name_buff, db_cl_name))
                 goto err;
             }
           }
@@ -2888,7 +2806,6 @@ static uint dump_events_for_db(char *db)
     }
     else
     {
-      fprintf(sql_file, "DELIMITER ;\n");
       fprintf(sql_file, "/*!50106 SET TIME_ZONE= @save_time_zone */ ;\n");
     }
 
@@ -3048,15 +2965,15 @@ static uint dump_routines_for_db(char *db)
               continue;
             }
 
-            switch_sql_mode(sql_file, ";", row[1]);
+            switch_sql_mode(sql_file, row[1]);
 
             if (opt_drop)
               fprintf(sql_file, "/*!50003 DROP %s IF EXISTS %s */;\n",
                       routine_type[i], routine_name);
 
             if (mysql_num_fields(routine_res) >= 6)
             {
-              if (switch_db_collation(sql_file, db, ";",
+              if (switch_db_collation(sql_file, db,
                                       db_cl_name, row[5], &db_cl_altered))
               {
                 mysql_free_result(routine_res);
@@ -3065,7 +2982,7 @@ static uint dump_routines_for_db(char *db)
                 DBUG_RETURN(1);
               }
 
-              switch_cs_variables(sql_file, ";",
+              switch_cs_variables(sql_file,
                                   row[3],   /* character_set_client */
                                   row[3],   /* character_set_results */
                                   row[4]);  /* collation_connection */
@@ -3096,15 +3013,15 @@ static uint dump_routines_for_db(char *db)
                     "DELIMITER ;\n",
                     (const char *) row[2]);
 
-            restore_sql_mode(sql_file, ";");
+            restore_sql_mode(sql_file);
 
             if (mysql_num_fields(routine_res) >= 6)
             {
-              restore_cs_variables(sql_file, ";");
+              restore_cs_variables(sql_file);
 
               if (db_cl_altered)
               {
-                if (restore_db_collation(sql_file, db, ";", db_cl_name))
+                if (restore_db_collation(sql_file, db, db_cl_name))
                 {
                   mysql_free_result(routine_res);
                   mysql_free_result(routine_list_res);
@@ -4010,16 +3927,16 @@ static int dump_trigger(FILE *sql_file, MYSQL_RES *show_create_trigger_rs,
       continue;
     }
 
-    if (switch_db_collation(sql_file, db_name, ";",
+    if (switch_db_collation(sql_file, db_name,
                             db_cl_name, row[5], &db_cl_altered))
       DBUG_RETURN(TRUE);
 
-    switch_cs_variables(sql_file, ";",
+    switch_cs_variables(sql_file,
                         row[3],   /* character_set_client */
                         row[3],   /* character_set_results */
                         row[4]);  /* collation_connection */
 
-    switch_sql_mode(sql_file, ";", row[1]);
+    switch_sql_mode(sql_file, row[1]);
 
     if (opt_drop_trigger)
       fprintf(sql_file, "/*!50032 DROP TRIGGER IF EXISTS %s */;\n",
@@ -4037,12 +3954,12 @@ static int dump_trigger(FILE *sql_file, MYSQL_RES *show_create_trigger_rs,
 
     my_free(query_str);
 
-    restore_sql_mode(sql_file, ";");
-    restore_cs_variables(sql_file, ";");
+    restore_sql_mode(sql_file);
+    restore_cs_variables(sql_file);
 
     if (db_cl_altered)
     {
-      if (restore_db_collation(sql_file, db_name, ";", db_cl_name))
+      if (restore_db_collation(sql_file, db_name, db_cl_name))
         DBUG_RETURN(TRUE);
     }
   }