Bug#53189 Table map version unused and can be removed

MYSQL_BIN_LOG m_table_map_version member and it's associated 
functions were not used in the logic of binlogging and replication,
this patch removed all related code.

sql/log.cc:
  removed unused m_table_map_version variable and functions
sql/log.h:
  removed unused m_table_map_version variable and functions
sql/log_event.h:
  Removed unused LOG_EVENT_UPDATE_TABLE_MAP_VERSION_F flag
sql/sql_class.cc:
  Removed unused LOG_EVENT_UPDATE_TABLE_MAP_VERSION_F flag
sql/sql_load.cc:
  Removed unused LOG_EVENT_UPDATE_TABLE_MAP_VERSION_F flag
sql/table.cc:
  removed unused table_map_version variable
sql/table.h:
  removed unused table_map_version variable

sql/log.cc

@@ -1440,11 +1440,6 @@ binlog_end_trans(THD *thd, binlog_trx_data *trx_data,
                                trx_data->has_incident());
     trx_data->reset();
 
-    /*
-      We need to step the table map version after writing the
-      transaction cache to disk.
-    */
-    mysql_bin_log.update_table_map_version();
     statistic_increment(binlog_cache_use, &LOCK_status);
     if (trans_log->disk_writes != 0)
     {
@@ -1470,13 +1465,6 @@ binlog_end_trans(THD *thd, binlog_trx_data *trx_data,
     }
     else                                        // ...statement
       trx_data->truncate(trx_data->before_stmt_pos);
-
-    /*
-      We need to step the table map version on a rollback to ensure
-      that a new table map event is generated instead of the one that
-      was written to the thrown-away transaction cache.
-    */
-    mysql_bin_log.update_table_map_version();
   }
 
   DBUG_ASSERT(thd->binlog_get_pending_rows_event() == NULL);
@@ -2437,7 +2425,7 @@ const char *MYSQL_LOG::generate_name(const char *log_name,
 
 MYSQL_BIN_LOG::MYSQL_BIN_LOG()
   :bytes_written(0), prepared_xids(0), file_id(1), open_count(1),
-   need_start_event(TRUE), m_table_map_version(0),
+   need_start_event(TRUE),
    is_relay_log(0),
    description_event_for_exec(0), description_event_for_queue(0)
 {
@@ -4078,7 +4066,6 @@ int THD::binlog_write_table_map(TABLE *table, bool is_trans)
     DBUG_RETURN(error);
 
   binlog_table_maps++;
-  table->s->table_map_version= mysql_bin_log.table_map_version();
   DBUG_RETURN(0);
 }
 
@@ -4169,10 +4156,8 @@ MYSQL_BIN_LOG::flush_and_set_pending_rows_event(THD *thd,
       file= &trx_data->trans_log;
 
     /*
-      If we are writing to the log file directly, we could avoid
-      locking the log. This does not work since we need to step the
-      m_table_map_version below, and that change has to be protected
-      by the LOCK_log mutex.
+      If we are not writing to the log file directly, we could avoid
+      locking the log.
     */
     pthread_mutex_lock(&LOCK_log);
 
@@ -4186,24 +4171,6 @@ MYSQL_BIN_LOG::flush_and_set_pending_rows_event(THD *thd,
       DBUG_RETURN(1);
     }
 
-    /*
-      We step the table map version if we are writing an event
-      representing the end of a statement.  We do this regardless of
-      wheather we write to the transaction cache or to directly to the
-      file.
-
-      In an ideal world, we could avoid stepping the table map version
-      if we were writing to a transaction cache, since we could then
-      reuse the table map that was written earlier in the transaction
-      cache.  This does not work since STMT_END_F implies closing all
-      table mappings on the slave side.
-
-      TODO: Find a solution so that table maps does not have to be
-      written several times within a transaction.
-     */
-    if (pending->get_flags(Rows_log_event::STMT_END_F))
-      ++m_table_map_version;
-
     delete pending;
 
     if (file == &log_file)
@@ -4417,9 +4384,6 @@ err:
       set_write_error(thd);
   }
 
-  if (event_info->flags & LOG_EVENT_UPDATE_TABLE_MAP_VERSION_F)
-    ++m_table_map_version;
-
   pthread_mutex_unlock(&LOCK_log);
   DBUG_RETURN(error);
 }

sql/log.h

@@ -272,8 +272,6 @@ class MYSQL_BIN_LOG: public TC_LOG, private MYSQL_LOG
   */
   bool no_auto_events;
 
-  ulonglong m_table_map_version;
-
   int write_to_file(IO_CACHE *cache);
   /*
     This is used to start writing to a new log file. The difference from
@@ -314,14 +312,6 @@ public:
   void unlog(ulong cookie, my_xid xid);
   int recover(IO_CACHE *log, Format_description_log_event *fdle);
 #if !defined(MYSQL_CLIENT)
-  bool is_table_mapped(TABLE *table) const
-  {
-    return table->s->table_map_version == table_map_version();
-  }
-
-  ulonglong table_map_version() const { return m_table_map_version; }
-  void update_table_map_version() { ++m_table_map_version; }
-
   int flush_and_set_pending_rows_event(THD *thd, Rows_log_event* event);
   int remove_pending_rows_event(THD *thd);
 

sql/log_event.h

@@ -463,10 +463,10 @@ struct sql_ex_info
 #define LOG_EVENT_SUPPRESS_USE_F    0x8
 
 /*
-  The table map version internal to the log should be increased after
-  the event has been written to the binary log.
+  Note: this is a place holder for the flag
+  LOG_EVENT_UPDATE_TABLE_MAP_VERSION_F (0x10), which is not used any
+  more, please do not reused this value for other flags.
  */
-#define LOG_EVENT_UPDATE_TABLE_MAP_VERSION_F 0x10
 
 /**
    @def LOG_EVENT_ARTIFICIAL_F

sql/sql_class.cc

@@ -3825,7 +3825,6 @@ int THD::binlog_flush_pending_rows_event(bool stmt_end)
     if (stmt_end)
     {
       pending->set_flags(Rows_log_event::STMT_END_F);
-      pending->flags|= LOG_EVENT_UPDATE_TABLE_MAP_VERSION_F;
       binlog_table_maps= 0;
     }
 
@@ -3953,7 +3952,6 @@ int THD::binlog_query(THD::enum_binlog_query_type qtype, char const *query_arg,
     {
       Query_log_event qinfo(this, query_arg, query_len, is_trans, suppress_use,
                             errcode);
-      qinfo.flags|= LOG_EVENT_UPDATE_TABLE_MAP_VERSION_F;
       /*
         Binlog table maps will be irrelevant after a Query_log_event
         (they are just removed on the slave side) so after the query

sql/sql_load.cc

@@ -511,7 +511,6 @@ int mysql_load(THD *thd,sql_exchange *ex,TABLE_LIST *table_list,
 	  else
 	  {
 	    Delete_file_log_event d(thd, db, transactional_table);
-            d.flags|= LOG_EVENT_UPDATE_TABLE_MAP_VERSION_F;
 	    (void) mysql_bin_log.write(&d);
 	  }
 	}
@@ -691,7 +690,6 @@ static bool write_execute_load_query_log_event(THD *thd, sql_exchange* ex,
       (duplicates == DUP_REPLACE) ? LOAD_DUP_REPLACE :
       (ignore ? LOAD_DUP_IGNORE : LOAD_DUP_ERROR),
       transactional_table, FALSE, errcode);
-  e.flags|= LOG_EVENT_UPDATE_TABLE_MAP_VERSION_F;
   return mysql_bin_log.write(&e);
 }
 

sql/table.cc

@@ -296,13 +296,6 @@ TABLE_SHARE *alloc_table_share(TABLE_LIST *table_list, char *key,
 
     share->version=       refresh_version;
 
-    /*
-      This constant is used to mark that no table map version has been
-      assigned.  No arithmetic is done on the value: it will be
-      overwritten with a value taken from MYSQL_BIN_LOG.
-    */
-    share->table_map_version= ~(ulonglong)0;
-
     /*
       Since alloc_table_share() can be called without any locking (for
       example, ha_create_table... functions), we do not assign a table
@@ -366,11 +359,6 @@ void init_tmp_table_share(THD *thd, TABLE_SHARE *share, const char *key,
   share->path.length= share->normalized_path.length= strlen(path);
   share->frm_version= 		 FRM_VER_TRUE_VARCHAR;
 
-  /*
-    Temporary tables are not replicated, but we set up these fields
-    anyway to be able to catch errors.
-   */
-  share->table_map_version= ~(ulonglong)0;
   share->cached_row_logging_check= -1;
 
   /*

sql/table.h

@@ -430,7 +430,6 @@ typedef struct st_table_share
   bool name_lock, replace_with_name_lock;
   bool waiting_on_cond;                 /* Protection against free */
   ulong table_map_id;                   /* for row-based replication */
-  ulonglong table_map_version;
 
   /*
     Cache for row-based replication table share checks that does not