Remove dead code: flush_version was never increased in the server,

therefore the logic associated with it never worked.


sql/ha_partition.cc:
  Remove dead code. Update comments.
sql/mysql_priv.h:
  Remove dead code (flush_version).
sql/mysqld.cc:
  Remove dead code (flush_version).
sql/sql_base.cc:
  Remove dead code.
sql/table.cc:
  Remove dead code.
sql/table.h:
  Remove dead code.

sql/ha_partition.cc

@@ -4466,7 +4466,7 @@ void ha_partition::get_dynamic_partition_info(PARTITION_INFO *stat_info,
     2) It is called from close_thread_table which in turn is called from
        close_thread_tables except in the case where the tables are locked
        in which case ha_commit_stmt is called instead.
-       It is only called from here if flush_version hasn't changed and the
+       It is only called from here if refresh_version hasn't changed and the
        table is not an old table when calling close_thread_table.
        close_thread_tables is called from many places as a general clean up
        function after completing a query.
@@ -4487,8 +4487,9 @@ void ha_partition::get_dynamic_partition_info(PARTITION_INFO *stat_info,
     The handler will set HA_KEYREAD_ONLY in its table flags to indicate this
     feature is supported.
   HA_EXTRA_FLUSH:
-    Indication to flush tables to disk, called at close_thread_table to
+    Indication to flush tables to disk, is supposed to be used to
     ensure disk based tables are flushed at end of query execution.
+    Currently is never used.
 
   2) Parameters used by some non-MyISAM handlers
   ----------------------------------------------

sql/mysql_priv.h

@@ -1558,7 +1558,7 @@ extern double log_01[32];
 extern ulonglong log_10_int[20];
 extern ulonglong keybuff_size;
 extern ulonglong thd_startup_options;
-extern ulong refresh_version,flush_version, thread_id;
+extern ulong refresh_version, thread_id;
 extern ulong binlog_cache_use, binlog_cache_disk_use;
 extern ulong aborted_threads,aborted_connects;
 extern ulong delayed_insert_timeout;

sql/mysqld.cc

@@ -469,7 +469,7 @@ ulong open_files_limit, max_binlog_size, max_relay_log_size;
 ulong slave_net_timeout, slave_trans_retries;
 ulong thread_cache_size=0, binlog_cache_size=0, max_binlog_cache_size=0;
 ulong query_cache_size=0;
-ulong refresh_version, flush_version;	/* Increments on each reload */
+ulong refresh_version;  /* Increments on each reload */
 query_id_t global_query_id;
 ulong aborted_threads, aborted_connects;
 ulong delayed_insert_timeout, delayed_insert_limit, delayed_queue_size;
@@ -7015,7 +7015,7 @@ static void mysql_init_variables(void)
                         OPTION_QUOTE_SHOW_CREATE | OPTION_SQL_NOTES);
   protocol_version= PROTOCOL_VERSION;
   what_to_log= ~ (1L << (uint) COM_TIME);
-  refresh_version= flush_version= 1L;	/* Increments on each reload */
+  refresh_version= 1L;	/* Increments on each reload */
   global_query_id= thread_id= 1L;
   strmov(server_version, MYSQL_SERVER_VERSION);
   myisam_recover_options_str= sql_mode_str= "OFF";

sql/sql_base.cc

@@ -1142,12 +1142,7 @@ bool close_thread_table(THD *thd, TABLE **table_ptr)
   }
   else
   {
-    if (table->s->flush_version != flush_version)
-    {
-      table->s->flush_version= flush_version;
-      table->file->extra(HA_EXTRA_FLUSH);
-    }
-    // Free memory and reset for next loop
+    /* Free memory and reset for next loop */
     table->file->ha_reset();
     table->in_use=0;
     if (unused_tables)
@@ -1777,7 +1772,6 @@ bool reopen_name_locked_table(THD* thd, TABLE_LIST* table_list)
 
   share= table->s;
   share->version=0;
-  share->flush_version=0;
   table->in_use = thd;
   check_unused();
   table->next = thd->open_tables;

sql/table.cc

@@ -120,7 +120,6 @@ TABLE_SHARE *alloc_table_share(TABLE_LIST *table_list, char *key,
     share->normalized_path.length= path_length;
 
     share->version=       refresh_version;
-    share->flush_version= flush_version;
 
     /*
       This constant is used to mark that no table map version has been

sql/table.h

@@ -168,7 +168,7 @@ typedef struct st_table_share
   ha_rows min_rows, max_rows;		/* create information */
   ulong   avg_row_length;		/* create information */
   ulong   raid_chunksize;
-  ulong   version, flush_version, mysql_version;
+  ulong   version, mysql_version;
   ulong   timestamp_offset;		/* Set to offset+1 of record */
   ulong   reclength;			/* Recordlength */