bk commit into 4.1 tree (sergefp:1.2411) BUG#12232

[Sergey Petrunia]

Below is the list of changes that have just been committed into a local
4.1 repository of psergey. When psergey does a push these changes will
be propagated to the main repository and, within 24 hours after the
push, to the public repository.
For information on how to access the public repository
see http://dev.mysql.com/doc/mysql/en/installing-source-tree.html

ChangeSet
  1.2411 05/09/16 03:15:15 sergefp@stripped +12 -0
  BUG#12232: Add a server option to treat NULL values as equal when calculating MyISAM
index 
  statistics (like it was done in 4.1) (patch #2, 1st review feedback addressed)

  sql/sql_class.h
    1.283 05/09/16 03:15:07 sergefp@stripped +1 -0
    BUG#12232: Add a server option to treat NULL values as equal when calculating MyISAM
index statistics

  sql/set_var.cc
    1.178 05/09/16 03:15:07 sergefp@stripped +19 -0
    BUG#12232: Add a server option to treat NULL values as equal when calculating MyISAM
index statistics

  sql/mysqld.cc
    1.596 05/09/16 03:15:06 sergefp@stripped +28 -0
    BUG#12232: Add a server option to treat NULL values as equal when calculating MyISAM
index statistics

  sql/handler.h
    1.143 05/09/16 03:15:06 sergefp@stripped +2 -0
    BUG#12232: Add a server option to treat NULL values as equal when calculating MyISAM
index statistics

  sql/handler.cc
    1.171 05/09/16 03:15:06 sergefp@stripped +3 -1
    BUG#12232: Add a server option to treat NULL values as equal when calculating MyISAM
index statistics

  sql/ha_myisam.cc
    1.160 05/09/16 03:15:06 sergefp@stripped +3 -0
    BUG#12232: Add a server option to treat NULL values as equal when calculating MyISAM
index statistics

  mysql-test/t/myisam.test
    1.41 05/09/16 03:15:06 sergefp@stripped +47 -0
    BUG#12232: Add a server option to treat NULL values as equal when calculating MyISAM
index statistics

  mysql-test/r/myisam.result
    1.52 05/09/16 03:15:06 sergefp@stripped +61 -0
    BUG#12232: Add a server option to treat NULL values as equal when calculating MyISAM
index statistics

  myisam/myisamdef.h
    1.80 05/09/16 03:15:06 sergefp@stripped +1 -0
    BUG#12232: Add a server option to treat NULL values as equal when calculating MyISAM
index statistics

  myisam/myisamchk.c
    1.126 05/09/16 03:15:06 sergefp@stripped +21 -1
    BUG#12232: Add a server option to treat NULL values as equal when calculating MyISAM
index statistics

  myisam/mi_check.c
    1.150 05/09/16 03:15:06 sergefp@stripped +18 -13
    BUG#12232: Add a server option to treat NULL values as equal when calculating MyISAM
index statistics

  include/myisam.h
    1.64 05/09/16 03:15:05 sergefp@stripped +18 -0
    BUG#12232: Add a server option to treat NULL values as equal when calculating MyISAM
index statistics

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	sergefp
# Host:	newbox.mylan
# Root:	/home/psergey/mysql-4.1-csc6030-r2

--- 1.63/include/myisam.h	2004-10-06 16:09:37 +04:00
+++ 1.64/include/myisam.h	2005-09-16 03:15:05 +04:00
@@ -311,6 +311,23 @@
 } SORT_KEY_BLOCKS;
 
 
+/* 
+  MyISAM supports several statistics collection methods. Currently statistics 
+  collection method is not stored in MyISAM file and has to be specified for 
+  each table analyze/repair operation in  MI_CHECK::stats_method.
+*/
+
+/* 
+  Treat NULLs as inequal when collecting statistics. This is the default for 
+  4.1/5.0 
+*/
+#define MI_STATS_METHOD_NULLS_NOT_EQUAL 0
+#define MI_STATS_METHOD_DEFAULT         0
+
+/* Treat NULLs as equal when collecting statistics. 4.0 used this method */
+#define MI_STATS_METHOD_NULLS_EQUAL     1
+
+
 typedef struct st_mi_check_param
 {
   ulonglong auto_increment_value;
@@ -341,6 +358,7 @@
   void *thd;
   char *db_name,*table_name;
   char *op_name;
+  uint stats_method; /* One of MI_STATS_METHOD_* values */
 } MI_CHECK;
 
 typedef struct st_sort_ft_buf

--- 1.149/myisam/mi_check.c	2005-09-05 15:40:55 +04:00
+++ 1.150/myisam/mi_check.c	2005-09-16 03:15:06 +04:00
@@ -80,6 +80,7 @@
   param->start_check_pos=0;
   param->max_record_length= LONGLONG_MAX;
   param->key_cache_block_size= KEY_CACHE_BLOCK_SIZE;
+  param->stats_method= MI_STATS_METHOD_DEFAULT;
 }
 
 	/* Check the status flags for the table */
@@ -558,10 +559,11 @@
 		     ha_checksum *key_checksum, uint level)
 {
   int flag;
-  uint used_length,comp_flag,nod_flag,key_length=0,not_used;
+  uint used_length,comp_flag,nod_flag,key_length=0;
   uchar key[MI_MAX_POSSIBLE_KEY_BUFF],*temp_buff,*keypos,*old_keypos,*endpos;
   my_off_t next_page,record;
   char llbuff[22];
+  uint diff_pos;
   DBUG_ENTER("chk_index");
   DBUG_DUMP("buff",(byte*) buff,mi_getint(buff));
 
@@ -619,7 +621,7 @@
     }
     if ((*keys)++ &&
 	(flag=ha_key_cmp(keyinfo->seg,info->lastkey,key,key_length,
-			 comp_flag, &not_used)) >=0)
+			 comp_flag, &diff_pos)) >=0)
     {
       DBUG_DUMP("old",(byte*) info->lastkey, info->lastkey_length);
       DBUG_DUMP("new",(byte*) key, key_length);
@@ -635,11 +637,11 @@
     {
       if (*keys != 1L)				/* not first_key */
       {
-	uint diff;
-	ha_key_cmp(keyinfo->seg,info->lastkey,key,USE_WHOLE_KEY,
-		   SEARCH_FIND | SEARCH_NULL_ARE_NOT_EQUAL,
-		   &diff);
-	param->unique_count[diff-1]++;
+        if (param->stats_method == MI_STATS_METHOD_NULLS_NOT_EQUAL)
+          ha_key_cmp(keyinfo->seg,info->lastkey,key,USE_WHOLE_KEY,
+                     SEARCH_FIND | SEARCH_NULL_ARE_NOT_EQUAL,
+                     &diff_pos);
+	param->unique_count[diff_pos-1]++;
       }
     }
     (*key_checksum)+= mi_byte_checksum((byte*) key,
@@ -2013,7 +2015,8 @@
   sort_param.sort_info=&sort_info;
   sort_param.fix_datafile= (my_bool) (! rep_quick);
   sort_param.master =1;
-
+  
+  sort_param.stats_method= param->stats_method;
   del=info->state->del;
   param->glob_crc=0;
   if (param->testflag & T_CALC_CHECKSUM)
@@ -3249,9 +3252,10 @@
     cmp=ha_key_cmp(sort_param->seg,sort_info->key_block->lastkey,
 		   (uchar*) a, USE_WHOLE_KEY,SEARCH_FIND | SEARCH_UPDATE,
 		   &diff_pos);
-    ha_key_cmp(sort_param->seg,sort_info->key_block->lastkey,
-               (uchar*) a, USE_WHOLE_KEY,SEARCH_FIND | SEARCH_NULL_ARE_NOT_EQUAL,
-               &diff_pos);
+    if (sort_param->stats_method == MI_STATS_METHOD_NULLS_NOT_EQUAL)
+      ha_key_cmp(sort_param->seg,sort_info->key_block->lastkey,
+                 (uchar*) a, USE_WHOLE_KEY,SEARCH_FIND | SEARCH_NULL_ARE_NOT_EQUAL,
+                 &diff_pos);
     sort_param->unique[diff_pos-1]++;
   }
   else
@@ -3989,9 +3993,10 @@
     unique[0]= (#different values of {keypart1}) - 1
     unique[1]= (#different values of {keypart2,keypart1} tuple) - unique[0] - 1
     ...
-    Here we assume that NULL != NULL (see SEARCH_NULL_ARE_NOT_EQUAL). The
-    'unique' array is collected in one sequential scan through the entire
+    The 'unique' array is collected in one sequential scan through the entire
     index. This is done in two places: in chk_index() and in sort_key_write().
+    Statistics collection may consider NULLs as either equal or inequal (see
+    SEARCH_NULL_ARE_NOT_EQUAL, MI_STATS_METHOD_*).
 
     Output is an array:
     rec_per_key_part[k] = 

--- 1.125/myisam/myisamchk.c	2005-08-25 13:08:20 +04:00
+++ 1.126/myisam/myisamchk.c	2005-09-16 03:15:06 +04:00
@@ -67,6 +67,7 @@
  "no zeros", "blob", "constant", "table-lockup",
  "always zero","varchar","unique-hash","?","?"};
 
+static const char *myisam_stats_method_str="nulls_inequal";
 
 static void get_options(int *argc,char * * *argv);
 static void print_version(void);
@@ -155,7 +156,7 @@
   OPT_READ_BUFFER_SIZE, OPT_WRITE_BUFFER_SIZE, OPT_SORT_BUFFER_SIZE,
   OPT_SORT_KEY_BLOCKS, OPT_DECODE_BITS, OPT_FT_MIN_WORD_LEN,
   OPT_FT_MAX_WORD_LEN, OPT_FT_STOPWORD_FILE,
-  OPT_MAX_RECORD_LENGTH, OPT_AUTO_CLOSE
+  OPT_MAX_RECORD_LENGTH, OPT_AUTO_CLOSE, OPT_STATS_METHOD
 };
 
 static struct my_option my_long_options[] =
@@ -336,6 +337,11 @@
     "Use stopwords from this file instead of built-in list.",
     (gptr*) &ft_stopword_file, (gptr*) &ft_stopword_file, 0, GET_STR,
     REQUIRED_ARG, 0, 0, 0, 0, 0, 0},
+  {"stats_method", OPT_STATS_METHOD,
+   "Specifies how index statistics collection code should threat NULLs. "
+   "Possible values of name are \"nulls_inequal\" (default behavior for 4.1/5.0), and
\"nulls_equal\" (emulate 4.0 behavior).",
+   (gptr*) &myisam_stats_method_str, (gptr*) &myisam_stats_method_str, 0,
+    GET_STR, REQUIRED_ARG, 0, 0, 0, 0, 0, 0},
   { 0, 0, 0, 0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0}
 };
 
@@ -684,6 +690,20 @@
     else
       check_param.testflag|= T_CALC_CHECKSUM;
     break;
+  case OPT_STATS_METHOD:
+  {
+    myisam_stats_method_str= argument;
+    if (!strcmp(argument, "nulls_inequal"))
+      check_param.stats_method= MI_STATS_METHOD_NULLS_NOT_EQUAL;
+    else if (!strcmp(argument, "nulls_equal"))
+      check_param.stats_method= MI_STATS_METHOD_NULLS_EQUAL;
+    else
+    {
+      fprintf(stderr, "Invalid value of myisam_stats_method: %s.\n", argument);
+      exit(1);
+    }
+    break;
+  }
 #ifdef DEBUG					/* Only useful if debugging */
   case OPT_START_CHECK_POS:
     check_param.start_check_pos= strtoull(argument, NULL, 0);

--- 1.79/myisam/myisamdef.h	2005-09-05 15:31:35 +04:00
+++ 1.80/myisam/myisamdef.h	2005-09-16 03:15:06 +04:00
@@ -318,6 +318,7 @@
   NEAR uint (*read_to_buffer)(IO_CACHE *,struct st_buffpek *, uint);
   NEAR int (*write_key)(struct st_mi_sort_param *, IO_CACHE *,char *,
                        uint, uint);
+  uint stats_method; /* One of MI_STATS_METHOD_* values */
 } MI_SORT_PARAM;
 	/* Some defines used by isam-funktions */
 

--- 1.159/sql/ha_myisam.cc	2005-06-05 21:38:39 +04:00
+++ 1.160/sql/ha_myisam.cc	2005-09-16 03:15:06 +04:00
@@ -278,6 +278,7 @@
   param.db_name    = table->table_cache_key;
   param.table_name = table->table_name;
   param.testflag = check_opt->flags | T_CHECK | T_SILENT;
+  param.stats_method= check_opt->myisam_stats_method;
 
   if (!(table->db_stat & HA_READ_ONLY))
     param.testflag|= T_STATISTICS;
@@ -367,6 +368,7 @@
   param.testflag=(T_FAST | T_CHECK | T_SILENT | T_STATISTICS |
 		  T_DONT_CHECK_CHECKSUM);
   param.using_global_keycache = 1;
+  param.stats_method= check_opt->myisam_stats_method;
 
   if (!(share->state.changed & STATE_NOT_ANALYZED))
     return HA_ADMIN_ALREADY_DONE;
@@ -920,6 +922,7 @@
                       T_CREATE_MISSING_KEYS);
     param.myf_rw&= ~MY_WAIT_IF_FULL;
     param.sort_buffer_length=  thd->variables.myisam_sort_buff_size;
+    param.stats_method= thd->variables.myisam_stats_method;
     param.tmpdir=&mysql_tmpdir_list;
     if ((error= (repair(thd,param,0) != HA_ADMIN_OK)) && param.retry_repair)
     {

--- 1.170/sql/handler.cc	2005-07-20 20:40:47 +04:00
+++ 1.171/sql/handler.cc	2005-09-16 03:15:06 +04:00
@@ -1405,8 +1405,10 @@
 
 void st_ha_check_opt::init()
 {
+  THD *thd= current_thd;
   flags= sql_flags= 0;
-  sort_buffer_size = current_thd->variables.myisam_sort_buff_size;
+  sort_buffer_size = thd->variables.myisam_sort_buff_size; 
+  myisam_stats_method= thd->variables.myisam_stats_method;
 }
 
 

--- 1.142/sql/handler.h	2005-08-30 02:05:12 +04:00
+++ 1.143/sql/handler.h	2005-09-16 03:15:06 +04:00
@@ -224,6 +224,8 @@
   uint flags;       /* isam layer flags (e.g. for myisamchk) */
   uint sql_flags;   /* sql layer flags - for something myisamchk cannot do */
   KEY_CACHE *key_cache;	/* new key cache when changing key cache */
+
+  uint myisam_stats_method;
   void init();
 } HA_CHECK_OPT;
 

--- 1.595/sql/mysqld.cc	2005-09-06 22:18:40 +04:00
+++ 1.596/sql/mysqld.cc	2005-09-16 03:15:06 +04:00
@@ -369,6 +369,7 @@
 char *my_bind_addr_str;
 const char **errmesg;			/* Error messages */
 const char *myisam_recover_options_str="OFF";
+const char *myisam_stats_method_str="nulls_inequal";
 const char *sql_mode_str="OFF";
 /* name of reference on left espression in rewritten IN subquery */
 const char *in_left_expr_name= "<left expr>";
@@ -4169,6 +4170,7 @@
   OPT_MAX_ERROR_COUNT, OPT_MYISAM_DATA_POINTER_SIZE,
   OPT_MYISAM_BLOCK_SIZE, OPT_MYISAM_MAX_EXTRA_SORT_FILE_SIZE,
   OPT_MYISAM_MAX_SORT_FILE_SIZE, OPT_MYISAM_SORT_BUFFER_SIZE,
+  OPT_MYISAM_STATS_METHOD,
   OPT_NET_BUFFER_LENGTH, OPT_NET_RETRY_COUNT,
   OPT_NET_READ_TIMEOUT, OPT_NET_WRITE_TIMEOUT,
   OPT_OPEN_FILES_LIMIT,
@@ -5208,6 +5210,11 @@
    (gptr*) &global_system_variables.myisam_sort_buff_size,
    (gptr*) &max_system_variables.myisam_sort_buff_size, 0,
    GET_ULONG, REQUIRED_ARG, 8192*1024, 4, ~0L, 0, 1, 0},
+  {"myisam_stats_method", OPT_MYISAM_STATS_METHOD,
+   "Specifies how MyISAM index statistics collection code should threat NULLs. "
+   "Possible values of name are \"nulls_inequal\" (default behavior for 4.1/5.0), and
\"nulls_equal\" (emulate 4.0 behavior).",
+   (gptr*) &myisam_stats_method_str, (gptr*) &myisam_stats_method_str, 0,
+    GET_STR, REQUIRED_ARG, 0, 0, 0, 0, 0, 0},
   {"net_buffer_length", OPT_NET_BUFFER_LENGTH,
    "Buffer length for TCP/IP and socket communication.",
    (gptr*) &global_system_variables.net_buffer_length,
@@ -5759,6 +5766,7 @@
   query_id= thread_id= 1L;
   strmov(server_version, MYSQL_SERVER_VERSION);
   myisam_recover_options_str= sql_mode_str= "OFF";
+  myisam_stats_method_str= "nulls_inequal";
   my_bind_addr = htonl(INADDR_ANY);
   threads.empty();
   thread_cache.empty();
@@ -5807,6 +5815,12 @@
   global_system_variables.max_join_size= (ulonglong) HA_POS_ERROR;
   max_system_variables.max_join_size=   (ulonglong) HA_POS_ERROR;
   global_system_variables.old_passwords= 0;
+  
+  /*
+    Default behavior for 4.1 and 5.0 is to treat NULL values as inequal
+    when collecting index statistics for MyISAM tables.
+  */
+  global_system_variables.myisam_stats_method= MI_STATS_METHOD_DEFAULT;
 
   /* Variables that depends on compile options */
 #ifndef DBUG_OFF
@@ -6386,6 +6400,20 @@
       }
     }
     ha_open_options|=HA_OPEN_ABORT_IF_CRASHED;
+    break;
+  }
+  case OPT_MYISAM_STATS_METHOD:
+  {
+    myisam_stats_method_str= argument;
+    if (!strcmp(argument, "nulls_equal"))
+      global_system_variables.myisam_stats_method= MI_STATS_METHOD_NULLS_EQUAL;
+    else if (!strcmp(argument, "nulls_inequal"))
+      global_system_variables.myisam_stats_method= MI_STATS_METHOD_NULLS_NOT_EQUAL;
+    else
+    {
+      fprintf(stderr, "Invalid value of myisam_stats_method: %s.\n", argument);
+      exit(1);
+    }
     break;
   }
   case OPT_SQL_MODE:

--- 1.282/sql/sql_class.h	2005-08-07 06:16:04 +04:00
+++ 1.283/sql/sql_class.h	2005-09-16 03:15:07 +04:00
@@ -363,6 +363,7 @@
   ulong max_insert_delayed_threads;
   ulong myisam_repair_threads;
   ulong myisam_sort_buff_size;
+  ulong myisam_stats_method;
   ulong net_buffer_length;
   ulong net_interactive_timeout;
   ulong net_read_timeout;

--- 1.51/mysql-test/r/myisam.result	2005-08-29 19:08:36 +04:00
+++ 1.52/mysql-test/r/myisam.result	2005-09-16 03:15:06 +04:00
@@ -609,3 +609,64 @@
 Table	Checksum
 test.t2	984116287
 drop table t1, t2;
+show variables like 'myisam_stats_method';
+Variable_name	Value
+myisam_stats_method	nulls_inequal
+create table t1 (a int, key(a));
+insert into t1 values (0),(1),(2),(3),(4);
+insert into t1 select NULL from t1;
+analyze table t1;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	OK
+show index from t1;
+Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment
+t1	1	a	1	a	A	10	NULL	NULL	YES	BTREE	
+insert into t1 values (11);
+delete from t1 where a=11;
+check table t1;
+Table	Op	Msg_type	Msg_text
+test.t1	check	status	OK
+show index from t1;
+Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment
+t1	1	a	1	a	A	10	NULL	NULL	YES	BTREE	
+set myisam_stats_method=nulls_equal;
+show variables like 'myisam_stats_method';
+Variable_name	Value
+myisam_stats_method	nulls_equal
+insert into t1 values (11);
+delete from t1 where a=11;
+analyze table t1;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	OK
+show index from t1;
+Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment
+t1	1	a	1	a	A	5	NULL	NULL	YES	BTREE	
+insert into t1 values (11);
+delete from t1 where a=11;
+check table t1;
+Table	Op	Msg_type	Msg_text
+test.t1	check	status	OK
+show index from t1;
+Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment
+t1	1	a	1	a	A	5	NULL	NULL	YES	BTREE	
+set myisam_stats_method=DEFAULT;
+show variables like 'myisam_stats_method';
+Variable_name	Value
+myisam_stats_method	nulls_inequal
+insert into t1 values (11);
+delete from t1 where a=11;
+analyze table t1;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	OK
+show index from t1;
+Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment
+t1	1	a	1	a	A	10	NULL	NULL	YES	BTREE	
+insert into t1 values (11);
+delete from t1 where a=11;
+check table t1;
+Table	Op	Msg_type	Msg_text
+test.t1	check	status	OK
+show index from t1;
+Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment
+t1	1	a	1	a	A	10	NULL	NULL	YES	BTREE	
+drop table t1;

--- 1.40/mysql-test/t/myisam.test	2005-08-29 19:08:36 +04:00
+++ 1.41/mysql-test/t/myisam.test	2005-09-16 03:15:06 +04:00
@@ -590,4 +590,51 @@
 checksum table t2;
 drop table t1, t2;
 
+# BUG#12232: New myisam_stats_method variable.
+show variables like 'myisam_stats_method';
+
+create table t1 (a int, key(a));
+insert into t1 values (0),(1),(2),(3),(4);
+insert into t1 select NULL from t1;
+
+# default: NULLs considered inequal
+analyze table t1; 
+show index from t1;
+insert into t1 values (11);
+delete from t1 where a=11;
+check table t1;
+show index from t1;
+
+# Set nulls to be equal:
+set myisam_stats_method=nulls_equal;
+show variables like 'myisam_stats_method';
+insert into t1 values (11);
+delete from t1 where a=11;
+
+analyze table t1; 
+show index from t1;
+
+insert into t1 values (11);
+delete from t1 where a=11;
+
+check table t1;
+show index from t1;
+
+# Set nulls back to be equal 
+set myisam_stats_method=DEFAULT;
+show variables like 'myisam_stats_method';
+insert into t1 values (11);
+delete from t1 where a=11;
+
+analyze table t1; 
+show index from t1;
+
+insert into t1 values (11);
+delete from t1 where a=11;
+
+check table t1;
+show index from t1;
+
+drop table t1;
+
 # End of 4.1 tests

--- 1.177/sql/set_var.cc	2005-09-06 13:18:21 +04:00
+++ 1.178/sql/set_var.cc	2005-09-16 03:15:07 +04:00
@@ -82,6 +82,14 @@
   delay_key_write_type_names, NULL
 };
 
+const char *myisam_stats_method_type_names[]= {"nulls_inequal", "nulls_equal",
+                                               NullS};
+TYPELIB myisam_stats_method_typelib=
+{
+  array_elements(myisam_stats_method_type_names)-1, "",
+  myisam_stats_method_type_names, NULL
+};
+
 static int  sys_check_charset(THD *thd, set_var *var);
 static bool sys_update_charset(THD *thd, set_var *var);
 static void sys_set_default_charset(THD *thd, enum_var_type type);
@@ -120,6 +128,7 @@
 static byte *get_warning_count(THD *thd);
 static byte *get_have_innodb(THD *thd);
 
+
 /*
   Variable definition list
 
@@ -256,6 +265,12 @@
 sys_var_thd_ulonglong	sys_myisam_max_sort_file_size("myisam_max_sort_file_size",
&SV::myisam_max_sort_file_size, fix_myisam_max_sort_file_size, 1);
 sys_var_thd_ulong       sys_myisam_repair_threads("myisam_repair_threads",
&SV::myisam_repair_threads);
 sys_var_thd_ulong	sys_myisam_sort_buffer_size("myisam_sort_buffer_size",
&SV::myisam_sort_buff_size);
+
+sys_var_thd_enum        sys_myisam_stats_method("myisam_stats_method",
+                                                &SV::myisam_stats_method,
+                                                &myisam_stats_method_typelib,
+                                                NULL);
+
 sys_var_thd_ulong	sys_net_buffer_length("net_buffer_length",
 					      &SV::net_buffer_length);
 sys_var_thd_ulong	sys_net_read_timeout("net_read_timeout",
@@ -574,6 +589,7 @@
   &sys_myisam_max_sort_file_size,
   &sys_myisam_repair_threads,
   &sys_myisam_sort_buffer_size,
+  &sys_myisam_stats_method,
   &sys_net_buffer_length,
   &sys_net_read_timeout,
   &sys_net_retry_count,
@@ -810,6 +826,9 @@
   {sys_myisam_repair_threads.name, (char*) &sys_myisam_repair_threads,
    SHOW_SYS},
   {sys_myisam_sort_buffer_size.name, (char*) &sys_myisam_sort_buffer_size, SHOW_SYS},
+  
+  {sys_myisam_stats_method.name, (char*) &sys_myisam_stats_method, SHOW_SYS},
+  
 #ifdef __NT__
   {"named_pipe",	      (char*) &opt_enable_named_pipe,       SHOW_MY_BOOL},
 #endif