1. sys_variables[] array is removed.

2. All have_xxx variables are now selectable.


sql/set_var.cc:
  1. sys_have_xxx variables added.
  2. Removed sys_var *sys_variables[] array as we don't need it any more.
  3. void set_var_init() changed to use sys_var_xxx chain insted of sys_variables[] array.
sql/set_var.h:
  1. add_sys_var() method added to the sys_var class. It's called from constructors
  to chain all successor objects. The first one is stored in the 'static sys_var *first'.
  The total number of variables is in the 'static uint sys_vars'. Each sys_var successor object
  has the 'sys_var *next' pointer to the next one in the chain. 
  2. sys_var_have_variable class introduced to make all have_xxx variables selectable.
sql/sql_lex.cc:
  trg_new_row_fake_var(0, 0) replaced with '(sys_var*) 0x01' as we don't want to have such fake variables in the sys_var_xxx chain.
sql/sql_lex.h:
  Proper use of the changed trg_new_row_fake_var.
sql/sql_yacc.yy:
  Proper use of the changed trg_new_row_fake_var.

sql/set_var.cc

@@ -120,7 +120,6 @@ static KEY_CACHE *create_key_cache(const char *name, uint length);
 void fix_sql_mode_var(THD *thd, enum_var_type type);
 static byte *get_error_count(THD *thd);
 static byte *get_warning_count(THD *thd);
-static byte *get_have_innodb(THD *thd);
 
 /*
   Variable definition list
@@ -129,6 +128,9 @@ static byte *get_have_innodb(THD *thd);
   alphabetic order
 */
 
+sys_var *sys_var::first= NULL;
+uint sys_var::sys_vars= 0;
+
 sys_var_thd_ulong	sys_auto_increment_increment("auto_increment_increment",
                                                      &SV::auto_increment_increment);
 sys_var_thd_ulong	sys_auto_increment_offset("auto_increment_offset",
@@ -552,203 +554,33 @@ sys_var_thd_time_zone            sys_time_zone("time_zone");
 /* Read only variables */
 
 sys_var_const_str		sys_os("version_compile_os", SYSTEM_TYPE);
-sys_var_readonly                sys_have_innodb("have_innodb", OPT_GLOBAL,
-                                                SHOW_CHAR, get_have_innodb);
-/* Global read-only variable describing server license */
-sys_var_const_str		sys_license("license", STRINGIFY_ARG(LICENSE));
-
 
-/*
-  List of all variables for initialisation and storage in hash
-  This is sorted in alphabetical order to make it easy to add new variables
-
-  If the variable is not in this list, it can't be changed with
-  SET variable_name=
-*/
+sys_var_have_variable sys_have_archive_db("have_archive", &have_archive_db);
+sys_var_have_variable sys_have_berkeley_db("have_bdb", &have_berkeley_db);
+sys_var_have_variable sys_have_blackhole_db("have_blackhole_engine",
+                                            &have_blackhole_db);
+sys_var_have_variable sys_have_compress("have_compress", &have_compress);
+sys_var_have_variable sys_have_crypt("have_crypt", &have_crypt);
+sys_var_have_variable sys_have_csv_db("have_csv", &have_csv_db);
+sys_var_have_variable sys_have_example_db("have_example_engine",
+                                          &have_example_db);
+sys_var_have_variable sys_have_federated_db("have_federated_engine",
+                                            &have_federated_db);
+sys_var_have_variable sys_have_geometry("have_geometry", &have_geometry);
+sys_var_have_variable sys_have_innodb("have_innodb", &have_innodb);
+sys_var_have_variable sys_have_isam("have_isam", &have_isam);
+sys_var_have_variable sys_have_ndbcluster("have_ndbcluster", &have_ndbcluster);
+sys_var_have_variable sys_have_openssl("have_openssl", &have_openssl);
+sys_var_have_variable sys_have_partition_db("have_partition_engine",
+                                            &have_partition_db);
+sys_var_have_variable sys_have_query_cache("have_query_cache",
+                                           &have_query_cache);
+sys_var_have_variable sys_have_raid("have_raid", &have_raid);
+sys_var_have_variable sys_have_rtree_keys("have_rtree_keys", &have_rtree_keys);
+sys_var_have_variable sys_have_symlink("have_symlink", &have_symlink);
 
-sys_var *sys_variables[]=
-{
-  &sys_auto_is_null,
-  &sys_auto_increment_increment,
-  &sys_auto_increment_offset,
-  &sys_autocommit,
-  &sys_automatic_sp_privileges,
-  &sys_big_tables,
-  &sys_big_selects,
-  &sys_binlog_cache_size,
-  &sys_buffer_results,
-  &sys_bulk_insert_buff_size,
-  &sys_character_set_server,
-  &sys_character_set_database,
-  &sys_character_set_client,
-  &sys_character_set_connection,
-  &sys_character_set_results,
-  &sys_charset_system,
-  &sys_collation_connection,
-  &sys_collation_database,
-  &sys_collation_server,
-  &sys_completion_type,
-  &sys_concurrent_insert,
-  &sys_connect_timeout,
-  &sys_date_format,
-  &sys_datetime_format,
-  &sys_div_precincrement,
-  &sys_default_week_format,
-  &sys_delay_key_write,
-  &sys_delayed_insert_limit,
-  &sys_delayed_insert_timeout,
-  &sys_delayed_queue_size,
-  &sys_error_count,
-  &sys_expire_logs_days,
-  &sys_flush,
-  &sys_flush_time,
-  &sys_ft_boolean_syntax,
-  &sys_foreign_key_checks,
-  &sys_group_concat_max_len,
-  &sys_have_innodb,
-  &sys_identity,
-  &sys_init_connect,
-  &sys_init_slave,
-  &sys_insert_id,
-  &sys_interactive_timeout,
-  &sys_join_buffer_size,
-  &sys_key_buffer_size,
-  &sys_key_cache_block_size,
-  &sys_key_cache_division_limit,
-  &sys_key_cache_age_threshold,
-  &sys_last_insert_id,
-  &sys_license,
-  &sys_local_infile,
-  &sys_log_binlog,
-  &sys_log_off,
-  &sys_log_update,
-  &sys_log_warnings,
-  &sys_long_query_time,
-  &sys_low_priority_updates,
-  &sys_max_allowed_packet,
-  &sys_max_binlog_cache_size,
-  &sys_max_binlog_size,
-  &sys_max_connect_errors,
-  &sys_max_connections,
-  &sys_max_delayed_threads,
-  &sys_max_error_count,
-  &sys_max_insert_delayed_threads,
-  &sys_max_heap_table_size,
-  &sys_max_join_size,
-  &sys_max_length_for_sort_data,
-  &sys_max_relay_log_size,
-  &sys_max_seeks_for_key,
-  &sys_max_sort_length,
-  &sys_max_tmp_tables,
-  &sys_max_user_connections,
-  &sys_max_write_lock_count,
-  &sys_multi_range_count,
-  &sys_myisam_data_pointer_size,
-  &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,
-  &sys_net_wait_timeout,
-  &sys_net_write_timeout,
-  &sys_new_mode,
-  &sys_old_alter_table,
-  &sys_old_passwords,
-  &sys_optimizer_prune_level,
-  &sys_optimizer_search_depth,
-  &sys_preload_buff_size,
-  &sys_pseudo_thread_id,
-  &sys_query_alloc_block_size,
-  &sys_query_cache_size,
-  &sys_query_prealloc_size,
-#ifdef HAVE_QUERY_CACHE
-  &sys_query_cache_limit,
-  &sys_query_cache_min_res_unit,
-  &sys_query_cache_type,
-  &sys_query_cache_wlock_invalidate,
-#endif /* HAVE_QUERY_CACHE */
-  &sys_quote_show_create,
-  &sys_rand_seed1,
-  &sys_rand_seed2,
-  &sys_range_alloc_block_size,
-  &sys_readonly,
-  &sys_read_buff_size,
-  &sys_read_rnd_buff_size,
-#ifdef HAVE_REPLICATION
-  &sys_relay_log_purge,
-#endif
-  &sys_rpl_recovery_rank,
-  &sys_safe_updates,
-  &sys_secure_auth,
-  &sys_select_limit,
-  &sys_server_id,
-#ifdef HAVE_REPLICATION
-  &sys_slave_compressed_protocol,
-  &sys_slave_net_timeout,
-  &sys_slave_trans_retries,
-  &sys_slave_skip_counter,
-#endif
-  &sys_slow_launch_time,
-  &sys_sort_buffer,
-  &sys_sql_big_tables,
-  &sys_sql_low_priority_updates,
-  &sys_sql_max_join_size,
-  &sys_sql_mode,
-  &sys_sql_warnings,
-  &sys_sql_notes,
-  &sys_storage_engine,
-#ifdef HAVE_REPLICATION
-  &sys_sync_binlog_period,
-  &sys_sync_replication,
-  &sys_sync_replication_slave_id,
-  &sys_sync_replication_timeout,
-#endif
-  &sys_sync_frm,
-  &sys_table_cache_size,
-  &sys_table_lock_wait_timeout,
-  &sys_table_type,
-  &sys_thread_cache_size,
-  &sys_time_format,
-  &sys_timed_mutexes,
-  &sys_timestamp,
-  &sys_time_zone,
-  &sys_tmp_table_size,
-  &sys_trans_alloc_block_size,
-  &sys_trans_prealloc_size,
-  &sys_tx_isolation,
-  &sys_os,
-#ifdef HAVE_INNOBASE_DB
-  &sys_innodb_fast_shutdown,
-  &sys_innodb_max_dirty_pages_pct,
-  &sys_innodb_max_purge_lag,
-  &sys_innodb_table_locks,
-  &sys_innodb_support_xa,
-  &sys_innodb_max_purge_lag,
-  &sys_innodb_autoextend_increment,
-  &sys_innodb_sync_spin_loops,
-  &sys_innodb_concurrency_tickets,
-  &sys_innodb_thread_sleep_delay,
-  &sys_innodb_thread_concurrency,
-  &sys_innodb_commit_concurrency,
-#endif  
-  &sys_trust_routine_creators,
-  &sys_engine_condition_pushdown,
-#ifdef HAVE_NDBCLUSTER_DB
-  &sys_ndb_autoincrement_prefetch_sz,
-  &sys_ndb_cache_check_time,
-  &sys_ndb_force_send,
-  &sys_ndb_use_exact_count,
-  &sys_ndb_use_transactions,
-  &sys_ndb_index_stat_enable,
-  &sys_ndb_index_stat_cache_entries,
-  &sys_ndb_index_stat_update_freq,
-#endif
-  &sys_unique_checks,
-  &sys_updatable_views_with_limit,
-  &sys_warning_count
-};
+/* Global read-only variable describing server license */
+sys_var_const_str		sys_license("license", STRINGIFY_ARG(LICENSE));
 
 
 /*
@@ -805,24 +637,24 @@ struct show_var_st init_vars[]= {
   {"ft_query_expansion_limit",(char*) &ft_query_expansion_limit,    SHOW_LONG},
   {"ft_stopword_file",        (char*) &ft_stopword_file,            SHOW_CHAR_PTR},
   {sys_group_concat_max_len.name, (char*) &sys_group_concat_max_len,  SHOW_SYS},
-  {"have_archive",	      (char*) &have_archive_db,	            SHOW_HAVE},
-  {"have_bdb",		      (char*) &have_berkeley_db,	    SHOW_HAVE},
-  {"have_blackhole_engine",   (char*) &have_blackhole_db,	    SHOW_HAVE},
-  {"have_compress",	      (char*) &have_compress,		    SHOW_HAVE},
-  {"have_crypt",	      (char*) &have_crypt,		    SHOW_HAVE},
-  {"have_csv",	              (char*) &have_csv_db,	            SHOW_HAVE},
-  {"have_example_engine",     (char*) &have_example_db,	            SHOW_HAVE},
-  {"have_federated_engine",   (char*) &have_federated_db,           SHOW_HAVE},
-  {"have_geometry",           (char*) &have_geometry,               SHOW_HAVE},
-  {"have_innodb",	      (char*) &have_innodb,		    SHOW_HAVE},
-  {"have_isam",		      (char*) &have_isam,		    SHOW_HAVE},
-  {"have_ndbcluster",         (char*) &have_ndbcluster,             SHOW_HAVE},
-  {"have_openssl",	      (char*) &have_openssl,		    SHOW_HAVE},
-  {"have_partition_engine",   (char*) &have_partition_db,	    SHOW_HAVE},
-  {"have_query_cache",        (char*) &have_query_cache,            SHOW_HAVE},
-  {"have_raid",		      (char*) &have_raid,		    SHOW_HAVE},
-  {"have_rtree_keys",         (char*) &have_rtree_keys,             SHOW_HAVE},
-  {"have_symlink",            (char*) &have_symlink,                SHOW_HAVE},
+  {sys_have_archive_db.name,  (char*) &have_archive_db,             SHOW_HAVE},
+  {sys_have_berkeley_db.name, (char*) &have_berkeley_db,            SHOW_HAVE},
+  {sys_have_blackhole_db.name,(char*) &have_blackhole_db,           SHOW_HAVE},
+  {sys_have_compress.name,    (char*) &have_compress,               SHOW_HAVE},
+  {sys_have_crypt.name,       (char*) &have_crypt,                  SHOW_HAVE},
+  {sys_have_csv_db.name,      (char*) &have_csv_db,                 SHOW_HAVE},
+  {sys_have_example_db.name,  (char*) &have_example_db,             SHOW_HAVE},
+  {sys_have_federated_db.name,(char*) &have_federated_db,           SHOW_HAVE},
+  {sys_have_geometry.name,    (char*) &have_geometry,               SHOW_HAVE},
+  {sys_have_innodb.name,      (char*) &have_innodb,                 SHOW_HAVE},
+  {sys_have_isam.name,        (char*) &have_isam,                   SHOW_HAVE},
+  {sys_have_ndbcluster.name,  (char*) &have_ndbcluster,             SHOW_HAVE},
+  {sys_have_openssl.name,     (char*) &have_openssl,                SHOW_HAVE},
+  {sys_have_partition_db.name,(char*) &have_partition_db,           SHOW_HAVE},
+  {sys_have_query_cache.name, (char*) &have_query_cache,            SHOW_HAVE},
+  {sys_have_raid.name,        (char*) &have_raid,                   SHOW_HAVE},
+  {sys_have_rtree_keys.name,  (char*) &have_rtree_keys,             SHOW_HAVE},
+  {sys_have_symlink.name,     (char*) &have_symlink,                SHOW_HAVE},
   {"init_connect",            (char*) &sys_init_connect,            SHOW_SYS},
   {"init_file",               (char*) &opt_init_file,               SHOW_CHAR_PTR},
   {"init_slave",              (char*) &sys_init_slave,              SHOW_SYS},
@@ -2794,12 +2626,6 @@ static byte *get_error_count(THD *thd)
 }
 
 
-static byte *get_have_innodb(THD *thd)
-{
-  return (byte*) show_comp_option_name[have_innodb];
-}
-
-
 /****************************************************************************
   Main handling of variables:
   - Initialisation
@@ -2858,17 +2684,15 @@ static byte *get_sys_var_length(const sys_var *var, uint *length,
 
 void set_var_init()
 {
-  hash_init(&system_variable_hash, system_charset_info,
-	    array_elements(sys_variables),0,0,
-	    (hash_get_key) get_sys_var_length,0,0);
-  sys_var **var, **end;
-  for (var= sys_variables, end= sys_variables+array_elements(sys_variables) ;
-       var < end;
-       var++)
-  {
-    (*var)->name_length= strlen((*var)->name);
-    (*var)->option_limits= find_option(my_long_options, (*var)->name);
-    my_hash_insert(&system_variable_hash, (byte*) *var);
+  sys_var *var;
+
+  hash_init(&system_variable_hash, system_charset_info, sys_var::sys_vars, 0,
+	    0, (hash_get_key) get_sys_var_length, 0, 0);
+  for (var= sys_var::first; var; var= var->next)
+  {
+    var->name_length= strlen(var->name);
+    var->option_limits= find_option(my_long_options, var->name);
+    my_hash_insert(&system_variable_hash, (byte*) var);
   }
   /*
     Special cases

sql/set_var.h

@@ -39,6 +39,9 @@ typedef byte *(*sys_value_ptr_func)(THD *thd);
 class sys_var
 {
 public:
+  static sys_var *first;
+  static uint sys_vars;
+  sys_var *next;
   struct my_option *option_limits;	/* Updated by by set_var_init() */
   uint name_length;			/* Updated by by set_var_init() */
   const char *name;
@@ -48,12 +51,18 @@ class sys_var
   sys_var(const char *name_arg)
     :name(name_arg), after_update(0)
     , no_support_one_shot(1)
-    {}
+  { add_sys_var(); }
   sys_var(const char *name_arg,sys_after_update_func func)
     :name(name_arg), after_update(func)
     , no_support_one_shot(1)
-  {}
+  { add_sys_var(); }
   virtual ~sys_var() {}
+  void add_sys_var()
+  {
+    next= first;
+    first= this;
+    sys_vars++;
+  }
   virtual bool check(THD *thd, set_var *var);
   bool check_enum(THD *thd, set_var *var, TYPELIB *enum_names);
   bool check_set(THD *thd, set_var *var, TYPELIB *enum_names);
@@ -701,6 +710,30 @@ class sys_var_readonly: public sys_var
   bool is_readonly() const { return 1; }
 };
 
+
+class sys_var_have_variable: public sys_var
+{
+  SHOW_COMP_OPTION *have_variable;
+
+public:
+  sys_var_have_variable(const char *variable_name,
+                        SHOW_COMP_OPTION *have_variable_arg):
+    sys_var(variable_name),
+    have_variable(have_variable_arg)
+  { }
+  byte *value_ptr(THD *thd, enum_var_type type, LEX_STRING *base)
+  {
+    return (byte*) show_comp_option_name[*have_variable];
+  }
+  bool update(THD *thd, set_var *var) { return 1; }
+  bool check_default(enum_var_type type) { return 1; }
+  bool check_type(enum_var_type type) { return type != OPT_GLOBAL; }
+  bool check_update_type(Item_result type) { return 1; }
+  SHOW_TYPE type() { return SHOW_CHAR; }
+  bool is_readonly() const { return 1; }
+};
+
+
 class sys_var_thd_time_zone :public sys_var_thd
 {
 public:

sql/sql_lex.cc

@@ -28,7 +28,8 @@
   We are using pointer to this variable for distinguishing between assignment
   to NEW row field (when parsing trigger definition) and structured variable.
 */
-sys_var_long_ptr trg_new_row_fake_var(0, 0);
+
+sys_var *trg_new_row_fake_var= (sys_var*) 0x01;
 
 /* Macros to look like lex */
 

sql/sql_lex.h

@@ -702,7 +702,7 @@ struct st_trg_chistics
   enum trg_event_type event;
 };
 
-extern sys_var_long_ptr trg_new_row_fake_var;
+extern sys_var *trg_new_row_fake_var;
 
 enum xa_option_words {XA_NONE, XA_JOIN, XA_RESUME, XA_ONE_PHASE,
                       XA_SUSPEND, XA_FOR_MIGRATE};

sql/sql_yacc.yy

@@ -8529,7 +8529,7 @@ sys_option_value:
         {
           LEX *lex=Lex;
 
-          if ($2.var == &trg_new_row_fake_var)
+          if ($2.var == trg_new_row_fake_var)
           {
             /* We are in trigger and assigning value to field of new row */
             Item *it;
@@ -8750,7 +8750,7 @@ internal_variable_name:
                 YYABORT;
               }
               /* This special combination will denote field of NEW row */
-              $$.var= &trg_new_row_fake_var;
+              $$.var= trg_new_row_fake_var;
               $$.base_name= $3;
             }
             else