struct TABLE

struct TABLE
{
  TABLE() {}                               /* Remove gcc warning */

  TABLE_SHARE    *s;
  handler    *file;
  TABLE *next, *prev;

private:
  /**
     Links for the lists of used/unused TABLE objects for this share.
     Declared as private to avoid direct manipulation with those objects.
     One should use methods of I_P_List template instead.
  */
  TABLE *share_next, **share_prev;

  friend struct TABLE_share;

public:

  THD    *in_use;                        /* Which thread uses this */
  Field **field;            /* Pointer to fields */

  uchar *record[];            /* Pointer to records */
  uchar *write_row_record;        /* Used as optimisation in
                       THD::write_row */
  uchar *insert_values;                  /* used by INSERT ... UPDATE */
  /*
    Map of keys that can be used to retrieve all data from this table
    needed by the query without reading the row.
  */
  key_map covering_keys;
  key_map quick_keys, merge_keys;
  /*
    A set of keys that can be used in the query that references this
    table.

    All indexes disabled on the table's TABLE_SHARE (see TABLE::s) will be
    subtracted from this set upon instantiation. Thus for any TABLE t it holds
    that t.keys_in_use_for_query is a subset of t.s.keys_in_use. Generally we
    must not introduce any new keys here (see setup_tables).

    The set is implemented as a bitmap.
  */
  key_map keys_in_use_for_query;
  /* Map of keys that can be used to calculate GROUP BY without sorting */
  key_map keys_in_use_for_group_by;
  /* Map of keys that can be used to calculate ORDER BY without sorting */
  key_map keys_in_use_for_order_by;
  KEY  *key_info;            /* data of keys in database */

  Field *next_number_field;        /* Set if next_number is activated */
  Field *found_next_number_field;    /* Set on open */
  Field_timestamp *timestamp_field;

  /* Table's triggers, 0 if there are no of them */
  Table_triggers_list *triggers;
  TABLE_LIST *pos_in_table_list;/* Element referring to this table */
  /* Position in thd->locked_table_list under LOCK TABLES */
  TABLE_LIST *pos_in_locked_tables;
  ORDER        *group;
  const char    *alias;                  /* alias or table name */
  uchar        *null_flags;
  my_bitmap_map    *bitmap_init_value;
  MY_BITMAP     def_read_set, def_write_set, tmp_set; /* containers */
  MY_BITMAP     *read_set, *write_set;          /* Active column sets */
  /*
   The ID of the query that opened and is using this table. Has different
   meanings depending on the table type.

   Temporary tables:

   table->query_id is set to thd->query_id for the duration of a statement
   and is reset to 0 once it is closed by the same statement. A non-zero
   table->query_id means that a statement is using the table even if it's
   not the current statement (table is in use by some outer statement).

   Non-temporary tables:

   Under pre-locked or LOCK TABLES mode: query_id is set to thd->query_id
   for the duration of a statement and is reset to 0 once it is closed by
   the same statement. A non-zero query_id is used to control which tables
   in the list of pre-opened and locked tables are actually being used.
  */
  query_id_t    query_id;

  /*
    For each key that has quick_keys.is_set(key) == TRUE: estimate of #records
    and max #key parts that range access would use.
  */
  ha_rows    quick_rows[MAX_KEY];

  /* Bitmaps of key parts that =const for the entire join. */
  key_part_map  const_key_parts[MAX_KEY];

  uint        quick_key_parts[MAX_KEY];
  uint        quick_n_ranges[MAX_KEY];

  /*
    Estimate of number of records that satisfy SARGable part of the table
    condition, or table->file->records if no SARGable condition could be
    constructed.
    This value is used by join optimizer as an estimate of number of records
    that will pass the table condition (condition that depends on fields of
    this table and constants)
  */
  ha_rows       quick_condition_rows;

  /*
    If this table has TIMESTAMP field with auto-set property (pointed by
    timestamp_field member) then this variable indicates during which
    operations (insert only/on update/in both cases) we should set this
    field to current timestamp. If there are no such field in this table
    or we should not automatically set its value during execution of current
    statement then the variable contains TIMESTAMP_NO_AUTO_SET (i.e. 0).

    Value of this variable is set for each statement in open_table() and
    if needed cleared later in statement processing code (see mysql_update()
    as example).
  */
  timestamp_auto_set_type timestamp_field_type;
  table_map    map;                    /* ID bit of table (1,2,4,8,16...) */

  uint          lock_position;          /* Position in MYSQL_LOCK.table */
  uint          lock_data_start;        /* Start pos. in MYSQL_LOCK.locks */
  uint          lock_count;             /* Number of locks */
  uint        tablenr,used_fields;
  uint          temp_pool_slot;        /* Used by intern temp tables */
  uint        status;                 /* What's in record[0] */
  uint        db_stat;        /* mode of file as in handler.h */
  /* number of select if it is derived table */
  uint          derived_select_number;
  int        current_lock;           /* Type of lock on table */
  my_bool copy_blobs;            /* copy_blobs when storing */

  /*
    0 or JOIN_TYPE_{LEFT|RIGHT}. Currently this is only compared to 0.
    If maybe_null !=0, this table is inner w.r.t. some outer join operation,
    and null_row may be true.
  */
  uint maybe_null;
  /*
    If true, the current table row is considered to have all columns set to
    NULL, including columns declared as "not null" (see maybe_null).
  */
  my_bool null_row;

  /*
    TODO: Each of the following flags take up 8 bits. They can just as easily
    be put into one single unsigned long and instead of taking up 18
    bytes, it would take up 4.
  */
  my_bool force_index;

  /**
    Flag set when the statement contains FORCE INDEX FOR ORDER BY
    See TABLE_LIST::process_index_hints().
  */
  my_bool force_index_order;

  /**
    Flag set when the statement contains FORCE INDEX FOR GROUP BY
    See TABLE_LIST::process_index_hints().
  */
  my_bool force_index_group;
  my_bool distinct,const_table,no_rows;

  /**
     If set, the optimizer has found that row retrieval should access index
     tree only.
   */
  my_bool key_read;
  my_bool no_keyread;
  my_bool locked_by_logger;
  my_bool no_replicate;
  my_bool locked_by_name;
  my_bool fulltext_searched;
  my_bool no_cache;
  /* To signal that the table is associated with a HANDLER statement */
  my_bool open_by_handler;
  /*
    To indicate that a non-null value of the auto_increment field
    was provided by the user or retrieved from the current record.
    Used only in the MODE_NO_AUTO_VALUE_ON_ZERO mode.
  */
  my_bool auto_increment_field_not_null;
  my_bool insert_or_update;             /* Can be used by the handler */
  my_bool alias_name_used;        /* true if table_name is alias */
  my_bool get_fields_in_item_tree;      /* Signal to fix_field */
  my_bool m_needs_reopen;

  REGINFO reginfo;            /* field connections */
  MEM_ROOT mem_root;
  GRANT_INFO grant;
  FILESORT_INFO sort;
#ifdef WITH_PARTITION_STORAGE_ENGINE
  partition_info *part_info;            /* Partition related information */
  bool no_partitions_used; /* If true, all partitions have been pruned away */
#endif
  MDL_ticket *mdl_ticket;

  void init(THD *thd, TABLE_LIST *tl);
  bool fill_item_list(List<Item> *item_list) const;
  void reset_item_list(List<Item> *item_list) const;
  void clear_column_bitmaps(void);
  void prepare_for_position(void);
  void mark_columns_used_by_index_no_reset(uint index, MY_BITMAP *map);
  void mark_columns_used_by_index(uint index);
  void add_read_columns_used_by_index(uint index);
  void restore_column_maps_after_mark_index();
  void mark_auto_increment_column(void);
  void mark_columns_needed_for_update(void);
  void mark_columns_needed_for_delete(void);
  void mark_columns_needed_for_insert(void);
  inline void column_bitmaps_set(MY_BITMAP *read_set_arg,
                                 MY_BITMAP *write_set_arg)
  {
    read_set= read_set_arg;
    write_set= write_set_arg;
    if (file)
      file->column_bitmaps_signal();
  }
  inline void column_bitmaps_set_no_signal(MY_BITMAP *read_set_arg,
                                           MY_BITMAP *write_set_arg)
  {
    read_set= read_set_arg;
    write_set= write_set_arg;
  }
  inline void use_all_columns()
  {
    column_bitmaps_set(&s->all_set, &s->all_set);
  }
  inline void default_column_bitmaps()
  {
    read_set= &def_read_set;
    write_set= &def_write_set;
  }
  /** Should this instance of the table be reopened? */
  inline bool needs_reopen()
  { return !db_stat || m_needs_reopen; }

  inline void set_keyread(bool flag)
  {
    DBUG_ASSERT(file);
    if (flag && !key_read)
    {
      key_read= ;
      file->extra(HA_EXTRA_KEYREAD);
    }
    else if (!flag && key_read)
    {
      key_read= ;
      file->extra(HA_EXTRA_NO_KEYREAD);
    }
  }

  bool update_const_key_parts(COND *conds);
};