ha_heap.h

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/*
   Copyright (c) 2000, 2025, Oracle and/or its affiliates.
 
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.
 
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   but not limited to OpenSSL) that is licensed under separate terms,
   as designated in a particular file or component or in included license
   documentation.  The authors of MySQL hereby grant you an additional
   permission to link the program and your derivative works with the
   separately licensed software that they have either included with
   the program or referenced in the documentation.
 
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License, version 2.0, for more details.
 
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */
 
/* class for the the heap handler */
 
#include <sys/types.h>
 
#include "heap.h"
#include "my_inttypes.h"
#include "sql/handler.h"
#include "sql/table.h"
 
class ha_heap : public handler {
  HP_INFO *file{nullptr};
  HP_SHARE *internal_share{nullptr};
  /* number of records changed since last statistics update */
  uint records_changed{0};
  uint key_stat_version{0};
  /// True if only one ha_heap is to exist for the table.
  bool single_instance{false};
 
 public:
  ha_heap(handlerton *hton, TABLE_SHARE *table);
  ~ha_heap() override = default;
  handler *clone(const char *name, MEM_ROOT *mem_root) override;
  const char *table_type() const override;
  enum ha_key_alg get_default_index_algorithm() const override {
    return HA_KEY_ALG_HASH;
  }
  bool is_index_algorithm_supported(enum ha_key_alg key_alg) const override {
    return key_alg == HA_KEY_ALG_BTREE || key_alg == HA_KEY_ALG_HASH;
  }
  /* Rows also use a fixed-size format */
  enum row_type get_real_row_type(const HA_CREATE_INFO *) const override {
    return ROW_TYPE_FIXED;
  }
  ulonglong table_flags() const override {
    return (HA_FAST_KEY_READ | HA_NO_BLOBS | HA_NULL_IN_KEY |
            HA_BINLOG_ROW_CAPABLE | HA_BINLOG_STMT_CAPABLE |
            HA_NO_TRANSACTIONS | HA_COUNT_ROWS_INSTANT |
            HA_STATS_RECORDS_IS_EXACT);
  }
  ulong index_flags(uint inx, uint, bool) const override {
    return ((table_share->key_info[inx].algorithm == HA_KEY_ALG_BTREE)
                ? HA_READ_NEXT | HA_READ_PREV | HA_READ_ORDER | HA_READ_RANGE
                : HA_ONLY_WHOLE_INDEX | HA_KEY_SCAN_NOT_ROR);
  }
  uint max_supported_keys() const override { return MAX_KEY; }
  uint max_supported_key_part_length(HA_CREATE_INFO *create_info
                                     [[maybe_unused]]) const override {
    return MAX_KEY_LENGTH;
  }
  double scan_time() override {
    return (double)(stats.records + stats.deleted) / 20.0 + 10;
  }
  double read_time(uint, uint, ha_rows rows) override {
    return (double)rows / 20.0 + 1;
  }
 
  int open(const char *name, int mode, uint test_if_locked,
           const dd::Table *table_def) override;
  int close(void) override;
  void set_keys_for_scanning(void);
  int write_row(uchar *buf) override;
  int update_row(const uchar *old_data, uchar *new_data) override;
  int delete_row(const uchar *buf) override;
  void get_auto_increment(ulonglong offset, ulonglong increment,
                          ulonglong nb_desired_values, ulonglong *first_value,
                          ulonglong *nb_reserved_values) override;
  int index_read_map(uchar *buf, const uchar *key, key_part_map keypart_map,
                     enum ha_rkey_function find_flag) override;
  int index_read_last_map(uchar *buf, const uchar *key,
                          key_part_map keypart_map) override;
  int index_read_idx_map(uchar *buf, uint index, const uchar *key,
                         key_part_map keypart_map,
                         enum ha_rkey_function find_flag) override;
  int index_next(uchar *buf) override;
  int index_prev(uchar *buf) override;
  int index_first(uchar *buf) override;
  int index_last(uchar *buf) override;
  int rnd_init(bool scan) override;
  int rnd_next(uchar *buf) override;
  int rnd_pos(uchar *buf, uchar *pos) override;
  void position(const uchar *record) override;
  int info(uint) override;
  int extra(enum ha_extra_function operation) override;
  int reset() override;
  int external_lock(THD *thd, int lock_type) override;
  int delete_all_rows(void) override;
  int disable_indexes(uint mode) override;
  int enable_indexes(uint mode) override;
  int indexes_are_disabled(void) override;
  ha_rows records_in_range(uint inx, key_range *min_key,
                           key_range *max_key) override;
  int delete_table(const char *from, const dd::Table *table_def) override;
  void drop_table(const char *name) override;
  int rename_table(const char *from, const char *to,
                   const dd::Table *from_table_def,
                   dd::Table *to_table_def) override;
  int create(const char *name, TABLE *form, HA_CREATE_INFO *create_info,
             dd::Table *table_def) override;
  void update_create_info(HA_CREATE_INFO *create_info) override;
 
  THR_LOCK_DATA **store_lock(THD *thd, THR_LOCK_DATA **to,
                             enum thr_lock_type lock_type) override;
  int cmp_ref(const uchar *ref1, const uchar *ref2) const override {
    return memcmp(ref1, ref2, sizeof(HEAP_PTR));
  }
  bool check_if_incompatible_data(HA_CREATE_INFO *info,
                                  uint table_changes) override;
 
 private:
  void update_key_stats();
};