pfs_engine_table.h

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/* Copyright (c) 2008, 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 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
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  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */
 
#ifndef PFS_ENGINE_TABLE_H
#define PFS_ENGINE_TABLE_H
 
#include <assert.h>
#include <mysql/components/services/pfs_plugin_table_service.h>
#include <stddef.h>
#include <sys/types.h>
#include <atomic>
#include <vector>
 
#include "my_base.h"
#include "my_compiler.h"
 
#include "my_inttypes.h"
#include "mysql/components/services/bits/mysql_mutex_bits.h"
#include "mysql/psi/mysql_mutex.h"
#include "sql/auth/auth_common.h" /* struct ACL_* */
#include "sql/key.h"
#include "storage/perfschema/pfs.h"
 
class PFS_engine_index_abstract;
class Plugin_table;
struct TABLE;
struct THR_LOCK;
template <class T>
class List;
 
/**
  @file storage/perfschema/pfs_engine_table.h
  Performance schema tables (declarations).
*/
 
class Field;
struct PFS_engine_table_share;
struct time_normalizer;
 
/**
  @addtogroup performance_schema_engine
  @{
*/
 
/**
  An abstract PERFORMANCE_SCHEMA table.
  Every table implemented in the performance schema schema and storage engine
  derives from this class.
*/
class PFS_engine_table {
 public:
  static PFS_engine_table_share *find_engine_table_share(const char *name);
 
  int read_row(TABLE *table, unsigned char *buf, Field **fields);
 
  int update_row(TABLE *table, const unsigned char *old_buf,
                 unsigned char *new_buf, Field **fields);
 
  /**
    Delete a row from this table.
    @param table Table handle
    @param buf the row buffer to delete
    @param fields Table fields
    @return 0 on success
  */
  int delete_row(TABLE *table, const unsigned char *buf, Field **fields);
 
  /** Initialize table scan. */
  virtual int rnd_init(bool scan [[maybe_unused]]) { return 0; }
 
  /** Fetch the next row in this cursor. */
  virtual int rnd_next() = 0;
 
  virtual int index_init(uint idx [[maybe_unused]],
                         bool sorted [[maybe_unused]]) {
    assert(false);
    return HA_ERR_UNSUPPORTED;
  }
 
  virtual int index_read(KEY *key_infos, uint index, const uchar *key,
                         uint key_len, enum ha_rkey_function find_flag);
 
  virtual int index_read_last(KEY *key_infos [[maybe_unused]],
                              const uchar *key [[maybe_unused]],
                              uint key_len [[maybe_unused]]) {
    return HA_ERR_UNSUPPORTED;
  }
 
  /** Find key in index, read record. */
  virtual int index_next() { return HA_ERR_UNSUPPORTED; }
 
  virtual int index_next_same(const uchar *key, uint key_len);
  virtual int index_prev() { return HA_ERR_UNSUPPORTED; }
 
  virtual int index_first() { return HA_ERR_UNSUPPORTED; }
 
  virtual int index_last() { return HA_ERR_UNSUPPORTED; }
 
  /**
    Fetch a row by position.
    @param pos              position to fetch
  */
  virtual int rnd_pos(const void *pos) = 0;
 
  void get_position(void *ref);
  void set_position(const void *ref);
  /** Reset the cursor position to the beginning of the table. */
  virtual void reset_position() = 0;
 
  /** Destructor. */
  virtual ~PFS_engine_table() = default;
 
 protected:
  /**
    Read the current row values.
    @param table            Table handle
    @param buf              row buffer
    @param fields           Table fields
    @param read_all         true if all columns are read.
  */
  virtual int read_row_values(TABLE *table, unsigned char *buf, Field **fields,
                              bool read_all) = 0;
 
  /**
    Update the current row values.
    @param table            Table handle
    @param old_buf          old row buffer
    @param new_buf          new row buffer
    @param fields           Table fields
  */
  virtual int update_row_values(TABLE *table, const unsigned char *old_buf,
                                unsigned char *new_buf, Field **fields);
 
  /**
    Delete a row.
    @param table            Table handle
    @param buf              Row buffer
    @param fields           Table fields
  */
  virtual int delete_row_values(TABLE *table, const unsigned char *buf,
                                Field **fields);
  /**
    Constructor.
    @param share            table share
    @param pos              address of the m_pos position member
  */
  PFS_engine_table(const PFS_engine_table_share *share, void *pos)
      : m_share_ptr(share),
        m_pos_ptr(pos),
        m_normalizer(nullptr),
        m_index(nullptr) {}
 
  /** Table share. */
  const PFS_engine_table_share *m_share_ptr;
  /** Opaque pointer to the @c m_pos position of this cursor. */
  void *m_pos_ptr;
  /** Current normalizer */
  time_normalizer *m_normalizer;
  /** Current index. */
  PFS_engine_index_abstract *m_index;
};
 
/** Callback to open a table. */
typedef PFS_engine_table *(*pfs_open_table_t)(PFS_engine_table_share *);
/** Callback to write a row. */
typedef int (*pfs_write_row_t)(PFS_engine_table *pfs_table, TABLE *table,
                               unsigned char *buf, Field **fields);
/** Callback to delete all rows. */
typedef int (*pfs_delete_all_rows_t)();
/** Callback to get a row count. */
typedef ha_rows (*pfs_get_row_count_t)();
 
/**
  PFS_key_reader: Convert key into internal format.
*/
struct PFS_key_reader {
  PFS_key_reader(const KEY *key_info, const uchar *key, uint key_len)
      : m_key_info(key_info),
        m_key_part_info(key_info->key_part),
        m_key(key),
        m_key_len(key_len),
        m_remaining_key_part_info(key_info->key_part),
        m_remaining_key(key),
        m_remaining_key_len(key_len),
        m_parts_found(0) {}
 
  enum ha_rkey_function read_int8(enum ha_rkey_function find_flag, bool &isnull,
                                  char *value);
 
  enum ha_rkey_function read_uint8(enum ha_rkey_function find_flag,
                                   bool &isnull, uchar *value);
 
  enum ha_rkey_function read_int16(enum ha_rkey_function find_flag,
                                   bool &isnull, short *value);
 
  enum ha_rkey_function read_uint16(enum ha_rkey_function find_flag,
                                    bool &isnull, ushort *value);
 
  enum ha_rkey_function read_int24(enum ha_rkey_function find_flag,
                                   bool &isnull, long *value);
 
  enum ha_rkey_function read_uint24(enum ha_rkey_function find_flag,
                                    bool &isnull, ulong *value);
 
  enum ha_rkey_function read_long(enum ha_rkey_function find_flag, bool &isnull,
                                  long *value);
 
  enum ha_rkey_function read_ulong(enum ha_rkey_function find_flag,
                                   bool &isnull, ulong *value);
 
  enum ha_rkey_function read_longlong(enum ha_rkey_function find_flag,
                                      bool &isnull, longlong *value);
 
  enum ha_rkey_function read_ulonglong(enum ha_rkey_function find_flag,
                                       bool &isnull, ulonglong *value);
 
  enum ha_rkey_function read_timestamp(enum ha_rkey_function find_flag,
                                       bool &isnull, ulonglong *value,
                                       uint dec);
 
  enum ha_rkey_function read_varchar_utf8(enum ha_rkey_function find_flag,
                                          bool &isnull, char *buffer,
                                          uint *buffer_length,
                                          uint buffer_capacity);
 
  enum ha_rkey_function read_text_utf8(enum ha_rkey_function find_flag,
                                       bool &isnull, char *buffer,
                                       uint *buffer_length,
                                       uint buffer_capacity);
 
  ha_base_keytype get_key_type() {
    return (enum ha_base_keytype)m_remaining_key_part_info->type;
  }
 
 private:
  const KEY *m_key_info;
  const KEY_PART_INFO *m_key_part_info;
  const uchar *m_key;
  uint m_key_len;
  const KEY_PART_INFO *m_remaining_key_part_info;
  const uchar *m_remaining_key;
  uint m_remaining_key_len;
 
 public:
  uint m_parts_found;
};
 
class PFS_engine_key {
 public:
  explicit PFS_engine_key(const char *name) : m_name(name), m_is_null(true) {}
 
  virtual ~PFS_engine_key() = default;
 
  virtual void read(PFS_key_reader &reader,
                    enum ha_rkey_function find_flag) = 0;
 
  const char *m_name;
 
 protected:
  enum ha_rkey_function m_find_flag;
  bool m_is_null;
};
 
class PFS_engine_index_abstract {
 public:
  PFS_engine_index_abstract() = default;
 
  virtual ~PFS_engine_index_abstract() = default;
 
  void set_key_info(KEY *key_info) { m_key_info = key_info; }
 
  virtual void read_key(const uchar *key, uint key_len,
                        enum ha_rkey_function find_flag) = 0;
 
 public:
  uint m_fields{0};
  KEY *m_key_info{nullptr};
  size_t m_key_fetch_count{0};
};
 
class PFS_engine_index : public PFS_engine_index_abstract {
 public:
  explicit PFS_engine_index(PFS_engine_key *key_1)
      : m_key_ptr_1(key_1),
        m_key_ptr_2(nullptr),
        m_key_ptr_3(nullptr),
        m_key_ptr_4(nullptr),
        m_key_ptr_5(nullptr) {}
 
  PFS_engine_index(PFS_engine_key *key_1, PFS_engine_key *key_2)
      : m_key_ptr_1(key_1),
        m_key_ptr_2(key_2),
        m_key_ptr_3(nullptr),
        m_key_ptr_4(nullptr),
        m_key_ptr_5(nullptr) {}
 
  PFS_engine_index(PFS_engine_key *key_1, PFS_engine_key *key_2,
                   PFS_engine_key *key_3)
      : m_key_ptr_1(key_1),
        m_key_ptr_2(key_2),
        m_key_ptr_3(key_3),
        m_key_ptr_4(nullptr),
        m_key_ptr_5(nullptr) {}
 
  PFS_engine_index(PFS_engine_key *key_1, PFS_engine_key *key_2,
                   PFS_engine_key *key_3, PFS_engine_key *key_4)
      : m_key_ptr_1(key_1),
        m_key_ptr_2(key_2),
        m_key_ptr_3(key_3),
        m_key_ptr_4(key_4),
        m_key_ptr_5(nullptr) {}
 
  PFS_engine_index(PFS_engine_key *key_1, PFS_engine_key *key_2,
                   PFS_engine_key *key_3, PFS_engine_key *key_4,
                   PFS_engine_key *key_5)
      : m_key_ptr_1(key_1),
        m_key_ptr_2(key_2),
        m_key_ptr_3(key_3),
        m_key_ptr_4(key_4),
        m_key_ptr_5(key_5) {}
 
  ~PFS_engine_index() override = default;
 
  void read_key(const uchar *key, uint key_len,
                enum ha_rkey_function find_flag) override;
 
  PFS_engine_key *m_key_ptr_1;
  PFS_engine_key *m_key_ptr_2;
  PFS_engine_key *m_key_ptr_3;
  PFS_engine_key *m_key_ptr_4;
  PFS_engine_key *m_key_ptr_5;
};
 
/**
 
  A PERFORMANCE_SCHEMA table share.
  This data is shared by all the table handles opened on the same table.
*/
struct PFS_engine_table_share {
  static void get_all_tables(List<const Plugin_table> *tables);
  static void init_all_locks();
  static void delete_all_locks();
 
  /** Get the row count. */
  ha_rows get_row_count() const;
  /** Write a row. */
  int write_row(PFS_engine_table *pfs_table, TABLE *table, unsigned char *buf,
                Field **fields) const;
  /** Table Access Control List. */
  const ACL_internal_table_access *m_acl;
  /** Open table function. */
  pfs_open_table_t m_open_table;
  /** Write row function. */
  pfs_write_row_t m_write_row;
  /** Delete all rows function. */
  pfs_delete_all_rows_t m_delete_all_rows;
  /** Get rows count function. */
  pfs_get_row_count_t m_get_row_count;
  /** Length of the @c m_pos position structure. */
  uint m_ref_length;
  /** The lock, stored on behalf of the SQL layer. */
  THR_LOCK *m_thr_lock_ptr;
  /** Table definition. */
  const Plugin_table *m_table_def;
  /** Table is available even if the Performance Schema is disabled. */
  bool m_perpetual;
 
  /* Interface to be implemented by plugin who adds its own table in PFS. */
  PFS_engine_table_proxy m_st_table;
  /* Number of table objects using this share currently. */
  std::atomic<int> m_ref_count;
  /* is marked to be deleted? */
  bool m_in_purgatory;
};
 
/**
 * A class to keep list of table shares for non-native performance schema
 * tables i.e. table created by plugins/components in performance schema.
 */
class PFS_dynamic_table_shares {
 public:
  PFS_dynamic_table_shares() = default;
 
  void init_mutex();
 
  void destroy_mutex();
 
  void lock_share_list() { mysql_mutex_lock(&LOCK_pfs_share_list); }
 
  void unlock_share_list() { mysql_mutex_unlock(&LOCK_pfs_share_list); }
 
  void add_share(PFS_engine_table_share *share) {
    mysql_mutex_assert_owner(&LOCK_pfs_share_list);
    shares_vector.push_back(share);
  }
 
  PFS_engine_table_share *find_share(const char *table_name, bool is_dead_too);
 
  void remove_share(PFS_engine_table_share *share);
 
 private:
  std::vector<PFS_engine_table_share *> shares_vector;
  mysql_mutex_t LOCK_pfs_share_list;
};
 
/* List of table shares added by plugin/component */
extern PFS_dynamic_table_shares pfs_external_table_shares;
 
/**
  Privileges for read only tables.
  The only operation allowed is SELECT.
*/
class PFS_readonly_acl : public ACL_internal_table_access {
 public:
  PFS_readonly_acl() = default;
 
  ~PFS_readonly_acl() override = default;
 
  ACL_internal_access_result check(Access_bitmask want_access,
                                   Access_bitmask *granted_access,
                                   bool any_combination_will_do) const override;
};
 
/** Singleton instance of PFS_readonly_acl. */
extern PFS_readonly_acl pfs_readonly_acl;
 
/**
  Privileges for truncatable tables.
  Operations allowed are SELECT and TRUNCATE.
*/
class PFS_truncatable_acl : public ACL_internal_table_access {
 public:
  PFS_truncatable_acl() = default;
 
  ~PFS_truncatable_acl() override = default;
 
  ACL_internal_access_result check(Access_bitmask want_access,
                                   Access_bitmask *granted_access,
                                   bool any_combination_will_do) const override;
};
 
/** Singleton instance of PFS_truncatable_acl. */
extern PFS_truncatable_acl pfs_truncatable_acl;
 
/**
  Privileges for updatable tables.
  Operations allowed are SELECT and UPDATE.
*/
class PFS_updatable_acl : public ACL_internal_table_access {
 public:
  PFS_updatable_acl() = default;
 
  ~PFS_updatable_acl() override = default;
 
  ACL_internal_access_result check(Access_bitmask want_access,
                                   Access_bitmask *granted_access,
                                   bool any_combination_will_do) const override;
};
 
/** Singleton instance of PFS_updatable_acl. */
extern PFS_updatable_acl pfs_updatable_acl;
 
/**
  Privileges for editable tables.
  Operations allowed are SELECT, INSERT, UPDATE, DELETE and TRUNCATE.
*/
class PFS_editable_acl : public ACL_internal_table_access {
 public:
  PFS_editable_acl() = default;
 
  ~PFS_editable_acl() override = default;
 
  ACL_internal_access_result check(Access_bitmask want_access,
                                   Access_bitmask *granted_access,
                                   bool any_combination_will_do) const override;
};
 
/** Singleton instance of PFS_editable_acl. */
extern PFS_editable_acl pfs_editable_acl;
 
/**
  Privileges for unknown tables.
*/
class PFS_unknown_acl : public ACL_internal_table_access {
 public:
  PFS_unknown_acl() = default;
 
  ~PFS_unknown_acl() override = default;
 
  ACL_internal_access_result check(Access_bitmask want_access,
                                   Access_bitmask *granted_access,
                                   bool any_combination_will_do) const override;
};
 
/** Singleton instance of PFS_unknown_acl. */
extern PFS_unknown_acl pfs_unknown_acl;
 
/**
  Privileges for world readable tables.
*/
class PFS_readonly_world_acl : public PFS_readonly_acl {
 public:
  PFS_readonly_world_acl() = default;
 
  ~PFS_readonly_world_acl() override = default;
  ACL_internal_access_result check(Access_bitmask want_access,
                                   Access_bitmask *save_priv,
                                   bool any_combination_will_do) const override;
};
 
/** Singleton instance of PFS_readonly_world_acl */
extern PFS_readonly_world_acl pfs_readonly_world_acl;
 
/**
Privileges for world readable truncatable tables.
*/
class PFS_truncatable_world_acl : public PFS_truncatable_acl {
 public:
  PFS_truncatable_world_acl() = default;
 
  ~PFS_truncatable_world_acl() override = default;
  ACL_internal_access_result check(Access_bitmask want_access,
                                   Access_bitmask *save_priv,
                                   bool any_combination_will_do) const override;
};
 
/** Singleton instance of PFS_readonly_world_acl */
extern PFS_truncatable_world_acl pfs_truncatable_world_acl;
 
/**
  Privileges for readable processlist tables.
*/
class PFS_readonly_processlist_acl : public PFS_readonly_acl {
 public:
  PFS_readonly_processlist_acl() = default;
 
  ~PFS_readonly_processlist_acl() override = default;
  ACL_internal_access_result check(Access_bitmask want_access,
                                   Access_bitmask *save_priv,
                                   bool any_combination_will_do) const override;
};
 
/** Singleton instance of PFS_readonly_processlist_acl */
extern PFS_readonly_processlist_acl pfs_readonly_processlist_acl;
 
/** Position of a cursor, for simple iterations. */
struct PFS_simple_index {
  /** Current row index. */
  uint m_index;
 
  /**
    Constructor.
    @param index the index initial value.
  */
  PFS_simple_index(uint index) : m_index(index) {}
 
  /**
    Set this index at a given position.
    @param index an index
  */
  void set_at(uint index) { m_index = index; }
 
  /**
    Set this index at a given position.
    @param other a position
  */
  void set_at(const PFS_simple_index *other) { m_index = other->m_index; }
 
  /**
    Set this index after a given position.
    @param other a position
  */
  void set_after(const PFS_simple_index *other) {
    m_index = other->m_index + 1;
  }
 
  /** Set this index to the next record. */
  void next() { m_index++; }
};
 
/** Position of a double cursor, for iterations using 2 nested loops. */
struct PFS_double_index {
  /** Outer index. */
  uint m_index_1;
  /** Current index within index_1. */
  uint m_index_2;
 
  /**
    Constructor.
    @param index_1 the first index initial value.
    @param index_2 the second index initial value.
  */
  PFS_double_index(uint index_1, uint index_2)
      : m_index_1(index_1), m_index_2(index_2) {}
 
  /**
    Set this index at a given position.
  */
  void set_at(uint index_1, uint index_2) {
    m_index_1 = index_1;
    m_index_2 = index_2;
  }
 
  /**
    Set this index at a given position.
    @param other a position
  */
  void set_at(const PFS_double_index *other) {
    m_index_1 = other->m_index_1;
    m_index_2 = other->m_index_2;
  }
 
  /**
    Set this index after a given position.
    @param other a position
  */
  void set_after(const PFS_double_index *other) {
    m_index_1 = other->m_index_1;
    m_index_2 = other->m_index_2 + 1;
  }
};
 
/** Position of a triple cursor, for iterations using 3 nested loops. */
struct PFS_triple_index {
  /** Outer index. */
  uint m_index_1;
  /** Current index within index_1. */
  uint m_index_2;
  /** Current index within index_2. */
  uint m_index_3;
 
  /**
    Constructor.
    @param index_1 the first index initial value.
    @param index_2 the second index initial value.
    @param index_3 the third index initial value.
  */
  PFS_triple_index(uint index_1, uint index_2, uint index_3)
      : m_index_1(index_1), m_index_2(index_2), m_index_3(index_3) {}
 
  /**
    Set this index at a given position.
  */
  void set_at(uint index_1, uint index_2, uint index_3) {
    m_index_1 = index_1;
    m_index_2 = index_2;
    m_index_3 = index_3;
  }
 
  /**
    Set this index at a given position.
    @param other a position
  */
  void set_at(const PFS_triple_index *other) {
    m_index_1 = other->m_index_1;
    m_index_2 = other->m_index_2;
    m_index_3 = other->m_index_3;
  }
 
  /**
    Set this index after a given position.
    @param other a position
  */
  void set_after(const PFS_triple_index *other) {
    m_index_1 = other->m_index_1;
    m_index_2 = other->m_index_2;
    m_index_3 = other->m_index_3 + 1;
  }
};
 
/** @} */
 
#endif