mariadb/storage/perfschema/pfs_engine_table.h

/* Copyright (c) 2008, 2023, 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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  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 included with MySQL.

  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,
  51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA */

#ifndef PFS_ENGINE_TABLE_H
#define PFS_ENGINE_TABLE_H

#include "table.h"
#include "sql_acl.h"

/*
  The performance schema is implemented as a storage engine, in memory.
  The current storage engine interface exposed by the server,
  and in particular handlerton::discover, uses 'FRM' files to describe a
  table structure, which are later stored on disk, by the server,
  in ha_create_table_from_engine().
  Because the table metadata is stored on disk, the table naming rules
  used by the performance schema then have to comply with the constraints
  imposed by the disk storage, and in particular with lower_case_table_names.
*/

using PFS_ident_db= Lex_ident_i_s_db;
using PFS_ident_table = Lex_ident_i_s_table;


/**
  @file storage/perfschema/pfs_engine_table.h
  Performance schema tables (declarations).
*/

#include "pfs_instr_class.h"
#include "pfs.h"

class Field;
struct PFS_engine_table_share;
struct time_normalizer;

/**
  @addtogroup Performance_schema_engine
  @{
*/

/**
  Store and retrieve table state information during a query.
*/
class PFS_table_context
{
public:
  PFS_table_context(ulonglong current_version, bool restore, void** thr_var_ptr);
  PFS_table_context(ulonglong current_version, ulong map_size, bool restore, void** thr_var_ptr);
~PFS_table_context(void);

  bool initialize(void);
  bool is_initialized(void) { return m_initialized; }
  ulonglong current_version(void) { return m_current_version; }
  ulonglong last_version(void) { return m_last_version; }
  bool versions_match(void) { return m_last_version == m_current_version; }
  void set_item(ulong n);
  bool is_item_set(ulong n);
  void** m_thr_varptr;

private:
  ulonglong m_current_version;
  ulonglong m_last_version;
  ulong *m_map;
  ulong m_map_size;
  static constexpr ulong m_word_size= 8 * sizeof(ulong);
  bool m_restore;
  bool m_initialized;
  ulong m_last_item;
};

/**
  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 const 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,
                 const 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){return 0;};

  /** Fetch the next row in this cursor. */
  virtual int rnd_next(void)= 0;
  /**
    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(void)= 0;

  /** Destructor. */
  virtual ~PFS_engine_table() = default;

  /**
    Helper, assign a value to a long field.
    @param f the field to set
    @param value the value to assign
  */
  static void set_field_long(Field *f, long value);
  /**
    Helper, assign a value to a ulong field.
    @param f the field to set
    @param value the value to assign
  */
  static void set_field_ulong(Field *f, ulong value);
  /**
    Helper, assign a value to a longlong field.
    @param f the field to set
    @param value the value to assign
  */
  static void set_field_longlong(Field *f, longlong value);
  /**
    Helper, assign a value to a ulonglong field.
    @param f the field to set
    @param value the value to assign
  */
  static void set_field_ulonglong(Field *f, ulonglong value);
  /**
    Helper, assign a value to a char utf8 field.
    @param f the field to set
    @param str the string to assign
    @param len the length of the string to assign
  */
  static void set_field_char_utf8(Field *f, const char *str, uint len);
  /**
    Helper, assign a value to a varchar utf8 field.
    @param f the field to set
    @param cs the string character set
    @param str the string to assign
    @param len the length of the string to assign
  */
  static void set_field_varchar(Field *f, const CHARSET_INFO *cs, const char *str, uint len);
  /**
    Helper, assign a value to a varchar utf8 field.
    @param f the field to set
    @param str the string to assign
    @param len the length of the string to assign
  */
  static void set_field_varchar_utf8(Field *f, const char *str, uint len);
  /**
    Helper, assign a value to a longtext utf8 field.
    @param f the field to set
    @param str the string to assign
    @param len the length of the string to assign
  */
  static void set_field_longtext_utf8(Field *f, const char *str, uint len);
  /**
    Helper, assign a value to a blob field.
    @param f the field to set
    @param val the value to assign
    @param len the length of the string to assign
  */
  static void set_field_blob(Field *f, const char *val, uint len);
  /**
    Helper, assign a value to an enum field.
    @param f the field to set
    @param value the value to assign
  */
  static void set_field_enum(Field *f, ulonglong value);
  /**
    Helper, assign a value to a timestamp field.
    @param f the field to set
    @param value the value to assign
  */
  static void set_field_timestamp(Field *f, ulonglong value);
  /**
    Helper, assign a value to a double field.
    @param f the field to set
    @param value the value to assign
  */
  static void set_field_double(Field *f, double value);
  /**
    Helper, read a value from an enum field.
    @param f the field to read
    @return the field value
  */
  static ulonglong get_field_enum(Field *f);
  /**
    Helper, read a value from a char utf8 field.
    @param f the field to read
    @param[out] val the field value
    @return the field value
  */
  static String *get_field_char_utf8(Field *f, String *val);
  /**
    Helper, read a value from a varchar utf8 field.
    @param f the field to read
    @param[out] val the field value
    @return the field value
  */
  static String *get_field_varchar_utf8(Field *f, String *val);

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,
                                const 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(NULL)
  {}

  /** Table share. */
  const PFS_engine_table_share *m_share_ptr;
  /** Opaque pointer to the m_pos position of this cursor. */
  void *m_pos_ptr;
  /** Current normalizer */
  time_normalizer *m_normalizer;
};

/** Callback to open a table. */
typedef PFS_engine_table* (*pfs_open_table_t)(void);
/** Callback to write a row. */
typedef int (*pfs_write_row_t)(TABLE *table,
                               const unsigned char *buf, Field **fields);
/** Callback to delete all rows. */
typedef int (*pfs_delete_all_rows_t)(void);
/** Callback to get a row count. */
typedef ha_rows (*pfs_get_row_count_t)(void);

struct PFS_engine_table_share_state {
  /** Schema integrity flag. */
  bool m_checked;
};

/**
  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 init_all_locks(void);
  static void delete_all_locks(void);
  /** Get the row count. */
  ha_rows get_row_count(void) const;
  /** Write a row. */
  int write_row(TABLE *table, const unsigned char *buf, Field **fields) const;

  /** Table name. */
  Lex_ident_table m_name;
  /** Table ACL. */
  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 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. */
  LEX_STRING sql;
  /** Table is available even if the Performance Schema is disabled. */
  bool m_perpetual;
  /** Table is optional. */
  bool m_optional;
  /** Dynamic state. */
  PFS_engine_table_share_state *m_state;
};

/**
  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() = default;

  ACL_internal_access_result check(privilege_t want_access,
    privilege_t *save_priv, 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() = default;

  ACL_internal_access_result check(privilege_t want_access,
    privilege_t *save_priv, 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() = default;

  ACL_internal_access_result check(privilege_t want_access,
    privilege_t *save_priv, 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() = default;

  ACL_internal_access_result check(privilege_t want_access,
    privilege_t *save_priv, 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() = default;

  ACL_internal_access_result check(privilege_t want_access,
    privilege_t *save_priv, 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()
  {}

  ~PFS_readonly_world_acl()
  {}
  ACL_internal_access_result check(privilege_t want_access,
    privilege_t *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()
  {}

  ~PFS_truncatable_world_acl()
  {}
  ACL_internal_access_result check(privilege_t want_access,
    privilege_t *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()
  {}

  ~PFS_readonly_processlist_acl()
  {}

  ACL_internal_access_result check(privilege_t want_access,
    privilege_t *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 struct PFS_simple_index *other)
  { m_index= other->m_index; }

  /**
    Set this index after a given position.
    @param other a position
  */
  void set_after(const struct PFS_simple_index *other)
  { m_index= other->m_index + 1; }

  /** Set this index to the next record. */
  void next(void)
  { 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 struct 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 struct 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 struct 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 struct 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;
  }
};

bool pfs_show_status(handlerton *hton, THD *thd,
                     stat_print_fn *print, enum ha_stat_type stat);

int pfs_discover_table_names(handlerton *hton, const LEX_CSTRING *db,
                             MY_DIR *dir,
                             handlerton::discovered_list *result);

/** @} */
#endif