buf0types.h

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/** @file include/buf0types.h
 The database buffer pool global types for the directory
 
 Created 11/17/1995 Heikki Tuuri
 *******************************************************/
 
#ifndef buf0types_h
#define buf0types_h
 
#include "os0event.h"
#include "sync0rw.h"
#include "ut0mutex.h"
#include "ut0ut.h"
 
/** Magic value to use instead of checksums when they are disabled */
#define BUF_NO_CHECKSUM_MAGIC 0xDEADBEEFUL
 
/** Buffer page (uncompressed or compressed) */
class buf_page_t;
/** Buffer block for which an uncompressed page exists */
struct buf_block_t;
/** Buffer pool chunk comprising buf_block_t */
struct buf_chunk_t;
/** Buffer pool comprising buf_chunk_t */
struct buf_pool_t;
/** Buffer pool statistics struct */
struct buf_pool_stat_t;
/** Buffer pool buddy statistics struct */
struct buf_buddy_stat_t;
/** Doublewrite memory struct */
struct buf_dblwr_t;
/** Flush observer for bulk create index */
class FlushObserver;
 
/** A buffer frame. @see page_t */
typedef byte buf_frame_t;
 
/** Flags for flush types */
enum buf_flush_t {
  BUF_FLUSH_LRU = 0,     /*!< flush via the LRU list */
  BUF_FLUSH_LIST,        /*!< flush via the flush list
                         of dirty blocks */
  BUF_FLUSH_SINGLE_PAGE, /*!< flush via the LRU list
                         but only a single page */
  BUF_FLUSH_N_TYPES      /*!< index of last element + 1  */
};
 
/** Algorithm to remove the pages for a tablespace from the buffer pool.
See buf_LRU_flush_or_remove_pages(). */
enum buf_remove_t {
  BUF_REMOVE_ALL_NO_WRITE,   /*!< Remove all pages from the buffer
                             pool, don't write or sync to disk */
  BUF_REMOVE_FLUSH_NO_WRITE, /*!< Remove only, from the flush list,
                             don't write or sync to disk */
  BUF_REMOVE_FLUSH_WRITE     /*!< Flush dirty pages to disk only
                             don't remove from the buffer pool */
};
 
/** Flags for io_fix types */
enum buf_io_fix {
  BUF_IO_NONE = 0, /**< no pending I/O */
  BUF_IO_READ,     /**< read pending */
  BUF_IO_WRITE,    /**< write pending */
  BUF_IO_PIN       /**< disallow relocation of
                   block and its removal of from
                   the flush_list */
};
 
/** Alternatives for srv_checksum_algorithm, which can be changed by
setting innodb_checksum_algorithm */
enum srv_checksum_algorithm_t {
  SRV_CHECKSUM_ALGORITHM_CRC32,         /*!< Write crc32, allow crc32,
                                        innodb or none when reading */
  SRV_CHECKSUM_ALGORITHM_STRICT_CRC32,  /*!< Write crc32, allow crc32
                                        when reading */
  SRV_CHECKSUM_ALGORITHM_INNODB,        /*!< Write innodb, allow crc32,
                                        innodb or none when reading */
  SRV_CHECKSUM_ALGORITHM_STRICT_INNODB, /*!< Write innodb, allow
                                        innodb when reading */
  SRV_CHECKSUM_ALGORITHM_NONE,          /*!< Write none, allow crc32,
                                        innodb or none when reading */
  SRV_CHECKSUM_ALGORITHM_STRICT_NONE    /*!< Write none, allow none
                                        when reading */
};
 
inline bool is_checksum_strict(srv_checksum_algorithm_t algo) {
  return (algo == SRV_CHECKSUM_ALGORITHM_STRICT_CRC32 ||
          algo == SRV_CHECKSUM_ALGORITHM_STRICT_INNODB ||
          algo == SRV_CHECKSUM_ALGORITHM_STRICT_NONE);
}
 
inline bool is_checksum_strict(ulint algo) {
  return (algo == SRV_CHECKSUM_ALGORITHM_STRICT_CRC32 ||
          algo == SRV_CHECKSUM_ALGORITHM_STRICT_INNODB ||
          algo == SRV_CHECKSUM_ALGORITHM_STRICT_NONE);
}
 
/** Parameters of binary buddy system for compressed pages (buf0buddy.h) */
/* @{ */
/** Zip shift value for the smallest page size */
#define BUF_BUDDY_LOW_SHIFT UNIV_ZIP_SIZE_SHIFT_MIN
 
/** Smallest buddy page size */
#define BUF_BUDDY_LOW (1U << BUF_BUDDY_LOW_SHIFT)
 
/** Actual number of buddy sizes based on current page size */
#define BUF_BUDDY_SIZES (UNIV_PAGE_SIZE_SHIFT - BUF_BUDDY_LOW_SHIFT)
 
/** Maximum number of buddy sizes based on the max page size */
#define BUF_BUDDY_SIZES_MAX (UNIV_PAGE_SIZE_SHIFT_MAX - BUF_BUDDY_LOW_SHIFT)
 
/** twice the maximum block size of the buddy system;
the underlying memory is aligned by this amount:
this must be equal to UNIV_PAGE_SIZE */
#define BUF_BUDDY_HIGH (BUF_BUDDY_LOW << BUF_BUDDY_SIZES)
/* @} */
 
typedef ib_bpmutex_t BPageMutex;
typedef ib_mutex_t BufListMutex;
typedef ib_mutex_t FlushListMutex;
typedef BPageMutex BufPoolZipMutex;
#ifndef UNIV_HOTBACKUP
typedef rw_lock_t BPageLock;
#endif /* !UNIV_HOTBACKUP */
 
/** Page identifier. */
class page_id_t {
 public:
  /** Default constructor */
  page_id_t() : m_space(), m_page_no(), m_fold() {}
 
  /** Constructor from (space, page_no).
  @param[in]    space   tablespace id
  @param[in]    page_no page number */
  page_id_t(space_id_t space, page_no_t page_no)
      : m_space(space), m_page_no(page_no), m_fold(ULINT_UNDEFINED) {}
 
  page_id_t(const page_id_t &) = default;
 
  /** Retrieve the tablespace id.
  @return tablespace id */
  inline space_id_t space() const { return (m_space); }
 
  /** Retrieve the page number.
  @return page number */
  inline page_no_t page_no() const { return (m_page_no); }
 
  /** Retrieve the fold value.
  @return fold value */
  inline ulint fold() const {
    /* Initialize m_fold if it has not been initialized yet. */
    if (m_fold == ULINT_UNDEFINED) {
      m_fold = (m_space << 20) + m_space + m_page_no;
      ut_ad(m_fold != ULINT_UNDEFINED);
    }
 
    return (m_fold);
  }
 
  /** Copy the values from a given page_id_t object.
  @param[in]    src     page id object whose values to fetch */
  inline void copy_from(const page_id_t &src) {
    m_space = src.space();
    m_page_no = src.page_no();
    m_fold = src.fold();
  }
 
  /** Reset the values from a (space, page_no).
  @param[in]    space   tablespace id
  @param[in]    page_no page number */
  inline void reset(space_id_t space, page_no_t page_no) {
    m_space = space;
    m_page_no = page_no;
    m_fold = ULINT_UNDEFINED;
  }
 
  /** Reset the page number only.
  @param[in]    page_no page number */
  inline void set_page_no(page_no_t page_no) {
    m_page_no = page_no;
    m_fold = ULINT_UNDEFINED;
  }
 
  /** Check if a given page_id_t object is equal to the current one.
  @param[in]    a       page_id_t object to compare
  @return true if equal */
  inline bool equals_to(const page_id_t &a) const {
    return (a.space() == m_space && a.page_no() == m_page_no);
  }
 
 private:
  /** Tablespace id. */
  space_id_t m_space;
 
  /** Page number. */
  page_no_t m_page_no;
 
  /** A fold value derived from m_space and m_page_no,
  used in hashing. */
  mutable ulint m_fold;
 
  /* Disable implicit copying. */
  void operator=(const page_id_t &) = delete;
 
  /** Declare the overloaded global operator<< as a friend of this
  class. Refer to the global declaration for further details.  Print
  the given page_id_t object.
  @param[in,out]        out     the output stream
  @param[in]    page_id the page_id_t object to be printed
  @return the output stream */
  friend std::ostream &operator<<(std::ostream &out, const page_id_t &page_id);
};
 
/** Print the given page_id_t object.
@param[in,out]  out     the output stream
@param[in]      page_id the page_id_t object to be printed
@return the output stream */
std::ostream &operator<<(std::ostream &out, const page_id_t &page_id);
 
#endif /* buf0types.h */