mariadb/include/buf0types.h

/******************************************************
The database buffer pool global types for the directory

(c) 1995 Innobase Oy

Created 11/17/1995 Heikki Tuuri
*******************************************************/

#ifndef buf0types_h
#define buf0types_h

typedef	struct buf_page_struct		buf_page_t;
typedef	struct buf_block_struct		buf_block_t;
typedef struct buf_chunk_struct		buf_chunk_t;
typedef	struct buf_pool_struct		buf_pool_t;

/* The 'type' used of a buffer frame */
typedef	byte	buf_frame_t;

/* Flags for flush types */
enum buf_flush {
	BUF_FLUSH_LRU = 0,
	BUF_FLUSH_SINGLE_PAGE,
	BUF_FLUSH_LIST,
	BUF_FLUSH_N_TYPES		/* index of last element + 1  */
};

/* 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 */
};

/* Parameters of binary buddy system for compressed pages (buf0buddy.h) */
#if UNIV_WORD_SIZE <= 4 /* 32-bit system */
# define BUF_BUDDY_LOW		64	/* minimum block size in the binary
					buddy system; must be at least
					sizeof(buf_page_t) */
# define BUF_BUDDY_SIZES	8	/* number of buddy sizes */
#else /* 64-bit system */
# define BUF_BUDDY_LOW		128	/* sizeof(buf_page_t) > 64 */
# define BUF_BUDDY_SIZES	7
#endif

/* 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)

#endif