These functions handle keyblock caching for ISAM and MyISAM tables. More...

#include <errno.h>
#include <stddef.h>
#include <string.h>
#include <sys/types.h>
#include <algorithm>
#include <bit>
#include "keycache.h"
#include "my_compiler.h"
#include "my_dbug.h"
#include "my_inttypes.h"
#include "my_io.h"
#include "my_macros.h"
#include "my_pointer_arithmetic.h"
#include "my_sys.h"
#include "my_thread_local.h"
#include "mysql/my_loglevel.h"
#include "mysql/psi/mysql_cond.h"
#include "mysql/psi/mysql_mutex.h"
#include "mysql/service_mysql_alloc.h"
#include "mysys/mysys_priv.h"
#include "mysys_err.h"
#include "template_utils.h"
#include "thr_mutex.h"

Classes
struct	KEYCACHE_PAGE

struct	HASH_LINK

struct	BLOCK_LINK

Macros
#define	STRUCT_PTR(TYPE, MEMBER, a) (TYPE )((char )(a)-offsetof(TYPE, MEMBER))

#define	COND_FOR_REQUESTED 0

#define	COND_FOR_SAVED 1

#define	BLOCK_ERROR 1 /* an error occurred when performing file i/o */

#define	BLOCK_READ 2 /* file block is in the block buffer */

#define	BLOCK_IN_SWITCH 4 /* block is preparing to read new page */

#define	BLOCK_REASSIGNED 8 /* blk does not accept requests for old page */

#define	BLOCK_IN_FLUSH 16 /* block is selected for flush */

#define	BLOCK_CHANGED 32 /* block buffer contains a dirty page */

#define	BLOCK_IN_USE 64 /* block is not free */

#define	BLOCK_IN_EVICTION 128 /* block is selected for eviction */

#define	BLOCK_IN_FLUSHWRITE 256 /* block is in write to file */

#define	BLOCK_FOR_UPDATE 512 /* block is selected for buffer modification */

#define	PAGE_READ 0

#define	PAGE_TO_BE_READ 1

#define	PAGE_WAIT_TO_BE_READ 2

#define	FLUSH_CACHE 2000 /* sort this many blocks at once */

#define	KEYCACHE_HASH(f, pos)

#define	FILE_HASH(f) ((uint)(f) & (CHANGED_BLOCKS_HASH - 1))

#define	BLOCK_NUMBER(b) ((uint)(((char )(b) - (char )keycache->block_root) / sizeof(BLOCK_LINK)))

#define	F_B_PRT(_f_, _v_) DBUG_PRINT("assert_fail", (_f_, _v_))

Typedefs
typedef mysql_cond_t	KEYCACHE_CONDVAR

Enumerations
enum	BLOCK_TEMPERATURE { BLOCK_COLD , BLOCK_WARM , BLOCK_HOT }

Functions
static void	change_key_cache_param (KEY_CACHE *keycache, ulonglong division_limit, ulonglong age_threshold)

static int	flush_all_key_blocks (KEY_CACHE keycache, st_keycache_thread_var thread_var)

static void	wait_on_queue (KEYCACHE_WQUEUE wqueue, mysql_mutex_t mutex, st_keycache_thread_var *thread)

static void	release_whole_queue (KEYCACHE_WQUEUE *wqueue)

static void	free_block (KEY_CACHE keycache, st_keycache_thread_var thread_var, BLOCK_LINK *block)

static int	fail_block (BLOCK_LINK *block)

static int	fail_hlink (HASH_LINK *hlink)

static int	cache_empty (KEY_CACHE *keycache)

static uint	next_power (uint value)

int	init_key_cache (KEY_CACHE *keycache, ulonglong key_cache_block_size, size_t use_mem, ulonglong division_limit, ulonglong age_threshold)

int	resize_key_cache (KEY_CACHE keycache, st_keycache_thread_var thread_var, ulonglong key_cache_block_size, size_t use_mem, ulonglong division_limit, ulonglong age_threshold)

static void	inc_counter_for_resize_op (KEY_CACHE *keycache)

static void	dec_counter_for_resize_op (KEY_CACHE *keycache)

void	end_key_cache (KEY_CACHE *keycache, bool cleanup)

static void	link_into_queue (KEYCACHE_WQUEUE wqueue, st_keycache_thread_var thread)
	Link a thread into double-linked queue of waiting threads. More...

static void	unlink_from_queue (KEYCACHE_WQUEUE wqueue, st_keycache_thread_var thread)
	Unlink a thread from double-linked queue of waiting threads. More...

static void	unlink_changed (BLOCK_LINK *block)

static void	link_changed (BLOCK_LINK block, BLOCK_LINK *phead)

static void	link_to_file_list (KEY_CACHE keycache, BLOCK_LINK block, int file, bool unlink_block)

static void	link_to_changed_list (KEY_CACHE keycache, BLOCK_LINK block)

static void	link_block (KEY_CACHE keycache, BLOCK_LINK block, bool hot, bool at_end)

static void	unlink_block (KEY_CACHE keycache, BLOCK_LINK block)

static void	reg_requests (KEY_CACHE keycache, BLOCK_LINK block, int count)

static void	unreg_request (KEY_CACHE keycache, BLOCK_LINK block, int at_end)

static void	remove_reader (BLOCK_LINK *block)

static void	wait_for_readers (KEY_CACHE keycache, BLOCK_LINK block, st_keycache_thread_var *thread)

static void	link_hash (HASH_LINK *start, HASH_LINK hash_link)

static void	unlink_hash (KEY_CACHE keycache, HASH_LINK hash_link)

static HASH_LINK *	get_hash_link (KEY_CACHE keycache, int file, my_off_t filepos, st_keycache_thread_var thread)

static BLOCK_LINK *	find_key_block (KEY_CACHE keycache, st_keycache_thread_var thread, File file, my_off_t filepos, int init_hits_left, int wrmode, int *page_st)

static void	read_block (KEY_CACHE keycache, st_keycache_thread_var thread_var, BLOCK_LINK *block, uint read_length, uint min_length, bool primary)

uchar *	key_cache_read (KEY_CACHE keycache, st_keycache_thread_var thread_var, File file, my_off_t filepos, int level, uchar *buff, uint length, uint block_length, int return_buffer)

int	key_cache_insert (KEY_CACHE keycache, st_keycache_thread_var thread_var, File file, my_off_t filepos, int level, uchar *buff, uint length)

int	key_cache_write (KEY_CACHE keycache, st_keycache_thread_var thread_var, File file, my_off_t filepos, int level, uchar *buff, uint length, uint block_length, int dont_write)

static int	flush_cached_blocks (KEY_CACHE keycache, st_keycache_thread_var thread_var, File file, BLOCK_LINK cache, BLOCK_LINK end, enum flush_type type)

static int	flush_key_blocks_int (KEY_CACHE keycache, st_keycache_thread_var thread_var, File file, enum flush_type type)

int	flush_key_blocks (KEY_CACHE keycache, st_keycache_thread_var thread_var, File file, enum flush_type type)

int	reset_key_cache_counters (std::string_view name, KEY_CACHE *key_cache)

Variables
KEY_CACHE	dflt_key_cache_var

KEY_CACHE *	dflt_key_cache = &dflt_key_cache_var

Detailed Description

These functions handle keyblock caching for ISAM and MyISAM tables.

One cache can handle many files. It must contain buffers of the same blocksize. init_key_cache() should be used to init cache handler.

The free list (free_block_list) is a stack like structure. When a block is freed by free_block(), it is pushed onto the stack. When a new block is required it is first tried to pop one from the stack. If the stack is empty, it is tried to get a never-used block from the pool. If this is empty too, then a block is taken from the LRU ring, flushing it to disk, if necessary. This is handled in find_key_block(). With the new free list, the blocks can have three temperatures: hot, warm and cold (which is free). This is remembered in the block header by the enum BLOCK_TEMPERATURE temperature variable. Remembering the temperature is necessary to correctly count the number of warm blocks, which is required to decide when blocks are allowed to become hot. Whenever a block is inserted to another (sub-)chain, we take the old and new temperature into account to decide if we got one more or less warm block. blocks_unused is the sum of never used blocks in the pool and of currently free blocks. blocks_used is the number of blocks fetched from the pool and as such gives the maximum number of in-use blocks at any time.

Macro Definition Documentation

◆ BLOCK_CHANGED

#define BLOCK_CHANGED 32 /* block buffer contains a dirty page */

◆ BLOCK_ERROR

#define BLOCK_ERROR 1 /* an error occurred when performing file i/o */

◆ BLOCK_FOR_UPDATE

#define BLOCK_FOR_UPDATE 512 /* block is selected for buffer modification */

◆ BLOCK_IN_EVICTION

#define BLOCK_IN_EVICTION 128 /* block is selected for eviction */

◆ BLOCK_IN_FLUSH

#define BLOCK_IN_FLUSH 16 /* block is selected for flush */

◆ BLOCK_IN_FLUSHWRITE

#define BLOCK_IN_FLUSHWRITE 256 /* block is in write to file */

◆ BLOCK_IN_SWITCH

#define BLOCK_IN_SWITCH 4 /* block is preparing to read new page */

◆ BLOCK_IN_USE

#define BLOCK_IN_USE 64 /* block is not free */

◆ BLOCK_NUMBER

#define BLOCK_NUMBER ( b ) ((uint)(((char *)(b) - (char *)keycache->block_root) / sizeof(BLOCK_LINK)))

◆ BLOCK_READ

#define BLOCK_READ 2 /* file block is in the block buffer */

◆ BLOCK_REASSIGNED

#define BLOCK_REASSIGNED 8 /* blk does not accept requests for old page */

◆ COND_FOR_REQUESTED

#define COND_FOR_REQUESTED 0

◆ COND_FOR_SAVED

#define COND_FOR_SAVED 1

◆ F_B_PRT

#define F_B_PRT	(	_f_,
		_v_
	)	DBUG_PRINT("assert_fail", (_f_, _v_))

◆ FILE_HASH

#define FILE_HASH ( f ) ((uint)(f) & (CHANGED_BLOCKS_HASH - 1))

◆ FLUSH_CACHE

#define FLUSH_CACHE 2000 /* sort this many blocks at once */

◆ KEYCACHE_HASH

#define KEYCACHE_HASH	(	f,
		pos
	)

Value:

(((ulong)((pos) / keycache->key_cache_block_size) + (ulong)(f)) & \

(keycache->hash_entries - 1))

◆ PAGE_READ

#define PAGE_READ 0

◆ PAGE_TO_BE_READ

#define PAGE_TO_BE_READ 1

◆ PAGE_WAIT_TO_BE_READ

#define PAGE_WAIT_TO_BE_READ 2

◆ STRUCT_PTR

#define STRUCT_PTR	(	TYPE,
		MEMBER,
		a
	)	(TYPE )((char )(a)-offsetof(TYPE, MEMBER))

Typedef Documentation

◆ KEYCACHE_CONDVAR

typedef mysql_cond_t KEYCACHE_CONDVAR

Enumeration Type Documentation

◆ BLOCK_TEMPERATURE

enum BLOCK_TEMPERATURE

Enumerator
BLOCK_COLD
BLOCK_WARM
BLOCK_HOT

Function Documentation

◆ cache_empty()

static int cache_empty ( KEY_CACHE * keycache )

static

◆ change_key_cache_param()

static void change_key_cache_param	(	KEY_CACHE *	keycache,
		ulonglong	division_limit,
		ulonglong	age_threshold
	)

static

◆ dec_counter_for_resize_op()

static void dec_counter_for_resize_op ( KEY_CACHE * keycache )

inlinestatic

◆ end_key_cache()

void end_key_cache	(	KEY_CACHE *	keycache,
		bool	cleanup
	)

◆ fail_block()

static int fail_block ( BLOCK_LINK * block )

static

◆ fail_hlink()

static int fail_hlink ( HASH_LINK * hlink )

static

◆ find_key_block()

static BLOCK_LINK * find_key_block	(	KEY_CACHE *	keycache,
		st_keycache_thread_var *	thread,
		File	file,
		my_off_t	filepos,
		int	init_hits_left,
		int	wrmode,
		int *	page_st
	)

static

◆ flush_all_key_blocks()

static int flush_all_key_blocks	(	KEY_CACHE *	keycache,
		st_keycache_thread_var *	thread_var
	)

static

◆ flush_cached_blocks()

static int flush_cached_blocks	(	KEY_CACHE *	keycache,
		st_keycache_thread_var *	thread_var,
		File	file,
		BLOCK_LINK **	cache,
		BLOCK_LINK **	end,
		enum flush_type	type
	)

static

◆ flush_key_blocks()

int flush_key_blocks	(	KEY_CACHE *	keycache,
		st_keycache_thread_var *	thread_var,
		File	file,
		enum flush_type	type
	)

◆ flush_key_blocks_int()

static int flush_key_blocks_int	(	KEY_CACHE *	keycache,
		st_keycache_thread_var *	thread_var,
		File	file,
		enum flush_type	type
	)

static

◆ free_block()

static void free_block	(	KEY_CACHE *	keycache,
		st_keycache_thread_var *	thread_var,
		BLOCK_LINK *	block
	)

static

◆ get_hash_link()

static HASH_LINK * get_hash_link	(	KEY_CACHE *	keycache,
		int	file,
		my_off_t	filepos,
		st_keycache_thread_var *	thread
	)

static

◆ inc_counter_for_resize_op()

static void inc_counter_for_resize_op ( KEY_CACHE * keycache )

inlinestatic

◆ init_key_cache()

int init_key_cache	(	KEY_CACHE *	keycache,
		ulonglong	key_cache_block_size,
		size_t	use_mem,
		ulonglong	division_limit,
		ulonglong	age_threshold
	)

◆ key_cache_insert()

int key_cache_insert	(	KEY_CACHE *	keycache,
		st_keycache_thread_var *	thread_var,
		File	file,
		my_off_t	filepos,
		int	level,
		uchar *	buff,
		uint	length
	)

◆ key_cache_read()

uchar * key_cache_read	(	KEY_CACHE *	keycache,
		st_keycache_thread_var *	thread_var,
		File	file,
		my_off_t	filepos,
		int	level,
		uchar *	buff,
		uint	length,
		uint	block_length,
		int	return_buffer
	)

◆ key_cache_write()

int key_cache_write	(	KEY_CACHE *	keycache,
		st_keycache_thread_var *	thread_var,
		File	file,
		my_off_t	filepos,
		int	level,
		uchar *	buff,
		uint	length,
		uint	block_length,
		int	dont_write
	)

◆ link_block()

static void link_block	(	KEY_CACHE *	keycache,
		BLOCK_LINK *	block,
		bool	hot,
		bool	at_end
	)

static

◆ link_changed()

static void link_changed	(	BLOCK_LINK *	block,
		BLOCK_LINK **	phead
	)

inlinestatic

◆ link_hash()

static void link_hash	(	HASH_LINK **	start,
		HASH_LINK *	hash_link
	)

inlinestatic

◆ link_into_queue()

static void link_into_queue	(	KEYCACHE_WQUEUE *	wqueue,
		st_keycache_thread_var *	thread
	)

static

Link a thread into double-linked queue of waiting threads.

Parameters

wqueue	pointer to the queue structure
thread	pointer to the keycache variables for the thread to be added to the queue

Queue is represented by a circular list of the keycache variable structures. Since each thread has its own keycache variables, this is equal to a list of threads. The list is double-linked of the type (**prev,*next), accessed by a pointer to the last element.

◆ link_to_changed_list()

static void link_to_changed_list	(	KEY_CACHE *	keycache,
		BLOCK_LINK *	block
	)

static

◆ link_to_file_list()

static void link_to_file_list	(	KEY_CACHE *	keycache,
		BLOCK_LINK *	block,
		int	file,
		bool	unlink_block
	)

static

◆ next_power()

static uint next_power ( uint value )

inlinestatic

◆ read_block()

static void read_block	(	KEY_CACHE *	keycache,
		st_keycache_thread_var *	thread_var,
		BLOCK_LINK *	block,
		uint	read_length,
		uint	min_length,
		bool	primary
	)

static

◆ reg_requests()

static void reg_requests	(	KEY_CACHE *	keycache,
		BLOCK_LINK *	block,
		int	count
	)

static

◆ release_whole_queue()

static void release_whole_queue ( KEYCACHE_WQUEUE * wqueue )

static

◆ remove_reader()

static void remove_reader ( BLOCK_LINK * block )

static

◆ reset_key_cache_counters()

int reset_key_cache_counters	(	std::string_view	name,
		KEY_CACHE *	key_cache
	)

◆ resize_key_cache()

int resize_key_cache	(	KEY_CACHE *	keycache,
		st_keycache_thread_var *	thread_var,
		ulonglong	key_cache_block_size,
		size_t	use_mem,
		ulonglong	division_limit,
		ulonglong	age_threshold
	)

◆ unlink_block()

static void unlink_block	(	KEY_CACHE *	keycache,
		BLOCK_LINK *	block
	)

static

◆ unlink_changed()

static void unlink_changed ( BLOCK_LINK * block )

inlinestatic

◆ unlink_from_queue()

static void unlink_from_queue	(	KEYCACHE_WQUEUE *	wqueue,
		st_keycache_thread_var *	thread
	)

static

Unlink a thread from double-linked queue of waiting threads.

Parameters

wqueue	pointer to the queue structure
thread	pointer to the keycache variables for the thread to be removed to the queue

Note: See link_into_queue

◆ unlink_hash()

static void unlink_hash	(	KEY_CACHE *	keycache,
		HASH_LINK *	hash_link
	)

static

◆ unreg_request()

static void unreg_request	(	KEY_CACHE *	keycache,
		BLOCK_LINK *	block,
		int	at_end
	)

static

◆ wait_for_readers()

static void wait_for_readers	(	KEY_CACHE *	keycache,
		BLOCK_LINK *	block,
		st_keycache_thread_var *	thread
	)

static

◆ wait_on_queue()

static void wait_on_queue	(	KEYCACHE_WQUEUE *	wqueue,
		mysql_mutex_t *	mutex,
		st_keycache_thread_var *	thread
	)

static

Variable Documentation

◆ dflt_key_cache

KEY_CACHE* dflt_key_cache = &dflt_key_cache_var

◆ dflt_key_cache_var

KEY_CACHE dflt_key_cache_var

Classes

Macros

Typedefs

Enumerations

Functions

Variables

Detailed Description

Macro Definition Documentation

◆ BLOCK_CHANGED

◆ BLOCK_ERROR

◆ BLOCK_FOR_UPDATE

◆ BLOCK_IN_EVICTION

◆ BLOCK_IN_FLUSH

◆ BLOCK_IN_FLUSHWRITE

◆ BLOCK_IN_SWITCH

◆ BLOCK_IN_USE

◆ BLOCK_NUMBER

◆ BLOCK_READ

◆ BLOCK_REASSIGNED

◆ COND_FOR_REQUESTED

◆ COND_FOR_SAVED

◆ F_B_PRT

◆ FILE_HASH

◆ FLUSH_CACHE

◆ KEYCACHE_HASH

◆ PAGE_READ

◆ PAGE_TO_BE_READ

◆ PAGE_WAIT_TO_BE_READ

◆ STRUCT_PTR

Typedef Documentation

◆ KEYCACHE_CONDVAR

Enumeration Type Documentation

◆ BLOCK_TEMPERATURE

Function Documentation

◆ cache_empty()

◆ change_key_cache_param()

◆ dec_counter_for_resize_op()

◆ end_key_cache()

◆ fail_block()

◆ fail_hlink()

◆ find_key_block()

◆ flush_all_key_blocks()

◆ flush_cached_blocks()

◆ flush_key_blocks()

◆ flush_key_blocks_int()

◆ free_block()

◆ get_hash_link()

◆ inc_counter_for_resize_op()

◆ init_key_cache()

◆ key_cache_insert()

◆ key_cache_read()

◆ key_cache_write()

◆ link_block()

◆ link_changed()

◆ link_hash()

◆ link_into_queue()

◆ link_to_changed_list()

◆ link_to_file_list()

◆ next_power()

◆ read_block()

◆ reg_requests()

◆ release_whole_queue()

◆ remove_reader()

◆ reset_key_cache_counters()

◆ resize_key_cache()

◆ unlink_block()

◆ unlink_changed()

◆ unlink_from_queue()

◆ unlink_hash()

◆ unreg_request()

◆ wait_for_readers()

◆ wait_on_queue()

Variable Documentation

◆ dflt_key_cache

◆ dflt_key_cache_var