#include "univ.i"
#include "ut0byte.h"
#include "ut0lst.h"
#include "sync0sync.h"
#include "sync0rw.h"
#include "log0log.ic"

Include dependency graph for log0log.h:

This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Data Structures
struct	log_group_t
struct	log_t

Macros
#define	LSN_MAX IB_UINT64_MAX
#define	LSN_PF UINT64PF
#define	LOG_MAX_N_GROUPS 32
#define	LOG_FLUSH 7652559
#define	LOG_CHECKPOINT 78656949
#define	LOG_RECOVER 98887331
#define	LOG_START_LSN ((lsn_t) (16 * OS_FILE_LOG_BLOCK_SIZE))
#define	LOG_BUFFER_SIZE (srv_log_buffer_size * UNIV_PAGE_SIZE)
#define	LOG_ARCHIVE_BUF_SIZE (srv_log_buffer_size * UNIV_PAGE_SIZE / 4)
#define	LOG_BLOCK_HDR_NO
#define	LOG_BLOCK_FLUSH_BIT_MASK 0x80000000UL
#define	LOG_BLOCK_HDR_DATA_LEN
#define	LOG_BLOCK_FIRST_REC_GROUP
#define	LOG_BLOCK_CHECKPOINT_NO
#define	LOG_BLOCK_HDR_SIZE
#define	LOG_BLOCK_CHECKSUM
#define	LOG_BLOCK_TRL_SIZE 4 /* trailer size in bytes */
#define	LOG_CHECKPOINT_NO 0
#define	LOG_CHECKPOINT_LSN 8
#define	LOG_CHECKPOINT_OFFSET_LOW32 16
#define	LOG_CHECKPOINT_LOG_BUF_SIZE 20
#define	LOG_CHECKPOINT_ARCHIVED_LSN 24
#define	LOG_CHECKPOINT_GROUP_ARRAY 32
#define	LOG_CHECKPOINT_ARCHIVED_FILE_NO 0
#define	LOG_CHECKPOINT_ARCHIVED_OFFSET 4
#define	LOG_CHECKPOINT_ARRAY_END
#define	LOG_CHECKPOINT_CHECKSUM_1 LOG_CHECKPOINT_ARRAY_END
#define	LOG_CHECKPOINT_CHECKSUM_2 (4 + LOG_CHECKPOINT_ARRAY_END)
#define	LOG_CHECKPOINT_OFFSET_HIGH32 (16 + LOG_CHECKPOINT_ARRAY_END)
#define	LOG_CHECKPOINT_SIZE (20 + LOG_CHECKPOINT_ARRAY_END)
#define	LOG_GROUP_ID 0 /* log group number */
#define	LOG_FILE_START_LSN
#define	LOG_FILE_NO
#define	LOG_FILE_WAS_CREATED_BY_HOT_BACKUP 16
#define	LOG_FILE_ARCH_COMPLETED OS_FILE_LOG_BLOCK_SIZE
#define	LOG_FILE_END_LSN (OS_FILE_LOG_BLOCK_SIZE + 4)
#define	LOG_CHECKPOINT_1 OS_FILE_LOG_BLOCK_SIZE
#define	LOG_CHECKPOINT_2 (3 * OS_FILE_LOG_BLOCK_SIZE)
#define	LOG_FILE_HDR_SIZE (4 * OS_FILE_LOG_BLOCK_SIZE)
#define	LOG_GROUP_OK 301
#define	LOG_GROUP_CORRUPTED 302
#define	log_flush_order_mutex_own() mutex_own(&log_sys->log_flush_order_mutex)
#define	log_flush_order_mutex_enter()
#define	log_flush_order_mutex_exit()

#define	LOG_NO_WAIT 91
#define	LOG_WAIT_ONE_GROUP 92
#define	LOG_WAIT_ALL_GROUPS 93

Typedefs
typedef ib_uint64_t	lsn_t

Functions
UNIV_INTERN ulint	log_calc_where_lsn_is (ib_int64_t *log_file_offset, ib_uint64_t first_header_lsn, ib_uint64_t lsn, ulint n_log_files, ib_int64_t log_file_size)
UNIV_INLINE lsn_t	log_reserve_and_write_fast (const void str, ulint len, lsn_t start_lsn)
UNIV_INLINE void	log_release (void)
UNIV_INLINE void	log_free_check (void)
UNIV_INTERN lsn_t	log_reserve_and_open (ulint len)
UNIV_INTERN void	log_write_low (byte *str, ulint str_len)
UNIV_INTERN lsn_t	log_close (void)
UNIV_INLINE lsn_t	log_get_lsn (void)
UNIV_INLINE lsn_t	log_get_capacity (void)
UNIV_INLINE lsn_t	log_get_max_modified_age_async (void)
UNIV_INTERN void	log_init (void)
UNIV_INTERN void	log_group_init (ulint id, ulint n_files, lsn_t file_size, ulint space_id, ulint archive_space_id)
UNIV_INTERN void	log_io_complete (log_group_t *group)
UNIV_INTERN void	log_write_up_to (lsn_t lsn, ulint wait, ibool flush_to_disk)
UNIV_INTERN void	log_buffer_flush_to_disk (void)
UNIV_INTERN void	log_buffer_sync_in_background (ibool flush)
UNIV_INTERN ibool	log_checkpoint (ibool sync, ibool write_always)
UNIV_INTERN void	log_make_checkpoint_at (lsn_t lsn, ibool write_always)
UNIV_INTERN void	logs_empty_and_mark_files_at_shutdown (void)
UNIV_INTERN void	log_group_read_checkpoint_info (log_group_t *group, ulint field)
UNIV_INTERN void	log_checkpoint_get_nth_group_info (const byte buf, ulint n, ulint file_no, ulint *offset)
UNIV_INTERN void	log_groups_write_checkpoint_info (void)
UNIV_INTERN ibool	log_archive_do (ibool sync, ulint *n_bytes)
UNIV_INTERN ulint	log_archive_stop (void)
UNIV_INTERN ulint	log_archive_start (void)
UNIV_INTERN ulint	log_archive_noarchivelog (void)
UNIV_INTERN ulint	log_archive_archivelog (void)
UNIV_INTERN void	log_archived_file_name_gen (char *buf, ulint id, ulint file_no)
UNIV_INTERN void	log_check_margins (void)
UNIV_INTERN void	log_group_read_log_seg (ulint type, byte buf, log_group_t group, lsn_t start_lsn, lsn_t end_lsn)
UNIV_INTERN void	log_group_write_buf (log_group_t group, byte buf, ulint len, lsn_t start_lsn, ulint new_data_offset)
UNIV_INTERN void	log_group_set_fields (log_group_t *group, lsn_t lsn)
UNIV_INTERN lsn_t	log_group_get_capacity (const log_group_t *group)
UNIV_INLINE ibool	log_block_get_flush_bit (const byte *log_block)
UNIV_INLINE ulint	log_block_get_hdr_no (const byte *log_block)
UNIV_INLINE ulint	log_block_get_data_len (const byte *log_block)
UNIV_INLINE void	log_block_set_data_len (byte *log_block, ulint len)
UNIV_INLINE ulint	log_block_calc_checksum (const byte *block)
UNIV_INLINE ulint	log_block_get_checksum (const byte *log_block)
UNIV_INLINE void	log_block_set_checksum (byte *log_block, ulint checksum)
UNIV_INLINE ulint	log_block_get_first_rec_group (const byte *log_block)
UNIV_INLINE void	log_block_set_first_rec_group (byte *log_block, ulint offset)
UNIV_INLINE ulint	log_block_get_checkpoint_no (const byte *log_block)
UNIV_INLINE void	log_block_init (byte *log_block, lsn_t lsn)
UNIV_INLINE void	log_block_init_in_old_format (byte *log_block, lsn_t lsn)
UNIV_INLINE ulint	log_block_convert_lsn_to_no (lsn_t lsn)
UNIV_INTERN void	log_print (FILE *file)
UNIV_INTERN ibool	log_peek_lsn (lsn_t *lsn)
UNIV_INTERN void	log_refresh_stats (void)
UNIV_INTERN void	log_group_close_all (void)
UNIV_INTERN void	log_shutdown (void)
UNIV_INTERN void	log_mem_free (void)

Variables
ibool	log_do_write
ibool	log_debug_writes
log_t *	log_sys

Detailed Description

Database log

Created 12/9/1995 Heikki Tuuri

Macro Definition Documentation

#define LOG_BLOCK_CHECKPOINT_NO

Value:

8       /* 4 lower bytes of the value of
                                        log_sys->next_checkpoint_no when the
                                        log block was last written to: if the
                                        block has not yet been written full,
                                        this value is only updated before a
                                        log buffer flush */

#define LOG_BLOCK_CHECKSUM

Value:

4       /* 4 byte checksum of the log block
                                        contents; in InnoDB versions
                                        < 3.23.52 this did not contain the
                                        checksum but the same value as
                                        .._HDR_NO */

#define LOG_BLOCK_FIRST_REC_GROUP

Value:

6       /* offset of the first start of an
                                        mtr log record group in this log block,
                                        0 if none; if the value is the same
                                        as LOG_BLOCK_HDR_DATA_LEN, it means
                                        that the first rec group has not yet
                                        been catenated to this log block, but
                                        if it will, it will start at this
                                        offset; an archive recovery can
                                        start parsing the log records starting
                                        from this offset in this log block,
                                        if value not 0 */

#define LOG_BLOCK_HDR_DATA_LEN

Value:

4 /* number of bytes of log written to

this block */

#define LOG_BLOCK_HDR_NO

Value:

0       /* block number which must be > 0 and
                                        is allowed to wrap around at 2G; the
                                        highest bit is set to 1 if this is the
                                        first log block in a log flush write
                                        segment */

#define LOG_BLOCK_HDR_SIZE

Value:

12 /* size of the log block header in

bytes */

#define LOG_CHECKPOINT_ARRAY_END

Value:

(LOG_CHECKPOINT_GROUP_ARRAY\

+ LOG_MAX_N_GROUPS * 8)

#define LOG_FILE_NO

Value:

12      /* 4-byte archived log file number;
                                        this field is only defined in an
                                        archived log file */

#define LOG_FILE_START_LSN

Value:

4 /* lsn of the start of data in this

log file */

#define log_flush_order_mutex_enter ( )

Value:

do {            \
        mutex_enter(&log_sys->log_flush_order_mutex);   \
} while (0)

Acquire the flush order mutex.

#define log_flush_order_mutex_exit ( )

Value:

do {            \
        mutex_exit(&log_sys->log_flush_order_mutex);    \
} while (0)

Release the flush order mutex.

#define log_flush_order_mutex_own ( ) mutex_own(&log_sys->log_flush_order_mutex)

Test if flush order mutex is owned.

#define LOG_MAX_N_GROUPS 32

Maximum number of log groups in log_group_t::checkpoint_buf

#define LOG_NO_WAIT 91

Wait modes for log_write_up_to

Function Documentation

UNIV_INTERN ulint log_archive_archivelog ( void )

Start archiving the log so that a gap may occur in the archived log files.

Returns: DB_SUCCESS or DB_ERROR

UNIV_INTERN ibool log_archive_do	(	ibool	sync,
		ulint *	n_bytes
	)

Starts an archiving operation.

Returns: TRUE if succeed, FALSE if an archiving operation was already running out: archive log buffer size, 0 if nothing to archive

Parameters

sync	in: TRUE if synchronous operation is desired

UNIV_INTERN ulint log_archive_noarchivelog ( void )

Stop archiving the log so that a gap may occur in the archived log files.

Returns: DB_SUCCESS or DB_ERROR

UNIV_INTERN ulint log_archive_start ( void )

Starts again archiving which has been stopped.

Returns: DB_SUCCESS or DB_ERROR

UNIV_INTERN ulint log_archive_stop ( void )

Writes the log contents to the archive up to the lsn when this function was called, and stops the archiving. When archiving is started again, the archived log file numbers start from a number one higher, so that the archiving will not write again to the archived log files which exist when this function returns.

Returns: DB_SUCCESS or DB_ERROR

UNIV_INTERN void log_archived_file_name_gen	(	char *	buf,
		ulint	id,
		ulint	file_no
	)

Generates an archived log file name. in: file number

Parameters

buf	in: buffer where to write
id	in: group id

UNIV_INLINE ulint log_block_calc_checksum ( const byte * block )

Calculates the checksum for a log block.

Returns: checksum in: log block

Calculates the checksum for a log block.

Returns: checksum

Parameters

block in: log block

UNIV_INLINE ulint log_block_convert_lsn_to_no ( lsn_t lsn )

Converts a lsn to a log block number.

Returns: log block number, it is > 0 and <= 1G in: lsn of a byte within the block

Converts a lsn to a log block number.

Returns: log block number, it is > 0 and <= 1G

Parameters

lsn	in: lsn of a byte within the block

UNIV_INLINE ulint log_block_get_checkpoint_no ( const byte * log_block )

Gets a log block checkpoint number field (4 lowest bytes).

Returns: checkpoint no (4 lowest bytes) in: log block

Gets a log block checkpoint number field (4 lowest bytes).

Returns: checkpoint no (4 lowest bytes)

Parameters

log_block in: log block

UNIV_INLINE ulint log_block_get_checksum ( const byte * log_block )

Gets a log block checksum field value.

Returns: checksum in: log block

Gets a log block checksum field value.

Returns: checksum

Parameters

log_block in: log block

UNIV_INLINE ulint log_block_get_data_len ( const byte * log_block )

Gets a log block data length.

Returns: log block data length measured as a byte offset from the block start in: log block

Gets a log block data length.

Returns: log block data length measured as a byte offset from the block start

Parameters

log_block in: log block

UNIV_INLINE ulint log_block_get_first_rec_group ( const byte * log_block )

Gets a log block first mtr log record group offset.

Returns: first mtr log record group byte offset from the block start, 0 if none in: log block

Gets a log block first mtr log record group offset.

Returns: first mtr log record group byte offset from the block start, 0 if none

Parameters

log_block in: log block

UNIV_INLINE ibool log_block_get_flush_bit ( const byte * log_block )

Gets a log block flush bit.

Returns: TRUE if this block was the first to be written in a log flush in: log block

Gets a log block flush bit.

Returns: TRUE if this block was the first to be written in a log flush

Parameters

log_block in: log block

UNIV_INLINE ulint log_block_get_hdr_no ( const byte * log_block )

Gets a log block number stored in the header.

Returns: log block number stored in the block header in: log block

Gets a log block number stored in the header.

Returns: log block number stored in the block header

Parameters

log_block in: log block

UNIV_INLINE void log_block_init	(	byte *	log_block,
		lsn_t	lsn
	)

Initializes a log block in the log buffer. in: lsn within the log block

Initializes a log block in the log buffer.

Parameters

log_block	in: pointer to the log buffer
lsn	in: lsn within the log block

UNIV_INLINE void log_block_init_in_old_format	(	byte *	log_block,
		lsn_t	lsn
	)

Initializes a log block in the log buffer in the old, < 3.23.52 format, where there was no checksum yet. in: lsn within the log block

Initializes a log block in the log buffer in the old format, where there was no checksum yet.

Parameters

log_block	in: pointer to the log buffer
lsn	in: lsn within the log block

UNIV_INLINE void log_block_set_checksum	(	byte *	log_block,
		ulint	checksum
	)

Sets a log block checksum field value. in: checksum

Sets a log block checksum field value.

Parameters

log_block	in/out: log block
checksum	in: checksum

UNIV_INLINE void log_block_set_data_len	(	byte *	log_block,
		ulint	len
	)

Sets the log block data length. in: data length

Sets the log block data length.

Parameters

log_block	in/out: log block
len	in: data length

UNIV_INLINE void log_block_set_first_rec_group	(	byte *	log_block,
		ulint	offset
	)

Sets the log block first mtr log record group offset. in: offset, 0 if none

Sets the log block first mtr log record group offset.

Parameters

log_block	in/out: log block
offset	in: offset, 0 if none

UNIV_INTERN void log_buffer_flush_to_disk ( void )

Does a syncronous flush of the log buffer to disk.

UNIV_INTERN void log_buffer_sync_in_background ( ibool flush )

This functions writes the log buffer to the log file and if 'flush' is set it forces a flush of the log file as well. This is meant to be called from background master thread only as it does not wait for the write (+ possible flush) to finish.

UNIV_INTERN ulint log_calc_where_lsn_is	(	ib_int64_t *	log_file_offset,
		ib_uint64_t	first_header_lsn,
		ib_uint64_t	lsn,
		ulint	n_log_files,
		ib_int64_t	log_file_size
	)

Calculates where in log files we find a specified lsn.

Returns: log file number in: log file size (including the header)

Parameters

log_file_offset	out: offset in that file (including the header)
first_header_lsn	in: first log file start lsn
lsn	in: lsn whose position to determine
n_log_files	in: total number of log files

UNIV_INTERN void log_check_margins ( void )

Checks that there is enough free space in the log to start a new query step. Flushes the log buffer or makes a new checkpoint if necessary. NOTE: this function may only be called if the calling thread owns no synchronization objects!

UNIV_INTERN ibool log_checkpoint	(	ibool	sync,
		ibool	write_always
	)

Makes a checkpoint. Note that this function does not flush dirty blocks from the buffer pool: it only checks what is lsn of the oldest modification in the pool, and writes information about the lsn in log files. Use log_make_checkpoint_at to flush also the pool.

Returns: TRUE if success, FALSE if a checkpoint write was already running in: the function normally checks if the the new checkpoint would have a greater lsn than the previous one: if not, then no physical write is done; by setting this parameter TRUE, a physical write will always be made to log files

Parameters

sync	in: TRUE if synchronous operation is desired

UNIV_INTERN void log_checkpoint_get_nth_group_info	(	const byte *	buf,
		ulint	n,
		ulint *	file_no,
		ulint *	offset
	)

Gets info from a checkpoint about a log group. out: archived file offset

Parameters

buf	in: buffer containing checkpoint info
n	in: nth slot
file_no	out: archived file number

UNIV_INTERN lsn_t log_close ( void )

Closes the log.

Returns: lsn

UNIV_INLINE void log_free_check ( void )

Checks if there is need for a log buffer flush or a new checkpoint, and does this if yes. Any database operation should call this when it has modified more than about 4 pages. NOTE that this function may only be called when the OS thread owns no synchronization objects except the dictionary mutex.

UNIV_INLINE lsn_t log_get_lsn ( void )

Gets the current lsn.

Returns: current lsn

UNIV_INTERN void log_group_close_all ( void )

Closes all log groups.

UNIV_INTERN lsn_t log_group_get_capacity ( const log_group_t * group )

Calculates the data capacity of a log group, when the log file headers are not included.

Returns: capacity in bytes in: log group

UNIV_INTERN void log_group_init	(	ulint	id,
		ulint	n_files,
		lsn_t	file_size,
		ulint	space_id,
		ulint	archive_space_id
	)

Inits a log group to the log system. in: space id of the file space which contains some archived log files for this group; currently, only for the first log group this is used

Parameters

id	in: group id
n_files	in: number of log files
file_size	in: log file size in bytes
space_id	in: space id of the file space which contains the log files of this group

UNIV_INTERN void log_group_read_checkpoint_info	(	log_group_t *	group,
		ulint	field
	)

Reads a checkpoint info from a log group header to log_sys->checkpoint_buf. in: LOG_CHECKPOINT_1 or LOG_CHECKPOINT_2

Parameters

group in: log group

UNIV_INTERN void log_group_read_log_seg	(	ulint	type,
		byte *	buf,
		log_group_t *	group,
		lsn_t	start_lsn,
		lsn_t	end_lsn
	)

Reads a specified log segment to a buffer. in: read area end

Parameters

type	in: LOG_ARCHIVE or LOG_RECOVER
buf	in: buffer where to read
group	in: log group
start_lsn	in: read area start

UNIV_INTERN void log_group_set_fields	(	log_group_t *	group,
		lsn_t	lsn
	)

Sets the field values in group to correspond to a given lsn. For this function to work, the values must already be correctly initialized to correspond to some lsn, for instance, a checkpoint lsn. in: lsn for which the values should be set

Parameters

group in/out: group

UNIV_INTERN void log_group_write_buf	(	log_group_t *	group,
		byte *	buf,
		ulint	len,
		lsn_t	start_lsn,
		ulint	new_data_offset
	)

Writes a buffer to a log file group. in: start offset of new data in buf: this parameter is used to decide if we have to write a new log file header

Parameters

group	in: log group
buf	in: buffer
len	in: buffer len; must be divisible by OS_FILE_LOG_BLOCK_SIZE
start_lsn	in: start lsn of the buffer; must be divisible by OS_FILE_LOG_BLOCK_SIZE

UNIV_INTERN void log_groups_write_checkpoint_info ( void )

Writes checkpoint info to groups.

UNIV_INTERN void log_init ( void )

Initializes the log.

UNIV_INTERN void log_io_complete ( log_group_t * group )

Completes an i/o to a log file. in: log group

UNIV_INTERN void log_make_checkpoint_at	(	lsn_t	lsn,
		ibool	write_always
	)

Makes a checkpoint at a given lsn or later. in: the function normally checks if the new checkpoint would have a greater lsn than the previous one: if not, then no physical write is done; by setting this parameter TRUE, a physical write will always be made to log files

Parameters

lsn	in: make a checkpoint at this or a later lsn, if LSN_MAX, makes a checkpoint at the latest lsn

UNIV_INTERN void log_mem_free ( void )

Free the log system data structures.

UNIV_INTERN ibool log_peek_lsn ( lsn_t * lsn )

Peeks the current lsn.

Returns: TRUE if success, FALSE if could not get the log system mutex out: if returns TRUE, current lsn is here

UNIV_INTERN void log_print ( FILE * file )

Prints info of the log. in: file where to print

UNIV_INTERN void log_refresh_stats ( void )

Refreshes the statistics used to print per-second averages.

UNIV_INLINE void log_release ( void )

Releases the log mutex.

UNIV_INTERN lsn_t log_reserve_and_open ( ulint len )

Opens the log for log_write_low. The log must be closed with log_close and released with log_release.

Returns: start lsn of the log record in: length of data to be catenated

UNIV_INLINE lsn_t log_reserve_and_write_fast	(	const void *	str,
		ulint	len,
		lsn_t *	start_lsn
	)

Writes to the log the string given. The log must be released with log_release.

Returns: end lsn of the log record, zero if did not succeed out: start lsn of the log record

Writes to the log the string given. The log must be released with log_release.

Returns: end lsn of the log record, zero if did not succeed

Parameters

str	in: string
len	in: string length
start_lsn	out: start lsn of the log record

UNIV_INTERN void log_shutdown ( void )

Shutdown the log system but do not release all the memory.

UNIV_INTERN void log_write_low	(	byte *	str,
		ulint	str_len
	)

Writes to the log the string given. It is assumed that the caller holds the log mutex. in: string length

Parameters

str	in: string

UNIV_INTERN void log_write_up_to	(	lsn_t	lsn,
		ulint	wait,
		ibool	flush_to_disk
	)

This function is called, e.g., when a transaction wants to commit. It checks that the log has been written to the log file up to the last log entry written by the transaction. If there is a flush running, it waits and checks if the flush flushed enough. If not, starts a new flush. in: TRUE if we want the written log also to be flushed to disk

Parameters

lsn	in: log sequence number up to which the log should be written, LSN_MAX if not specified
wait	in: LOG_NO_WAIT, LOG_WAIT_ONE_GROUP, or LOG_WAIT_ALL_GROUPS

UNIV_INTERN void logs_empty_and_mark_files_at_shutdown ( void )

Makes a checkpoint at the latest lsn and writes it to first page of each data file in the database, so that we know that the file spaces contain all modifications up to that lsn. This can only be called at database shutdown. This function also writes all log in log files to the log archive.

Variable Documentation

ibool log_debug_writes

Flag: enable debug output when writing to the log?

ibool log_do_write

Flag: write to log file?

Data Structures

Macros

Typedefs

Functions

Variables

Detailed Description

Macro Definition Documentation

Function Documentation

Variable Documentation