log0chkp.h File Reference

#include "fil0pages_persistence_interface.h"
#include "log0log.h"
#include "log0sys.h"
#include "log0types.h"
#include "srv0srv.h"
#include "sync0debug.h"
#include "sync0types.h"
#include "ut0new.h"

Go to the source code of this file.

Classes
class	Log_checkpointing

Macros
Log - checkpointer mutex
#define	log_checkpointer_mutex_enter()    mutex_enter(&(log_checkpointing->checkpoint_mutex))
#define	log_checkpointer_mutex_exit()    mutex_exit(&(log_checkpointing->checkpoint_mutex))
#define	log_checkpointer_mutex_own()
Log - limits mutex
#define	log_limits_mutex_enter()   mutex_enter(&(log_checkpointing->limits_mutex))
#define	log_limits_mutex_exit()   mutex_exit(&(log_checkpointing->limits_mutex))
#define	log_limits_mutex_own()   mutex_own(&(log_checkpointing->limits_mutex))

Functions
lsn_t	log_get_checkpoint_age ()
	Calculates age of current checkpoint as number of bytes since last checkpoint. More...
void	log_update_exported_lsns ()
	Updates: More...
Log - checkpointer thread
Redo log functions related to checkpointing and log free check.
bool	log_checkpointer_is_active ()
	Checks if log checkpointer thread is active. More...
Log - basic information about checkpoints.
Log_checkpoint_header_no	log_next_checkpoint_header (Log_checkpoint_header_no checkpoint_header_no)
	Provides opposite checkpoint header number to the given checkpoint header number. More...
Log - other functions related to checkpoints.
dberr_t	log_files_write_checkpoint_low (log_t &log, Log_file_handle &checkpoint_file_handle, Log_checkpoint_header_no checkpoint_header_no, lsn_t next_checkpoint_lsn)
	Writes checkpoint to the file containing the written checkpoint_lsn. More...
dberr_t	log_files_write_first_data_block_low (log_t &log, Log_file_handle &file_handle, lsn_t checkpoint_lsn, lsn_t file_start_lsn)
	Writes the first data block to the log file using the provided handle to the opened log file. More...
dberr_t	log_files_next_checkpoint (log_t &log, lsn_t lsn)
	Writes the next checkpoint to the log file, by writing a single checkpoint header with the checkpoint lsn. More...

Variables
Log_checkpointing *	log_checkpointing
	Redo log checkpointing. More...

Macro Definition Documentation

log_checkpointer_mutex_enter

#define log_checkpointer_mutex_enter

(

)

mutex_enter(&(log_checkpointing->checkpoint_mutex))

log_checkpointer_mutex_exit

#define log_checkpointer_mutex_exit

(

)

mutex_exit(&(log_checkpointing->checkpoint_mutex))

log_checkpointer_mutex_own

#define log_checkpointer_mutex_own

(

)

Value:

  (mutex_own(&(log_checkpointing->checkpoint_mutex)) || \
   !log_checkpointer_is_active())

log_limits_mutex_enter

#define log_limits_mutex_enter

(

)

mutex_enter(&(log_checkpointing->limits_mutex))

log_limits_mutex_exit

#define log_limits_mutex_exit

(

)

mutex_exit(&(log_checkpointing->limits_mutex))

log_limits_mutex_own

#define log_limits_mutex_own

(

)

mutex_own(&(log_checkpointing->limits_mutex))

Function Documentation

log_checkpointer_is_active()

bool log_checkpointer_is_active ( )

inline

Checks if log checkpointer thread is active.

Returns

true if and only if the log checkpointer thread is active

log_files_next_checkpoint()

dberr_t log_files_next_checkpoint	(	log_t &	log,
		lsn_t	lsn
	)

Writes the next checkpoint to the log file, by writing a single checkpoint header with the checkpoint lsn.

Flushes the file after the write and updates the log.last_checkpoint_lsn.

Remarks

Note that two checkpoint headers are used alternately for consecutive checkpoints. If InnoDB crashed during the write, it would still have the previous checkpoint info and recovery would work.

Parameters

[in,out]	log	redo log
[in]	lsn	writes checkpoint at this lsn

Returns

DB_SUCCESS or error

log_files_write_checkpoint_low()

dberr_t log_files_write_checkpoint_low	(	log_t &	log,
		Log_file_handle &	checkpoint_file_handle,
		Log_checkpoint_header_no	checkpoint_header_no,
		lsn_t	next_checkpoint_lsn
	)

Writes checkpoint to the file containing the written checkpoint_lsn.

The checkpoint is written to the given checkpoint header. Unless InnoDB is starting: checkpointer, writer and files mutexes must be acquired before calling this function.

Parameters

[in,out]	log	redo log
[in]	checkpoint_file_handle	handle to opened file
[in]	checkpoint_header_no	checkpoint header to be written
[in]	next_checkpoint_lsn	the checkpoint lsn to write

Returns

DB_SUCCESS or error

log_files_write_first_data_block_low()

dberr_t log_files_write_first_data_block_low	(	log_t &	log,
		Log_file_handle &	file_handle,
		lsn_t	checkpoint_lsn,
		lsn_t	file_start_lsn
	)

Writes the first data block to the log file using the provided handle to the opened log file.

The block is addressed by the given checkpoint_lsn, filled with 0x00 and its data length points to checkpoint_lsn inside, making the block logically empty.

Remarks

This is used only during creation of new log files.

Parameters

[in,out]	log	redo log
[in]	file_handle	handle to the opened log file
[in]	checkpoint_lsn	the checkpoint lsn
[in]	file_start_lsn	start_lsn of the file

Returns

DB_SUCCESS or error

log_get_checkpoint_age()

lsn_t log_get_checkpoint_age ( )

inline

Calculates age of current checkpoint as number of bytes since last checkpoint.

This includes bytes for headers and footers of all log blocks. The calculation is based on the latest written checkpoint lsn, and the current lsn, which points to the first non reserved data byte. Note that the current lsn could not fit the free space in the log files. This means that the checkpoint age could potentially be larger than capacity of the log files. However we do the best effort to avoid such situations, and if they happen, user threads wait until the space is reclaimed.

Returns

checkpoint age as number of bytes

log_next_checkpoint_header()

Log_checkpoint_header_no log_next_checkpoint_header

(

Log_checkpoint_header_no

checkpoint_header_no

)

Provides opposite checkpoint header number to the given checkpoint header number.

Parameters

[in]

checkpoint_header_no

the given checkpoint header number

Returns

the opposite checkpoint header number

log_update_exported_lsns()

void log_update_exported_lsns

(

)

Updates:

• Innodb_redo_log_checkpoint_lsn,
• Innodb_redo_log_current_lsn,
• Innodb_redo_log_flushed_to_disk_lsn. They should be updated "together", to present a consistent state to the user, that is one in which checkpoint_lsn <= flushed_to_disk_lsn <= current_lsn. Calls are protected by log_checkpointer->limits_mutex, which is to avoid torn writes to these exposed fields, but otherwise does not enforce above inequalities. Instead they follow from loading atomics in the order from the conceptually smallest to the largest - a load synchronizes with the store, which in turn should happen after the conceptually larger atomic already was at least equal to the stored value, so can be only larger now.

Variable Documentation

log_checkpointing

Log_checkpointing* log_checkpointing

extern

Redo log checkpointing.