Drizzled Public API Documentation

log_struct Struct Reference

#include <log0log.h>

Public Attributes

byte pad [64]
ib_uint64_t lsn
ulint buf_free
mutex_t mutex
mutex_t log_flush_order_mutex
byte * buf_ptr
byte * buf
ulint buf_size
ulint max_buf_free
ulint old_buf_free
ib_uint64_t old_lsn
ibool check_flush_or_checkpoint
 log_groups
ulint buf_next_to_write
ib_uint64_t written_to_some_lsn
ib_uint64_t written_to_all_lsn
ib_uint64_t write_lsn
ulint write_end_offset
ib_uint64_t current_flush_lsn
ib_uint64_t flushed_to_disk_lsn
ulint n_pending_writes
os_event_t no_flush_event
ibool one_flushed
os_event_t one_flushed_event
ulint n_log_ios
ulint n_log_ios_old
time_t last_printout_time
ulint log_group_capacity
ulint max_modified_age_async
ulint max_modified_age_sync
ulint adm_checkpoint_interval
ulint max_checkpoint_age_async
ulint max_checkpoint_age
ib_uint64_t next_checkpoint_no
ib_uint64_t last_checkpoint_lsn
ib_uint64_t next_checkpoint_lsn
ulint n_pending_checkpoint_writes
rw_lock_t checkpoint_lock
byte * checkpoint_buf_ptr
byte * checkpoint_buf

Detailed Description

Redo log buffer

Definition at line 732 of file log0log.h.

Member Data Documentation

ulint log_struct::adm_checkpoint_interval

administrator-specified checkpoint interval in terms of log growth in bytes; the interval actually used by the database can be smaller

Definition at line 871 of file log0log.h.

Referenced by log_init().

byte* log_struct::buf
ulint log_struct::buf_free

first free offset within the log buffer

Definition at line 737 of file log0log.h.

Referenced by log_close(), log_init(), log_reserve_and_open(), log_write_low(), log_write_up_to(), recv_recovery_from_checkpoint_start_func(), and recv_reset_logs().

ulint log_struct::buf_next_to_write

The fields involved in the log buffer flush first offset in the log buffer where the byte content may not exist written to file, e.g., the start offset of a log record catenated later; this is advanced when a flush operation is completed to all the log groups

Definition at line 778 of file log0log.h.

Referenced by log_init(), log_write_up_to(), recv_recovery_from_checkpoint_start_func(), and recv_reset_logs().

ulint log_struct::buf_size

log buffer size in bytes

Definition at line 753 of file log0log.h.

Referenced by log_init(), log_reserve_and_open(), and log_write_low().

ibool log_struct::check_flush_or_checkpoint

this is set to TRUE when there may be need to flush the log buffer, or preflush buffer pool pages, or make a checkpoint; this MUST be TRUE when lsn - last_checkpoint_lsn > max_checkpoint_age; this flag is peeked at by log_free_check(), which does not reserve the log mutex

Definition at line 764 of file log0log.h.

Referenced by log_check_margins(), log_close(), and log_init().

byte* log_struct::checkpoint_buf

checkpoint header is read to this buffer

Definition at line 899 of file log0log.h.

Referenced by log_group_read_checkpoint_info(), log_init(), and recv_recovery_from_checkpoint_start_func().

rw_lock_t log_struct::checkpoint_lock

this latch is x-locked when a checkpoint write is running; a thread should wait for this without owning the log mutex

Definition at line 893 of file log0log.h.

Referenced by log_checkpoint(), and log_init().

ib_uint64_t log_struct::current_flush_lsn

end lsn for the current running write + flush operation

Definition at line 814 of file log0log.h.

Referenced by log_init(), and log_write_up_to().

ib_uint64_t log_struct::flushed_to_disk_lsn

how far we have written the log AND flushed to disk

Definition at line 817 of file log0log.h.

Referenced by log_checkpoint(), log_init(), log_print(), and log_write_up_to().

ib_uint64_t log_struct::last_checkpoint_lsn
time_t log_struct::last_printout_time

when log_print was last time called

Definition at line 848 of file log0log.h.

Referenced by log_init(), log_print(), and log_refresh_stats().

mutex_t log_struct::log_flush_order_mutex

mutex to serialize access to the flush list when we are putting dirty blocks in the list. The idea behind this mutex is to be able to release log_sys->mutex during mtr_commit and still ensure that insertions in the flush_list happen in the LSN order.

Definition at line 743 of file log0log.h.

Referenced by log_init().

ulint log_struct::log_group_capacity

Fields involved in checkpoints capacity of the log group; if the checkpoint age exceeds this, it is a serious error because it is possible we will then overwrite log and spoil crash recovery

Definition at line 853 of file log0log.h.

Referenced by log_close().

ulint log_struct::max_buf_free

recommended maximum value of buf_free, after which the buffer is flushed

Definition at line 754 of file log0log.h.

Referenced by log_close(), and log_init().

ulint log_struct::max_checkpoint_age

this is the maximum allowed value for lsn - last_checkpoint_lsn when a new query step is started

Definition at line 881 of file log0log.h.

Referenced by log_print(), and srv_master_thread().

ulint log_struct::max_checkpoint_age_async

when this checkpoint age is exceeded we start an asynchronous writing of a new checkpoint

Definition at line 876 of file log0log.h.

ulint log_struct::max_modified_age_async

when this recommended value for lsn - buf_pool_get_oldest_modification() is exceeded, we start an asynchronous preflush of pool pages

Definition at line 859 of file log0log.h.

Referenced by srv_master_thread().

ulint log_struct::max_modified_age_sync

when this recommended value for lsn - buf_pool_get_oldest_modification() is exceeded, we start a synchronous preflush of pool pages

Definition at line 865 of file log0log.h.

ulint log_struct::n_log_ios

number of log i/os initiated thus far

Definition at line 844 of file log0log.h.

Referenced by log_group_read_checkpoint_info(), log_group_read_log_seg(), log_group_write_buf(), log_init(), log_print(), log_refresh_stats(), and srv_master_thread().

ulint log_struct::n_log_ios_old

number of log i/o's at the previous printout

Definition at line 846 of file log0log.h.

Referenced by log_init(), log_print(), and log_refresh_stats().

ulint log_struct::n_pending_checkpoint_writes

number of currently pending checkpoint writes

Definition at line 891 of file log0log.h.

Referenced by log_checkpoint(), log_init(), log_print(), and logs_empty_and_mark_files_at_shutdown().

ulint log_struct::n_pending_writes

number of currently pending flushes or writes

Definition at line 819 of file log0log.h.

Referenced by log_init(), log_io_complete(), log_print(), log_write_up_to(), logs_empty_and_mark_files_at_shutdown(), and srv_master_thread().

ib_uint64_t log_struct::next_checkpoint_lsn

next checkpoint lsn

Definition at line 889 of file log0log.h.

Referenced by log_checkpoint(), and recv_recovery_from_checkpoint_start_func().

ib_uint64_t log_struct::next_checkpoint_no
os_event_t log_struct::no_flush_event

this event is in the reset state when a flush or a write is running; a thread should wait for this without owning the log mutex, but NOTE that to set or reset this event, the thread MUST own the log mutex!

Definition at line 825 of file log0log.h.

Referenced by log_init(), and log_write_up_to().

ulint log_struct::old_buf_free

value of buf free when log was last time opened; only in the debug version

Definition at line 757 of file log0log.h.

Referenced by log_close(), and log_reserve_and_open().

ib_uint64_t log_struct::old_lsn

value of lsn when log was last time opened; only in the debug version

Definition at line 760 of file log0log.h.

Referenced by log_close(), and log_reserve_and_open().

ibool log_struct::one_flushed

during a flush, this is first FALSE and becomes TRUE when one log group has been written or flushed

Definition at line 831 of file log0log.h.

Referenced by log_write_up_to().

os_event_t log_struct::one_flushed_event

this event is reset when the flush or write has not yet completed for any log group; e.g., this means that a transaction has been committed when this is set; a thread should wait for this without owning the log mutex, but NOTE that to set or reset this event, the thread MUST own the log mutex!

Definition at line 835 of file log0log.h.

Referenced by log_init(), and log_write_up_to().

byte log_struct::pad[64]

padding to prevent other memory update hotspots from residing on the same memory cache line

Definition at line 733 of file log0log.h.

ulint log_struct::write_end_offset

the data in buffer has been written up to this offset when the current write ends: this field will then be copied to buf_next_to_write

Definition at line 809 of file log0log.h.

Referenced by log_write_up_to().

ib_uint64_t log_struct::write_lsn

end lsn for the current running write

Definition at line 807 of file log0log.h.

Referenced by log_init(), and log_write_up_to().

ib_uint64_t log_struct::written_to_all_lsn

first log sequence number not yet written to some log group; for this to be advanced, it is enough that the write i/o has been completed for all log groups. Note that since InnoDB currently has only one log group therefore this value is redundant. Also it is possible that this value falls behind the flushed_to_disk_lsn transiently. It is appropriate to use either flushed_to_disk_lsn or write_lsn which are always up-to-date and accurate.

Definition at line 792 of file log0log.h.

Referenced by log_init(), log_write_up_to(), recv_recovery_from_checkpoint_start_func(), and recv_reset_logs().

ib_uint64_t log_struct::written_to_some_lsn

first log sequence number not yet written to any log group; for this to be advanced, it is enough that the write i/o has been completed for any one log group

Definition at line 786 of file log0log.h.

Referenced by log_init(), log_write_up_to(), recv_recovery_from_checkpoint_start_func(), and recv_reset_logs().


The documentation for this struct was generated from the following file: