Adaptive_flush Namespace Reference

Functions
bool	initialize (ulint n_pages_last)
	Initialize flush parameters for current iteration. More...
void	set_average ()
	Set average LSN and page flush speed across multiple iterations. More...
ulint	get_pct_for_dirty ()
	Calculates if flushing is required based on number of dirty pages in the buffer pool. More...
ulint	get_pct_for_lsn (lsn_t age)
	Calculates if flushing is required based on redo generation rate. More...
ulint	set_flush_target_by_lsn (bool sync_flush, lsn_t sync_flush_limit_lsn)
	Set page flush target based on LSN change and checkpoint age. More...
ulint	set_flush_target_by_page (ulint n_pages_lsn)
	Set page flush target based on dirty pages in buffer pool. More...
ulint	page_recommendation (ulint last_pages_in, bool is_sync_flush, lsn_t sync_flush_limit_lsn)
	This function is called approximately once every second by the page_cleaner thread, unless it is sync flushing mode, in which case it is called every small round. More...

Variables
std::chrono::steady_clock::time_point	cur_iter_time
	Time stamp of current iteration. More...
lsn_t	cur_iter_lsn = 0
	LSN at current iteration. More...
ulint	cur_iter_pages_dirty = 0
	Number of dirty pages in flush list in current iteration. More...
ulint	cur_iter_dirty_pct = 0
	Dirty page percentage in buffer pool. More...
std::chrono::steady_clock::time_point	prev_iter_time
	Time stamp of previous iteration. More...
ulint	prev_iter_pages_dirty = 0
	Number of dirty pages in flush list at previous iteration. More...
ulint	prev_iter_pages_flushed = 0
	Actual number of pages flushed by last iteration. More...
lsn_t	lsn_avg_rate = 0
	Average redo generation rate. More...
ulint	page_avg_rate = 0
	Average page flush rate. More...
lsn_t	prev_lsn = 0
	LSN when last average rates are computed. More...
std::chrono::steady_clock::time_point	prev_time
	Time stamp when last average rates are computed. More...
ulint	n_iterations = 0
	Number of iteration till average rates are computed. More...
ulint	sum_pages = 0
	Pages flushed till last average rates are computed. More...

Function Documentation

get_pct_for_dirty()

ulint Adaptive_flush::get_pct_for_dirty

(

)

Calculates if flushing is required based on number of dirty pages in the buffer pool.

Returns

percent of io_capacity to flush to manage dirty page ratio

get_pct_for_lsn()

ulint Adaptive_flush::get_pct_for_lsn

(

lsn_t

age

)

Calculates if flushing is required based on redo generation rate.

Returns

percent of io_capacity to flush to manage redo space

Parameters

age	in: current age of LSN.

initialize()

bool Adaptive_flush::initialize

(

ulint

n_pages_last

)

Initialize flush parameters for current iteration.

Parameters

[in]

n_pages_last

number of pages flushed in last iteration

Returns

true if current iteration should be skipped.

page_recommendation()

ulint Adaptive_flush::page_recommendation	(	ulint	last_pages_in,
		bool	is_sync_flush,
		lsn_t	sync_flush_limit_lsn
	)

This function is called approximately once every second by the page_cleaner thread, unless it is sync flushing mode, in which case it is called every small round.

Based on various factors it decides if there is a need to do flushing.

Parameters

last_pages_in	the number of pages flushed by the last flush_list flushing
is_sync_flush	true iff this is sync flush mode
sync_flush_limit_lsn	low limit for oldest_modification if is_sync_flush is true

Returns

number of pages recommended to be flushed

set_average()

void Adaptive_flush::set_average

(

)

Set average LSN and page flush speed across multiple iterations.

set_flush_target_by_lsn()

ulint Adaptive_flush::set_flush_target_by_lsn	(	bool	sync_flush,
		lsn_t	sync_flush_limit_lsn
	)

Set page flush target based on LSN change and checkpoint age.

Parameters

[in]	sync_flush	true iff this is sync flush mode
[in]	sync_flush_limit_lsn	low limit for oldest_modification if sync_flush is true

Returns

number of pages requested to flush

set_flush_target_by_page()

ulint Adaptive_flush::set_flush_target_by_page

(

ulint

n_pages_lsn

)

Set page flush target based on dirty pages in buffer pool.

Set only if the target are is found to be higher than the target evaluated based on LSN.

Parameters

[in]

n_pages_lsn

number of pages estimated and set based on LSN

Returns

page flush target.

Variable Documentation

cur_iter_dirty_pct

ulint Adaptive_flush::cur_iter_dirty_pct = 0

Dirty page percentage in buffer pool.

cur_iter_lsn

lsn_t Adaptive_flush::cur_iter_lsn = 0

LSN at current iteration.

cur_iter_pages_dirty

ulint Adaptive_flush::cur_iter_pages_dirty = 0

Number of dirty pages in flush list in current iteration.

cur_iter_time

std::chrono::steady_clock::time_point Adaptive_flush::cur_iter_time

Time stamp of current iteration.

lsn_avg_rate

lsn_t Adaptive_flush::lsn_avg_rate = 0

Average redo generation rate.

n_iterations

ulint Adaptive_flush::n_iterations = 0

Number of iteration till average rates are computed.

page_avg_rate

ulint Adaptive_flush::page_avg_rate = 0

Average page flush rate.

prev_iter_pages_dirty

ulint Adaptive_flush::prev_iter_pages_dirty = 0

Number of dirty pages in flush list at previous iteration.

prev_iter_pages_flushed

ulint Adaptive_flush::prev_iter_pages_flushed = 0

Actual number of pages flushed by last iteration.

prev_iter_time

std::chrono::steady_clock::time_point Adaptive_flush::prev_iter_time

Time stamp of previous iteration.

prev_lsn

lsn_t Adaptive_flush::prev_lsn = 0

LSN when last average rates are computed.

prev_time

std::chrono::steady_clock::time_point Adaptive_flush::prev_time

Time stamp when last average rates are computed.

sum_pages

ulint Adaptive_flush::sum_pages = 0

Pages flushed till last average rates are computed.