void master_thread()

{

int innodb_io_capacity = 200 ；//表示磁盘IO吞吐量

int innodb_max_dirty_pages_pct = 75 ；//最大脏页百分比

goto loop;

loop:

//1秒循环

for(int i = o; i<10; i++)

{

thread_sleep(1);//innodb 优化，压力大时不总是等待1秒

//日志缓冲刷新到磁盘

do log buffer flush to disk;

//如果磁盘压力小，合并插入缓冲

if ( last_one_second_ios < innodb_io_capacity*5%  )

{

do merge at most innodb_io_capacity*5% insert buffer;

}

//判断脏页比例

if ( buf_get_modified_ratio_pct > innodb_max_dirty_pages_pct )

{

do buffer pool flush innodb_io_capacity*100% dirty page;

}

//如果开启自适应刷新，通过判断产生重做日志的速度来判断合适的刷新脏页数量

else if enable adaptive flush

{

do buffer pool flush desired amount dirty page;

}

//如果无用户活动，切换到 backgroud loop

if ( no user activity )

{

goto backgroud loop;

}

}

//10秒循环

//如果磁盘压力小，刷新innodb_io_capacity*100%的脏页到磁盘

if ( last_ten_second_ios < innodb_io_capacity )

{

do buffer pool flush innodb_io_capacity*100% dirty page;

}

//合并插入缓冲

do merge at most innodb_io_capacity*5% insert buffer;

//日志缓冲刷新到磁盘

do log buffer flush to disk;

//删除无用undo页，每次最多删除20个undo页

do full purge;

//判断脏页比例

if ( buf_get_modified_ratio_pct >70% )//---------

{

do buffer pool flush innodb_io_capacity*100% dirty page;

}

else

{

do buffer pool flush innodb_io_capacity*10% dirty page;

}

//产生一个模糊检查点，只是将最老日志序列号的页写入磁盘

do fuzzy checkpoint;

goto loop;

//backgroud

backgroud loop:

//删除无用undo页

do full purge;

//合并插入缓冲

do merge innodb_io_capacity*100% insert buffer;

//不空闲跳回主循环，空闲则进入flush loop

if not idle

{

goto loop;

}

else

{

goto flush loop;

}

//flush loop

flush loop:

//不断刷新脏页到磁盘，直到脏页比例小于innodb_max_dirty_pages_pct，则进入suspend loop

do buffer pool flush innodb_io_capacity*100% dirty page;

while ( buf_get_modified_ratio_pct > innodb_max_dirty_pages_pct );

goto suspend loop;

//suspend loop

suspend loop:

suspend_thread();

waiting event;

goto loop;

}