mysql note级别_Mysql5.7 的错误日志中最常见的note级别日志解释

在使用mysql5.7的时候,发现了不少在mysql5.6上不曾见过的日志,级别为note, 最常见的note日志以下三种,下面我们来逐个解释。

第一种,Aborted connection. 如上图,信息如下:

2016-03-17T14:44:24.102542Z 59 [Note] Aborted connection 59 to db: ‘unconnected’ user: ‘mha’ host: ‘197.xx.xx.xx’ (Got an error reading communication packets)

2016-03-17T14:44:31.273897Z 61 [Note] Aborted connection 61 to db: ‘unconnected’ user: ‘mha’ host: ‘197.xx.xx.xx(Got an error reading communication packets)

2016-03-17T14:44:31.273897Z 61 [Note] Aborted connection 61 to db: ‘unconnected’ user: ‘mha’ host: ‘197.xx.xx.xx(Got an error reading communication packets)

2016-03-17T14:44:31.273897Z 61 [Note] Aborted connection 61 to db: ‘unconnected’ user: ‘mha’ host: ‘197.xx.xx.xx(Got  timeout  reading communication packets)

上面两个是连接中断的错误信息,原因不一样,Got an error reading communication packets  的原因是因为网络等原因导致。 Got  timeout  reading communication packets 这个错误的原因是会话的idle时间达到了数据库指定的timeout时间。

第二种:SLAVE多线程同步的信息

信息如下:

2016-03-14T15:48:26.432150Z 73 [Note]Multi-threaded slave statistics for channel ”: seconds elapsed = 121; eventsassigned = 100374529; worker queues filled over

overrun level = 0; waited due aWorker queue full = 0; waited due the total size = 0; waited at clock conflicts= 1451875661700 waited (count) when Workers occupied = 3211993 waited whenWorkers occupied = 445032386000

2016-03-14T15:50:28.398745Z 73 [Note]Multi-threaded slave statistics for channel ”: seconds elapsed = 122; eventsassigned = 100500481; worker queues filled over

overrun level = 0; waited due aWorker queue full = 0; waited due the total size = 0; waited at clock conflicts= 1452001865500 waited (count) when Workers occupied = 3211993 waited whenWorkers occupied = 445032386000

我们通过源代码,找到下面一段,该段实现了上述日志的输出。

if ((my_now

– rli->mts_last_online_stat)>=

mts_online_stat_period)

{

sql_print_information(“Multi-threadedslave

statistics%s: “

“seconds

elapsed = %lu; “

“events

assigned = %llu; “

“worker

queues filled over overrun level = %lu;”

“waited

due a Worker queue full = %lu; “

“waited

due the total size = %lu; “

“waited

at clock conflicts = %llu “

“waited(count)

when Workers occupied = %lu “

“waited

when Workers occupied = %llu”,

rli->get_for_channel_str(),

static_cast

(my_now – rli->mts_last_online_stat),

rli->mts_events_assigned,

rli->mts_wq_overrun_cnt,

rli->mts_wq_overfill_cnt,

rli->wq_size_waits_cnt,

rli->mts_total_wait_overlap,

rli->mts_wq_no_underrun_cnt,

rli->mts_total_wait_worker_avail);

rli->mts_last_online_stat=my_now;

通过这一句(my_now

– rli->mts_last_online_stat),  以及最后一句rli->mts_last_online_stat=my_now;   可以得知,

seconds elapsed 就是上一次统计跟这一次统计的时间间隔。

而mts_online_stat_period =120秒,硬代码,因此就是几乎每隔120秒,就有上述日志的输出。

通过进一步查看原代码,初步了解上述日志信息的含义,如下:

events assigned:总共有多少个event被分配执行,计的是总数。

worker queues filled over overrun level:多线程同步中,worker 的私有队列长度超长的次数,计的是总数。

waited due a Worker queue full :因为worker的队列超长而产生等待的次数,计的是总数。

waited due the total size :超过最大size的次数,这个由参数slave_pending_jobs_size_max  指定。

waited at clock conflicts :因为逻辑时间产生冲突的等待时间,单位是纳秒。

waited (count) when Workers occupied :因为workder被占用而出现等待的次数。(总计值)。

waited when Workersoccupied :因为workder被占用而出现等待的总时间,总计值,单位是纳秒。

第三种:page_cleaner线程的输出日志

如图,信息如下:

2016-03-24T17:45:28.005117Z 0 [Note] InnoDB:page_cleaner: 1000ms intended loop took 4750ms.The

settings might not be optimal. (flushed=1519 and evicted=0, during the time.)

查找源代码,发现是上面的日志由下面一段代码输出:

if (ret_sleep

== OS_SYNC_TIME_EXCEEDED) {

ulint

curr_time = ut_time_ms();

if (curr_time

>next_loop_time + 3000) {

if (warn_count

== 0) {

ib::info()

<< “page_cleaner: 1000ms”

” intended

loop took “

<<1000 + curr_time

– next_loop_time

<

settings might not”

” be optimal.

(flushed=”

<

<

<

<

the time.)”;

if (warn_interval

>300) {

warn_interval= 600;

}else {

warn_interval*= 2;

}

warn_count= warn_interval;

} else {

–warn_count;

}

} else {

/* reset counter */

warn_interval= 1;

warn_count= 0;

}

next_loop_time= curr_time + 1000;

n_flushed_last= n_evicted = 0;

}

通过分析源代码, 输出上述日志的条件是curr_time> next_loop_time + 3000 ,即比原定的循环时间next_loop_time多3000毫秒,而next_loop_time的标准时间是1000毫秒,即1秒钟做一次刷新页的操作。

loop took 4750ms ,即是这次刷新循环的实际经历时间。

后面还有一个(flushed=1519 and evicted=0,during the time.)这样的日志,即对应n_flushed_last与n_evicted 变量,而这两个变量又由n_flushed_list与n_flushed_lru赋值。

./storage/innobase/buf/buf0flu.cc:3322:                 n_flushed_last +=n_flushed_list;

./storage/innobase/buf/buf0flu.cc:3321:                 n_evicted += n_flushed_lru;

而n_flushed_list与n_flushed_lru赋值函数为pc_wait_finished,如下,我们来看看该函数的注释。

pc_wait_finished(&n_flushed_lru,&n_flushed_list);

/**

Wait until all flush requests are finished.

@param n_flushed_lru    numberof pages flushed from the end of the LRU list.

@param n_flushed_list   numberof pages flushed from the end of the

flush_list.

@return         trueif all flush_list flushing batch were success. */

static

bool

pc_wait_finished(

ulint*  n_flushed_lru,

ulint*  n_flushed_list)

{

。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。

}

通过源代码的注释,我们获知如下信息:

n_flushed_lru  number of pages flushed from the end of the LRU list.

n_flushed_lru  这个值表示从lru 列表尾部刷新的页数,也就是日志中如evicted=0 指标的所表示的值,如果该值不为零,则存在innodbbuffer不够的嫌疑。

n_flushed_list 这个是从刷新列表中刷新的页数,也就是脏页数,也就是日志中flushed=1519 的值。

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