innodb的锁时间

时间:2024-01-09 20:29:50

观察innodb的锁时间,需要关注:

mysqladmin extended-status -r -i 1 -uroot | grep "Innodb_row_lock_time"

Innodb_row_lock_current_waits:当前正在等待锁定的数量;

Innodb_row_lock_time :从系统启动到现在锁定的总时间长度,单位ms;

Innodb_row_lock_time_avg :每次等待所花平均时间;

Innodb_row_lock_time_max:从系统启动到现在等待最长的一次所花的时间;

Innodb_row_lock_waits :从系统启动到现在总共等待的次数。

如我的压测语句:

insert into i0( id, type, num, iid, uid, iid, sid,bid, cid, q, gmt_create, gmt_modified, status, version, time_out, time_number, o_gmt_create,aid, ff, flag, code, cache, sq, rq) values( :v_id, '',:v_opt_num, '', 1640350003, 16441266176, 0, '','', '', now(), now(), '', '', null, '', now(), '', null, '', 'C', 1, null, null);
update q0 set q=q-0, v=v+1, gmt_modified=now(), rq = CASE WHEN ((rq + 2 ) >= 0 ) then rq + 2 ELSE 0 END where id =6060 and iid = 16441266176 and sid = 0 and (q - rq - 2) >= 0 and q-0>=0;

压测结果:

Summary: SQL01 exec=11756, rows=11756=100/e, avg=518 us
Summary: SQL02 exec=12800, rows=12800=100/e, avg=14483 us
Summary: exec=8488/s, qtps=16343/s

观察到的锁情况:

| Innodb_row_lock_time                     | 868           |
| Innodb_row_lock_time_avg | 0 |
| Innodb_row_lock_time_max | 0 |
| Innodb_row_lock_time | 114932 |
| Innodb_row_lock_time_avg | 0 |
| Innodb_row_lock_time_max | 0 |
| Innodb_row_lock_time | 61775 |
| Innodb_row_lock_time_avg | 0 |
| Innodb_row_lock_time_max | 0 |
| Innodb_row_lock_time | 0 |

从占有锁到释放锁一共消耗:114932ms,不可能是一条记录的时间,再根据实时状态:

-------- -----load-avg---- ---cpu-usage--- ---swap---                     -QPS- -TPS-         -Hit%- ---innodb rows status---
time | 1m 5m 15m |usr sys idl iow| si so| ins upd del sel iud| lor hit| ins upd del read|
19:47:20| 1.26 1.21 1.20| 5 1 93 0| 0 0| 0 0 0 0 0| 0 100.00| 0 0 0 0|
19:47:21| 1.26 1.21 1.20| 1 1 98 0| 0 0| 0 1 0 5 1| 9 100.00| 0 1 0 1|
19:47:22| 1.24 1.21 1.20| 0 0 100 0| 0 0| 0 0 0 6 0| 1 100.00| 0 0 0 0|
19:47:23| 1.24 1.21 1.20| 7 3 90 0| 0 0| 2932 2930 0 6 5862| 100502 99.91| 2712 2809 0 2809|
19:47:24| 1.24 1.21 1.20| 16 4 79 0| 0 0| 7939 7940 0 6 15879| 293693 99.91| 7257 7954 0 7954|
19:47:25| 1.24 1.21 1.20| 5 2 93 0| 0 0| 1929 1932 0 6 3861| 101527 99.94| 1762 2039 0 2039|

实际每秒update 7940条,平均每条消耗:

root@(none) 07:47:33>select 114932/7940ms;
+-------------+
| 114932/7940 |
+-------------+
| 14.4751 |
+-------------+

平均每条消耗14.4751ms和压测结果avg=14483 us吻合,对于单条语句的更新来说这个锁占用的时间还是挺长的。