MySQL Replication--复制延迟02--exec_time测试

复制延迟(Seconds_Behind_Master)测试

测试环境： MySQL 5.7.19

测试主从时间差：

检查主从系统时间差，同时在主库和从库执行SELECT NOW()语句：
主库：2019-06-24 10:57:56
从库：2019-06-24 10:58:10
从库比主库提前14秒，主从时间差14秒。

在主库上执行(使用基于语句格式复制)：

select now();
update tb003 set c1=SLEEP(20) where id=1;
select now();

主库上上执行效果：

mysql> select now();
+---------------------+
| now()               |
+---------------------+
| 2019-06-24 11:01:54 |
+---------------------+
1 row in set (0.00 sec)

mysql> update tb003 set c1=SLEEP(20) where id=1;
Query OK, 1 row affected, 1 warning (20.06 sec)
Rows matched: 1  Changed: 1  Warnings: 1

mysql> select now();
+---------------------+
| now()               |
+---------------------+
| 2019-06-24 11:02:14 |
+---------------------+
1 row in set (0.00 sec)

主库上生成的binlog解析结果:

#190624 11:01:54 server id 1614520  end_log_pos 259 CRC32 0xcf2313f1     GTID    last_committed=0    sequence_number=1    rbr_only=no
SET @@SESSION.GTID_NEXT= '025fd638-89ea-11e9-a749-40f2e9cf3aaa:9'/*!*/;
# at 259
#190624 11:01:54 server id 1614520  end_log_pos 340 CRC32 0xa14a2bcb     Query    thread_id=3186    exec_time=20    error_code=0
SET TIMESTAMP=1561345314/*!*/;
BEGIN
/*!*/;
# at 340
#190624 11:01:54 server id 1614520  end_log_pos 456 CRC32 0xc283c9af     Query    thread_id=3186    exec_time=20    error_code=0
use `db001`/*!*/;
SET TIMESTAMP=1561345314/*!*/;
update tb003 set c1=SLEEP(20) where id=1
/*!*/;
# at 456
#190624 11:01:54 server id 1614520  end_log_pos 487 CRC32 0x0f3bdc57     Xid = 10020
COMMIT/*!*/;

从库上relay log解析结果：

BINLOG '
+zwQXQ+4ohgAdwAAAAAAAAAgAAQANS43LjE5LWxvZwAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAEzgNAAgAEgAEBAQEEgAAXwAEGggAAAAICAgCAAAACgoKKioAEjQA
Af0UlBk=
'/*!*/;
# at 313
#190624 11:01:54 server id 1614520  end_log_pos 259 CRC32 0xcf2313f1     GTID    last_committed=0    sequence_number=1    rbr_only=no
SET @@SESSION.GTID_NEXT= '025fd638-89ea-11e9-a749-40f2e9cf3aaa:9'/*!*/;
# at 378
#190624 11:01:54 server id 1614520  end_log_pos 340 CRC32 0xa14a2bcb     Query    thread_id=3186    exec_time=20    error_code=0
SET TIMESTAMP=1561345314/*!*/;
BEGIN
/*!*/;
# at 459
#190624 11:01:54 server id 1614520  end_log_pos 456 CRC32 0xc283c9af     Query    thread_id=3186    exec_time=20    error_code=0
use `db001`/*!*/;
SET TIMESTAMP=1561345314/*!*/;
update tb003 set c1=SLEEP(20) where id=1
/*!*/;
# at 575
#190624 11:01:54 server id 1614520  end_log_pos 487 CRC32 0x0f3bdc57     Xid = 10020
COMMIT/*!*/;

从库上生成binlog解析结果(从库上默认binlog_format=row)：

#190624 11:01:54 server id 1614520  end_log_pos 259 CRC32 0x6e1a971f     GTID    last_committed=0    sequence_number=1    rbr_only=yes
/*!50718 SET TRANSACTION ISOLATION LEVEL READ COMMITTED*//*!*/;
SET @@SESSION.GTID_NEXT= '025fd638-89ea-11e9-a749-40f2e9cf3aaa:9'/*!*/;
# at 259
#190624 11:01:54 server id 1614520  end_log_pos 332 CRC32 0x063cd6ca     Query    thread_id=3186    exec_time=54    error_code=0
SET TIMESTAMP=1561345314/*!*/;
BEGIN
/*!*/;
# at 332
#190624 11:01:54 server id 1614520  end_log_pos 396 CRC32 0x405b61c7     Rows_query
# update tb003 set c1=SLEEP(20) where id=1
# at 396
#190624 11:01:54 server id 1614520  end_log_pos 448 CRC32 0x015803f1     Table_map: `db001`.`tb003` mapped to number 232
# at 448
#190624 11:01:54 server id 1614520  end_log_pos 518 CRC32 0xb59069f9     Update_rows: table id 232 flags: STMT_END_F

BINLOG '
Ij0QXR24ohgAQAAAAIwBAACAACh1cGRhdGUgdGIwMDMgc2V0IGMxPVNMRUVQKDIwKSB3aGVyZSBp
ZD0xx2FbQA==
Ij0QXRO4ohgANAAAAMABAAAAAOgAAAAAAAEABWRiMDAxAAV0YjAwMwADCAMRAQAC8QNYAQ==
Ij0QXR+4ohgARgAAAAYCAAAAAOgAAAAAAAEAAgAD///4AQAAAAAAAAABAAAAXRA89fgBAAAAAAAA
AAAAAABdED0i+WmQtQ==
'/*!*/;
### UPDATE `db001`.`tb003`
### WHERE
###   @1=1 /* LONGINT meta=0 nullable=0 is_null=0 */
###   @2=1 /* INT meta=0 nullable=1 is_null=0 */
###   @3=1561345269 /* TIMESTAMP(0) meta=0 nullable=0 is_null=0 */
### SET
###   @1=1 /* LONGINT meta=0 nullable=0 is_null=0 */
###   @2=0 /* INT meta=0 nullable=1 is_null=0 */
###   @3=1561345314 /* TIMESTAMP(0) meta=0 nullable=0 is_null=0 */
# at 518
#190624 11:01:54 server id 1614520  end_log_pos 549 CRC32 0xae037515     Xid = 6241
COMMIT/*!*/;

无论时主库binlog事件中还是从库relaylog事件以及从库binlog事件中记录的时间都是事务语句执行开始时间：

SET TIMESTAMP=1561345314/*!*/;

SELECT FROM_UNIXTIME(1561345314);
+---------------------------+
| FROM_UNIXTIME(1561345314) |
+---------------------------+
| 2019-06-24 11:01:54       |
+---------------------------+

exec_time计算：The time from when the query started to when it was logged in the binlog, in seconds.

1、由于SQL语句中使用函数SLEEP(20),因此SQL语句执行时间=SLEEP(20)的执行时间+UPDATE操作的执行时间，而UPDATE操作的执行时间在10ms以内，因此整个SQL语句在主库的执行时间=20S，因此主库binlog的中记录exec_time=20

2、从库的relaylog用来存放主库传递过来的binlog，因此从库relaylog与主库binlog相同，从库relaylog中记录也是exec_time=20

3、由于主库使用binlog_format=statement的复制格式，因此SQL语句被传递到从库并原样执行，同样执行需要20S，但该语句在主库的开始执行时间(the query started)为2019-06-24 11:01:54，而在从库执行结束时间(log in binlog)为2019-06-24 11:02:48，因此从库binlog中记录时间exec_time=54,忽略主从事务日志落盘和网络传输时间，exec_time=54S=主库语句执行时间(20)+从库语句执行时间(20S)+主从时间差(14S)。

在主库上执行(使用基于行格式复制)：

mysql> select now();
+---------------------+
| now()               |
+---------------------+
| 2019-06-25 08:40:05 |
+---------------------+
1 row in set (0.00 sec)

mysql> update tb003 set c1=SLEEP(20) where id in (3,4);
Query OK, 2 rows affected (40.04 sec)
Rows matched: 2  Changed: 2  Warnings: 0

mysql> select now();
+---------------------+
| now()               |
+---------------------+
| 2019-06-25 08:40:45 |
+---------------------+
1 row in set (0.00 sec)

产生的binlog解析结果为：

# at 549
#190625  8:40:05 server id 1614520  end_log_pos 614 CRC32 0x037e9b24     GTID    last_committed=1    sequence_number=2    rbr_only=yes
/*!50718 SET TRANSACTION ISOLATION LEVEL READ COMMITTED*//*!*/;
SET @@SESSION.GTID_NEXT= '025fd638-89ea-11e9-a749-40f2e9cf3aaa:65'/*!*/;
# at 614
#190625  8:40:05 server id 1614520  end_log_pos 687 CRC32 0xe186daee     Query    thread_id=837    exec_time=20  error_code=0
SET TIMESTAMP=1561423205/*!*/;
BEGIN
/*!*/;
# at 687
#190625  8:40:05 server id 1614520  end_log_pos 758 CRC32 0x9f76a54a     Rows_query
# update tb003 set c1=SLEEP(20) where id in (3,4)
# at 758
#190625  8:40:05 server id 1614520  end_log_pos 810 CRC32 0x139892d9     Table_map: `db001`.`tb003` mapped to number 108
# at 810
#190625  8:40:05 server id 1614520  end_log_pos 914 CRC32 0xf7980c93     Update_rows: table id 108 flags: STMT_END_F

BINLOG '
ZW0RXR24ohgARwAAAPYCAACAAC91cGRhdGUgdGIwMDMgc2V0IGMxPVNMRUVQKDIwKSB3aGVyZSBp
ZCBpbiAoMyw0KUqldp8=
ZW0RXRO4ohgANAAAACoDAAAAAGwAAAAAAAEABWRiMDAxAAV0YjAwMwADCAMRAQAC2ZKYEw==
ZW0RXR+4ohgAaAAAAJIDAAAAAGwAAAAAAAEAAgAD///4AwAAAAAAAAABAAAAXRFrW/gDAAAAAAAA
AAAAAABdEW1l+AQAAAAAAAAAAQAAAF0Ra1v4BAAAAAAAAAAAAAAAXRFtZZMMmPc=
'/*!*/;
### UPDATE `db001`.`tb003`
### WHERE
###   @1=3 /* LONGINT meta=0 nullable=0 is_null=0 */
###   @2=1 /* INT meta=0 nullable=1 is_null=0 */
###   @3=1561422683 /* TIMESTAMP(0) meta=0 nullable=0 is_null=0 */
### SET
###   @1=3 /* LONGINT meta=0 nullable=0 is_null=0 */
###   @2=0 /* INT meta=0 nullable=1 is_null=0 */
###   @3=1561423205 /* TIMESTAMP(0) meta=0 nullable=0 is_null=0 */
### UPDATE `db001`.`tb003`
### WHERE
###   @1=4 /* LONGINT meta=0 nullable=0 is_null=0 */
###   @2=1 /* INT meta=0 nullable=1 is_null=0 */
###   @3=1561422683 /* TIMESTAMP(0) meta=0 nullable=0 is_null=0 */
### SET
###   @1=4 /* LONGINT meta=0 nullable=0 is_null=0 */
###   @2=0 /* INT meta=0 nullable=1 is_null=0 */
###   @3=1561423205 /* TIMESTAMP(0) meta=0 nullable=0 is_null=0 */
# at 914
#190625  8:40:05 server id 1614520  end_log_pos 945 CRC32 0x1f65c801     Xid = 2610
COMMIT/*!*/;

在主库上执行(使用基于行格式复制+两条语句组合事务操作)：

mysql> select now();
+---------------------+
| now()               |
+---------------------+
| 2019-06-25 08:55:56 |
+---------------------+
1 row in set (0.00 sec)

mysql> begin;
Query OK, 0 rows affected (0.00 sec)

mysql> update tb003 set c1=SLEEP(20) where id =5;
Query OK, 1 row affected (20.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> update tb003 set c1=SLEEP(20) where id =6;
Query OK, 1 row affected (20.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> commit;
Query OK, 0 rows affected (0.05 sec)

mysql> select now();
+---------------------+
| now()               |
+---------------------+
| 2019-06-25 08:56:36 |
+---------------------+
1 row in set (0.00 sec)

产生的binlog解析结果为：

# at 945
#190625  8:56:36 server id 1614520  end_log_pos 1010 CRC32 0x5a8cb5f0     GTID    last_committed=2    sequence_number=3    rbr_only=yes
/*!50718 SET TRANSACTION ISOLATION LEVEL READ COMMITTED*//*!*/;
SET @@SESSION.GTID_NEXT= '025fd638-89ea-11e9-a749-40f2e9cf3aaa:66'/*!*/;
# at 1010
#190625  8:55:56 server id 1614520  end_log_pos 1083 CRC32 0x5217a928     Query    thread_id=838    exec_time=20  error_code=0
SET TIMESTAMP=1561424156/*!*/;
BEGIN
/*!*/;
# at 1083
#190625  8:55:56 server id 1614520  end_log_pos 1148 CRC32 0x1a70cac7     Rows_query
# update tb003 set c1=SLEEP(20) where id =5
# at 1148
#190625  8:55:56 server id 1614520  end_log_pos 1200 CRC32 0x4cf6d8c7     Table_map: `db001`.`tb003` mapped to number 108
# at 1200
#190625  8:55:56 server id 1614520  end_log_pos 1270 CRC32 0x033f26f8     Update_rows: table id 108 flags: STMT_END_F

BINLOG '
HHERXR24ohgAQQAAAHwEAACAACl1cGRhdGUgdGIwMDMgc2V0IGMxPVNMRUVQKDIwKSB3aGVyZSBp
ZCA9NcfKcBo=
HHERXRO4ohgANAAAALAEAAAAAGwAAAAAAAEABWRiMDAxAAV0YjAwMwADCAMRAQACx9j2TA==
HHERXR+4ohgARgAAAPYEAAAAAGwAAAAAAAEAAgAD///4BQAAAAAAAAABAAAAXRDBV/gFAAAAAAAA
AAAAAABdEXEc+CY/Aw==
'/*!*/;
### UPDATE `db001`.`tb003`
### WHERE
###   @1=5 /* LONGINT meta=0 nullable=0 is_null=0 */
###   @2=1 /* INT meta=0 nullable=1 is_null=0 */
###   @3=1561379159 /* TIMESTAMP(0) meta=0 nullable=0 is_null=0 */
### SET
###   @1=5 /* LONGINT meta=0 nullable=0 is_null=0 */
###   @2=0 /* INT meta=0 nullable=1 is_null=0 */
###   @3=1561424156 /* TIMESTAMP(0) meta=0 nullable=0 is_null=0 */
# at 1270
#190625  8:56:16 server id 1614520  end_log_pos 1335 CRC32 0x3b3202fa     Rows_query
# update tb003 set c1=SLEEP(20) where id =6
# at 1335
#190625  8:56:16 server id 1614520  end_log_pos 1387 CRC32 0x8b013c05     Table_map: `db001`.`tb003` mapped to number 108
# at 1387
#190625  8:56:16 server id 1614520  end_log_pos 1457 CRC32 0xf7d67996     Update_rows: table id 108 flags: STMT_END_F

BINLOG '
MHERXR24ohgAQQAAADcFAACAACl1cGRhdGUgdGIwMDMgc2V0IGMxPVNMRUVQKDIwKSB3aGVyZSBp
ZCA9NvoCMjs=
MHERXRO4ohgANAAAAGsFAAAAAGwAAAAAAAEABWRiMDAxAAV0YjAwMwADCAMRAQACBTwBiw==
MHERXR+4ohgARgAAALEFAAAAAGwAAAAAAAEAAgAD///4BgAAAAAAAAABAAAAXRB9NvgGAAAAAAAA
AAAAAABdEXEwlnnW9w==
'/*!*/;
### UPDATE `db001`.`tb003`
### WHERE
###   @1=6 /* LONGINT meta=0 nullable=0 is_null=0 */
###   @2=1 /* INT meta=0 nullable=1 is_null=0 */
###   @3=1561361718 /* TIMESTAMP(0) meta=0 nullable=0 is_null=0 */
### SET
###   @1=6 /* LONGINT meta=0 nullable=0 is_null=0 */
###   @2=0 /* INT meta=0 nullable=1 is_null=0 */
###   @3=1561424176 /* TIMESTAMP(0) meta=0 nullable=0 is_null=0 */
# at 1457
#190625  8:56:36 server id 1614520  end_log_pos 1488 CRC32 0x8b074201     Xid = 2625
COMMIT/*!*/;

可以发现上面两个操作都执行了40秒，但在事务开始前(BEGIN)的exec_time都仅为20,且事务内部单个操作没有exec_time。

ev->exec_time的计算在sql/log_event.cc中的代码如下：

  /*
  exec_time calculation has changed to use the same method that is used
  to fill out "thd_arg->start_time"
  */

  struct timeval end_time;
  ulonglong micro_end_time= my_micro_time();
  my_micro_time_to_timeval(micro_end_time, &end_time);

  exec_time= end_time.tv_sec - thd_arg->start_time.tv_sec;

exec_time在文件sql/log_event.h中的注解如下：

  <tr>
    <td>exec_time</td>
    <td>4 byte unsigned integer</td>
    <td>The time from when the query started to when it was logged in the binlog, in seconds.</td>
  </tr>