MySQL如何获取binlog的开始时间和结束时间
MySQL数据库恢复到指定时间点时，我们必须通过MySQL全备+MySQL增量备份（可选）+MySQL的二进制日志（binlog）进行重放来恢复到指定时间点，实际的生产环境中，可能一段时间内生成了多个二进制日志文件（binlog）, MySQL本身不会存储二进制日志文件（binlog）的开始时间和结束时间，如果要还原到某个时间点，我们需要知道还原后重放哪些二进制日志文件。那么就必须获取二进制日志（binlog)的开始时间和结束时间。那么我们如何获取MySQL二进制日志文件（binlog）的开始时间和结束时间呢？下面简单总结几个方法,以供参考。
1：通过xtrabackup_info文件获取
Xtrabckup还原全备或增量备份时，会生成一个xtrabackup_info文件，如下所示：
$ more xtrabackup_info
uuid = 3bd8a0f7-ea2f-11ed-9896-00505697b437
name =
tool_name = xtrabackup
tool_command = --defaults-file=/data/conf/my.cnf --login-path=**** --backup --target-dir=/db_backup/mysql_backup/db_backup/backup_cycle_2023_04_30/full_backup_2023_05_04_11_53_25
tool_version = 8.0.31-24
ibbackup_version = 8.0.31-24
server_version = 8.0.31
start_time = 2023-05-04 11:53:26
end_time = 2023-05-04 11:53:30
lock_time = 0
binlog_pos = filename 'mysql_binlog.000042', position '289', GTID of the last change 'd01ecb4f-c944-11ed-9896-00505697b437:1-111:100
0108-1953894,d01edb91-c944-11ed-9896-00505697b437:1-5,f8ef839e-c942-11ed-9bd2-00505697b437:1-13'
innodb_from_lsn = 0
innodb_to_lsn = 824007891
partial = N
incremental = N
format = file
compressed = N
encrypted = N
如上所示，你可以看到一行关于binlog_pos的信息：binlog文件名为mysql_binlog.000042，起始位置为289，我们应用MySQL二进制日志（binlog）可以从这个二进制日志开始：
mysqlbinlog --start-position="289" ./mysql_binlog.000042 > restore.sql
这个方法有局限性，只能被动获取我们需要重放二进制日志的文件名和开始位置。这里仅供参考。
2:通过mysqlbinlog解析获取
如下所示，我们想知道mysql_binlog.000042什么时候开始生成，什么时候开始结束的，其实MySQL二进制日志里面包含有这样的信息，如下所示：
$ mysqlbinlog mysql_binlog.000042 | head -10
# The proper term is pseudo_replica_mode, but we use this compatibility alias
# to make the statement usable on server versions 8.0.24 and older.
/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=1*/;
/*!50003 SET @OLD_COMPLETION_TYPE=@@COMPLETION_TYPE,COMPLETION_TYPE=0*/;
DELIMITER /*!*/;
# at 4
#230504 11:53:30 server id 1 end_log_pos 126 Start: binlog v 4, server v 8.0.31 created 230504 11:53:30
BINLOG '
OixTZA8BAAAAegAAAH4AAAAAAAQAOC4wLjMxAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAEwANAAgAAAAABAAEAAAAYgAEGggAAAAICAgCAAAACgoKKioAEjQA
我们可以通过获取关键字Start: binlog获取这一行的信息，从而获取MySQL二进制日志（binlog）的开始时间，如下所示：
$ mysqlbinlog mysql_binlog.000042 |grep "Start: binlog"
#230504 11:53:30 server id 1 end_log_pos 126 Start: binlog v 4, server v 8.0.31 created 230504 11:53:30
$ mysqlbinlog mysql_binlog.000042 |grep "Start: binlog" | awk -F "server id" '{print $1}'
#230504 11:53:30
如上所示，生成mysql_binlog.000042的时间点为230504 11:53:30，这里年份使用了缩写模式，即2023缩写为23，230504代表的是2023-05-04.
如果要获取二进制日志（binlog）的结束时间，这个还要看二进制日志是正常循环结束还是实例关闭结束，它们会对应不同的信息
STOP_EVENTA STOP_EVENT has not payload or post-header
ROTATE_EVENT
The rotate event is added to the binlog as last event to tell the reader what binlog to request next.
如下所示：
$ mysqlbinlog mysql_binlog.000042 | tail -10
# at 533
#230504 12:13:35 server id 3 end_log_pos 560 Xid = 50948183
COMMIT/*!*/;
# at 560
#230504 12:14:03 server id 1 end_log_pos 606 Rotate to mysql_binlog.000043 pos: 4
SET @@SESSION.GTID_NEXT= 'AUTOMATIC' /* added by mysqlbinlog */ /*!*/;
DELIMITER ;
# End of log file
/*!50003 SET COMPLETION_TYPE=@OLD_COMPLETION_TYPE*/;
/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=0*/;
$ mysqlbinlog mysql_binlog.000042 |grep Rotate
#230504 12:14:03 server id 1 end_log_pos 606 Rotate to mysql_binlog.000043 pos: 4
$ mysqlbinlog mysql_binlog.000042 |grep Rotate | awk -F "server id" '{print $1}'
#230504 12:14:03
如果MySQL关闭后，对应的MySQL二进制日志的格式如下所示：
$ mysqlbinlog mysql_binlog.000045 | tail -10
# at 126
#230504 17:02:23 server id 10 end_log_pos 157 CRC32 0x2d378ba5 Previous-GTIDs
# [empty]
# at 157
#230504 17:08:11 server id 10 end_log_pos 180 CRC32 0xb6b08f2c Stop
SET @@SESSION.GTID_NEXT= 'AUTOMATIC' /* added by mysqlbinlog */ /*!*/;
DELIMITER ;
# End of log file
/*!50003 SET COMPLETION_TYPE=@OLD_COMPLETION_TYPE*/;
/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=0*/;
$ mysqlbinlog mysql_binlog.000045 | grep Stop | awk -F "server id" '{print $1}'
方法3：stat命令查看创建时间
在Linux平台，我们可以通过stat命令查看文件的创建时间，如下所示
$ stat mysql_binlog.000042
File: mysql_binlog.000042
Size: 606 Blocks: 8 IO Block: 4096 regular file
Device: fd08h/64776d Inode: 100663444 Links: 1
Access: (0640/-rw-r-----) Uid: ( 801/ mysql) Gid: ( 800/ mysql)
Access: 2023-05-04 13:36:54.872910222 +0800
Modify: 2023-05-04 12:14:18.712310369 +0800
Change: 2023-05-04 12:14:18.712310369 +0800
Birth: 2023-05-04 11:53:30.640989646 +0800
如上所示，我们可以通过Birth字段信息，知道mysql_binlog.000042是2023-05-04 11:53:30创建的。但是我们没法获取二进制日志的结束时间，不过由于MySQL的二进制日志文件是有数字序列的，所以我们可以通过下一个二进制日志文件（binlog）的开始时间来判断上一个二进制日志文件（binlog）的结束时间。
$ stat mysql_binlog.000043
File: mysql_binlog.000043
Size: 335 Blocks: 8 IO Block: 4096 regular file
Device: fd08h/64776d Inode: 100663430 Links: 1
Access: (0640/-rw-r-----) Uid: ( 801/ mysql) Gid: ( 800/ mysql)
Access: 2023-05-04 13:36:58.524978710 +0800
Modify: 2023-05-04 16:55:07.161545830 +0800
Change: 2023-05-04 16:55:07.161545830 +0800
Birth: 2023-05-04 12:14:18.713310387 +0800
