MySQL主库binlog(master-log)与从库relay-log关系代码详解
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2022-11-16 21:49:17
主库binlog:
# at 2420
#170809 17:16:20 server id 1882073306 end_log_pos 2451 crc...
主库binlog:
# at 2420 #170809 17:16:20 server id 1882073306 end_log_pos 2451 crc32 0x58f2db87 xid = 32880 commit/*!*/; # at 2451 #170814 11:07:18 server id 1882073306 end_log_pos 2528 crc32 0x40774a4b query thread_id=92 exec_time=0 error_code=0 set timestamp=1502680038/*!*/; begin /*!*/; # at 2528 # at 2560 #170814 11:07:18 server id 1882073306 end_log_pos 2560 crc32 0x7bdf274b intvar set insert_id=107/*!*/; #170814 11:07:18 server id 1882073306 end_log_pos 2669 crc32 0x68e441c8 query thread_id=92 exec_time=0 error_code=0 set timestamp=1502680038/*!*/; insert into t2 (name) values ('a100') /*!*/; # at 2669 # at 2701 #170814 11:07:27 server id 1882073306 end_log_pos 2701 crc32 0xcf89b910 intvar set insert_id=108/*!*/; #170814 11:07:27 server id 1882073306 end_log_pos 2810 crc32 0x78466d7b query thread_id=92 exec_time=0 error_code=0 set timestamp=1502680047/*!*/; insert into t2 (name) values ('a200') /*!*/; # at 2810 # at 2842 #170814 11:07:30 server id 1882073306 end_log_pos 2842 crc32 0x1e5a0847 intvar set insert_id=109/*!*/; #170814 11:07:30 server id 1882073306 end_log_pos 2951 crc32 0xebeb947c query thread_id=92 exec_time=0 error_code=0 set timestamp=1502680050/*!*/; insert into t2 (name) values ('a300') /*!*/; # at 2951 #170814 11:07:34 server id 1882073306 end_log_pos 2982 crc32 0x6436ad60 xid = 32934 commit/*!*/;
从库relay-log:
/*!50530 set @@session.pseudo_slave_mode=1*/; /*!40019 set @@session.max_insert_delayed_threads=0*/; /*!50003 set @old_completion_type=@@completion_type,completion_type=0*/; delimiter /*!*/; # at 4 #170809 17:17:24 server id 1882083306 end_log_pos 120 crc32 0x5df4221c start: binlog v 4, server v 5.6.23-72.1-log created 170809 17:17:24 # at 120 #700101 8:00:00 server id 1882073306 end_log_pos 0 crc32 0x0b8a412f rotate to test-mysql-bin.000116 pos: 2451 # at 172 #170809 16:28:12 server id 1882073306 end_log_pos 0 crc32 0xd0d3bf30 start: binlog v 4, server v 5.6.23-72.1-log created 170809 16:28:12 # at 288 #170814 11:07:18 server id 1882073306 end_log_pos 2528 crc32 0x40774a4b query thread_id=92 exec_time=0 error_code=0 set timestamp=1502680038/*!*/; set @@session.pseudo_thread_id=92/*!*/; set @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/; set @@session.sql_mode=1073741824/*!*/; set @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/; /*!\c utf8 *//*!*/; set @@session.character_set_client=33,@@session.collation_connection=33,@@session.collation_server=33/*!*/; set @@session.lc_time_names=0/*!*/; set @@session.collation_database=default/*!*/; begin /*!*/; # at 365 # at 397 #170814 11:07:18 server id 1882073306 end_log_pos 2560 crc32 0x7bdf274b intvar set insert_id=107/*!*/; #170814 11:07:18 server id 1882073306 end_log_pos 2669 crc32 0x68e441c8 query thread_id=92 exec_time=0 error_code=0 use `db1`/*!*/; set timestamp=1502680038/*!*/; insert into t2 (name) values ('a100') /*!*/; # at 506 # at 538 #170814 11:07:27 server id 1882073306 end_log_pos 2701 crc32 0xcf89b910 intvar set insert_id=108/*!*/; #170814 11:07:27 server id 1882073306 end_log_pos 2810 crc32 0x78466d7b query thread_id=92 exec_time=0 error_code=0 set timestamp=1502680047/*!*/; insert into t2 (name) values ('a200') /*!*/; # at 647 # at 679 #170814 11:07:30 server id 1882073306 end_log_pos 2842 crc32 0x1e5a0847 intvar set insert_id=109/*!*/; #170814 11:07:30 server id 1882073306 end_log_pos 2951 crc32 0xebeb947c query thread_id=92 exec_time=0 error_code=0 set timestamp=1502680050/*!*/; insert into t2 (name) values ('a300') /*!*/; # at 788 #170814 11:07:34 server id 1882073306 end_log_pos 2982 crc32 0x6436ad60 xid = 32934 commit/*!*/;
注意relay log的这一行:
#700101 8:00:00 server id 1882073306 end_log_pos 0 crc32 0x0b8a412f rotate to test-mysql-bin.000116 pos: 2451
说明此relay log保存的是主库 test-mysql-bin.000116 的信息,从position 2451 开始。
看一个具体的对应关系:
主库的binlog如下:
# at 2560 #170814 11:07:18 server id 1882073306 end_log_pos 2560 crc32 0x7bdf274b intvar set insert_id=107/*!*/; #170814 11:07:18 server id 1882073306 end_log_pos 2669 crc32 0x68e441c8 query thread_id=92 exec_time=0 error_code=0 set timestamp=1502680038/*!*/; insert into t2 (name) values ('a100') /*!*/; # at 2669
对应从库relay-log如下几行:
# at 397 #170814 11:07:18 server id 1882073306 end_log_pos 2560 crc32 0x7bdf274b intvar set insert_id=107/*!*/; #170814 11:07:18 server id 1882073306 end_log_pos 2669 crc32 0x68e441c8 query thread_id=92 exec_time=0 error_code=0 use `db1`/*!*/; set timestamp=1502680038/*!*/; insert into t2 (name) values ('a100') /*!*/; # at 506
另外注意show slave status\g的以下几行的关系:
master_log_file: test-mysql-bin.000117 read_master_log_pos: 774
上面二行代表io线程,相对于主库
relay_log_file: relay-log.000038 relay_log_pos: 723
上面二行代表了sql线程,相对于从库
relay_master_log_file: test-mysql-bin.000117 exec_master_log_pos: 555
上面二行代表了sql线程,相对主库
其中relay_log_pos: 723 和 exec_master_log_pos: 555 对应的sql语句一致。
总结
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