MySQL:简单记录删除binarylog的接口
欢迎关注我的《深入理解MySQL主从原理 32讲 》，如下：
成都创新互联公司是网站建设专家,致力于互联网品牌建设与网络营销，专业领域包括网站建设、成都网站制作、电商网站制作开发、微信小程序、微信营销、系统平台开发，与其他网站设计及系统开发公司不同，我们的整合解决方案结合了恒基网络品牌建设经验和互联网整合营销的理念，并将策略和执行紧密结合，且不断评估并优化我们的方案，为客户提供全方位的互联网品牌整合方案！
如果图片不能显示可查看下面链接：
https://www.jianshu.com/p/d636215d767f
一、栈帧
#0 my_delete (name=0x7ffff0fa0490 "./binlog.000005", MyFlags=0) at /root/softm/percona-server-5.7.22-22/mysys/my_delete.c:25#1 0x000000000186416f in inline_mysql_file_delete (key=2, src_file=0x2293340 "/root/softm/percona-server-5.7.22-22/sql/binlog.cc", src_line=6735, name=0x7ffff0fa0490 "./binlog.000005", flags=0) at /root/softm/percona-server-5.7.22-22/include/mysql/psi/mysql_file.h:1331#2 0x0000000001871497 in MYSQL_BIN_LOG::purge_index_entry (this=0x2e39c40, thd=0x7fffa4000b70, decrease_log_space=0x0, need_lock_index=false) at /root/softm/percona-server-5.7.22-22/sql/binlog.cc:6735#3 0x0000000001870b35 in MYSQL_BIN_LOG::purge_logs (this=0x2e39c40, to_log=0x7ffff0fa0a80 "./binlog.000007", included=false, need_lock_index=true, need_update_threads=true, decrease_log_space=0x0, auto_purge=false) at /root/softm/percona-server-5.7.22-22/sql/binlog.cc:6495#4 0x0000000001868839 in purge_master_logs (thd=0x7fffa4000b70, to_log=0x7fffa4006570 "binlog.000007") at /root/softm/percona-server-5.7.22-22/sql/binlog.cc:3127#5 0x00000000015b7874 in mysql_execute_command (thd=0x7fffa4000b70, first_level=true) at /root/softm/percona-server-5.7.22-22/sql/sql_parse.cc:2989#6 0x00000000015c0362 in mysql_parse (thd=0x7fffa4000b70, parser_state=0x7ffff0fa2600) at /root/softm/percona-server-5.7.22-22/sql/sql_parse.cc:5901#7 0x00000000015b3ef6 in dispatch_command (thd=0x7fffa4000b70, com_data=0x7ffff0fa2d70, command=COM_QUERY) at /root/softm/percona-server-5.7.22-22/sql/sql_parse.cc:1490#8 0x00000000015b2c83 in do_command (thd=0x7fffa4000b70) at /root/softm/percona-server-5.7.22-22/sql/sql_parse.cc:1021#9 0x00000000016fb8fc in handle_connection (arg=0x38f2910) at /root/softm/percona-server-5.7.22-22/sql/conn_handler/connection_handler_per_thread.cc:312#10 0x0000000001932112 in pfs_spawn_thread (arg=0x3860a50) at /root/softm/percona-server-5.7.22-22/storage/perfschema/pfs.cc:2190#11 0x00007ffff7bc6aa1 in start_thread () from /lib64/libpthread.so.0#12 0x00007ffff6719bcd in clone () from /lib64/libc.so.6
二、大概过程
整个删除过程大概是：
- 先提取需要删除的binary log 记录到一个 临时的index文件binlog.~rec~中。
- 将需要保留的binary log文件存放到一个叫做binlog.index_crash_safe的文件中。
- 将原有的binlog.index进行删除，将binlog.index_crash_safe重新命名为binlog.index。
下面是中间时刻的文件列表。
-rw-r----- 1 root root 80 Jun 26 10:25 binlog.index-rw-r----- 1 root root 32 Jun 26 10:38 binlog.~rec~-rw-r----- 1 root root 48 Jun 26 10:39 binlog.index_crash_safe
- 然后就删除binlog.~rec~记录中的binary log文件。
- 最后删除binlog.~rec~文件。整个过程集中在。
函数MYSQL_BIN_LOG::purge_logs中，我们可以将断点设置在my_delete函数上很容易看出这种过程。
下面是我的debug中的一部分：
(gdb) p purge_index_file->file $6 = 61OS中我们可以看到这个文件描述符为61 -> /root/softm/percona-server-5.7.22-22/mysql-test/var/mysqld.1/data/binlog.~rec~
当前题目：MySQL:简单记录删除binarylog的接口
文章出自：http://cdiso.cn/article/josoeh.html
