级联slave中延缓计算和query event exe time获取方法的示例分析
发布时间：2022-01-11 02:11:42 所属栏目：MySql教程 来源：互联网
导读：这篇文章主要为大家展示了级联slave中延迟计算和query event exe time获取方法的示例分析，内容简而易懂，条理清晰，希望能够帮助大家解决疑惑，下面让小编带领大家一起研究并学习一下级联slave中延迟计算和query event exe time获取方法的示例分析这篇文
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这篇文章主要为大家展示了“级联slave中延迟计算和query event exe time获取方法的示例分析”，内容简而易懂，条理清晰，希望能够帮助大家解决疑惑，下面让小编带领大家一起研究并学习一下“级联slave中延迟计算和query event exe time获取方法的示例分析”这篇文章吧。 一、级联时间计算方式 逻辑如下： 级联中的Event依然是主库的时间，因此其延迟还是相对主库而言。 虽然apply_event_and_update_pos函数中由设置为当前时间thd->set_time() 但是最终设置还是在Query_log_event::do_apply_event和Query_log_event::do_apply_event中的 的 THD::set_time (this=0x7ffe74007da0, t=0x7ffe74007828) 因为只有做了数据库修改才会触发记录Event的工作 设个设置就是设置为event header的timestamp，因此还是级联中记录的Event的时间还是 主库的时间，计算延迟就是相对主库的时间。 栈帧 #0 THD::set_time (this=0x7ffe74007da0, t=0x7ffe7493c4d0) at /root/mysqlall/percona-server-locks-detail-5.7.22/sql/sql_class.h:3526 #1 0x00000000018459ab in Query_log_event::do_apply_event (this=0x7ffe7493c3b0, rli=0x676be60, query_arg=0x7ffe740061dc "BEGIN", q_len_arg=5) at /root/mysqlall/percona-server-locks-detail-5.7.22/sql/log_event.cc:4714 #2 0x0000000001845287 in Query_log_event::do_apply_event (this=0x7ffe7493c3b0, rli=0x676be60) at /root/mysqlall/percona-server-locks-detail-5.7.22/sql/log_event.cc:4567 #3 0x00000000018420d4 in Log_event::apply_event (this=0x7ffe7493c3b0, rli=0x676be60) at /root/mysqlall/percona-server-locks-detail-5.7.22/sql/log_event.cc:3570 #4 0x00000000018bc078 in apply_event_and_update_pos (ptr_ev=0x7fffec094830, thd=0x7ffe74007da0, rli=0x676be60) at /root/mysqlall/percona-server-locks-detail-5.7.22/sql/rpl_slave.cc:4766 #5 0x00000000018bd773 in exec_relay_log_event (thd=0x7ffe74007da0, rli=0x676be60) at /root/mysqlall/percona-server-locks-detail-5.7.22/sql/rpl_slave.cc:5300 #6 0x00000000018c46e4 in handle_slave_sql (arg=0x6675d30) at /root/mysqlall/percona-server-locks-detail-5.7.22/sql/rpl_slave.cc:7543 #7 0x0000000001945620 in pfs_spawn_thread (arg=0x7ffe7c02c6c0) at /root/mysqlall/percona-server-locks-detail-5.7.22/storage/perfschema/pfs.cc:2190 #8 0x00007ffff7bc6aa1 in start_thread () from /lib64/libpthread.so.0 #9 0x00007ffff6719bcd in clone () from /lib64/libc.so.6 #0 THD::set_time (this=0x7ffe74007da0, t=0x7ffe7493c4d0) at /root/mysqlall/percona-server-locks-detail-5.7.22/sql/sql_class.h:3526 #1 0x00000000018459ab in Query_log_event::do_apply_event (this=0x7ffe7493c3b0, rli=0x676be60, query_arg=0x7ffe740061dc "BEGIN", q_len_arg=5) at /root/mysqlall/percona-server-locks-detail-5.7.22/sql/log_event.cc:4714 #2 0x0000000001845287 in Query_log_event::do_apply_event (this=0x7ffe7493c3b0, rli=0x676be60) at /root/mysqlall/percona-server-locks-detail-5.7.22/sql/log_event.cc:4567 #3 0x00000000018420d4 in Log_event::apply_event (this=0x7ffe7493c3b0, rli=0x676be60) at /root/mysqlall/percona-server-locks-detail-5.7.22/sql/log_event.cc:3570 #4 0x00000000018bc078 in apply_event_and_update_pos (ptr_ev=0x7fffec094830, thd=0x7ffe74007da0, rli=0x676be60) at /root/mysqlall/percona-server-locks-detail-5.7.22/sql/rpl_slave.cc:4766 #5 0x00000000018bd773 in exec_relay_log_event (thd=0x7ffe74007da0, rli=0x676be60) at /root/mysqlall/percona-server-locks-detail-5.7.22/sql/rpl_slave.cc:5300 #6 0x00000000018c46e4 in handle_slave_sql (arg=0x6675d30) at /root/mysqlall/percona-server-locks-detail-5.7.22/sql/rpl_slave.cc:7543 #7 0x0000000001945620 in pfs_spawn_thread (arg=0x7ffe7c02c6c0) at /root/mysqlall/percona-server-locks-detail-5.7.22/storage/perfschema/pfs.cc:2190 #8 0x00007ffff7bc6aa1 in start_thread () from /lib64/libpthread.so.0 #9 0x00007ffff6719bcd in clone () from /lib64/libc.so.6 query map event在修改的第一条数据 记录时间 这个时间肯定是Log_event::apply_event的时间， GTID自然是在最后commit的时候 ,XID EVENT也是正确的主库时间。 实际上第一个THD::set_time(header->timestamp)后user_time 就正确，下面的逻辑不会设置为当前时间。 inline void set_time() { start_utime= utime_after_lock= my_micro_time(); if (user_time.tv_sec || user_time.tv_usec) { start_time= user_time; } else my_micro_time_to_timeval(start_utime, &start_time); #ifdef HAVE_PSI_THREAD_INTERFACE PSI_THREAD_CALL(set_thread_start_time)(start_time.tv_sec); #endif } 但是主库dispatch_command的时候不会设置user_time user_time为0，因此设置为当前时间。 #0 THD::set_time (this=0x7ffedc0009c0) at /mysqldata/percona-server-locks-detail-5.7.22/sql/sql_class.h:3514 #1 0x00000000015c5fe8 in dispatch_command (thd=0x7ffedc0009c0, com_data=0x7fffec5bdd70, command=COM_QUERY) at /mysqldata/percona-server-locks-detail-5.7.22/sql/sql_parse.cc:1247 #2 0x00000000015c58ff in do_command (thd=0x7ffedc0009c0) at /mysqldata/percona-server-locks-detail-5.7.22/sql/sql_parse.cc:1021 #3 0x000000000170e578 in handle_connection (arg=0x67d01a0) at /mysqldata/percona-server-locks-detail-5.7.22/sql/conn_handler/connection_handler_per_thread.cc:312 #4 0x0000000001945538 in pfs_spawn_thread (arg=0x67c9dc0) at /mysqldata/percona-server-locks-detail-5.7.22/storage/perfschema/pfs.cc:2190 #5 0x00007ffff7bcfaa1 in start_thread () from /lib64/libpthread.so.0 #6 0x00007ffff6b37c4d in clone () from /lib64/libc.so.6 二、header中的timestamp和query_event的exe time计算方式 common_header：中的时间来自 命令发起的时间。下面是其初始化 Log_event::Log_event(THD* thd_arg, uint16 flags_arg, enum_event_cache_type cache_type_arg, enum_event_logging_type logging_type_arg, Log_event_header *header, Log_event_footer *footer) : is_valid_param(false), temp_buf(0), exec_time(0), event_cache_type(cache_type_arg), event_logging_type(logging_type_arg), crc(0), common_header(header), common_footer(footer), thd(thd_arg) { server_id= thd->server_id; common_header->unmasked_server_id= server_id; common_header->when= thd->start_time; common_header->log_pos= 0; common_header->flags= flags_arg; } dispatch_command调用时间 Query_log_event::Query_log_event(THD* thd_arg, const char* query_arg, size_t query_length, bool using_trans, bool immediate, bool suppress_use, int errcode, bool ignore_cmd_internals) : binary_log::Query_event(query_arg, thd_arg->catalog().str, thd_arg->db().str, query_length, thd_arg->thread_id(), thd_arg->variables.sql_mode, thd_arg->variables.auto_increment_increment, thd_arg->variables.auto_increment_offset, thd_arg->variables.lc_time_names->number, (ulonglong)thd_arg->table_map_for_update, errcode, thd_arg->db().str ? strlen(thd_arg->db().str) : 0, thd_arg->catalog().str ? strlen(thd_arg->catalog().str) : 0), Log_event(thd_arg, (thd_arg->thread_specific_used ? LOG_EVENT_THREAD_SPECIFIC_F : 0) | (suppress_use ? LOG_EVENT_SUPPRESS_USE_F : 0), using_trans ? Log_event::EVENT_TRANSACTIONAL_CACHE : Log_event::EVENT_STMT_CACHE, Log_event::EVENT_NORMAL_LOGGING, header(), footer()), data_buf(0) { DBUG_EXECUTE_IF("debug_lock_before_query_log_event", DBUG_SYNC_POINT("debug_lock.before_query_log_event", 10);); /* save the original thread id; we already know the server id */ slave_proxy_id= thd_arg->variables.pseudo_thread_id; if (query != 0) is_valid_param= true; /* 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();//这里获取时间 query event my_micro_time_to_timeval(micro_end_time, &end_time); exec_time= end_time.tv_sec - thd_arg->start_time.tv_sec;//这里计算时间 以上是“级联slave中延迟计算和query event exe time获取方法的示例分析”这篇文章的所有内容，感谢各位的阅读！ （编辑：源码网） 【声明】本站内容均来自网络，其相关言论仅代表作者个人观点，不代表本站立场。若无意侵犯到您的权利，请及时与联系站长删除相关内容! |
