MySQL中Bug发现过程分析
发布时间：2021-12-21 11:18:38 所属栏目：MySql教程 来源：互联网
导读：本篇内容介绍了MySQL中Bug发现过程分析的有关知识，在实际案例的操作过程中，不少人都会遇到这样的困境，接下来就让小编带领大家学习一下如何处理这些情况吧！希望大家仔细阅读，能够学有所成！ 使用的是PXC环境如下: MySQL:5.7.18-15 wsrep:29.20 os:Red H
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本篇内容介绍了“MySQL中Bug发现过程分析”的有关知识，在实际案例的操作过程中，不少人都会遇到这样的困境，接下来就让小编带领大家学习一下如何处理这些情况吧！希望大家仔细阅读，能够学有所成！ 使用的是PXC环境如下: MySQL:5.7.18-15 wsrep:29.20 os:Red Hat Enterprise Linux Server release 6.5 所以show processlist的state只是一个状态值，它代表是代码某一段到某一段的执行阶段，下面是一个典型的 select的状态切换流程。但是要确认问题，有时候光靠这个是不够的。 T@2: | THD::enter_stage: 'starting' /root/mysql5.7.14/percona-server-5.7.14-7/sql/conn_handler/socket_connection.cc:100 T@2: | | | | | THD::enter_stage: 'checking permissions' /root/mysql5.7.14/percona-server-5.7.14-7/sql/auth/sql_authorization.cc:843 T@2: | | | | | | THD::enter_stage: 'Opening tables' /root/mysql5.7.14/percona-server-5.7.14-7/sql/sql_base.cc:5719 T@2: | | | | | THD::enter_stage: 'init' /root/mysql5.7.14/percona-server-5.7.14-7/sql/sql_select.cc:121 T@2: | | | | | | | THD::enter_stage: 'System lock' /root/mysql5.7.14/percona-server-5.7.14-7/sql/lock.cc:321 T@2: | | | | | | | THD::enter_stage: 'optimizing' /root/mysql5.7.14/percona-server-5.7.14-7/sql/sql_optimizer.cc:151 T@2: | | | | | | | THD::enter_stage: 'statistics' /root/mysql5.7.14/percona-server-5.7.14-7/sql/sql_optimizer.cc:386 T@2: | | | | | | | THD::enter_stage: 'preparing' /root/mysql5.7.14/percona-server-5.7.14-7/sql/sql_optimizer.cc:494 T@2: | | | | | | THD::enter_stage: 'executing' /root/mysql5.7.14/percona-server-5.7.14-7/sql/sql_executor.cc:119 T@2: | | | | | | THD::enter_stage: 'Sending data' /root/mysql5.7.14/percona-server-5.7.14-7/sql/sql_executor.cc:195 T@2: | | | | | THD::enter_stage: 'end' /root/mysql5.7.14/percona-server-5.7.14-7/sql/sql_select.cc:199 T@2: | | | | THD::enter_stage: 'query end' /root/mysql5.7.14/percona-server-5.7.14-7/sql/sql_parse.cc:5174 T@2: | | | | THD::enter_stage: 'closing tables' /root/mysql5.7.14/percona-server-5.7.14-7/sql/sql_parse.cc:5252 T@2: | | | THD::enter_stage: 'freeing items' /root/mysql5.7.14/percona-server-5.7.14-7/sql/sql_parse.cc:5855 T@2: | | THD::enter_stage: 'cleaning up' /root/mysql5.7.14/percona-server-5.7.14-7/sql/sql_parse.cc:1884 三、详细的分析pstack 因为pstack日志太长了。我就不贴了。详细的分析pstack日志在开头给出的bug连接。其实要在冗长的pstack中找到有用的信息和合理的解释是一个困难的过程，因为源码能力非常有限，某些时候只能通过搜索临界区来确认问题。下面是我分析的结果，也是提交bug给出了的： I use pstack to review stack discover Dead lock Analyze pstack i find some problem: Thread 56: lock:trx_sys (when parameter wsrep_log_conflicts=ON lock0lock.cc 2281 line) requisite:LOCK_wsrep_thd Thread 9: lock: LOCK_thd_list (mysql_thread_manager.cc 339 line) requisite:LOCK_thd_data (sql_parse.h 175 line) Thread 26: lock: LOCK_thd_data (in PFS_status_variable_cache::do_materialize_all after PFS_status_variable_cache::manifest release LOCK_thd_data ,but hang) requisite:trx_sys->mutex (srv0srv.cc 1703 line) a lot of Thread wait when call function trx_allocate_for_mysql at mutex trx_sys a lot of Thread wait when call function THD::release_resources at mutex LOCK_thd_data a lot of Thread wait when call function Global_THD_manager::add_thd at mutex LOCK_thd_list and any other mutex wait!! but I not find which thread hold LOCK_wsrep_thd mutex. Now we do follow things hope to resolve this problem: 1、wsrep_log_conflicts=off 2、SET global optimizer_switch = 'materialization=off'; 3、at high load time not execute sql 'show [global] status/select * from performance_schema.global_status' 简单的说我发现有多个线程获取mutex近乎出现环状，但是其中一环没有找到。最终percona恢复如下： Your problem sounds quite similar to one mentioned here: https://jira.percona.com/browse/PXC-877 Said release fix the issue https://www.percona.com/blog/2018/01/26/percona-xtradb-cluster-5-7-20-29-24-is-now-available/ You may want to consider an upgrade to latest one though which has more fixes 5.7.21. “MySQL中Bug发现过程分析”的内容就介绍到这里了，感谢大家的阅读。如果想了解更多行业相关的知识可以关注亿速云网站，小编将为大家输出更多高质量的实用文章！ （编辑：温州站长网） 【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! |
