Question

之前的rake db：rollback停滞不前。现在，在尝试新迁移时，我们收到以下错误：

rake aborted!
ActiveRecord::ConcurrentMigrationError: 

Cannot run migrations because another migration process is currently running.

/home/me/.rvm/gems/ruby-2.4.1@global/gems/activerecord-    5.1.4/lib/active_record/migration.rb:1315:in `with_advisory_lock'
/home/me/.rvm/gems/ruby-2.4.1@global/gems/activerecord-5.1.4/lib/active_record/migration.rb:1148:in `migrate'
/home/me/.rvm/gems/ruby-2.4.1@global/gems/activerecord-5.1.4/lib/active_record/migration.rb:1007:in `up'
/home/me/.rvm/gems/ruby-2.4.1@global/gems/activerecord-5.1.4/lib/active_record/migration.rb:985:in `migrate'
/home/me/.rvm/gems/ruby-2.4.1@global/gems/activerecord-5.1.4/lib/active_record/tasks/database_tasks.rb:171:in `migrate'
/home/me/.rvm/gems/ruby-2.4.1@global/gems/activerecord-5.1.4/lib/active_record/railties/databases.rake:58:in `block (2 levels) in <top (required)>'
/home/me/.rvm/gems/ruby-2.4.1/gems/rake-12.1.0/exe/rake:27:in `<top (required)>'
/home/me/.rvm/gems/ruby-2.4.1/bin/ruby_executable_hooks:15:in `eval'
/home/me/.rvm/gems/ruby-2.4.1/bin/ruby_executable_hooks:15:in `<main>'
Tasks: TOP => db:migrate
(See full trace by running task with --trace)

我们正在使用Postresql

Answer 1

在Rails 5中添加了通知锁定，以防止在迁移期间发生意外的并发错误。修复是清除留在原地的数据库锁。

通过针对您的数据库运行此SQL来检查锁：

SELECT DISTINCT age(now(), query_start) AS age, pg_stat_activity.pid,pg_locks.granted,pg_stat_activity.application_name,pg_stat_activity.backend_start, pg_stat_activity.xact_start, pg_stat_activity.state_change, pg_stat_activity.waiting, pg_stat_activity.state, pg_stat_activity.query_start, left(pg_stat_activity.query, 60) FROM pg_stat_activity, pg_locks WHERE pg_locks.pid = pg_stat_activity.pid

要清除锁定，请针对您的数据库运行此SQL：

select pg_advisory_unlock({the pid of the lock you want to release})

Answer 2

对我来说，这种解决方法是这样的：

选择咨询锁：

SELECT pid, locktype, mode FROM pg_locks WHERE locktype = 'advisory';

SELECT pg_terminate_backend(<PID>);

Answer 3

所以在我看来，查询是不同的

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这基本上会告诉您pids

SELECT DISTINCT age(now(), query_start) AS age, pg_stat_activity.pid,pg_locks.granted,pg_stat_activity.application_name,pg_stat_activity.backend_start, pg_stat_activity.xact_start, pg_stat_activity.state_change, pg_stat_activity.state, pg_stat_activity.query_start, left(pg_stat_activity.query, 60)
    FROM pg_stat_activity, pg_locks
    WHERE pg_locks.pid = pg_stat_activity.pid

，然后您可以使用以下命令简单地解锁pid： 0 years 0 mons 0 days 0 hours 0 mins -0.01005 secs 360 true PostgreSQL JDBC Driver 2019-04-03 16:57:16.873609 2019-04-03 16:58:00.531675 2019-04-03 16:58:00.541727 active 2019-04-03 16:58:00.541725 SELECT DISTINCT age(now(), query_start) AS age, pg_stat_acti 17272 true "" <insufficient privilege> 22640 true "" <insufficient privilege> 29466 true "" <insufficient privilege>

例如：

select pg_advisory_unlock(#{target_pid})

干杯！

Answer 4

如果您正在使用数据库中的数据进行操作，而不是使用表格和列设置，那么一次rake任务可能是更好的地方吗？

Rails 5 db migration：如何修复ActiveRecord :: ConcurrentMigrationError

4 个答案: