Mysql2 ::错误：关闭MySQL连接

运行：Mysql2 ::错误：关闭MySQL连接

Timeout.timeout(1) { User.find_by_sql('SELECT sleep(2) FROM users;') }

返回如下：

User Load (1004.2ms) SELECT sleep(2) FROM users; 
ActiveRecord::StatementInvalid: : execution expired: SELECT sleep(2) FROM users; 
    from /Users/Chris/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/active_record/connection_adapters/mysql2_adapter.rb:687:in `query' 
    from /Users/Chris/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/active_record/connection_adapters/mysql2_adapter.rb:687:in `block in exec_query' 
    from /Users/Chris/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/active_record/connection_adapters/abstract_adapter.rb:244:in `block in log' 
    from /Users/Chris/.rvm/gems/ruby-1.9.2-p290/gems/activesupport-3.1.3/lib/active_support/notifications/instrumenter.rb:21:in `instrument' 
    from /Users/Chris/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/active_record/connection_adapters/abstract_adapter.rb:239:in `log' 
    from /Users/Chris/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/active_record/connection_adapters/mysql2_adapter.rb:685:in `exec_query' 
    from /Users/Chris/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/active_record/connection_adapters/mysql2_adapter.rb:679:in `select' 
    from /Users/Chris/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/active_record/connection_adapters/abstract/database_statements.rb:18:in `select_all' 
    from /Users/Chris/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/active_record/connection_adapters/abstract/query_cache.rb:63:in `select_all' 
    from /Users/Chris/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/active_record/base.rb:470:in `find_by_sql' 
    from (irb):1:in `block in irb_binding' 
    from /Users/Chris/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/timeout.rb:58:in `timeout' 
    from (irb):1 
    from /Users/Chris/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.3/lib/rails/commands/console.rb:45:in `start' 
    from /Users/Chris/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.3/lib/rails/commands/console.rb:8:in `start' 
    from /Users/Chris/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.3/lib/rails/commands.rb:40:in `<top (required)>' 
    from script/rails:6:in `require' 
    from script/rails:6:in `

下不会出现与PGSQL发生。 Mysql2或ActiveRecord中是否存在错误？

我读过这种情况时，有太多的连接，哪些mysql无法处理。但为什么PgSql不会发生这种情况呢？

PS。如果这有所作为，我正在使用Amazon RDS。

来源

2012-03-09 Christian Fazzini

这对我有效：在config/database.yml中，将'：reconnect'更改为'true'，和'：pool'到'20'。看到类似的问题：http://stackoverflow.com/questions/11773930/ruby-exception-occured-mysql2error-closed-mysql-connection/13714846#13714846 – 2012-12-05 01:22:14

当然，你在Timeout.timeout(1)区块做这个，我认为你应该让超时时间更长。

来源

2012-03-09 16:08:06 user973254

它应该没关系。在大多数情况下，Web应用程序会通过多个连接来访问数据库。相同的命令不会导致PgSql错误 – 2012-03-09 16:16:37

但是，仍然引发超时错误。 – user973254 2012-03-09 16:19:31

它在MySql中给出错误但不是PgSql的原因是sleep是有效的Mysql函数，但不是有效的Pgsql函数。后者中的正确功能是pg_sleep。也就是说，在Ruby代码中，查询会休眠2秒，因此会限制执行1秒，因此会引发超时异常。对于Pg的情况，它应该给出另一种例外，例如“睡眠不是有效的pgsql函数”

来源

2013-01-17 11:21:29 hammady

Mysql2 ::错误：关闭MySQL连接

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