Rails 应用程序数据库拉取期间的 Heroku 问题：Mysql::Error MySQL 服务器已消失

Question

尝试从 Heroku 中提取数据库会在过程中途出现错误（如下）。

使用：雪豹； heroku-1.8.2；水龙头-0.2.26；导轨-2.3.5； mysql-5.1.42。从错误消息中可以看出，数据库很小。

Heroku 技术支持表示这是我的系统上的问题，但没有提供解决方法。

我之前见过这个问题 - 例如此处 。我该如何解决这个问题？

错误：

$ heroku db:pull
Auto-detected local database: mysql://[...]@localhost/[...]?encoding=utf8
Receiving schema
Receiving data
17 tables, 9,609 records
[...]
/Library/Ruby/Gems/1.8/gems/sequel-3.0.0/lib/sequel/adapters/mysql.rb:166:in `query': Mysql::Error MySQL server has gone away (Sequel::DatabaseError)
    from /Library/Ruby/Gems/1.8/gems/sequel-3.0.0/lib/sequel/adapters/mysql.rb:166:in `_execute'
    from /Library/Ruby/Gems/1.8/gems/sequel-3.0.0/lib/sequel/adapters/mysql.rb:125:in `execute'
    from /Library/Ruby/Gems/1.8/gems/sequel-3.0.0/lib/sequel/connection_pool.rb:101:in `hold'
    from /Library/Ruby/Gems/1.8/gems/sequel-3.0.0/lib/sequel/database.rb:461:in `synchronize'
    from /Library/Ruby/Gems/1.8/gems/sequel-3.0.0/lib/sequel/adapters/mysql.rb:125:in `execute'
    from /Library/Ruby/Gems/1.8/gems/sequel-3.0.0/lib/sequel/database.rb:296:in `execute_dui'
    from /Library/Ruby/Gems/1.8/gems/sequel-3.0.0/lib/sequel/dataset.rb:276:in `execute_dui'
    from /Library/Ruby/Gems/1.8/gems/sequel-3.0.0/lib/sequel/adapters/mysql.rb:365:in `execute_dui'
    from /Library/Ruby/Gems/1.8/gems/sequel-3.0.0/lib/sequel/dataset/convenience.rb:126:in `import'
    from /Library/Ruby/Gems/1.8/gems/sequel-3.0.0/lib/sequel/dataset/convenience.rb:126:in `each'
    from /Library/Ruby/Gems/1.8/gems/sequel-3.0.0/lib/sequel/dataset/convenience.rb:126:in `import'
    from /Library/Ruby/Gems/1.8/gems/sequel-3.0.0/lib/sequel/adapters/mysql.rb:144:in `transaction'
    from /Library/Ruby/Gems/1.8/gems/sequel-3.0.0/lib/sequel/connection_pool.rb:108:in `hold'
    from /Library/Ruby/Gems/1.8/gems/sequel-3.0.0/lib/sequel/database.rb:461:in `synchronize'
    from /Library/Ruby/Gems/1.8/gems/sequel-3.0.0/lib/sequel/adapters/mysql.rb:138:in `transaction'
    from /Library/Ruby/Gems/1.8/gems/sequel-3.0.0/lib/sequel/dataset/convenience.rb:126:in `import'
    from /Library/Ruby/Gems/1.8/gems/taps-0.2.26/lib/taps/client_session.rb:211:in `cmd_receive_data'
    from /Library/Ruby/Gems/1.8/gems/taps-0.2.26/lib/taps/client_session.rb:203:in `loop'
    from /Library/Ruby/Gems/1.8/gems/taps-0.2.26/lib/taps/client_session.rb:203:in `cmd_receive_data'
    from /Library/Ruby/Gems/1.8/gems/taps-0.2.26/lib/taps/client_session.rb:196:in `each'
    from /Library/Ruby/Gems/1.8/gems/taps-0.2.26/lib/taps/client_session.rb:196:in `cmd_receive_data'
    from /Library/Ruby/Gems/1.8/gems/taps-0.2.26/lib/taps/client_session.rb:175:in `cmd_receive'
    from /Library/Ruby/Gems/1.8/gems/heroku-1.8.2/bin/../lib/heroku/commands/db.rb:17:in `pull'
    from /Library/Ruby/Gems/1.8/gems/heroku-1.8.2/bin/../lib/heroku/commands/db.rb:119:in `taps_client'
    from /Library/Ruby/Gems/1.8/gems/taps-0.2.26/lib/taps/client_session.rb:21:in `start'
    from /Library/Ruby/Gems/1.8/gems/heroku-1.8.2/bin/../lib/heroku/commands/db.rb:115:in `taps_client'
    from /Library/Ruby/Gems/1.8/gems/heroku-1.8.2/bin/../lib/heroku/commands/db.rb:16:in `pull'
    from /Library/Ruby/Gems/1.8/gems/heroku-1.8.2/bin/../lib/heroku/command.rb:45:in `send'
    from /Library/Ruby/Gems/1.8/gems/heroku-1.8.2/bin/../lib/heroku/command.rb:45:in `run_internal'
    from /Library/Ruby/Gems/1.8/gems/heroku-1.8.2/bin/../lib/heroku/command.rb:17:in `run'
    from /Library/Ruby/Gems/1.8/gems/heroku-1.8.2/bin/heroku:14
    from /usr/bin/heroku:19:in `load'
    from /usr/bin/heroku:19

Answer 1

我在我的系统上遇到了同样的问题。我终于明白问题出在错误所在。

深入研究 Sequel 库，我能够确定我收到的实际错误是“得到的数据包大于‘max_allowed_pa​​cket’字节”。在 /etc/my.cnf 中设置以下内容并重新启动 mysql 解决了我的问题。

[mysqld]
   max_allowed_packet = 32M

默认情况下，mysql 配置为允许最大 1 兆数据加载。上面将限制设置为 32 兆。

Answer 2

这是你的系统有问题。在尝试推送到 Heroku 时，您与本地 MySQL 服务器的连接已断开。新版本的 Sequel 可能会有所帮助，但我不确定 Taps 是否会使用它。

Answer 3

如上所述，这确实有效。只需创建一个文件：
/etc/my.cnf 并重新启动 mysql。

[mysql]
max_allowed_packet=32M
[mysqld]
max_allowed_packet=32M