Rails - 在文本列中插入超过7786个字符时，获取'Mysql服务器已消失'

Question

I have a 'blog_articles' class which contains a text column named 'content'. Here is the migration :

create_table :blog_articles do |t|
  t.references :blog_user
  t.string :title
  t.text :summary
  t.text :content

  t.boolean :published, :default => false
  t.timestamps
end

I also have a custom rake task rake db:rebuild , which executes drop , create , migrate then seed . Here is the rake task :

namespace :db do
  desc "run db:drop, db:create, db:migrate and db:seed tasks in a row."
  task :rebuild => :environment do
    if Rails.env == "production"
      # Do nothing
    else
      Rake::Task["db:drop"].invoke
      Rake::Task["db:create"].invoke
      Rake::Task["db:migrate"].invoke
      Rake::Task["db:seed"].invoke
    end
  end
end

--

So my problem is, when I try to insert an article (in the seeds.rb file), with a content of more than 7768 caracters, I get a Mysql2::Error: MySQL server has gone away : INSERT INTO 'blog_articles' [...] error, using the rake db:rebuild task.

There is no problem at all if I run the rake db:seed manualy, or if I create the article in a controller.

How can I fix this ? I use a lot of my new db:rebuild task.

---

edit :

So, I solve my problem by changing my rebuild task to this

namespace :db do
  desc "run db:drop, db:create, db:migrate and db:seed tasks in a row."
  task :rebuild => :environment do
    if Rails.env == "production"
      # Do nothing
    else      
      system "rake db:drop"
      system "rake db:create"
      system "rake db:migrate"
      system "rake db:seed"
    end
  end
end

I don't understand what difference it makes but this works. Does anyone have an explication ?

Answer 1

Try modifying your my.cnf , increasing max_allowed_packet

[mysqld]
max_allowed_packet=512M

http://dev.mysql.com/doc/refman/5.1/en/packet-too-large.html

When a MySQL client or the mysqld server receives a packet bigger than max_allowed_packet bytes, it issues an ER_NET_PACKET_TOO_LARGE error and closes the connection. With some clients, you may also get a Lost connection to MySQL server during query error if the communication packet is too large.