Mysql2 Error MySQL server has gone away

Question

I am getting this error occasionally. I have read some solutions in stackoverflow but they were about rails 2 or mysql. Any help will be appreciated.

ActiveRecord::StatementInvalid (Mysql2::Error: MySQL server has gone away

Answer 1

I got this error while trying to import a large file through seeds.rb with rake db:seed by calling one statement:

ActiveRecord::Base.connection.execute(IO.read("path/to/file.sql"))

And I kept on getting ActiveRecord::StatementInvalid (Mysql2::Error: MySQL server has gone away...

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SOLUTION

I resolved this by a combination of two things:

1. Add reconnect: true to the database specification in database.yml

2. Read the SQL file and execute the statement individually, as such:

   f = File.new('path/to/file.sql')
   
   while statements = f.gets("") do
     ActiveRecord::Base.connection.execute(statements)
   end  
   

I had to modify to remove some comments from my SQL file -- they made ActiveRecord throw errors for some reason, but that resolved my problem.

Answer 2

There are numerous causes for the error. See below page for possible causes. Perhaps your packet size is set too small.

http://dev.mysql.com/doc/refman/5.0/en/gone-away.html